Merge branch 'master' into seatbelt_multirotor

2013-06-10 16:21:10 +04:00 · 2013-06-10 16:21:10 +04:00 · afb34950a3
parent 4bf49cfc35 42ce3112ad
commit afb34950a3
37 changed files with 3632 additions and 227 deletions
--- a/ROMFS/px4fmu_common/mixers/IO_pass.mix
+++ b/ROMFS/px4fmu_common/mixers/IO_pass.mix
@ -0,0 +1,38 @@
+Passthrough mixer for PX4IO
+============================
+
+This file defines passthrough mixers suitable for testing.
+
+Channel group 0, channels 0-7 are passed directly through to the outputs.
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 0  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 1  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 2  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 3  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 4  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 5  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 6  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 7  10000  10000      0 -10000  10000
--- a/Tools/sdlog2_dump.py
+++ b/Tools/sdlog2_dump.py
@ -0,0 +1,293 @@
+#!/usr/bin/env python
+
+"""Dump binary log generated by sdlog2 or APM as CSV
+    
+Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MSG[.field1,field2,...]]
+    
+    -v  Use plain debug output instead of CSV.
+    
+	-e	Recover from errors.
+    
+    -d  Use "delimiter" in CSV. Default is ",".
+    
+    -n  Use "null" as placeholder for empty values in CSV. Default is empty.
+    
+    -m MSG[.field1,field2,...]
+        Dump only messages of specified type, and only specified fields.
+        Multiple -m options allowed."""
+
+__author__  = "Anton Babushkin"
+__version__ = "1.2"
+
+import struct, sys
+
+class SDLog2Parser:
+    BLOCK_SIZE = 8192
+    MSG_HEADER_LEN = 3
+    MSG_HEAD1 = 0xA3
+    MSG_HEAD2 = 0x95
+    MSG_FORMAT_PACKET_LEN = 89
+    MSG_FORMAT_STRUCT = "BB4s16s64s"
+    MSG_TYPE_FORMAT = 0x80
+    FORMAT_TO_STRUCT = {
+        "b": ("b", None),
+        "B": ("B", None),
+        "h": ("h", None),
+        "H": ("H", None),
+        "i": ("i", None),
+        "I": ("I", None),
+        "f": ("f", None),
+        "n": ("4s", None),
+        "N": ("16s", None),
+        "Z": ("64s", None),
+        "c": ("h", 0.01),
+        "C": ("H", 0.01),
+        "e": ("i", 0.01),
+        "E": ("I", 0.01),
+        "L": ("i", 0.0000001),
+        "M": ("b", None),
+        "q": ("q", None),
+        "Q": ("Q", None),
+    }
+    __csv_delim = ","
+    __csv_null = ""
+    __msg_filter = []
+    __time_msg = None
+    __debug_out = False
+    __correct_errors = False
+    
+    def __init__(self):
+        return
+    
+    def reset(self):
+        self.__msg_descrs = {}      # message descriptions by message type map
+        self.__msg_labels = {}      # message labels by message name map
+        self.__msg_names = []       # message names in the same order as FORMAT messages
+        self.__buffer = ""          # buffer for input binary data
+        self.__ptr = 0              # read pointer in buffer
+        self.__csv_columns = []     # CSV file columns in correct order in format "MSG.label"
+        self.__csv_data = {}        # current values for all columns
+        self.__csv_updated = False
+        self.__msg_filter_map = {}  # filter in form of map, with '*" expanded to full list of fields
+    
+    def setCSVDelimiter(self, csv_delim):
+        self.__csv_delim = csv_delim
+    
+    def setCSVNull(self, csv_null):
+        self.__csv_null = csv_null
+    
+    def setMsgFilter(self, msg_filter):
+        self.__msg_filter = msg_filter
+    
+    def setTimeMsg(self, time_msg):
+        self.__time_msg = time_msg
+    
+    def setDebugOut(self, debug_out):
+        self.__debug_out = debug_out
+
+    def setCorrectErrors(self, correct_errors):
+        self.__correct_errors = correct_errors
+    
+    def process(self, fn):
+        self.reset()
+        if self.__debug_out:
+            # init __msg_filter_map
+            for msg_name, show_fields in self.__msg_filter:
+                self.__msg_filter_map[msg_name] = show_fields
+        first_data_msg = True
+        f = open(fn, "r")
+        bytes_read = 0
+        while True:
+            chunk = f.read(self.BLOCK_SIZE)
+            if len(chunk) == 0:
+                break
+            self.__buffer = self.__buffer[self.__ptr:] + chunk
+            self.__ptr = 0
+            while self.__bytesLeft() >= self.MSG_HEADER_LEN:
+                head1 = ord(self.__buffer[self.__ptr])
+                head2 = ord(self.__buffer[self.__ptr+1])
+                if (head1 != self.MSG_HEAD1 or head2 != self.MSG_HEAD2):
+                    if self.__correct_errors:
+                        self.__ptr += 1
+                        continue
+                    else:
+                        raise Exception("Invalid header at %i (0x%X): %02X %02X, must be %02X %02X" % (bytes_read + self.__ptr, bytes_read + self.__ptr, head1, head2, self.MSG_HEAD1, self.MSG_HEAD2))
+                msg_type = ord(self.__buffer[self.__ptr+2])
+                if msg_type == self.MSG_TYPE_FORMAT:
+                    # parse FORMAT message
+                    if self.__bytesLeft() < self.MSG_FORMAT_PACKET_LEN:
+                        break
+                    self.__parseMsgDescr()
+                else:
+                    # parse data message
+                    msg_descr = self.__msg_descrs[msg_type]
+                    if msg_descr == None:
+                        raise Exception("Unknown msg type: %i" % msg_type)
+                    msg_length = msg_descr[0]
+                    if self.__bytesLeft() < msg_length:
+                        break
+                    if first_data_msg:
+                        # build CSV columns and init data map
+                        self.__initCSV()
+                        first_data_msg = False
+                    self.__parseMsg(msg_descr)
+            bytes_read += self.__ptr
+        if not self.__debug_out and self.__time_msg != None and self.__csv_updated:
+            self.__printCSVRow()
+        f.close()
+    
+    def __bytesLeft(self):
+        return len(self.__buffer) - self.__ptr
+    
+    def __filterMsg(self, msg_name):
+        show_fields = "*"
+        if len(self.__msg_filter_map) > 0:
+            show_fields = self.__msg_filter_map.get(msg_name)
+        return show_fields
+    
+    def __initCSV(self):
+        if len(self.__msg_filter) == 0:
+            for msg_name in self.__msg_names:
+                self.__msg_filter.append((msg_name, "*"))
+        for msg_name, show_fields in self.__msg_filter:
+            if show_fields == "*":
+                show_fields = self.__msg_labels.get(msg_name, [])
+            self.__msg_filter_map[msg_name] = show_fields
+            for field in show_fields:
+                full_label = msg_name + "." + field
+                self.__csv_columns.append(full_label)
+                self.__csv_data[full_label] = None
+        print self.__csv_delim.join(self.__csv_columns)
+
+    def __printCSVRow(self):
+        s = []
+        for full_label in self.__csv_columns:
+            v = self.__csv_data[full_label]
+            if v == None:
+                v = self.__csv_null
+            else:
+                v = str(v)
+            s.append(v)
+        print self.__csv_delim.join(s)
+
+    def __parseMsgDescr(self):
+        data = struct.unpack(self.MSG_FORMAT_STRUCT, self.__buffer[self.__ptr + 3 : self.__ptr + self.MSG_FORMAT_PACKET_LEN])
+        msg_type = data[0]
+        if msg_type != self.MSG_TYPE_FORMAT:
+            msg_length = data[1]
+            msg_name = data[2].strip("\0")
+            msg_format = data[3].strip("\0")
+            msg_labels = data[4].strip("\0").split(",")
+            # Convert msg_format to struct.unpack format string
+            msg_struct = ""
+            msg_mults = []
+            for c in msg_format:
+                try:
+                    f = self.FORMAT_TO_STRUCT[c]
+                    msg_struct += f[0]
+                    msg_mults.append(f[1])
+                except KeyError as e:
+                    raise Exception("Unsupported format char: %s in message %s (%i)" % (c, msg_name, msg_type))
+            msg_struct = "<" + msg_struct   # force little-endian
+            self.__msg_descrs[msg_type] = (msg_length, msg_name, msg_format, msg_labels, msg_struct, msg_mults)
+            self.__msg_labels[msg_name] = msg_labels
+            self.__msg_names.append(msg_name)
+            if self.__debug_out:
+                if self.__filterMsg(msg_name) != None:
+                    print "MSG FORMAT: type = %i, length = %i, name = %s, format = %s, labels = %s, struct = %s, mults = %s" % (
+                                msg_type, msg_length, msg_name, msg_format, str(msg_labels), msg_struct, msg_mults)
+        self.__ptr += self.MSG_FORMAT_PACKET_LEN
+    
+    def __parseMsg(self, msg_descr):
+        msg_length, msg_name, msg_format, msg_labels, msg_struct, msg_mults = msg_descr
+        if not self.__debug_out and self.__time_msg != None and msg_name == self.__time_msg and self.__csv_updated:
+            self.__printCSVRow()
+            self.__csv_updated = False
+        show_fields = self.__filterMsg(msg_name)
+        if (show_fields != None):
+            data = list(struct.unpack(msg_struct, self.__buffer[self.__ptr+self.MSG_HEADER_LEN:self.__ptr+msg_length]))
+            for i in xrange(len(data)):
+                if type(data[i]) is str:
+                    data[i] = data[i].strip("\0")
+                m = msg_mults[i]
+                if m != None:
+                    data[i] = data[i] * m
+            if self.__debug_out:
+                s = []
+                for i in xrange(len(data)):
+                    label = msg_labels[i]
+                    if show_fields == "*" or label in show_fields:
+                        s.append(label + "=" + str(data[i]))
+                print "MSG %s: %s" % (msg_name, ", ".join(s))
+            else:
+                # update CSV data buffer
+                for i in xrange(len(data)):
+                    label = msg_labels[i]
+                    if label in show_fields:
+                        self.__csv_data[msg_name + "." + label] = data[i]
+                        if self.__time_msg != None and msg_name != self.__time_msg:
+                            self.__csv_updated = True
+                if self.__time_msg == None:
+                    self.__printCSVRow()
+        self.__ptr += msg_length
+
+def _main():
+    if len(sys.argv) < 2:
+        print "Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MSG[.field1,field2,...]] [-t TIME_MSG_NAME]\n"
+        print "\t-v\tUse plain debug output instead of CSV.\n"
+        print "\t-e\tRecover from errors.\n"
+        print "\t-d\tUse \"delimiter\" in CSV. Default is \",\".\n"
+        print "\t-n\tUse \"null\" as placeholder for empty values in CSV. Default is empty.\n"
+        print "\t-m MSG[.field1,field2,...]\n\t\tDump only messages of specified type, and only specified fields.\n\t\tMultiple -m options allowed."
+        print "\t-t\tSpecify TIME message name to group data messages by time and significantly reduce duplicate output.\n"
+        return
+    fn = sys.argv[1]
+    debug_out = False
+    correct_errors = False
+    msg_filter = []
+    csv_null = ""
+    csv_delim = ","
+    time_msg = None
+    opt = None
+    for arg in sys.argv[2:]:
+        if opt != None:
+            if opt == "d":
+                csv_delim = arg
+            elif opt == "n":
+                csv_null = arg
+            elif opt == "t":
+                time_msg = arg
+            elif opt == "m":
+                show_fields = "*"
+                a = arg.split(".")
+                if len(a) > 1:
+                    show_fields = a[1].split(",")
+                msg_filter.append((a[0], show_fields))
+            opt = None
+        else:
+            if arg == "-v":
+                debug_out = True
+            elif arg == "-e":
+                correct_errors = True
+            elif arg == "-d":
+                opt = "d"
+            elif arg == "-n":
+                opt = "n"
+            elif arg == "-m":
+                opt = "m"
+            elif arg == "-t":
+                opt = "t"
+
+    if csv_delim == "\\t":
+        csv_delim = "\t"
+    parser = SDLog2Parser()
+    parser.setCSVDelimiter(csv_delim)
+    parser.setCSVNull(csv_null)
+    parser.setMsgFilter(msg_filter)
+    parser.setTimeMsg(time_msg)
+    parser.setDebugOut(debug_out)
+    parser.setCorrectErrors(correct_errors)
+    parser.process(fn)
+
+if __name__ == "__main__":
+    _main()
--- a/makefiles/config_px4fmu_default.mk
+++ b/makefiles/config_px4fmu_default.mk
@ -62,7 +62,8 @@ MODULES		+= modules/gpio_led
 # Estimation modules (EKF / other filters)
 #
 MODULES		+= modules/attitude_estimator_ekf
-MODULES		+= modules/position_estimator_mc
+MODULES		+= modules/attitude_estimator_so3_comp
+#MODULES		+= modules/position_estimator_mc
 MODULES		+= modules/position_estimator
 MODULES		+= modules/att_pos_estimator_ekf
 MODULES		+= modules/position_estimator_inav
@ -80,6 +81,7 @@ MODULES		+= modules/multirotor_pos_control
 # Logging
 #
 MODULES		+= modules/sdlog
+MODULES		+= modules/sdlog2

 #
 # Library modules
--- a/makefiles/firmware.mk
+++ b/makefiles/firmware.mk
@ -176,6 +176,12 @@ GLOBAL_DEPS		+= $(MAKEFILE_LIST)
 #
 EXTRA_CLEANS		 = 

+################################################################################
+# NuttX libraries and paths
+################################################################################
+
+include $(PX4_MK_DIR)/nuttx.mk
+
 ################################################################################
 # Modules
 ################################################################################
@ -296,12 +302,6 @@ $(LIBRARY_CLEANS):
 	LIBRARY_MK=$(mkfile) \
 	clean

-################################################################################
-# NuttX libraries and paths
-################################################################################
-
-include $(PX4_MK_DIR)/nuttx.mk
-
 ################################################################################
 # ROMFS generation
 ################################################################################
--- a/makefiles/nuttx.mk
+++ b/makefiles/nuttx.mk
@ -69,10 +69,14 @@ INCLUDE_DIRS		+= $(NUTTX_EXPORT_DIR)include \

 LIB_DIRS		+= $(NUTTX_EXPORT_DIR)libs
 LIBS			+= -lapps -lnuttx
-LINK_DEPS		+= $(NUTTX_EXPORT_DIR)libs/libapps.a \
+NUTTX_LIBS		 = $(NUTTX_EXPORT_DIR)libs/libapps.a \
 			   $(NUTTX_EXPORT_DIR)libs/libnuttx.a
+LINK_DEPS		+= $(NUTTX_LIBS)

 $(NUTTX_CONFIG_HEADER):	$(NUTTX_ARCHIVE)
 	@$(ECHO) %% Unpacking $(NUTTX_ARCHIVE)
 	$(Q) $(UNZIP_CMD) -q -o -d $(WORK_DIR) $(NUTTX_ARCHIVE)
 	$(Q) $(TOUCH) $@
+
+ $(LDSCRIPT): $(NUTTX_CONFIG_HEADER)
+ $(NUTTX_LIBS): $(NUTTX_CONFIG_HEADER)
--- a/makefiles/toolchain_gnu-arm-eabi.mk
+++ b/makefiles/toolchain_gnu-arm-eabi.mk
@ -50,7 +50,7 @@ OBJDUMP			 = $(CROSSDEV)objdump

 # XXX this is pulled pretty directly from the fmu Make.defs - needs cleanup

-MAXOPTIMIZATION		 = -O3
+MAXOPTIMIZATION		 ?= -O3

 # Base CPU flags for each of the supported architectures.
 #
@ -70,6 +70,14 @@ ARCHCPUFLAGS_CORTEXM3	 = -mcpu=cortex-m3 \
 			   -march=armv7-m \
 			   -mfloat-abi=soft

+ARCHINSTRUMENTATIONDEFINES_CORTEXM4F = -finstrument-functions \
+			   -ffixed-r10
+
+ARCHINSTRUMENTATIONDEFINES_CORTEXM4 = -finstrument-functions \
+			   -ffixed-r10
+
+ARCHINSTRUMENTATIONDEFINES_CORTEXM3 = 
+
 # Pick the right set of flags for the architecture.
 #
 ARCHCPUFLAGS		 = $(ARCHCPUFLAGS_$(CONFIG_ARCH))
@ -91,8 +99,8 @@ ARCHOPTIMIZATION	 = $(MAXOPTIMIZATION) \

 # enable precise stack overflow tracking
 # note - requires corresponding support in NuttX
-INSTRUMENTATIONDEFINES	 = -finstrument-functions \
-			   -ffixed-r10
+INSTRUMENTATIONDEFINES	 = $(ARCHINSTRUMENTATIONDEFINES_$(CONFIG_ARCH))
+
 # Language-specific flags
 #
 ARCHCFLAGS		 = -std=gnu99
--- a/nuttx/arch/arm/src/armv7-m/Toolchain.defs
+++ b/nuttx/arch/arm/src/armv7-m/Toolchain.defs
@ -243,7 +243,7 @@ endif
 ifeq ($(CONFIG_ARMV7M_TOOLCHAIN),GNU_EABI)
  CROSSDEV ?= arm-none-eabi-
  ARCROSSDEV ?= arm-none-eabi-
-  MAXOPTIMIZATION = -O3
+  MAXOPTIMIZATION ?= -O3
  ifeq ($(CONFIG_ARCH_CORTEXM4),y)
    ifeq ($(CONFIG_ARCH_FPU),y)
      ARCHCPUFLAGS = -mcpu=cortex-m4 -mthumb -march=armv7e-m -mfpu=fpv4-sp-d16 -mfloat-abi=hard
--- a/nuttx/configs/px4fmu/common/Make.defs
+++ b/nuttx/configs/px4fmu/common/Make.defs
@ -58,7 +58,7 @@ NM			 = $(CROSSDEV)nm
 OBJCOPY			 = $(CROSSDEV)objcopy
 OBJDUMP			 = $(CROSSDEV)objdump

-MAXOPTIMIZATION		 = -O3
+MAXOPTIMIZATION		 ?= -O3
 ARCHCPUFLAGS		 = -mcpu=cortex-m4 \
 			   -mthumb \
 			   -march=armv7e-m \
--- a/nuttx/configs/px4fmu/nsh/defconfig
+++ b/nuttx/configs/px4fmu/nsh/defconfig
@ -248,7 +248,7 @@ CONFIG_SERIAL_TERMIOS=y
 CONFIG_SERIAL_CONSOLE_REINIT=y
 CONFIG_STANDARD_SERIAL=y

-CONFIG_USART1_SERIAL_CONSOLE=y
+CONFIG_USART1_SERIAL_CONSOLE=n
 CONFIG_USART2_SERIAL_CONSOLE=n
 CONFIG_USART3_SERIAL_CONSOLE=n
 CONFIG_UART4_SERIAL_CONSOLE=n
@ -561,7 +561,7 @@ CONFIG_START_MONTH=1
 CONFIG_START_DAY=1
 CONFIG_GREGORIAN_TIME=n
 CONFIG_JULIAN_TIME=n
-CONFIG_DEV_CONSOLE=y
+CONFIG_DEV_CONSOLE=n
 CONFIG_DEV_LOWCONSOLE=n
 CONFIG_MUTEX_TYPES=n
 CONFIG_PRIORITY_INHERITANCE=y
@ -717,7 +717,7 @@ CONFIG_ARCH_BZERO=n
 #   zero for all dynamic allocations.
 #
 CONFIG_MAX_TASKS=32
-CONFIG_MAX_TASK_ARGS=8
+CONFIG_MAX_TASK_ARGS=10
 CONFIG_NPTHREAD_KEYS=4
 CONFIG_NFILE_DESCRIPTORS=32
 CONFIG_NFILE_STREAMS=25
@ -925,7 +925,7 @@ CONFIG_USBDEV_TRACE_NRECORDS=512
 #   Size of the serial receive/transmit buffers. Default 256.
 #
 CONFIG_CDCACM=y
-CONFIG_CDCACM_CONSOLE=n
+CONFIG_CDCACM_CONSOLE=y
 #CONFIG_CDCACM_EP0MAXPACKET
 CONFIG_CDCACM_EPINTIN=1
 #CONFIG_CDCACM_EPINTIN_FSSIZE
@ -955,7 +955,7 @@ CONFIG_CDCACM_PRODUCTSTR="PX4 FMU v1.6"
 # CONFIG_NSH_FILEIOSIZE - Size of a static I/O buffer
 # CONFIG_NSH_STRERROR - Use strerror(errno)
 # CONFIG_NSH_LINELEN - Maximum length of one command line
-# CONFIG_NSH_MAX_ARGUMENTS - Maximum number of arguments for command line
+# CONFIG_NSH_MAXARGUMENTS - Maximum number of arguments for command line
 # CONFIG_NSH_NESTDEPTH - Max number of nested if-then[-else]-fi
 # CONFIG_NSH_DISABLESCRIPT - Disable scripting support
 # CONFIG_NSH_DISABLEBG - Disable background commands
@ -988,7 +988,7 @@ CONFIG_NSH_BUILTIN_APPS=y
 CONFIG_NSH_FILEIOSIZE=512
 CONFIG_NSH_STRERROR=y
 CONFIG_NSH_LINELEN=128
-CONFIG_NSH_MAX_ARGUMENTS=12
+CONFIG_NSH_MAXARGUMENTS=12
 CONFIG_NSH_NESTDEPTH=8
 CONFIG_NSH_DISABLESCRIPT=n
 CONFIG_NSH_DISABLEBG=n
--- a/nuttx/configs/px4io/common/Make.defs
+++ b/nuttx/configs/px4io/common/Make.defs
@ -58,7 +58,7 @@ NM			 = $(CROSSDEV)nm
 OBJCOPY			 = $(CROSSDEV)objcopy
 OBJDUMP			 = $(CROSSDEV)objdump

-MAXOPTIMIZATION		 = -O3
+MAXOPTIMIZATION		 ?= -O3
 ARCHCPUFLAGS		 = -mcpu=cortex-m3 \
 			   -mthumb \
 			   -march=armv7-m
--- a/src/drivers/hott_telemetry/hott_telemetry_main.c
+++ b/src/drivers/hott_telemetry/hott_telemetry_main.c
@ -53,6 +53,7 @@
 #include <termios.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
+#include <systemlib/err.h>
 #include <systemlib/systemlib.h>

 #include "messages.h"
@ -60,56 +61,44 @@
 static int thread_should_exit = false;		/**< Deamon exit flag */
 static int thread_running = false;		/**< Deamon status flag */
 static int deamon_task;				/**< Handle of deamon task / thread */
-static char *daemon_name = "hott_telemetry";
-static char *commandline_usage = "usage: hott_telemetry start|status|stop [-d <device>]";
+static const char daemon_name[] = "hott_telemetry";
+static const char commandline_usage[] = "usage: hott_telemetry start|status|stop [-d <device>]";

-
-/* A little console messaging experiment - console helper macro */
-#define FATAL_MSG(_msg)		fprintf(stderr, "[%s] %s\n", daemon_name, _msg); exit(1);
-#define ERROR_MSG(_msg)		fprintf(stderr, "[%s] %s\n", daemon_name, _msg);
-#define INFO_MSG(_msg)		printf("[%s] %s\n", daemon_name, _msg);
 /**
 * Deamon management function.
 */
 __EXPORT int hott_telemetry_main(int argc, char *argv[]);

 /**
- * Mainloop of deamon.
+ * Mainloop of daemon.
 */
 int hott_telemetry_thread_main(int argc, char *argv[]);

-static int read_data(int uart, int *id);
-static int send_data(int uart, uint8_t *buffer, int size);
+static int recv_req_id(int uart, uint8_t *id);
+static int send_data(int uart, uint8_t *buffer, size_t size);

-static int open_uart(const char *device, struct termios *uart_config_original)
+static int
+open_uart(const char *device, struct termios *uart_config_original)
 {
 	/* baud rate */
-	int speed = B19200;
-	int uart;
+	static const speed_t speed = B19200;

 	/* open uart */
-	uart = open(device, O_RDWR | O_NOCTTY);
+	const int uart = open(device, O_RDWR | O_NOCTTY);

 	if (uart < 0) {
-		char msg[80];
-		sprintf(msg, "Error opening port: %s\n", device);
-		FATAL_MSG(msg);
+		err(1, "Error opening port: %s", device);
 	}
-
-	/* Try to set baud rate */
-	struct termios uart_config;
+	
+	/* Back up the original uart configuration to restore it after exit */	
 	int termios_state;
-
-	/* Back up the original uart configuration to restore it after exit */
-	char msg[80];
-
 	if ((termios_state = tcgetattr(uart, uart_config_original)) < 0) {
-		sprintf(msg, "Error getting baudrate / termios config for %s: %d\n", device, termios_state);
 		close(uart);
-		FATAL_MSG(msg);
+		err(1, "Error getting baudrate / termios config for %s: %d", device, termios_state);
 	}

 	/* Fill the struct for the new configuration */
+	struct termios uart_config;
 	tcgetattr(uart, &uart_config);

 	/* Clear ONLCR flag (which appends a CR for every LF) */
@ -117,16 +106,14 @@ static int open_uart(const char *device, struct termios *uart_config_original)

 	/* Set baud rate */
 	if (cfsetispeed(&uart_config, speed) < 0 || cfsetospeed(&uart_config, speed) < 0) {
-		sprintf(msg, "Error setting baudrate / termios config for %s: %d (cfsetispeed, cfsetospeed)\n",
-			device, termios_state);
 		close(uart);
-		FATAL_MSG(msg);
+		err(1, "Error setting baudrate / termios config for %s: %d (cfsetispeed, cfsetospeed)",
+			 device, termios_state);
 	}

 	if ((termios_state = tcsetattr(uart, TCSANOW, &uart_config)) < 0) {
-		sprintf(msg, "Error setting baudrate / termios config for %s (tcsetattr)\n", device);
 		close(uart);
-		FATAL_MSG(msg);
+		err(1, "Error setting baudrate / termios config for %s (tcsetattr)", device);
 	}

 	/* Activate single wire mode */
@ -135,39 +122,41 @@ static int open_uart(const char *device, struct termios *uart_config_original)
 	return uart;
 }

-int read_data(int uart, int *id)
+int
+recv_req_id(int uart, uint8_t *id)
 {
-	const int timeout = 1000;
+	static const int timeout_ms = 1000;  // TODO make it a define
 	struct pollfd fds[] = { { .fd = uart, .events = POLLIN } };

-	char mode;
+	uint8_t mode;

-	if (poll(fds, 1, timeout) > 0) {
+	if (poll(fds, 1, timeout_ms) > 0) {
 		/* Get the mode: binary or text  */
-		read(uart, &mode, 1);
-		/* Read the device ID being polled */
-		read(uart, id, 1);
+		read(uart, &mode, sizeof(mode));

 		/* if we have a binary mode request */
 		if (mode != BINARY_MODE_REQUEST_ID) {
 			return ERROR;
 		}

+		/* Read the device ID being polled */
+		read(uart, id, sizeof(*id));
 	} else {
-		ERROR_MSG("UART timeout on TX/RX port");
+		warnx("UART timeout on TX/RX port");
 		return ERROR;
 	}

 	return OK;
 }

-int send_data(int uart, uint8_t *buffer, int size)
+int
+send_data(int uart, uint8_t *buffer, size_t size)
 {
 	usleep(POST_READ_DELAY_IN_USECS);

 	uint16_t checksum = 0;

-	for (int i = 0; i < size; i++) {
+	for (size_t i = 0; i < size; i++) {
 		if (i == size - 1) {
 			/* Set the checksum: the first uint8_t is taken as the checksum. */
 			buffer[i] = checksum & 0xff;
@ -176,7 +165,7 @@ int send_data(int uart, uint8_t *buffer, int size)
 			checksum += buffer[i];
 		}

-		write(uart, &buffer[i], 1);
+		write(uart, &buffer[i], sizeof(buffer[i]));

 		/* Sleep before sending the next byte. */
 		usleep(POST_WRITE_DELAY_IN_USECS);
@ -190,13 +179,14 @@ int send_data(int uart, uint8_t *buffer, int size)
 	return OK;
 }

-int hott_telemetry_thread_main(int argc, char *argv[])
+int
+hott_telemetry_thread_main(int argc, char *argv[])
 {
-	INFO_MSG("starting");
+	warnx("starting");

 	thread_running = true;

-	char *device = "/dev/ttyS1";		/**< Default telemetry port: USART2 */
+	const char *device = "/dev/ttyS1";		/**< Default telemetry port: USART2 */

 	/* read commandline arguments */
 	for (int i = 0; i < argc && argv[i]; i++) {
@ -206,45 +196,55 @@ int hott_telemetry_thread_main(int argc, char *argv[])

 			} else {
 				thread_running = false;
-				ERROR_MSG("missing parameter to -d");
-				ERROR_MSG(commandline_usage);
-				exit(1);
+				errx(1, "missing parameter to -d\n%s", commandline_usage);
 			}
 		}
 	}

 	/* enable UART, writes potentially an empty buffer, but multiplexing is disabled */
 	struct termios uart_config_original;
-	int uart = open_uart(device, &uart_config_original);
+	const int uart = open_uart(device, &uart_config_original);

 	if (uart < 0) {
-		ERROR_MSG("Failed opening HoTT UART, exiting.");
+		errx(1, "Failed opening HoTT UART, exiting.");
 		thread_running = false;
-		exit(ERROR);
 	}

 	messages_init();

 	uint8_t buffer[MESSAGE_BUFFER_SIZE];
-	int size = 0;
-	int id = 0;
+	size_t size = 0;
+	uint8_t id = 0;
+	bool connected = true;

 	while (!thread_should_exit) {
-		if (read_data(uart, &id) == OK) {
+		if (recv_req_id(uart, &id) == OK) {
+			if (!connected) {
+				connected = true;
+				warnx("OK");
+			}
+
 			switch (id) {
-			case ELECTRIC_AIR_MODULE:
+			case EAM_SENSOR_ID:
 				build_eam_response(buffer, &size);
 				break;

+			case GPS_SENSOR_ID:
+				build_gps_response(buffer, &size);
+				break;
+
 			default:
 				continue;	// Not a module we support.
 			}

 			send_data(uart, buffer, size);
+		} else {
+			connected = false;
+			warnx("syncing");
 		}
 	}

-	INFO_MSG("exiting");
+	warnx("exiting");

 	close(uart);

@ -256,23 +256,22 @@ int hott_telemetry_thread_main(int argc, char *argv[])
 /**
 * Process command line arguments and tart the daemon.
 */
-int hott_telemetry_main(int argc, char *argv[])
+int
+hott_telemetry_main(int argc, char *argv[])
 {
 	if (argc < 1) {
-		ERROR_MSG("missing command");
-		ERROR_MSG(commandline_usage);
-		exit(1);
+		errx(1, "missing command\n%s", commandline_usage);
 	}

 	if (!strcmp(argv[1], "start")) {

 		if (thread_running) {
-			INFO_MSG("deamon already running");
+			warnx("deamon already running");
 			exit(0);
 		}

 		thread_should_exit = false;
-		deamon_task = task_spawn("hott_telemetry",
+		deamon_task = task_spawn(daemon_name,
 					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_MAX - 40,
 					 2048,
@ -288,19 +287,14 @@ int hott_telemetry_main(int argc, char *argv[])

 	if (!strcmp(argv[1], "status")) {
 		if (thread_running) {
-			INFO_MSG("daemon is running");
+			warnx("daemon is running");

 		} else {
-			INFO_MSG("daemon not started");
+			warnx("daemon not started");
 		}

 		exit(0);
 	}

-	ERROR_MSG("unrecognized command");
-	ERROR_MSG(commandline_usage);
-	exit(1);
+	errx(1, "unrecognized command\n%s", commandline_usage);
 }
-
-
-
--- a/src/drivers/hott_telemetry/messages.c
+++ b/src/drivers/hott_telemetry/messages.c
@ -1,7 +1,7 @@
 /****************************************************************************
 *
- *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
- *   Author: Simon Wilks <sjwilks@gmail.com>
+ *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Author: @author Simon Wilks <sjwilks@gmail.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
@ -34,30 +34,44 @@

 /**
 * @file messages.c
- * @author Simon Wilks <sjwilks@gmail.com>
+ *
 */

 #include "messages.h"

+#include <math.h>
+#include <stdio.h>
 #include <string.h>
-#include <systemlib/systemlib.h>
+#include <systemlib/geo/geo.h>
 #include <unistd.h>
-#include <uORB/topics/airspeed.h>
 #include <uORB/topics/battery_status.h>
+#include <uORB/topics/home_position.h>
 #include <uORB/topics/sensor_combined.h>
+#include <uORB/topics/vehicle_gps_position.h>
+
+/* The board is very roughly 5 deg warmer than the surrounding air */
+#define BOARD_TEMP_OFFSET_DEG 5

-static int airspeed_sub = -1;
 static int battery_sub = -1;
+static int gps_sub = -1;
+static int home_sub = -1;
 static int sensor_sub = -1;

-void messages_init(void)
+static bool home_position_set = false;
+static double home_lat = 0.0d;
+static double home_lon = 0.0d;
+
+void 
+messages_init(void)
 {
 	battery_sub = orb_subscribe(ORB_ID(battery_status));
+	gps_sub = orb_subscribe(ORB_ID(vehicle_gps_position));
+	home_sub = orb_subscribe(ORB_ID(home_position));
 	sensor_sub = orb_subscribe(ORB_ID(sensor_combined));
-	airspeed_sub = orb_subscribe(ORB_ID(airspeed));
 }

-void build_eam_response(uint8_t *buffer, int *size)
+void 
+build_eam_response(uint8_t *buffer, size_t *size)
 {
 	/* get a local copy of the current sensor values */
 	struct sensor_combined_s raw;
@ -74,26 +88,144 @@ void build_eam_response(uint8_t *buffer, int *size)
 	memset(&msg, 0, *size);

 	msg.start = START_BYTE;
-	msg.eam_sensor_id = ELECTRIC_AIR_MODULE;
-	msg.sensor_id = EAM_SENSOR_ID;
+	msg.eam_sensor_id = EAM_SENSOR_ID;
+	msg.sensor_id = EAM_SENSOR_TEXT_ID;
+	
 	msg.temperature1 = (uint8_t)(raw.baro_temp_celcius + 20);
-	msg.temperature2 = TEMP_ZERO_CELSIUS;
+	msg.temperature2 = msg.temperature1 - BOARD_TEMP_OFFSET_DEG;
+
 	msg.main_voltage_L = (uint8_t)(battery.voltage_v * 10);

 	uint16_t alt = (uint16_t)(raw.baro_alt_meter + 500);
 	msg.altitude_L = (uint8_t)alt & 0xff;
 	msg.altitude_H = (uint8_t)(alt >> 8) & 0xff;

-	/* get a local copy of the current sensor values */
-	struct airspeed_s airspeed;
-	memset(&airspeed, 0, sizeof(airspeed));
-	orb_copy(ORB_ID(airspeed), airspeed_sub, &airspeed);
+	msg.stop = STOP_BYTE;
+	memcpy(buffer, &msg, *size);
+}

-	uint16_t speed = (uint16_t)(airspeed.indicated_airspeed_m_s * 3.6);
-	msg.speed_L = (uint8_t)speed & 0xff;
-	msg.speed_H = (uint8_t)(speed >> 8) & 0xff;
+void 
+build_gps_response(uint8_t *buffer, size_t *size)
+{
+	/* get a local copy of the current sensor values */
+	struct sensor_combined_s raw;
+	memset(&raw, 0, sizeof(raw));
+	orb_copy(ORB_ID(sensor_combined), sensor_sub, &raw);
+
+ 	/* get a local copy of the battery data */
+	struct vehicle_gps_position_s gps;
+	memset(&gps, 0, sizeof(gps));
+	orb_copy(ORB_ID(vehicle_gps_position), gps_sub, &gps);
+
+	struct gps_module_msg msg = { 0 };
+	*size = sizeof(msg);
+	memset(&msg, 0, *size);
+
+	msg.start = START_BYTE;
+	msg.sensor_id = GPS_SENSOR_ID;
+	msg.sensor_text_id = GPS_SENSOR_TEXT_ID;
+
+	msg.gps_num_sat = gps.satellites_visible;
+
+	/* The GPS fix type: 0 = none, 2 = 2D, 3 = 3D */
+	msg.gps_fix_char = (uint8_t)(gps.fix_type + 48);
+	msg.gps_fix = (uint8_t)(gps.fix_type + 48);
+
+	/* No point collecting more data if we don't have a 3D fix yet */
+	if (gps.fix_type > 2) {
+		/* Current flight direction */
+		msg.flight_direction = (uint8_t)(gps.cog_rad * M_RAD_TO_DEG_F);
+
+		/* GPS speed */
+		uint16_t speed = (uint16_t)(gps.vel_m_s * 3.6);
+		msg.gps_speed_L = (uint8_t)speed & 0xff;
+		msg.gps_speed_H = (uint8_t)(speed >> 8) & 0xff;
+		
+		/* Get latitude in degrees, minutes and seconds */
+		double lat = ((double)(gps.lat))*1e-7d;
+
+		/* Set the N or S specifier */		
+		msg.latitude_ns = 0;
+		if (lat < 0) {
+			msg.latitude_ns = 1;
+			lat = abs(lat);
+		}
+
+		int deg;
+		int min;
+		int sec;
+		convert_to_degrees_minutes_seconds(lat, &deg, &min, &sec);
+
+		uint16_t lat_min = (uint16_t)(deg * 100 + min);
+		msg.latitude_min_L = (uint8_t)lat_min & 0xff;
+		msg.latitude_min_H = (uint8_t)(lat_min >> 8) & 0xff;
+		uint16_t lat_sec = (uint16_t)(sec);
+		msg.latitude_sec_L = (uint8_t)lat_sec & 0xff;
+		msg.latitude_sec_H = (uint8_t)(lat_sec >> 8) & 0xff;
+
+		/* Get longitude in degrees, minutes and seconds */
+		double lon = ((double)(gps.lon))*1e-7d;
+
+		/* Set the E or W specifier */
+		msg.longitude_ew = 0;
+		if (lon < 0) {
+			msg.longitude_ew = 1;
+			lon = abs(lon);
+		}
+
+		convert_to_degrees_minutes_seconds(lon, &deg, &min, &sec);
+		
+		uint16_t lon_min = (uint16_t)(deg * 100 + min);
+		msg.longitude_min_L = (uint8_t)lon_min & 0xff;
+		msg.longitude_min_H = (uint8_t)(lon_min >> 8) & 0xff;
+		uint16_t lon_sec = (uint16_t)(sec);
+		msg.longitude_sec_L = (uint8_t)lon_sec & 0xff;
+		msg.longitude_sec_H = (uint8_t)(lon_sec >> 8) & 0xff;
+		
+		/* Altitude */
+		uint16_t alt = (uint16_t)(gps.alt*1e-3 + 500.0f);
+		msg.altitude_L = (uint8_t)alt & 0xff;
+		msg.altitude_H = (uint8_t)(alt >> 8) & 0xff;
+
+		/* Get any (and probably only ever one) home_sub postion report */
+		bool updated;
+		orb_check(home_sub, &updated);
+		if (updated) {
+			/* get a local copy of the home position data */
+			struct home_position_s home;
+			memset(&home, 0, sizeof(home));
+			orb_copy(ORB_ID(home_position), home_sub, &home);
+
+			home_lat = ((double)(home.lat))*1e-7d;
+			home_lon = ((double)(home.lon))*1e-7d;
+			home_position_set = true;
+		}
+
+		/* Distance from home */
+		if (home_position_set) {
+			uint16_t dist = (uint16_t)get_distance_to_next_waypoint(home_lat, home_lon, lat, lon);
+
+			msg.distance_L = (uint8_t)dist & 0xff;
+			msg.distance_H = (uint8_t)(dist >> 8) & 0xff;
+
+			/* Direction back to home */
+			uint16_t bearing = (uint16_t)(get_bearing_to_next_waypoint(home_lat, home_lon, lat, lon) * M_RAD_TO_DEG_F);
+			msg.home_direction = (uint8_t)bearing >> 1;
+		}
+	}

 	msg.stop = STOP_BYTE;
-
 	memcpy(buffer, &msg, *size);
-}
+}
+
+void
+convert_to_degrees_minutes_seconds(double val, int *deg, int *min, int *sec)
+{
+	*deg = (int)val;
+
+	double delta = val - *deg;
+	const double min_d = delta * 60.0d;
+	*min = (int)min_d;
+	delta = min_d - *min;
+	*sec = (int)(delta * 10000.0d);
+}
--- a/src/drivers/hott_telemetry/messages.h
+++ b/src/drivers/hott_telemetry/messages.h
@ -44,11 +44,6 @@

 #include <stdlib.h>

-/* The buffer size used to store messages. This must be at least as big as the number of
- * fields in the largest message struct.
- */
-#define MESSAGE_BUFFER_SIZE 50
-
 /* The HoTT receiver demands a minimum 5ms period of silence after delivering its request.
 * Note that the value specified here is lower than 5000 (5ms) as time is lost constucting
 * the message after the read which takes some milliseconds.
@ -66,18 +61,18 @@
 #define TEMP_ZERO_CELSIUS	0x14

 /* Electric Air Module (EAM) constants. */
-#define ELECTRIC_AIR_MODULE	0x8e
-#define EAM_SENSOR_ID		0xe0
+#define EAM_SENSOR_ID			0x8e
+#define EAM_SENSOR_TEXT_ID		0xe0

 /* The Electric Air Module message. */
 struct eam_module_msg {
-	uint8_t start;			/**< Start byte   				*/
-	uint8_t eam_sensor_id;		/**< EAM sensor ID 				*/
+	uint8_t start;				/**< Start byte   				*/
+	uint8_t eam_sensor_id;		/**< EAM sensor					*/
 	uint8_t warning;
-	uint8_t sensor_id;		/**< Sensor ID, why different? 			*/
+	uint8_t sensor_id;			/**< Sensor ID, why different?	*/
 	uint8_t alarm_inverse1;
 	uint8_t alarm_inverse2;
-	uint8_t cell1_L;		/**< Lipo cell voltages. Not supported. 	*/
+	uint8_t cell1_L;			/**< Lipo cell voltages. Not supported.	*/
 	uint8_t cell2_L;
 	uint8_t cell3_L;
 	uint8_t cell4_L;
@ -95,30 +90,107 @@ struct eam_module_msg {
 	uint8_t batt1_voltage_H;
 	uint8_t batt2_voltage_L;	/**< Battery 2 voltage, lower 8-bits in steps of 0.02V 	*/
 	uint8_t batt2_voltage_H;
-	uint8_t temperature1;		/**< Temperature sensor 1. 20 = 0 degrees 		*/
+	uint8_t temperature1;		/**< Temperature sensor 1. 20 = 0 degrees */
 	uint8_t temperature2;
-	uint8_t altitude_L;		/**< Attitude (meters) lower 8-bits. 500 = 0 meters 	*/
+	uint8_t altitude_L;			/**< Attitude (meters) lower 8-bits. 500 = 0 meters */
 	uint8_t altitude_H;
-	uint8_t current_L;		/**< Current (mAh) lower 8-bits in steps of 0.1V 	*/
+	uint8_t current_L;			/**< Current (mAh) lower 8-bits in steps of 0.1V */
 	uint8_t current_H;
-	uint8_t main_voltage_L;		/**< Main power voltage lower 8-bits in steps of 0.1V 	*/
+	uint8_t main_voltage_L;		/**< Main power voltage lower 8-bits in steps of 0.1V */
 	uint8_t main_voltage_H;
-	uint8_t battery_capacity_L;	/**< Used battery capacity in steps of 10mAh 		*/
+	uint8_t battery_capacity_L;	/**< Used battery capacity in steps of 10mAh */
 	uint8_t battery_capacity_H;
-	uint8_t climbrate_L;		/**< Climb rate in 0.01m/s. 0m/s = 30000 		*/
+	uint8_t climbrate_L;		/**< Climb rate in 0.01m/s. 0m/s = 30000 */
 	uint8_t climbrate_H;
-	uint8_t climbrate_3s;		/**< Climb rate in m/3sec. 0m/3sec = 120 		*/
-	uint8_t rpm_L;			/**< RPM Lower 8-bits In steps of 10 U/min 		*/
+	uint8_t climbrate_3s;		/**< Climb rate in m/3sec. 0m/3sec = 120 */
+	uint8_t rpm_L;				/**< RPM Lower 8-bits In steps of 10 U/min */
 	uint8_t rpm_H;
-	uint8_t electric_min;		/**< Flight time in minutes. 				*/
-	uint8_t electric_sec;		/**< Flight time in seconds. 				*/
-	uint8_t speed_L;		/**< Airspeed in km/h in steps of 1 km/h 		*/
+	uint8_t electric_min;		/**< Flight time in minutes. */
+	uint8_t electric_sec;		/**< Flight time in seconds. */
+	uint8_t speed_L;			/**< Airspeed in km/h in steps of 1 km/h */
 	uint8_t speed_H;
-	uint8_t stop;			/**< Stop byte 						*/
-	uint8_t checksum;		/**< Lower 8-bits of all bytes summed. 			*/
+	uint8_t stop;				/**< Stop byte */
+	uint8_t checksum;			/**< Lower 8-bits of all bytes summed. */
 };

+/** 
+ * The maximum buffer size required to store a HoTT message.
+ */
+#define MESSAGE_BUFFER_SIZE sizeof(union { 	\
+    struct eam_module_msg eam; 				\
+})
+
+/* GPS sensor constants. */
+#define GPS_SENSOR_ID		0x8A
+#define GPS_SENSOR_TEXT_ID	0xA0
+
+/** 
+ * The GPS sensor message
+ * Struct based on: https://code.google.com/p/diy-hott-gps/downloads 
+ */
+struct gps_module_msg { 
+	uint8_t start;				/**< Start byte */
+	uint8_t sensor_id;			/**< GPS sensor ID*/
+	uint8_t warning;			/**< Byte 3: 0…= warning beeps */
+	uint8_t sensor_text_id;		/**< GPS Sensor text mode ID */
+	uint8_t alarm_inverse1;		/**< Byte 5: 01 inverse status */
+	uint8_t alarm_inverse2;		/**< Byte 6: 00 inverse status status 1 = no GPS Signal */
+	uint8_t flight_direction;	/**< Byte 7: 119 = Flightdir./dir. 1 = 2°; 0° (North), 9 0° (East), 180° (South), 270° (West) */
+	uint8_t gps_speed_L;		/**< Byte 8: 8 = /GPS speed low byte 8km/h */
+	uint8_t gps_speed_H;		/**< Byte 9: 0 = /GPS speed high byte */
+	  
+	uint8_t latitude_ns;		/**< Byte 10: 000 = N = 48°39’988 */
+	uint8_t latitude_min_L;		/**< Byte 11: 231 0xE7 = 0x12E7 = 4839 */
+	uint8_t latitude_min_H;		/**< Byte 12: 018 18 = 0x12 */
+	uint8_t latitude_sec_L;		/**< Byte 13: 171 220 = 0xDC = 0x03DC =0988 */
+	uint8_t latitude_sec_H;		/**< Byte 14: 016 3 = 0x03 */
+	 
+	uint8_t longitude_ew;		/**< Byte 15: 000  = E= 9° 25’9360 */
+	uint8_t longitude_min_L;	/**< Byte 16: 150 157 = 0x9D = 0x039D = 0925 */
+	uint8_t longitude_min_H;	/**< Byte 17: 003 3 = 0x03 */
+	uint8_t longitude_sec_L;	/**< Byte 18: 056 144 = 0x90 0x2490 = 9360*/
+	uint8_t longitude_sec_H;	/**< Byte 19: 004 36 = 0x24 */
+	  
+	uint8_t distance_L;			/**< Byte 20: 027 123 = /distance low byte 6 = 6 m */
+	uint8_t distance_H;			/**< Byte 21: 036 35 = /distance high byte */
+	uint8_t altitude_L;			/**< Byte 22: 243 244 = /Altitude low byte 500 = 0m */
+	uint8_t altitude_H;			/**< Byte 23: 001 1 = /Altitude high byte */
+	uint8_t resolution_L;		/**< Byte 24: 48 = Low Byte m/s resolution 0.01m 48 = 30000 = 0.00m/s (1=0.01m/s) */
+	uint8_t resolution_H;		/**< Byte 25: 117 = High Byte m/s resolution 0.01m */
+	uint8_t unknown1;			/**< Byte 26: 120 = 0m/3s */
+	uint8_t gps_num_sat;		/**< Byte 27: GPS.Satellites (number of satelites) (1 byte) */
+	uint8_t gps_fix_char;		/**< Byte 28: GPS.FixChar. (GPS fix character. display, if DGPS, 2D oder 3D) (1 byte) */
+	uint8_t home_direction;		/**< Byte 29: HomeDirection (direction from starting point to Model position) (1 byte) */
+	uint8_t angle_x_direction;	/**< Byte 30: angle x-direction (1 byte) */
+	uint8_t angle_y_direction;	/**< Byte 31: angle y-direction (1 byte) */
+	uint8_t angle_z_direction;	/**< Byte 32: angle z-direction (1 byte) */
+	uint8_t gyro_x_L;			/**< Byte 33: gyro x low byte (2 bytes) */
+	uint8_t gyro_x_H;			/**< Byte 34: gyro x high byte */
+	uint8_t gyro_y_L;			/**< Byte 35: gyro y low byte (2 bytes) */
+	uint8_t gyro_y_H;			/**< Byte 36: gyro y high byte */
+	uint8_t gyro_z_L;			/**< Byte 37: gyro z low byte (2 bytes) */
+	uint8_t gyro_z_H;			/**< Byte 38: gyro z high byte */
+	uint8_t vibration;			/**< Byte 39: vibration (1 bytes) */
+	uint8_t ascii4;				/**< Byte 40: 00 ASCII Free Character [4] */
+	uint8_t ascii5;				/**< Byte 41: 00 ASCII Free Character [5] */
+	uint8_t gps_fix;			/**< Byte 42: 00 ASCII Free Character [6], we use it for GPS FIX */
+	uint8_t version;			/**< Byte 43: 00 version number */
+	uint8_t stop;				/**< Byte 44: 0x7D Ende byte */
+	uint8_t checksum;			/**< Byte 45: Parity Byte */
+};
+
+/** 
+ * The maximum buffer size required to store a HoTT message.
+ */
+#define GPS_MESSAGE_BUFFER_SIZE sizeof(union { 	\
+    struct gps_module_msg gps; 				\
+})
+
 void messages_init(void);
-void build_eam_response(uint8_t *buffer, int *size);
+void build_eam_response(uint8_t *buffer, size_t *size);
+void build_gps_response(uint8_t *buffer, size_t *size);
+float _get_distance_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);
+void convert_to_degrees_minutes_seconds(double lat, int *deg, int *min, int *sec);
+

 #endif /* MESSAGES_H_ */
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@ -106,7 +106,7 @@ public:
 	* @param rate    The rate in Hz actuator outpus are sent to IO.
 	*      Min 10 Hz, max 400 Hz
 	*/
-	int      set_update_rate(int rate);
+	int      		set_update_rate(int rate);

 	/**
 	* Set the battery current scaling and bias
@ -114,7 +114,15 @@ public:
 	* @param amp_per_volt
 	* @param amp_bias
 	*/
-	void      set_battery_current_scaling(float amp_per_volt, float amp_bias);
+	void      		set_battery_current_scaling(float amp_per_volt, float amp_bias);
+
+	/**
+	 * Push failsafe values to IO.
+	 *
+	 * @param vals Failsafe control inputs: in us PPM (900 for zero, 1500 for centered, 2100 for full)
+	 * @param len Number of channels, could up to 8
+	 */
+	int			set_failsafe_values(const uint16_t *vals, unsigned len);

 	/**
 	* Print the current status of IO
@ -326,11 +334,11 @@ PX4IO::PX4IO() :
 	_to_actuators_effective(0),
 	_to_outputs(0),
 	_to_battery(0),
+	_primary_pwm_device(false),
 	_battery_amp_per_volt(90.0f/5.0f), // this matches the 3DR current sensor
 	_battery_amp_bias(0),
 	_battery_mamphour_total(0),
-	_battery_last_timestamp(0),
-	_primary_pwm_device(false)
+	_battery_last_timestamp(0)
 {
 	/* we need this potentially before it could be set in task_main */
 	g_dev = this;
@ -689,6 +697,19 @@ PX4IO::io_set_control_state()
 	return io_reg_set(PX4IO_PAGE_CONTROLS, 0, regs, _max_controls);
 }

+int
+PX4IO::set_failsafe_values(const uint16_t *vals, unsigned len)
+{
+	uint16_t 		regs[_max_actuators];
+
+	if (len > _max_actuators)
+		/* fail with error */
+		return E2BIG;
+
+	/* copy values to registers in IO */
+	return io_reg_set(PX4IO_PAGE_FAILSAFE_PWM, 0, vals, len);
+}
+
 int
 PX4IO::io_set_arming_state()
 {
@ -1250,7 +1271,7 @@ PX4IO::print_status()
 	printf("%u bytes free\n",
 		io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FREEMEM));
 	uint16_t flags = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_FLAGS);
-	printf("status 0x%04x%s%s%s%s%s%s%s%s%s%s%s\n",
+	printf("status 0x%04x%s%s%s%s%s%s%s%s%s%s%s%s\n",
 		flags,
 		((flags & PX4IO_P_STATUS_FLAGS_ARMED)    ? " ARMED" : ""),
 		((flags & PX4IO_P_STATUS_FLAGS_OVERRIDE) ? " OVERRIDE" : ""),
@ -1262,7 +1283,8 @@ PX4IO::print_status()
 		((flags & PX4IO_P_STATUS_FLAGS_RAW_PWM)  ? " RAW_PPM" : ""),
 		((flags & PX4IO_P_STATUS_FLAGS_MIXER_OK) ? " MIXER_OK" : " MIXER_FAIL"),
 		((flags & PX4IO_P_STATUS_FLAGS_ARM_SYNC) ? " ARM_SYNC" : " ARM_NO_SYNC"),
-		((flags & PX4IO_P_STATUS_FLAGS_INIT_OK)  ? " INIT_OK" : " INIT_FAIL"));
+		((flags & PX4IO_P_STATUS_FLAGS_INIT_OK)  ? " INIT_OK" : " INIT_FAIL"),
+		((flags & PX4IO_P_STATUS_FLAGS_FAILSAFE)  ? " FAILSAFE" : ""));
 	uint16_t alarms = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_ALARMS);
 	printf("alarms 0x%04x%s%s%s%s%s%s%s\n",
 		alarms,
@ -1280,7 +1302,7 @@ PX4IO::print_status()
 	       io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_VBATT),
 	       io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_IBATT),
 	       io_reg_get(PX4IO_PAGE_SETUP, PX4IO_P_SETUP_VBATT_SCALE));
-	printf("amp_per_volt %.3f amp_offset %.3f mAhDischarged %.3f\n",
+	printf("amp_per_volt %.3f amp_offset %.3f mAh discharged %.3f\n",
 	       (double)_battery_amp_per_volt,
 	       (double)_battery_amp_bias,
 	       (double)_battery_mamphour_total);
@ -1474,7 +1496,7 @@ PX4IO::ioctl(file *filep, int cmd, unsigned long arg)

 	case MIXERIOCLOADBUF: {
 		const char *buf = (const char *)arg;
-		ret = mixer_send(buf, strnlen(buf, 1024));
+		ret = mixer_send(buf, strnlen(buf, 2048));
 		break;
 	}

@ -1615,6 +1637,13 @@ test(void)
 	if (ioctl(fd, PWM_SERVO_ARM, 0))
 		err(1, "failed to arm servos");

+	/* Open console directly to grab CTRL-C signal */
+	int console = open("/dev/console", O_NONBLOCK | O_RDONLY | O_NOCTTY);
+	if (!console)
+		err(1, "failed opening console");
+
+	warnx("Press CTRL-C or 'c' to abort.");
+
 	for (;;) {

 		/* sweep all servos between 1000..2000 */
@ -1649,6 +1678,16 @@ test(void)
 			if (value != servos[i])
 				errx(1, "servo %d readback error, got %u expected %u", i, value, servos[i]);
 		}
+
+		/* Check if user wants to quit */
+		char c;
+		if (read(console, &c, 1) == 1) {
+			if (c == 0x03 || c == 0x63) {
+				warnx("User abort\n");
+				close(console);
+				exit(0);
+			}
+		}
 	}
 }

@ -1718,6 +1757,41 @@ px4io_main(int argc, char *argv[])
 		exit(0);
 	}

+	if (!strcmp(argv[1], "failsafe")) {
+
+		if (argc < 3) {
+			errx(1, "failsafe command needs at least one channel value (ppm)");
+		}
+
+		if (g_dev != nullptr) {
+
+			/* set values for first 8 channels, fill unassigned channels with 1500. */
+			uint16_t failsafe[8];
+
+			for (int i = 0; i < sizeof(failsafe) / sizeof(failsafe[0]); i++)
+			{
+				/* set channel to commanline argument or to 900 for non-provided channels */
+				if (argc > i + 2) {
+					failsafe[i] = atoi(argv[i+2]);
+					if (failsafe[i] < 800 || failsafe[i] > 2200) {
+						errx(1, "value out of range of 800 < value < 2200. Aborting.");
+					}
+				} else {
+					/* a zero value will result in stopping to output any pulse */
+					failsafe[i] = 0;
+				}
+			}
+
+			int ret = g_dev->set_failsafe_values(failsafe, sizeof(failsafe) / sizeof(failsafe[0]));
+
+			if (ret != OK)
+				errx(ret, "failed setting failsafe values");
+		} else {
+			errx(1, "not loaded");
+		}
+		exit(0);
+	}
+
 	if (!strcmp(argv[1], "recovery")) {

 		if (g_dev != nullptr) {
@ -1845,5 +1919,5 @@ px4io_main(int argc, char *argv[])
 		monitor();

 	out:
-	errx(1, "need a command, try 'start', 'stop', 'status', 'test', 'monitor', 'debug', 'recovery', 'limit', 'current' or 'update'");
+	errx(1, "need a command, try 'start', 'stop', 'status', 'test', 'monitor', 'debug', 'recovery', 'limit', 'current', 'failsafe' or 'update'");
 }
--- a/src/examples/px4_daemon_app/px4_daemon_app.c
+++ b/src/examples/px4_daemon_app/px4_daemon_app.c
@ -1,7 +1,6 @@
 /****************************************************************************
 *
- *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
- *   Author: @author Example User <mail@example.com>
+ *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
@ -33,27 +32,33 @@
 ****************************************************************************/

 /**
- * @file px4_deamon_app.c
- * Deamon application example for PX4 autopilot
+ * @file px4_daemon_app.c
+ * daemon application example for PX4 autopilot
+ * 
+ * @author Example User <mail@example.com>
 */

 #include <nuttx/config.h>
+#include <nuttx/sched.h>
 #include <unistd.h>
 #include <stdio.h>

-static bool thread_should_exit = false;		/**< Deamon exit flag */
-static bool thread_running = false;		/**< Deamon status flag */
-static int deamon_task;				/**< Handle of deamon task / thread */
+#include <systemlib/systemlib.h>
+#include <systemlib/err.h>
+
+static bool thread_should_exit = false;		/**< daemon exit flag */
+static bool thread_running = false;		/**< daemon status flag */
+static int daemon_task;				/**< Handle of daemon task / thread */

 /**
- * Deamon management function.
+ * daemon management function.
 */
-__EXPORT int px4_deamon_app_main(int argc, char *argv[]);
+__EXPORT int px4_daemon_app_main(int argc, char *argv[]);

 /**
- * Mainloop of deamon.
+ * Mainloop of daemon.
 */
-int px4_deamon_thread_main(int argc, char *argv[]);
+int px4_daemon_thread_main(int argc, char *argv[]);

 /**
 * Print the correct usage.
@ -64,20 +69,19 @@ static void
 usage(const char *reason)
 {
 	if (reason)
-		fprintf(stderr, "%s\n", reason);
-	fprintf(stderr, "usage: deamon {start|stop|status} [-p <additional params>]\n\n");
-	exit(1);
+		warnx("%s\n", reason);
+	errx(1, "usage: daemon {start|stop|status} [-p <additional params>]\n\n");
 }

 /**
- * The deamon app only briefly exists to start
+ * The daemon app only briefly exists to start
 * the background job. The stack size assigned in the
 * Makefile does only apply to this management task.
 * 
 * The actual stack size should be set in the call
 * to task_create().
 */
-int px4_deamon_app_main(int argc, char *argv[])
+int px4_daemon_app_main(int argc, char *argv[])
 {
 	if (argc < 1)
 		usage("missing command");
@ -85,17 +89,17 @@ int px4_deamon_app_main(int argc, char *argv[])
 	if (!strcmp(argv[1], "start")) {

 		if (thread_running) {
-			printf("deamon already running\n");
+			warnx("daemon already running\n");
 			/* this is not an error */
 			exit(0);
 		}

 		thread_should_exit = false;
-		deamon_task = task_spawn("deamon",
+		daemon_task = task_spawn("daemon",
 					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_DEFAULT,
 					 4096,
-					 px4_deamon_thread_main,
+					 px4_daemon_thread_main,
 					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
 		exit(0);
 	}
@ -107,9 +111,9 @@ int px4_deamon_app_main(int argc, char *argv[])

 	if (!strcmp(argv[1], "status")) {
 		if (thread_running) {
-			printf("\tdeamon app is running\n");
+			warnx("\trunning\n");
 		} else {
-			printf("\tdeamon app not started\n");
+			warnx("\tnot started\n");
 		}
 		exit(0);
 	}
@ -118,18 +122,18 @@ int px4_deamon_app_main(int argc, char *argv[])
 	exit(1);
 }

-int px4_deamon_thread_main(int argc, char *argv[]) {
+int px4_daemon_thread_main(int argc, char *argv[]) {

-	printf("[deamon] starting\n");
+	warnx("[daemon] starting\n");

 	thread_running = true;

 	while (!thread_should_exit) {
-		printf("Hello Deamon!\n");
+		warnx("Hello daemon!\n");
 		sleep(10);
 	}

-	printf("[deamon] exiting.\n");
+	warnx("[daemon] exiting.\n");

 	thread_running = false;

--- a/src/modules/att_pos_estimator_ekf/KalmanNav.cpp
+++ b/src/modules/att_pos_estimator_ekf/KalmanNav.cpp
@ -683,7 +683,8 @@ int KalmanNav::correctPos()
 	// fault detetcion
 	float beta = y.dot(S.inverse() * y);

-	if (beta > _faultPos.get()) {
+	static int counter = 0;
+	if (beta > _faultPos.get() && (counter % 10 == 0)) {
 		printf("fault in gps: beta = %8.4f\n", (double)beta);
 		printf("Y/N: vN: %8.4f, vE: %8.4f, lat: %8.4f, lon: %8.4f, alt: %8.4f\n",
 		       double(y(0) / sqrtf(RPos(0, 0))),
@ -693,6 +694,7 @@ int KalmanNav::correctPos()
 		       double(y(4) / sqrtf(RPos(4, 4))),
 		       double(y(5) / sqrtf(RPos(5, 5))));
 	}
+	counter++;

 	return ret_ok;
 }
--- a/src/modules/att_pos_estimator_ekf/kalman_main.cpp
+++ b/src/modules/att_pos_estimator_ekf/kalman_main.cpp
@ -44,6 +44,7 @@
 #include <string.h>
 #include <systemlib/systemlib.h>
 #include <systemlib/param/param.h>
+#include <systemlib/err.h>
 #include <drivers/drv_hrt.h>
 #include <math.h>
 #include "KalmanNav.hpp"
@ -73,7 +74,7 @@ usage(const char *reason)
 	if (reason)
 		fprintf(stderr, "%s\n", reason);

-	fprintf(stderr, "usage: kalman_demo {start|stop|status} [-p <additional params>]\n\n");
+	warnx("usage: att_pos_estimator_ekf {start|stop|status} [-p <additional params>]");
 	exit(1);
 }

@ -94,13 +95,13 @@ int att_pos_estimator_ekf_main(int argc, char *argv[])
 	if (!strcmp(argv[1], "start")) {

 		if (thread_running) {
-			printf("kalman_demo already running\n");
+			warnx("already running");
 			/* this is not an error */
 			exit(0);
 		}

 		thread_should_exit = false;
-		deamon_task = task_spawn("kalman_demo",
+		deamon_task = task_spawn("att_pos_estimator_ekf",
 					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_MAX - 5,
 					 4096,
@ -116,10 +117,10 @@ int att_pos_estimator_ekf_main(int argc, char *argv[])

 	if (!strcmp(argv[1], "status")) {
 		if (thread_running) {
-			printf("\tkalman_demo app is running\n");
+			warnx("is running\n");

 		} else {
-			printf("\tkalman_demo app not started\n");
+			warnx("not started\n");
 		}

 		exit(0);
@ -132,7 +133,7 @@ int att_pos_estimator_ekf_main(int argc, char *argv[])
 int kalman_demo_thread_main(int argc, char *argv[])
 {

-	printf("[kalman_demo] starting\n");
+	warnx("starting\n");

 	using namespace math;

@ -144,7 +145,7 @@ int kalman_demo_thread_main(int argc, char *argv[])
 		nav.update();
 	}

-	printf("[kalman_demo] exiting.\n");
+	printf("exiting.\n");

 	thread_running = false;

--- a/src/modules/attitude_estimator_so3_comp/README
+++ b/src/modules/attitude_estimator_so3_comp/README
@ -0,0 +1,5 @@
+Synopsis
+
+ nsh> attitude_estimator_so3_comp start -d /dev/ttyS1 -b 115200
+
+Option -d is for debugging packet. See code for detailed packet structure.
--- a/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_main.cpp
+++ b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_main.cpp
@ -0,0 +1,833 @@
+/*
+ * Author: Hyon Lim <limhyon@gmail.com, hyonlim@snu.ac.kr>
+ *
+ * @file attitude_estimator_so3_comp_main.c
+ *
+ * Implementation of nonlinear complementary filters on the SO(3).
+ * This code performs attitude estimation by using accelerometer, gyroscopes and magnetometer.
+ * Result is provided as quaternion, 1-2-3 Euler angle and rotation matrix.
+ * 
+ * Theory of nonlinear complementary filters on the SO(3) is based on [1].
+ * Quaternion realization of [1] is based on [2].
+ * Optmized quaternion update code is based on Sebastian Madgwick's implementation.
+ * 
+ * References
+ *  [1] Mahony, R.; Hamel, T.; Pflimlin, Jean-Michel, "Nonlinear Complementary Filters on the Special Orthogonal Group," Automatic Control, IEEE Transactions on , vol.53, no.5, pp.1203,1218, June 2008
+ *  [2] Euston, M.; Coote, P.; Mahony, R.; Jonghyuk Kim; Hamel, T., "A complementary filter for attitude estimation of a fixed-wing UAV," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.340,345, 22-26 Sept. 2008
+ */
+
+#include <nuttx/config.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <poll.h>
+#include <fcntl.h>
+#include <float.h>
+#include <nuttx/sched.h>
+#include <sys/prctl.h>
+#include <termios.h>
+#include <errno.h>
+#include <limits.h>
+#include <math.h>
+#include <uORB/uORB.h>
+#include <uORB/topics/debug_key_value.h>
+#include <uORB/topics/sensor_combined.h>
+#include <uORB/topics/vehicle_attitude.h>
+#include <uORB/topics/vehicle_status.h>
+#include <uORB/topics/parameter_update.h>
+#include <drivers/drv_hrt.h>
+
+#include <systemlib/systemlib.h>
+#include <systemlib/perf_counter.h>
+#include <systemlib/err.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include "attitude_estimator_so3_comp_params.h"
+#ifdef __cplusplus
+}
+#endif
+
+extern "C" __EXPORT int attitude_estimator_so3_comp_main(int argc, char *argv[]);
+
+static bool thread_should_exit = false;		/**< Deamon exit flag */
+static bool thread_running = false;		/**< Deamon status flag */
+static int attitude_estimator_so3_comp_task;				/**< Handle of deamon task / thread */
+static float q0 = 1.0f, q1 = 0.0f, q2 = 0.0f, q3 = 0.0f;	/** quaternion of sensor frame relative to auxiliary frame */
+static float dq0 = 0.0f, dq1 = 0.0f, dq2 = 0.0f, dq3 = 0.0f;	/** quaternion of sensor frame relative to auxiliary frame */
+static float gyro_bias[3] = {0.0f, 0.0f, 0.0f}; /** bias estimation */
+static bool bFilterInit = false;
+
+//! Auxiliary variables to reduce number of repeated operations
+static float q0q0, q0q1, q0q2, q0q3;
+static float q1q1, q1q2, q1q3;
+static float q2q2, q2q3;
+static float q3q3;
+
+//! Serial packet related
+static int uart;
+static int baudrate;
+
+/**
+ * Mainloop of attitude_estimator_so3_comp.
+ */
+int attitude_estimator_so3_comp_thread_main(int argc, char *argv[]);
+
+/**
+ * Print the correct usage.
+ */
+static void usage(const char *reason);
+
+static void
+usage(const char *reason)
+{
+	if (reason)
+		fprintf(stderr, "%s\n", reason);
+
+	fprintf(stderr, "usage: attitude_estimator_so3_comp {start|stop|status} [-d <devicename>] [-b <baud rate>]\n"
+		"-d and -b options are for separate visualization with raw data (quaternion packet) transfer\n"
+		"ex) attitude_estimator_so3_comp start -d /dev/ttyS1 -b 115200\n");
+	exit(1);
+}
+
+/**
+ * The attitude_estimator_so3_comp app only briefly exists to start
+ * the background job. The stack size assigned in the
+ * Makefile does only apply to this management task.
+ *
+ * The actual stack size should be set in the call
+ * to task_create().
+ */
+int attitude_estimator_so3_comp_main(int argc, char *argv[])
+{
+	if (argc < 1)
+		usage("missing command");
+
+	
+
+	if (!strcmp(argv[1], "start")) {
+
+		if (thread_running) {
+			printf("attitude_estimator_so3_comp already running\n");
+			/* this is not an error */
+			exit(0);
+		}
+
+		thread_should_exit = false;
+		attitude_estimator_so3_comp_task = task_spawn("attitude_estimator_so3_comp",
+					      SCHED_DEFAULT,
+					      SCHED_PRIORITY_MAX - 5,
+					      12400,
+					      attitude_estimator_so3_comp_thread_main,
+					      (const char **)argv);
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "stop")) {
+		thread_should_exit = true;
+
+		while(thread_running){
+			usleep(200000);
+			printf(".");
+		}
+		printf("terminated.");
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "status")) {
+		if (thread_running) {
+			printf("\tattitude_estimator_so3_comp app is running\n");
+
+		} else {
+			printf("\tattitude_estimator_so3_comp app not started\n");
+		}
+
+		exit(0);
+	}
+
+	usage("unrecognized command");
+	exit(1);
+}
+
+//---------------------------------------------------------------------------------------------------
+// Fast inverse square-root
+// See: http://en.wikipedia.org/wiki/Fast_inverse_square_root
+float invSqrt(float number) {
+    volatile long i;
+    volatile float x, y;
+    volatile const float f = 1.5F;
+
+    x = number * 0.5F;
+    y = number;
+    i = * (( long * ) &y);
+    i = 0x5f375a86 - ( i >> 1 );
+    y = * (( float * ) &i);
+    y = y * ( f - ( x * y * y ) );
+    return y;
+}
+
+//! Using accelerometer, sense the gravity vector.
+//! Using magnetometer, sense yaw.
+void NonlinearSO3AHRSinit(float ax, float ay, float az, float mx, float my, float mz)
+{
+    float initialRoll, initialPitch;
+    float cosRoll, sinRoll, cosPitch, sinPitch;
+    float magX, magY;
+    float initialHdg, cosHeading, sinHeading;
+
+    initialRoll = atan2(-ay, -az);
+    initialPitch = atan2(ax, -az);
+
+    cosRoll = cosf(initialRoll);
+    sinRoll = sinf(initialRoll);
+    cosPitch = cosf(initialPitch);
+    sinPitch = sinf(initialPitch);
+
+    magX = mx * cosPitch + my * sinRoll * sinPitch + mz * cosRoll * sinPitch;
+
+    magY = my * cosRoll - mz * sinRoll;
+
+    initialHdg = atan2f(-magY, magX);
+
+    cosRoll = cosf(initialRoll * 0.5f);
+    sinRoll = sinf(initialRoll * 0.5f);
+
+    cosPitch = cosf(initialPitch * 0.5f);
+    sinPitch = sinf(initialPitch * 0.5f);
+
+    cosHeading = cosf(initialHdg * 0.5f);
+    sinHeading = sinf(initialHdg * 0.5f);
+
+    q0 = cosRoll * cosPitch * cosHeading + sinRoll * sinPitch * sinHeading;
+    q1 = sinRoll * cosPitch * cosHeading - cosRoll * sinPitch * sinHeading;
+    q2 = cosRoll * sinPitch * cosHeading + sinRoll * cosPitch * sinHeading;
+    q3 = cosRoll * cosPitch * sinHeading - sinRoll * sinPitch * cosHeading;
+
+    // auxillary variables to reduce number of repeated operations, for 1st pass
+    q0q0 = q0 * q0;
+    q0q1 = q0 * q1;
+    q0q2 = q0 * q2;
+    q0q3 = q0 * q3;
+    q1q1 = q1 * q1;
+    q1q2 = q1 * q2;
+    q1q3 = q1 * q3;
+    q2q2 = q2 * q2;
+    q2q3 = q2 * q3;
+    q3q3 = q3 * q3;
+}
+
+void NonlinearSO3AHRSupdate(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz, float twoKp, float twoKi, float dt) {
+	float recipNorm;
+	float halfex = 0.0f, halfey = 0.0f, halfez = 0.0f;
+
+	//! Make filter converge to initial solution faster
+	//! This function assumes you are in static position.
+	//! WARNING : in case air reboot, this can cause problem. But this is very
+	//!	      unlikely happen.
+	if(bFilterInit == false)
+	{
+		NonlinearSO3AHRSinit(ax,ay,az,mx,my,mz);
+		bFilterInit = true;
+	}
+        	
+	//! If magnetometer measurement is available, use it.
+	if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f)) {
+		float hx, hy, hz, bx, bz;
+		float halfwx, halfwy, halfwz;
+	
+		// Normalise magnetometer measurement
+		// Will sqrt work better? PX4 system is powerful enough?
+    		recipNorm = invSqrt(mx * mx + my * my + mz * mz);
+    		mx *= recipNorm;
+    		my *= recipNorm;
+    		mz *= recipNorm;
+    
+    		// Reference direction of Earth's magnetic field
+    		hx = 2.0f * (mx * (0.5f - q2q2 - q3q3) + my * (q1q2 - q0q3) + mz * (q1q3 + q0q2));
+    		hy = 2.0f * (mx * (q1q2 + q0q3) + my * (0.5f - q1q1 - q3q3) + mz * (q2q3 - q0q1));
+		hz = 2 * mx * (q1q3 - q0q2) + 2 * my * (q2q3 + q0q1) + 2 * mz * (0.5 - q1q1 - q2q2);
+    		bx = sqrt(hx * hx + hy * hy);
+    		bz = hz;
+    
+    		// Estimated direction of magnetic field
+    		halfwx = bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2);
+    		halfwy = bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3);
+    		halfwz = bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2);
+    
+    		// Error is sum of cross product between estimated direction and measured direction of field vectors
+    		halfex += (my * halfwz - mz * halfwy);
+    		halfey += (mz * halfwx - mx * halfwz);
+    		halfez += (mx * halfwy - my * halfwx);
+	}
+
+	// Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
+	if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) {
+		float halfvx, halfvy, halfvz;
+	
+		// Normalise accelerometer measurement
+		recipNorm = invSqrt(ax * ax + ay * ay + az * az);
+		ax *= recipNorm;
+		ay *= recipNorm;
+		az *= recipNorm;
+
+		// Estimated direction of gravity and magnetic field
+		halfvx = q1q3 - q0q2;
+		halfvy = q0q1 + q2q3;
+		halfvz = q0q0 - 0.5f + q3q3;
+	
+		// Error is sum of cross product between estimated direction and measured direction of field vectors
+		halfex += ay * halfvz - az * halfvy;
+		halfey += az * halfvx - ax * halfvz;
+		halfez += ax * halfvy - ay * halfvx;
+	}
+
+	// Apply feedback only when valid data has been gathered from the accelerometer or magnetometer
+	if(halfex != 0.0f && halfey != 0.0f && halfez != 0.0f) {
+		// Compute and apply integral feedback if enabled
+		if(twoKi > 0.0f) {
+			gyro_bias[0] += twoKi * halfex * dt;	// integral error scaled by Ki
+			gyro_bias[1] += twoKi * halfey * dt;
+			gyro_bias[2] += twoKi * halfez * dt;
+			gx += gyro_bias[0];	// apply integral feedback
+			gy += gyro_bias[1];
+			gz += gyro_bias[2];
+		}
+		else {
+			gyro_bias[0] = 0.0f;	// prevent integral windup
+			gyro_bias[1] = 0.0f;
+			gyro_bias[2] = 0.0f;
+		}
+
+		// Apply proportional feedback
+		gx += twoKp * halfex;
+		gy += twoKp * halfey;
+		gz += twoKp * halfez;
+	}
+	
+	//! Integrate rate of change of quaternion
+#if 0
+	gx *= (0.5f * dt);		// pre-multiply common factors
+	gy *= (0.5f * dt);
+	gz *= (0.5f * dt);
+#endif 
+
+	// Time derivative of quaternion. q_dot = 0.5*q\otimes omega.
+	//! q_k = q_{k-1} + dt*\dot{q}
+	//! \dot{q} = 0.5*q \otimes P(\omega)
+	dq0 = 0.5f*(-q1 * gx - q2 * gy - q3 * gz);
+	dq1 = 0.5f*(q0 * gx + q2 * gz - q3 * gy);
+	dq2 = 0.5f*(q0 * gy - q1 * gz + q3 * gx);
+	dq3 = 0.5f*(q0 * gz + q1 * gy - q2 * gx); 
+
+	q0 += dt*dq0;
+	q1 += dt*dq1;
+	q2 += dt*dq2;
+	q3 += dt*dq3;
+	
+	// Normalise quaternion
+	recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
+	q0 *= recipNorm;
+	q1 *= recipNorm;
+	q2 *= recipNorm;
+	q3 *= recipNorm;
+
+	// Auxiliary variables to avoid repeated arithmetic
+        q0q0 = q0 * q0;
+       	q0q1 = q0 * q1;
+       	q0q2 = q0 * q2;
+       	q0q3 = q0 * q3;
+       	q1q1 = q1 * q1;
+       	q1q2 = q1 * q2;
+   	q1q3 = q1 * q3;
+       	q2q2 = q2 * q2;
+       	q2q3 = q2 * q3;
+       	q3q3 = q3 * q3;   
+}
+
+void send_uart_byte(char c)
+{
+	write(uart,&c,1);
+}
+
+void send_uart_bytes(uint8_t *data, int length)
+{
+	write(uart,data,(size_t)(sizeof(uint8_t)*length));
+}
+
+void send_uart_float(float f) {
+  uint8_t * b = (uint8_t *) &f;
+
+  //! Assume float is 4-bytes
+  for(int i=0; i<4; i++) {
+    
+    uint8_t b1 = (b[i] >> 4) & 0x0f;
+    uint8_t b2 = (b[i] & 0x0f);
+    
+    uint8_t c1 = (b1 < 10) ? ('0' + b1) : 'A' + b1 - 10;
+    uint8_t c2 = (b2 < 10) ? ('0' + b2) : 'A' + b2 - 10;
+    
+    send_uart_bytes(&c1,1);
+    send_uart_bytes(&c2,1);
+  }
+}
+
+void send_uart_float_arr(float *arr, int length)
+{
+	for(int i=0;i<length;++i)
+	{
+		send_uart_float(arr[i]);
+		send_uart_byte(',');
+	}
+}
+
+int open_uart(int baud, const char *uart_name, struct termios *uart_config_original, bool *is_usb)
+{
+	int speed;
+	
+	switch (baud) {
+        case 0:      speed = B0;      break;
+        case 50:     speed = B50;     break;
+        case 75:     speed = B75;     break;
+        case 110:    speed = B110;    break;
+        case 134:    speed = B134;    break;
+        case 150:    speed = B150;    break;
+        case 200:    speed = B200;    break;
+        case 300:    speed = B300;    break;
+        case 600:    speed = B600;    break;
+        case 1200:   speed = B1200;   break;
+        case 1800:   speed = B1800;   break;
+        case 2400:   speed = B2400;   break;
+        case 4800:   speed = B4800;   break;
+        case 9600:   speed = B9600;   break;
+        case 19200:  speed = B19200;  break;
+        case 38400:  speed = B38400;  break;
+        case 57600:  speed = B57600;  break;
+        case 115200: speed = B115200; break;
+        case 230400: speed = B230400; break;
+        case 460800: speed = B460800; break;
+        case 921600: speed = B921600; break;
+        default:
+                printf("ERROR: Unsupported baudrate: %d\n\tsupported examples:\n\n\t9600\n19200\n38400\n57600\n115200\n230400\n460800\n921600\n\n", baud);
+                return -EINVAL;
+        }
+
+	printf("[so3_comp_filt] UART is %s, baudrate is %d\n", uart_name, baud);
+        uart = open(uart_name, O_RDWR | O_NOCTTY);
+
+	/* Try to set baud rate */
+        struct termios uart_config;
+        int termios_state;
+        *is_usb = false;
+
+	/* make some wild guesses including that USB serial is indicated by either /dev/ttyACM0 or /dev/console */
+        if (strcmp(uart_name, "/dev/ttyACM0") != OK && strcmp(uart_name, "/dev/console") != OK) {
+                /* Back up the original uart configuration to restore it after exit */
+                if ((termios_state = tcgetattr(uart, uart_config_original)) < 0) {
+                        printf("ERROR getting baudrate / termios config for %s: %d\n", uart_name, termios_state);
+                        close(uart);
+                        return -1;
+                }
+
+                /* Fill the struct for the new configuration */
+                tcgetattr(uart, &uart_config);
+
+                /* Clear ONLCR flag (which appends a CR for every LF) */
+                uart_config.c_oflag &= ~ONLCR;
+
+                /* Set baud rate */
+                if (cfsetispeed(&uart_config, speed) < 0 || cfsetospeed(&uart_config, speed) < 0) {
+                        printf("ERROR setting baudrate / termios config for %s: %d (cfsetispeed, cfsetospeed)\n", uart_name, termios_state);
+                        close(uart);
+                        return -1;
+                }
+
+
+                if ((termios_state = tcsetattr(uart, TCSANOW, &uart_config)) < 0) {
+                        printf("ERROR setting baudrate / termios config for %s (tcsetattr)\n", uart_name);
+                        close(uart);
+                        return -1;
+                }
+
+        } else {
+                *is_usb = true;
+        }
+
+        return uart;
+}
+
+/*
+ * [Rot_matrix,x_aposteriori,P_aposteriori] = attitudeKalmanfilter(dt,z_k,x_aposteriori_k,P_aposteriori_k,knownConst)
+ */
+
+/*
+ * EKF Attitude Estimator main function.
+ *
+ * Estimates the attitude recursively once started.
+ *
+ * @param argc number of commandline arguments (plus command name)
+ * @param argv strings containing the arguments
+ */
+int attitude_estimator_so3_comp_thread_main(int argc, char *argv[])
+{
+
+const unsigned int loop_interval_alarm = 6500;	// loop interval in microseconds
+
+	//! Serial debug related
+	int ch;
+	struct termios uart_config_original;
+	bool usb_uart;
+	bool debug_mode = false;
+	char *device_name = "/dev/ttyS2";
+	baudrate = 115200;
+
+	//! Time constant
+	float dt = 0.005f;
+	
+	/* output euler angles */
+	float euler[3] = {0.0f, 0.0f, 0.0f};
+
+	float Rot_matrix[9] = {1.f,  0,  0,
+			      0,  1.f,  0,
+			      0,  0,  1.f
+			     };		/**< init: identity matrix */
+
+	float acc[3] = {0.0f, 0.0f, 0.0f};
+	float gyro[3] = {0.0f, 0.0f, 0.0f};
+	float mag[3] = {0.0f, 0.0f, 0.0f};
+
+	/* work around some stupidity in task_create's argv handling */
+	argc -= 2;
+	argv += 2;
+
+	//! -d <device_name>, default : /dev/ttyS2
+	//! -b <baud_rate>,   default : 115200
+	while ((ch = getopt(argc,argv,"d:b:")) != EOF){
+		switch(ch){
+			case 'b':
+				baudrate = strtoul(optarg, NULL, 10);
+				if(baudrate == 0)
+					printf("invalid baud rate '%s'",optarg);
+				break;
+			case 'd':
+				device_name = optarg;
+				debug_mode = true;
+				break;
+			default:
+				usage("invalid argument");
+		}
+	}
+
+	if(debug_mode){
+		printf("Opening debugging port for 3D visualization\n");
+		uart = open_uart(baudrate, device_name, &uart_config_original, &usb_uart);
+		if (uart < 0)
+                	printf("could not open %s", device_name);
+		else
+			printf("Open port success\n");
+	}
+
+	// print text
+	printf("Nonlinear SO3 Attitude Estimator initialized..\n\n");
+	fflush(stdout);
+
+	int overloadcounter = 19;
+
+	/* store start time to guard against too slow update rates */
+	uint64_t last_run = hrt_absolute_time();
+
+	struct sensor_combined_s raw;
+	memset(&raw, 0, sizeof(raw));
+
+	//! Initialize attitude vehicle uORB message.
+	struct vehicle_attitude_s att;
+	memset(&att, 0, sizeof(att));
+
+	struct vehicle_status_s state;
+	memset(&state, 0, sizeof(state));
+
+	uint64_t last_data = 0;
+	uint64_t last_measurement = 0;
+
+	/* subscribe to raw data */
+	int sub_raw = orb_subscribe(ORB_ID(sensor_combined));
+	/* rate-limit raw data updates to 200Hz */
+	orb_set_interval(sub_raw, 4);
+
+	/* subscribe to param changes */
+	int sub_params = orb_subscribe(ORB_ID(parameter_update));
+
+	/* subscribe to system state*/
+	int sub_state = orb_subscribe(ORB_ID(vehicle_status));
+
+	/* advertise attitude */
+	orb_advert_t pub_att = orb_advertise(ORB_ID(vehicle_attitude), &att);
+
+	int loopcounter = 0;
+	int printcounter = 0;
+
+	thread_running = true;
+
+	/* advertise debug value */
+	// struct debug_key_value_s dbg = { .key = "", .value = 0.0f };
+	// orb_advert_t pub_dbg = -1;
+
+	float sensor_update_hz[3] = {0.0f, 0.0f, 0.0f};
+	// XXX write this out to perf regs
+
+	/* keep track of sensor updates */
+	uint32_t sensor_last_count[3] = {0, 0, 0};
+	uint64_t sensor_last_timestamp[3] = {0, 0, 0};
+
+	struct attitude_estimator_so3_comp_params so3_comp_params;
+	struct attitude_estimator_so3_comp_param_handles so3_comp_param_handles;
+
+	/* initialize parameter handles */
+	parameters_init(&so3_comp_param_handles);
+
+	uint64_t start_time = hrt_absolute_time();
+	bool initialized = false;
+
+	float gyro_offsets[3] = { 0.0f, 0.0f, 0.0f };
+	unsigned offset_count = 0;
+
+	/* register the perf counter */
+	perf_counter_t so3_comp_loop_perf = perf_alloc(PC_ELAPSED, "attitude_estimator_so3_comp");
+
+	/* Main loop*/
+	while (!thread_should_exit) {
+
+		struct pollfd fds[2];
+		fds[0].fd = sub_raw;
+		fds[0].events = POLLIN;
+		fds[1].fd = sub_params;
+		fds[1].events = POLLIN;
+		int ret = poll(fds, 2, 1000);
+
+		if (ret < 0) {
+			/* XXX this is seriously bad - should be an emergency */
+		} else if (ret == 0) {
+			/* check if we're in HIL - not getting sensor data is fine then */
+			orb_copy(ORB_ID(vehicle_status), sub_state, &state);
+
+			if (!state.flag_hil_enabled) {
+				fprintf(stderr,
+					"[att so3_comp] WARNING: Not getting sensors - sensor app running?\n");
+			}
+
+		} else {
+
+			/* only update parameters if they changed */
+			if (fds[1].revents & POLLIN) {
+				/* read from param to clear updated flag */
+				struct parameter_update_s update;
+				orb_copy(ORB_ID(parameter_update), sub_params, &update);
+
+				/* update parameters */
+				parameters_update(&so3_comp_param_handles, &so3_comp_params);
+			}
+
+			/* only run filter if sensor values changed */
+			if (fds[0].revents & POLLIN) {
+
+				/* get latest measurements */
+				orb_copy(ORB_ID(sensor_combined), sub_raw, &raw);
+
+				if (!initialized) {
+
+					gyro_offsets[0] += raw.gyro_rad_s[0];
+					gyro_offsets[1] += raw.gyro_rad_s[1];
+					gyro_offsets[2] += raw.gyro_rad_s[2];
+					offset_count++;
+
+					if (hrt_absolute_time() - start_time > 3000000LL) {
+						initialized = true;
+						gyro_offsets[0] /= offset_count;
+						gyro_offsets[1] /= offset_count;
+						gyro_offsets[2] /= offset_count;
+					}
+
+				} else {
+
+					perf_begin(so3_comp_loop_perf);
+
+					/* Calculate data time difference in seconds */
+					dt = (raw.timestamp - last_measurement) / 1000000.0f;
+					last_measurement = raw.timestamp;
+					uint8_t update_vect[3] = {0, 0, 0};
+
+					/* Fill in gyro measurements */
+					if (sensor_last_count[0] != raw.gyro_counter) {
+						update_vect[0] = 1;
+						sensor_last_count[0] = raw.gyro_counter;
+						sensor_update_hz[0] = 1e6f / (raw.timestamp - sensor_last_timestamp[0]);
+						sensor_last_timestamp[0] = raw.timestamp;
+					}
+
+					gyro[0] =  raw.gyro_rad_s[0] - gyro_offsets[0];
+					gyro[1] =  raw.gyro_rad_s[1] - gyro_offsets[1];
+					gyro[2] =  raw.gyro_rad_s[2] - gyro_offsets[2];
+
+					/* update accelerometer measurements */
+					if (sensor_last_count[1] != raw.accelerometer_counter) {
+						update_vect[1] = 1;
+						sensor_last_count[1] = raw.accelerometer_counter;
+						sensor_update_hz[1] = 1e6f / (raw.timestamp - sensor_last_timestamp[1]);
+						sensor_last_timestamp[1] = raw.timestamp;
+					}
+
+					acc[0] = raw.accelerometer_m_s2[0];
+					acc[1] = raw.accelerometer_m_s2[1];
+					acc[2] = raw.accelerometer_m_s2[2];
+
+					/* update magnetometer measurements */
+					if (sensor_last_count[2] != raw.magnetometer_counter) {
+						update_vect[2] = 1;
+						sensor_last_count[2] = raw.magnetometer_counter;
+						sensor_update_hz[2] = 1e6f / (raw.timestamp - sensor_last_timestamp[2]);
+						sensor_last_timestamp[2] = raw.timestamp;
+					}
+
+					mag[0] = raw.magnetometer_ga[0];
+					mag[1] = raw.magnetometer_ga[1];
+					mag[2] = raw.magnetometer_ga[2];
+
+					uint64_t now = hrt_absolute_time();
+					unsigned int time_elapsed = now - last_run;
+					last_run = now;
+
+					if (time_elapsed > loop_interval_alarm) {
+						//TODO: add warning, cpu overload here
+						// if (overloadcounter == 20) {
+						// 	printf("CPU OVERLOAD DETECTED IN ATTITUDE ESTIMATOR EKF (%lu > %lu)\n", time_elapsed, loop_interval_alarm);
+						// 	overloadcounter = 0;
+						// }
+
+						overloadcounter++;
+					}
+
+					static bool const_initialized = false;
+
+					/* initialize with good values once we have a reasonable dt estimate */
+					if (!const_initialized && dt < 0.05f && dt > 0.005f) {
+						dt = 0.005f;
+						parameters_update(&so3_comp_param_handles, &so3_comp_params);
+						const_initialized = true;
+					}
+
+					/* do not execute the filter if not initialized */
+					if (!const_initialized) {
+						continue;
+					}
+
+					uint64_t timing_start = hrt_absolute_time();
+
+					// NOTE : Accelerometer is reversed.
+					// Because proper mount of PX4 will give you a reversed accelerometer readings.
+					NonlinearSO3AHRSupdate(gyro[0],gyro[1],gyro[2],-acc[0],-acc[1],-acc[2],mag[0],mag[1],mag[2],so3_comp_params.Kp,so3_comp_params.Ki, dt);
+
+					// Convert q->R.
+					Rot_matrix[0] = q0q0 + q1q1 - q2q2 - q3q3;// 11
+        				Rot_matrix[1] = 2.0 * (q1*q2 + q0*q3);	// 12
+        				Rot_matrix[2] = 2.0 * (q1*q3 - q0*q2);	// 13
+        				Rot_matrix[3] = 2.0 * (q1*q2 - q0*q3);	// 21
+        				Rot_matrix[4] = q0q0 - q1q1 + q2q2 - q3q3;// 22
+        				Rot_matrix[5] = 2.0 * (q2*q3 + q0*q1);	// 23
+        				Rot_matrix[6] = 2.0 * (q1*q3 + q0*q2);	// 31
+        				Rot_matrix[7] = 2.0 * (q2*q3 - q0*q1);	// 32
+        				Rot_matrix[8] = q0q0 - q1q1 - q2q2 + q3q3;// 33
+
+					//1-2-3 Representation.
+					//Equation (290) 
+					//Representing Attitude: Euler Angles, Unit Quaternions, and Rotation Vectors, James Diebel.
+					// Existing PX4 EKF code was generated by MATLAB which uses coloum major order matrix.
+					euler[0] = atan2f(Rot_matrix[5], Rot_matrix[8]);	//! Roll
+					euler[1] = -asinf(Rot_matrix[2]);	//! Pitch
+					euler[2] = atan2f(Rot_matrix[1],Rot_matrix[0]);		//! Yaw
+					
+					/* swap values for next iteration, check for fatal inputs */
+					if (isfinite(euler[0]) && isfinite(euler[1]) && isfinite(euler[2])) {
+						/* Do something */
+					} else {
+						/* due to inputs or numerical failure the output is invalid, skip it */
+						continue;
+					}
+
+					if (last_data > 0 && raw.timestamp - last_data > 12000) printf("[attitude estimator so3_comp] sensor data missed! (%llu)\n", raw.timestamp - last_data);
+
+					last_data = raw.timestamp;
+
+					/* send out */
+					att.timestamp = raw.timestamp;
+
+					// XXX Apply the same transformation to the rotation matrix
+					att.roll = euler[0] - so3_comp_params.roll_off;
+					att.pitch = euler[1] - so3_comp_params.pitch_off;
+					att.yaw = euler[2] - so3_comp_params.yaw_off;
+
+					//! Euler angle rate. But it needs to be investigated again.
+					/*
+					att.rollspeed = 2.0f*(-q1*dq0 + q0*dq1 - q3*dq2 + q2*dq3);
+					att.pitchspeed = 2.0f*(-q2*dq0 + q3*dq1 + q0*dq2 - q1*dq3);
+					att.yawspeed = 2.0f*(-q3*dq0 -q2*dq1 + q1*dq2 + q0*dq3);
+					*/
+					att.rollspeed = gyro[0];
+					att.pitchspeed = gyro[1];
+					att.yawspeed = gyro[2];
+
+					att.rollacc = 0;
+					att.pitchacc = 0;
+					att.yawacc = 0;
+
+					//! Quaternion
+					att.q[0] = q0;
+					att.q[1] = q1;
+					att.q[2] = q2;
+					att.q[3] = q3;
+					att.q_valid = true;
+
+					/* TODO: Bias estimation required */
+					memcpy(&att.rate_offsets, &(gyro_bias), sizeof(att.rate_offsets));
+
+					/* copy rotation matrix */
+					memcpy(&att.R, Rot_matrix, sizeof(Rot_matrix));
+					att.R_valid = true;
+
+					if (isfinite(att.roll) && isfinite(att.pitch) && isfinite(att.yaw)) {
+						// Broadcast
+						orb_publish(ORB_ID(vehicle_attitude), pub_att, &att);
+
+					} else {
+						warnx("NaN in roll/pitch/yaw estimate!");
+					}
+
+					perf_end(so3_comp_loop_perf);
+
+					//! This will print out debug packet to visualization software
+					if(debug_mode)
+					{
+						float quat[4];
+						quat[0] = q0;
+						quat[1] = q1;
+						quat[2] = q2;
+						quat[3] = q3;
+						send_uart_float_arr(quat,4);
+						send_uart_byte('\n');
+					}
+				}
+			}
+		}
+
+		loopcounter++;
+	}// while
+
+	thread_running = false;
+
+	/* Reset the UART flags to original state */
+        if (!usb_uart)
+                tcsetattr(uart, TCSANOW, &uart_config_original);
+
+	return 0;
+}
--- a/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.c
+++ b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.c
@ -0,0 +1,63 @@
+/*
+ * Author: Hyon Lim <limhyon@gmail.com, hyonlim@snu.ac.kr>
+ *
+ * @file attitude_estimator_so3_comp_params.c
+ *
+ * Implementation of nonlinear complementary filters on the SO(3).
+ * This code performs attitude estimation by using accelerometer, gyroscopes and magnetometer.
+ * Result is provided as quaternion, 1-2-3 Euler angle and rotation matrix.
+ * 
+ * Theory of nonlinear complementary filters on the SO(3) is based on [1].
+ * Quaternion realization of [1] is based on [2].
+ * Optmized quaternion update code is based on Sebastian Madgwick's implementation.
+ * 
+ * References
+ *  [1] Mahony, R.; Hamel, T.; Pflimlin, Jean-Michel, "Nonlinear Complementary Filters on the Special Orthogonal Group," Automatic Control, IEEE Transactions on , vol.53, no.5, pp.1203,1218, June 2008
+ *  [2] Euston, M.; Coote, P.; Mahony, R.; Jonghyuk Kim; Hamel, T., "A complementary filter for attitude estimation of a fixed-wing UAV," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.340,345, 22-26 Sept. 2008
+ */
+
+#include "attitude_estimator_so3_comp_params.h"
+
+/* This is filter gain for nonlinear SO3 complementary filter */
+/* NOTE : How to tune the gain? First of all, stick with this default gain. And let the quad in stable place.
+   Log the steady state reponse of filter. If it is too slow, increase SO3_COMP_KP.
+   If you are flying from ground to high altitude in short amount of time, please increase SO3_COMP_KI which
+   will compensate gyro bias which depends on temperature and vibration of your vehicle */
+PARAM_DEFINE_FLOAT(SO3_COMP_KP, 1.0f); //! This parameter will give you about 15 seconds convergence time.
+                                       //! You can set this gain higher if you want more fast response.
+                                       //! But note that higher gain will give you also higher overshoot.
+PARAM_DEFINE_FLOAT(SO3_COMP_KI, 0.05f); //! This gain will incorporate slow time-varying bias (e.g., temperature change)
+					//! This gain is depend on your vehicle status.
+
+/* offsets in roll, pitch and yaw of sensor plane and body */
+PARAM_DEFINE_FLOAT(ATT_ROLL_OFFS, 0.0f);
+PARAM_DEFINE_FLOAT(ATT_PITCH_OFFS, 0.0f);
+PARAM_DEFINE_FLOAT(ATT_YAW_OFFS, 0.0f);
+
+int parameters_init(struct attitude_estimator_so3_comp_param_handles *h)
+{
+	/* Filter gain parameters */
+	h->Kp = 	param_find("SO3_COMP_KP");
+	h->Ki = 	param_find("SO3_COMP_KI");
+
+	/* Attitude offset (WARNING: Do not change if you do not know what exactly this variable wil lchange) */
+	h->roll_off  =	param_find("ATT_ROLL_OFFS");
+	h->pitch_off =	param_find("ATT_PITCH_OFFS");
+	h->yaw_off   =	param_find("ATT_YAW_OFFS");
+
+	return OK;
+}
+
+int parameters_update(const struct attitude_estimator_so3_comp_param_handles *h, struct attitude_estimator_so3_comp_params *p)
+{
+	/* Update filter gain */
+	param_get(h->Kp, &(p->Kp));
+	param_get(h->Ki, &(p->Ki));
+
+	/* Update attitude offset */
+	param_get(h->roll_off, &(p->roll_off));
+	param_get(h->pitch_off, &(p->pitch_off));
+	param_get(h->yaw_off, &(p->yaw_off));
+
+	return OK;
+}
--- a/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.h
+++ b/src/modules/attitude_estimator_so3_comp/attitude_estimator_so3_comp_params.h
@ -0,0 +1,44 @@
+/*
+ * Author: Hyon Lim <limhyon@gmail.com, hyonlim@snu.ac.kr>
+ *
+ * @file attitude_estimator_so3_comp_params.h
+ *
+ * Implementation of nonlinear complementary filters on the SO(3).
+ * This code performs attitude estimation by using accelerometer, gyroscopes and magnetometer.
+ * Result is provided as quaternion, 1-2-3 Euler angle and rotation matrix.
+ * 
+ * Theory of nonlinear complementary filters on the SO(3) is based on [1].
+ * Quaternion realization of [1] is based on [2].
+ * Optmized quaternion update code is based on Sebastian Madgwick's implementation.
+ * 
+ * References
+ *  [1] Mahony, R.; Hamel, T.; Pflimlin, Jean-Michel, "Nonlinear Complementary Filters on the Special Orthogonal Group," Automatic Control, IEEE Transactions on , vol.53, no.5, pp.1203,1218, June 2008
+ *  [2] Euston, M.; Coote, P.; Mahony, R.; Jonghyuk Kim; Hamel, T., "A complementary filter for attitude estimation of a fixed-wing UAV," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.340,345, 22-26 Sept. 2008
+ */
+
+#include <systemlib/param/param.h>
+
+struct attitude_estimator_so3_comp_params {
+	float Kp;
+	float Ki;
+	float roll_off;
+	float pitch_off;
+	float yaw_off;
+};
+
+struct attitude_estimator_so3_comp_param_handles {
+	param_t Kp, Ki;
+	param_t roll_off, pitch_off, yaw_off;
+};
+
+/**
+ * Initialize all parameter handles and values
+ *
+ */
+int parameters_init(struct attitude_estimator_so3_comp_param_handles *h);
+
+/**
+ * Update all parameters
+ *
+ */
+int parameters_update(const struct attitude_estimator_so3_comp_param_handles *h, struct attitude_estimator_so3_comp_params *p);
--- a/src/modules/attitude_estimator_so3_comp/module.mk
+++ b/src/modules/attitude_estimator_so3_comp/module.mk
@ -0,0 +1,8 @@
+#
+# Attitude estimator (Nonlinear SO3 complementary Filter)
+#
+
+MODULE_COMMAND	 = attitude_estimator_so3_comp
+
+SRCS		 = attitude_estimator_so3_comp_main.cpp \
+		   attitude_estimator_so3_comp_params.c
--- a/src/modules/fixedwing_backside/fixedwing_backside_main.cpp
+++ b/src/modules/fixedwing_backside/fixedwing_backside_main.cpp
@ -47,6 +47,7 @@
 #include <systemlib/systemlib.h>
 #include <controllib/fixedwing.hpp>
 #include <systemlib/param/param.h>
+#include <systemlib/err.h>
 #include <drivers/drv_hrt.h>
 #include <math.h>

@ -80,7 +81,7 @@ usage(const char *reason)
 	if (reason)
 		fprintf(stderr, "%s\n", reason);

-	fprintf(stderr, "usage: control_demo {start|stop|status} [-p <additional params>]\n\n");
+	fprintf(stderr, "usage: fixedwing_backside {start|stop|status} [-p <additional params>]\n\n");
 	exit(1);
 }

@ -101,13 +102,13 @@ int fixedwing_backside_main(int argc, char *argv[])
 	if (!strcmp(argv[1], "start")) {

 		if (thread_running) {
-			printf("control_demo already running\n");
+			warnx("already running");
 			/* this is not an error */
 			exit(0);
 		}

 		thread_should_exit = false;
-		deamon_task = task_spawn("control_demo",
+		deamon_task = task_spawn("fixedwing_backside",
 					 SCHED_DEFAULT,
 					 SCHED_PRIORITY_MAX - 10,
 					 5120,
@ -128,10 +129,10 @@ int fixedwing_backside_main(int argc, char *argv[])

 	if (!strcmp(argv[1], "status")) {
 		if (thread_running) {
-			printf("\tcontrol_demo app is running\n");
+			warnx("is running");

 		} else {
-			printf("\tcontrol_demo app not started\n");
+			warnx("not started");
 		}

 		exit(0);
@ -144,7 +145,7 @@ int fixedwing_backside_main(int argc, char *argv[])
 int control_demo_thread_main(int argc, char *argv[])
 {

-	printf("[control_Demo] starting\n");
+	warnx("starting");

 	using namespace control;

@ -156,7 +157,7 @@ int control_demo_thread_main(int argc, char *argv[])
 		autopilot.update();
 	}

-	printf("[control_demo] exiting.\n");
+	warnx("exiting.");

 	thread_running = false;

@ -165,6 +166,6 @@ int control_demo_thread_main(int argc, char *argv[])

 void test()
 {
-	printf("beginning control lib test\n");
+	warnx("beginning control lib test");
 	control::basicBlocksTest();
 }
--- a/src/modules/gpio_led/gpio_led.c
+++ b/src/modules/gpio_led/gpio_led.c
@ -48,6 +48,7 @@
 #include <nuttx/wqueue.h>
 #include <nuttx/clock.h>
 #include <systemlib/systemlib.h>
+#include <systemlib/err.h>
 #include <uORB/uORB.h>
 #include <uORB/topics/vehicle_status.h>
 #include <poll.h>
@ -64,6 +65,7 @@ struct gpio_led_s {
 };

 static struct gpio_led_s gpio_led_data;
+static bool gpio_led_started = false;

 __EXPORT int gpio_led_main(int argc, char *argv[]);

@ -75,31 +77,54 @@ int gpio_led_main(int argc, char *argv[])
 {
 	int pin = GPIO_EXT_1;

-	if (argc > 1) {
-		if (!strcmp(argv[1], "-p")) {
-			if (!strcmp(argv[2], "1")) {
-				pin = GPIO_EXT_1;
+	if (argc < 2) {
+		errx(1, "no argument provided. Try 'start' or 'stop' [-p 1/2]");

-			} else if (!strcmp(argv[2], "2")) {
-				pin = GPIO_EXT_2;
+	} else {
+
+		/* START COMMAND HANDLING */
+		if (!strcmp(argv[1], "start")) {
+
+			if (argc > 2) {
+				if (!strcmp(argv[1], "-p")) {
+					if (!strcmp(argv[2], "1")) {
+						pin = GPIO_EXT_1;
+
+					} else if (!strcmp(argv[2], "2")) {
+						pin = GPIO_EXT_2;
+
+					} else {
+						warnx("[gpio_led] Unsupported pin: %s\n", argv[2]);
+						exit(1);
+					}
+				}
+			}
+
+			memset(&gpio_led_data, 0, sizeof(gpio_led_data));
+			gpio_led_data.pin = pin;
+			int ret = work_queue(LPWORK, &gpio_led_data.work, gpio_led_start, &gpio_led_data, 0);
+
+			if (ret != 0) {
+				warnx("[gpio_led] Failed to queue work: %d\n", ret);
+				exit(1);

 			} else {
-				printf("[gpio_led] Unsupported pin: %s\n", argv[2]);
-				exit(1);
+				gpio_led_started = true;
 			}
+
+			exit(0);
+
+			/* STOP COMMAND HANDLING */
+
+		} else if (!strcmp(argv[1], "stop")) {
+			gpio_led_started = false;
+
+			/* INVALID COMMAND */
+
+		} else {
+			errx(1, "unrecognized command '%s', only supporting 'start' or 'stop'", argv[1]);
 		}
 	}
-
-	memset(&gpio_led_data, 0, sizeof(gpio_led_data));
-	gpio_led_data.pin = pin;
-	int ret = work_queue(LPWORK, &gpio_led_data.work, gpio_led_start, &gpio_led_data, 0);
-
-	if (ret != 0) {
-		printf("[gpio_led] Failed to queue work: %d\n", ret);
-		exit(1);
-	}
-
-	exit(0);
 }

 void gpio_led_start(FAR void *arg)
@ -110,7 +135,7 @@ void gpio_led_start(FAR void *arg)
 	priv->gpio_fd = open(GPIO_DEVICE_PATH, 0);

 	if (priv->gpio_fd < 0) {
-		printf("[gpio_led] GPIO: open fail\n");
+		warnx("[gpio_led] GPIO: open fail\n");
 		return;
 	}

@ -125,11 +150,11 @@ void gpio_led_start(FAR void *arg)
 	int ret = work_queue(LPWORK, &priv->work, gpio_led_cycle, priv, 0);

 	if (ret != 0) {
-		printf("[gpio_led] Failed to queue work: %d\n", ret);
+		warnx("[gpio_led] Failed to queue work: %d\n", ret);
 		return;
 	}

-	printf("[gpio_led] Started, using pin GPIO_EXT%i\n", priv->pin);
+	warnx("[gpio_led] Started, using pin GPIO_EXT%i\n", priv->pin);
 }

 void gpio_led_cycle(FAR void *arg)
@ -187,5 +212,6 @@ void gpio_led_cycle(FAR void *arg)
 		priv->counter = 0;

 	/* repeat cycle at 5 Hz*/
-	work_queue(LPWORK, &priv->work, gpio_led_cycle, priv, USEC2TICK(200000));
+	if (gpio_led_started)
+		work_queue(LPWORK, &priv->work, gpio_led_cycle, priv, USEC2TICK(200000));
 }
--- a/src/modules/px4iofirmware/mixer.cpp
+++ b/src/modules/px4iofirmware/mixer.cpp
@ -85,6 +85,9 @@ static int	mixer_callback(uintptr_t handle,

 static MixerGroup mixer_group(mixer_callback, 0);

+/* Set the failsafe values of all mixed channels (based on zero throttle, controls centered) */
+static void mixer_set_failsafe();
+
 void
 mixer_tick(void)
 {
@ -102,13 +105,16 @@ mixer_tick(void)
 		r_status_flags |= PX4IO_P_STATUS_FLAGS_FMU_OK;
 	}

+	/* default to failsafe mixing */
 	source = MIX_FAILSAFE;

 	/*
 	 * Decide which set of controls we're using.
 	 */
-	if ((r_status_flags & PX4IO_P_STATUS_FLAGS_RAW_PWM) ||
-		!(r_status_flags & PX4IO_P_STATUS_FLAGS_MIXER_OK)) {
+
+	/* do not mix if mixer is invalid or if RAW_PWM mode is on and FMU is good */
+	if ((r_status_flags & PX4IO_P_STATUS_FLAGS_RAW_PWM) &&
+	        !(r_status_flags & PX4IO_P_STATUS_FLAGS_MIXER_OK)) {

 		/* don't actually mix anything - we already have raw PWM values or
 		 not a valid mixer. */
@ -117,6 +123,7 @@ mixer_tick(void)
 	} else {

 		if (!(r_status_flags & PX4IO_P_STATUS_FLAGS_OVERRIDE) &&
+		     (r_status_flags & PX4IO_P_STATUS_FLAGS_FMU_OK) &&
 		     (r_status_flags & PX4IO_P_STATUS_FLAGS_MIXER_OK)) {

 			/* mix from FMU controls */
@ -132,15 +139,29 @@ mixer_tick(void)
 		}
 	}

+	/*
+	 * Set failsafe status flag depending on mixing source
+	 */
+	if (source == MIX_FAILSAFE) {
+		r_status_flags |= PX4IO_P_STATUS_FLAGS_FAILSAFE;
+	} else {
+		r_status_flags &= ~(PX4IO_P_STATUS_FLAGS_FAILSAFE);
+	}
+
 	/*
 	 * Run the mixers.
 	 */
 	if (source == MIX_FAILSAFE) {

 		/* copy failsafe values to the servo outputs */
-		for (unsigned i = 0; i < IO_SERVO_COUNT; i++)
+		for (unsigned i = 0; i < IO_SERVO_COUNT; i++) {
 			r_page_servos[i] = r_page_servo_failsafe[i];

+			/* safe actuators for FMU feedback */
+			r_page_actuators[i] = (r_page_servos[i] - 1500) / 600.0f;
+		}
+
+
 	} else if (source != MIX_NONE) {

 		float	outputs[IO_SERVO_COUNT];
@ -156,7 +177,7 @@ mixer_tick(void)
 			r_page_actuators[i] = FLOAT_TO_REG(outputs[i]);

 			/* scale to servo output */
-			r_page_servos[i] = (outputs[i] * 500.0f) + 1500;
+			r_page_servos[i] = (outputs[i] * 600.0f) + 1500;

 		}
 		for (unsigned i = mixed; i < IO_SERVO_COUNT; i++)
@ -175,7 +196,7 @@ mixer_tick(void)
 	bool should_arm = (
 	    /* FMU is armed */ (r_setup_arming & PX4IO_P_SETUP_ARMING_FMU_ARMED) &&
 	 	/* IO is armed */  (r_status_flags & PX4IO_P_STATUS_FLAGS_ARMED) &&
-		/* there is valid input */ (r_status_flags & (PX4IO_P_STATUS_FLAGS_RAW_PWM | PX4IO_P_STATUS_FLAGS_MIXER_OK)) &&
+		/* there is valid input via direct PWM or mixer */ (r_status_flags & (PX4IO_P_STATUS_FLAGS_RAW_PWM | PX4IO_P_STATUS_FLAGS_MIXER_OK)) &&
 		/* IO initialised without error */  (r_status_flags & PX4IO_P_STATUS_FLAGS_INIT_OK) &&
 		/* FMU is available or FMU is not available but override is an option */
 		((r_status_flags & PX4IO_P_STATUS_FLAGS_FMU_OK) || (!(r_status_flags & PX4IO_P_STATUS_FLAGS_FMU_OK) && (r_setup_arming & PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK) ))
@ -225,7 +246,7 @@ mixer_callback(uintptr_t handle,

 	case MIX_FAILSAFE:
 	case MIX_NONE:
-		/* XXX we could allow for configuration of per-output failsafe values */
+		control = 0.0f;
 		return -1;
 	}

@ -273,8 +294,7 @@ mixer_handle_text(const void *buffer, size_t length)
 	case F2I_MIXER_ACTION_APPEND:
 		isr_debug(2, "append %d", length);

-		/* check for overflow - this is really fatal */
-		/* XXX could add just what will fit & try to parse, then repeat... */
+		/* check for overflow - this would be really fatal */
 		if ((mixer_text_length + text_length + 1) > sizeof(mixer_text)) {
 			r_status_flags &= ~PX4IO_P_STATUS_FLAGS_MIXER_OK;
 			return;
@ -293,8 +313,13 @@ mixer_handle_text(const void *buffer, size_t length)
 		/* if anything was parsed */
 		if (resid != mixer_text_length) {

-			/* ideally, this should test resid == 0 ? */
-			r_status_flags |= PX4IO_P_STATUS_FLAGS_MIXER_OK;
+			/* only set mixer ok if no residual is left over */
+			if (resid == 0) {
+				r_status_flags |= PX4IO_P_STATUS_FLAGS_MIXER_OK;
+			} else {
+				/* not yet reached the end of the mixer, set as not ok */
+				r_status_flags &= ~PX4IO_P_STATUS_FLAGS_MIXER_OK;
+			}

 			isr_debug(2, "used %u", mixer_text_length - resid);

@ -303,8 +328,43 @@ mixer_handle_text(const void *buffer, size_t length)
 				memcpy(&mixer_text[0], &mixer_text[mixer_text_length - resid], resid);

 			mixer_text_length = resid;
+
+			/* update failsafe values */
+			mixer_set_failsafe();
 		}

 		break;
 	}
 }
+
+static void
+mixer_set_failsafe()
+{
+	/* 
+	 * Check if a custom failsafe value has been written,
+	 * or if the mixer is not ok and bail out.
+	 */
+	if ((r_setup_arming & PX4IO_P_SETUP_ARMING_FAILSAFE_CUSTOM) ||
+		!(r_status_flags & PX4IO_P_STATUS_FLAGS_MIXER_OK))
+		return;
+
+	/* set failsafe defaults to the values for all inputs = 0 */
+	float	outputs[IO_SERVO_COUNT];
+	unsigned mixed;
+
+	/* mix */
+	mixed = mixer_group.mix(&outputs[0], IO_SERVO_COUNT);
+
+	/* scale to PWM and update the servo outputs as required */
+	for (unsigned i = 0; i < mixed; i++) {
+
+		/* scale to servo output */
+		r_page_servo_failsafe[i] = (outputs[i] * 600.0f) + 1500;
+
+	}
+
+	/* disable the rest of the outputs */
+	for (unsigned i = mixed; i < IO_SERVO_COUNT; i++)
+		r_page_servo_failsafe[i] = 0;
+
+}
--- a/src/modules/px4iofirmware/protocol.h
+++ b/src/modules/px4iofirmware/protocol.h
@ -85,7 +85,7 @@
 #define PX4IO_P_CONFIG_ACTUATOR_COUNT		5	/* hardcoded max actuator output count */
 #define PX4IO_P_CONFIG_RC_INPUT_COUNT		6	/* hardcoded max R/C input count supported */
 #define PX4IO_P_CONFIG_ADC_INPUT_COUNT		7	/* hardcoded max ADC inputs */
-#define PX4IO_P_CONFIG_RELAY_COUNT		8	/* harcoded # of relay outputs */
+#define PX4IO_P_CONFIG_RELAY_COUNT		8	/* hardcoded # of relay outputs */

 /* dynamic status page */
 #define PX4IO_PAGE_STATUS		1
@ -104,6 +104,7 @@
 #define PX4IO_P_STATUS_FLAGS_MIXER_OK		(1 << 8) /* mixer is OK */
 #define PX4IO_P_STATUS_FLAGS_ARM_SYNC		(1 << 9) /* the arming state between IO and FMU is in sync */
 #define PX4IO_P_STATUS_FLAGS_INIT_OK		(1 << 10) /* initialisation of the IO completed without error */
+#define PX4IO_P_STATUS_FLAGS_FAILSAFE		(1 << 11) /* failsafe is active */

 #define PX4IO_P_STATUS_ALARMS			3	 /* alarm flags - alarms latch, write 1 to a bit to clear it */
 #define PX4IO_P_STATUS_ALARMS_VBATT_LOW		(1 << 0) /* VBatt is very close to regulator dropout */
@ -148,6 +149,7 @@
 #define PX4IO_P_SETUP_ARMING_IO_ARM_OK		(1 << 0) /* OK to arm the IO side */
 #define PX4IO_P_SETUP_ARMING_FMU_ARMED		(1 << 1) /* FMU is already armed */
 #define PX4IO_P_SETUP_ARMING_MANUAL_OVERRIDE_OK	(1 << 2) /* OK to switch to manual override via override RC channel */
+#define PX4IO_P_SETUP_ARMING_FAILSAFE_CUSTOM	(1 << 3) /* use custom failsafe values, not 0 values of mixer */
 #define PX4IO_P_SETUP_ARMING_INAIR_RESTART_OK	(1 << 4) /* OK to try in-air restart */

 #define PX4IO_P_SETUP_PWM_RATES			2	/* bitmask, 0 = low rate, 1 = high rate */
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@ -41,6 +41,7 @@

 #include <stdbool.h>
 #include <stdlib.h>
+#include <string.h>

 #include <drivers/drv_hrt.h>

@ -178,8 +179,10 @@ uint16_t		r_page_rc_input_config[MAX_CONTROL_CHANNELS * PX4IO_P_RC_CONFIG_STRIDE
 * PAGE 105
 *
 * Failsafe servo PWM values
+ * 
+ * Disable pulses as default.
 */
-uint16_t		r_page_servo_failsafe[IO_SERVO_COUNT];
+uint16_t		r_page_servo_failsafe[IO_SERVO_COUNT] = { 0 };

 void
 registers_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num_values)
@ -230,11 +233,14 @@ registers_set(uint8_t page, uint8_t offset, const uint16_t *values, unsigned num
 	case PX4IO_PAGE_FAILSAFE_PWM:

 		/* copy channel data */
-		while ((offset < PX4IO_CONTROL_CHANNELS) && (num_values > 0)) {
+		while ((offset < IO_SERVO_COUNT) && (num_values > 0)) {

 			/* XXX range-check value? */
 			r_page_servo_failsafe[offset] = *values;

+			/* flag the failsafe values as custom */
+			r_setup_arming |= PX4IO_P_SETUP_ARMING_FAILSAFE_CUSTOM;
+
 			offset++;
 			num_values--;
 			values++;
--- a/src/modules/sdlog2/logbuffer.c
+++ b/src/modules/sdlog2/logbuffer.c
@ -0,0 +1,134 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Anton Babushkin <rk3dov@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file logbuffer.c
+ *
+ * Ring FIFO buffer for binary log data.
+ *
+ * @author Anton Babushkin <rk3dov@gmail.com>
+ */
+
+#include <string.h>
+#include <stdlib.h>
+
+#include "logbuffer.h"
+
+int logbuffer_init(struct logbuffer_s *lb, int size)
+{
+	lb->size  = size;
+	lb->write_ptr = 0;
+	lb->read_ptr = 0;
+	lb->data = malloc(lb->size);
+	return (lb->data == 0) ? ERROR : OK;
+}
+
+int logbuffer_count(struct logbuffer_s *lb)
+{
+	int n = lb->write_ptr - lb->read_ptr;
+
+	if (n < 0) {
+		n += lb->size;
+	}
+
+	return n;
+}
+
+int logbuffer_is_empty(struct logbuffer_s *lb)
+{
+	return lb->read_ptr == lb->write_ptr;
+}
+
+bool logbuffer_write(struct logbuffer_s *lb, void *ptr, int size)
+{
+	// bytes available to write
+	int available = lb->read_ptr - lb->write_ptr - 1;
+
+	if (available < 0)
+		available += lb->size;
+
+	if (size > available) {
+		// buffer overflow
+		return false;
+	}
+
+	char *c = (char *) ptr;
+	int n = lb->size - lb->write_ptr;	// bytes to end of the buffer
+
+	if (n < size) {
+		// message goes over end of the buffer
+		memcpy(&(lb->data[lb->write_ptr]), c, n);
+		lb->write_ptr = 0;
+
+	} else {
+		n = 0;
+	}
+
+	// now: n = bytes already written
+	int p = size - n;	// number of bytes to write
+	memcpy(&(lb->data[lb->write_ptr]), &(c[n]), p);
+	lb->write_ptr = (lb->write_ptr + p) % lb->size;
+	return true;
+}
+
+int logbuffer_get_ptr(struct logbuffer_s *lb, void **ptr, bool *is_part)
+{
+	// bytes available to read
+	int available = lb->write_ptr - lb->read_ptr;
+
+	if (available == 0) {
+		return 0;	// buffer is empty
+	}
+
+	int n = 0;
+
+	if (available > 0) {
+		// read pointer is before write pointer, all available bytes can be read
+		n = available;
+		*is_part = false;
+
+	} else {
+		// read pointer is after write pointer, read bytes from read_ptr to end of the buffer
+		n = lb->size - lb->read_ptr;
+		*is_part = true;
+	}
+
+	*ptr = &(lb->data[lb->read_ptr]);
+	return n;
+}
+
+void logbuffer_mark_read(struct logbuffer_s *lb, int n)
+{
+	lb->read_ptr = (lb->read_ptr + n) % lb->size;
+}
--- a/src/modules/sdlog2/logbuffer.h
+++ b/src/modules/sdlog2/logbuffer.h
@ -0,0 +1,68 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Anton Babushkin <rk3dov@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file logbuffer.h
+ *
+ * Ring FIFO buffer for binary log data.
+ *
+ * @author Anton Babushkin <rk3dov@gmail.com>
+ */
+
+#ifndef SDLOG2_RINGBUFFER_H_
+#define SDLOG2_RINGBUFFER_H_
+
+#include <stdbool.h>
+
+struct logbuffer_s {
+	// pointers and size are in bytes
+	int write_ptr;
+	int read_ptr;
+	int size;
+	char *data;
+};
+
+int logbuffer_init(struct logbuffer_s *lb, int size);
+
+int logbuffer_count(struct logbuffer_s *lb);
+
+int logbuffer_is_empty(struct logbuffer_s *lb);
+
+bool logbuffer_write(struct logbuffer_s *lb, void *ptr, int size);
+
+int logbuffer_get_ptr(struct logbuffer_s *lb, void **ptr, bool *is_part);
+
+void logbuffer_mark_read(struct logbuffer_s *lb, int n);
+
+#endif
--- a/src/modules/sdlog2/module.mk
+++ b/src/modules/sdlog2/module.mk
@ -0,0 +1,43 @@
+############################################################################
+#
+#   Copyright (c) 2013 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+#
+# sdlog2 Application
+#
+
+MODULE_COMMAND  = sdlog2
+# The main thread only buffers to RAM, needs a high priority
+MODULE_PRIORITY = "SCHED_PRIORITY_MAX-30"
+
+SRCS = sdlog2.c \
+       logbuffer.c
--- a/src/modules/sdlog2/sdlog2.c
+++ b/src/modules/sdlog2/sdlog2.c
--- a/src/modules/sdlog2/sdlog2_format.h
+++ b/src/modules/sdlog2/sdlog2_format.h
@ -0,0 +1,98 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Anton Babushkin <rk3dov@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file sdlog2_format.h
+ *
+ * General log format structures and macro.
+ *
+ * @author Anton Babushkin <rk3dov@gmail.com>
+ */
+
+/*
+Format characters in the format string for binary log messages
+  b   : int8_t
+  B   : uint8_t
+  h   : int16_t
+  H   : uint16_t
+  i   : int32_t
+  I   : uint32_t
+  f   : float
+  n   : char[4]
+  N   : char[16]
+  Z   : char[64]
+  c   : int16_t * 100
+  C   : uint16_t * 100
+  e   : int32_t * 100
+  E   : uint32_t * 100
+  L   : int32_t latitude/longitude
+  M   : uint8_t flight mode
+
+  q   : int64_t
+  Q   : uint64_t
+ */
+
+#ifndef SDLOG2_FORMAT_H_
+#define SDLOG2_FORMAT_H_
+
+#define LOG_PACKET_HEADER_LEN	   3
+#define LOG_PACKET_HEADER	       uint8_t head1, head2, msg_type;
+#define LOG_PACKET_HEADER_INIT(id) .head1 = HEAD_BYTE1, .head2 = HEAD_BYTE2, .msg_type = id
+
+// once the logging code is all converted we will remove these from
+// this header
+#define HEAD_BYTE1  0xA3    // Decimal 163
+#define HEAD_BYTE2  0x95    // Decimal 149
+
+struct log_format_s {
+	uint8_t type;
+	uint8_t length;		// full packet length including header
+	char name[4];
+	char format[16];
+	char labels[64];
+};
+
+#define LOG_FORMAT(_name, _format, _labels) { \
+		.type = LOG_##_name##_MSG, \
+		.length = sizeof(struct log_##_name##_s) + LOG_PACKET_HEADER_LEN, \
+		.name = #_name, \
+		.format = _format, \
+		.labels = _labels \
+	}
+
+#define LOG_FORMAT_MSG	  0x80
+
+#define LOG_PACKET_SIZE(_name)	LOG_PACKET_HEADER_LEN + sizeof(struct log_##_name##_s)
+
+#endif /* SDLOG2_FORMAT_H_ */
--- a/src/modules/sdlog2/sdlog2_messages.h
+++ b/src/modules/sdlog2/sdlog2_messages.h
@ -0,0 +1,191 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Anton Babushkin <rk3dov@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file sdlog2_messages.h
+ *
+ * Log messages and structures definition.
+ *
+ * @author Anton Babushkin <rk3dov@gmail.com>
+ */
+
+#ifndef SDLOG2_MESSAGES_H_
+#define SDLOG2_MESSAGES_H_
+
+#include "sdlog2_format.h"
+
+/* define message formats */
+
+#pragma pack(push, 1)
+/* --- TIME - TIME STAMP --- */
+#define LOG_TIME_MSG 1
+struct log_TIME_s {
+	uint64_t t;
+};
+
+/* --- ATT - ATTITUDE --- */
+#define LOG_ATT_MSG 2
+struct log_ATT_s {
+	float roll;
+	float pitch;
+	float yaw;
+};
+
+/* --- ATSP - ATTITUDE SET POINT --- */
+#define LOG_ATSP_MSG 3
+struct log_ATSP_s {
+	float roll_sp;
+	float pitch_sp;
+	float yaw_sp;
+};
+
+/* --- IMU - IMU SENSORS --- */
+#define LOG_IMU_MSG 4
+struct log_IMU_s {
+	float acc_x;
+	float acc_y;
+	float acc_z;
+	float gyro_x;
+	float gyro_y;
+	float gyro_z;
+	float mag_x;
+	float mag_y;
+	float mag_z;
+};
+
+/* --- SENS - OTHER SENSORS --- */
+#define LOG_SENS_MSG 5
+struct log_SENS_s {
+	float baro_pres;
+	float baro_alt;
+	float baro_temp;
+	float diff_pres;
+};
+
+/* --- LPOS - LOCAL POSITION --- */
+#define LOG_LPOS_MSG 6
+struct log_LPOS_s {
+	float x;
+	float y;
+	float z;
+	float vx;
+	float vy;
+	float vz;
+	float hdg;
+	int32_t home_lat;
+	int32_t home_lon;
+	float home_alt;
+};
+
+/* --- LPSP - LOCAL POSITION SETPOINT --- */
+#define LOG_LPSP_MSG 7
+struct log_LPSP_s {
+	float x;
+	float y;
+	float z;
+	float yaw;
+};
+
+/* --- GPS - GPS POSITION --- */
+#define LOG_GPS_MSG 8
+struct log_GPS_s {
+	uint64_t gps_time;
+	uint8_t fix_type;
+	float eph;
+	float epv;
+	int32_t lat;
+	int32_t lon;
+	float alt;
+	float vel_n;
+	float vel_e;
+	float vel_d;
+	float cog;
+};
+
+/* --- ATTC - ATTITUDE CONTROLS (ACTUATOR_0 CONTROLS)--- */
+#define LOG_ATTC_MSG 9
+struct log_ATTC_s {
+	float roll;
+	float pitch;
+	float yaw;
+	float thrust;
+};
+
+/* --- STAT - VEHICLE STATE --- */
+#define LOG_STAT_MSG 10
+struct log_STAT_s {
+	unsigned char state;
+	unsigned char flight_mode;
+	unsigned char manual_control_mode;
+	unsigned char manual_sas_mode;
+	unsigned char armed;
+	float battery_voltage;
+	float battery_current;
+	float battery_remaining;
+	unsigned char battery_warning;
+};
+
+/* --- RC - RC INPUT CHANNELS --- */
+#define LOG_RC_MSG 11
+struct log_RC_s {
+	float channel[8];
+};
+
+/* --- OUT0 - ACTUATOR_0 OUTPUT --- */
+#define LOG_OUT0_MSG 12
+struct log_OUT0_s {
+	float output[8];
+};
+#pragma pack(pop)
+
+/* construct list of all message formats */
+
+static const struct log_format_s log_formats[] = {
+	LOG_FORMAT(TIME, "Q", "StartTime"),
+	LOG_FORMAT(ATT, "fff", "Roll,Pitch,Yaw"),
+	LOG_FORMAT(ATSP, "fff", "RollSP,PitchSP,YawSP"),
+	LOG_FORMAT(IMU, "fffffffff", "AccX,AccY,AccZ,GyroX,GyroY,GyroZ,MagX,MagY,MagZ"),
+	LOG_FORMAT(SENS, "ffff", "BaroPres,BaroAlt,BaroTemp,DiffPres"),
+	LOG_FORMAT(LPOS, "fffffffLLf", "X,Y,Z,VX,VY,VZ,Heading,HomeLat,HomeLon,HomeAlt"),
+	LOG_FORMAT(LPSP, "ffff", "X,Y,Z,Yaw"),
+	LOG_FORMAT(GPS, "QBffLLfffff", "GPSTime,FixType,EPH,EPV,Lat,Lon,Alt,VelN,VelE,VelD,Cog"),
+	LOG_FORMAT(ATTC, "ffff", "Roll,Pitch,Yaw,Thrust"),
+	LOG_FORMAT(STAT, "BBBBBfffB", "State,FlightMode,CtlMode,SASMode,Armed,BatV,BatC,BatRem,BatWarn"),
+	LOG_FORMAT(RC, "ffffffff", "Ch0,Ch1,Ch2,Ch3,Ch4,Ch5,Ch6,Ch7"),
+	LOG_FORMAT(OUT0, "ffffffff", "Out0,Out1,Out2,Out3,Out4,Out5,Out6,Out7"),
+};
+
+static const int log_formats_num = sizeof(log_formats) / sizeof(struct log_format_s);
+
+#endif /* SDLOG2_MESSAGES_H_ */
--- a/src/modules/systemlib/geo/geo.c
+++ b/src/modules/systemlib/geo/geo.c
@ -185,12 +185,11 @@ __EXPORT float get_distance_to_next_waypoint(double lat_now, double lon_now, dou
 	double d_lat = lat_next_rad - lat_now_rad;
 	double d_lon = lon_next_rad - lon_now_rad;

-	double a = sin(d_lat / 2.0d) * sin(d_lat / 2.0) + sin(d_lon / 2.0d) * sin(d_lon / 2.0d) * cos(lat_now_rad) * cos(lat_next_rad);
+	double a = sin(d_lat / 2.0d) * sin(d_lat / 2.0d) + sin(d_lon / 2.0d) * sin(d_lon / 2.0d) * cos(lat_now_rad) * cos(lat_next_rad);
 	double c = 2.0d * atan2(sqrt(a), sqrt(1.0d - a));

 	const double radius_earth = 6371000.0d;
-
-	return radius_earth * c;
+	return radius_earth * c; 
 }

 __EXPORT float get_bearing_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next)
--- a/src/modules/systemlib/geo/geo.h
+++ b/src/modules/systemlib/geo/geo.h
@ -82,8 +82,24 @@ __EXPORT void map_projection_project(double lat, double lon, float *x, float *y)
 */
 __EXPORT void map_projection_reproject(float x, float y, double *lat, double *lon);

+/**
+ * Returns the distance to the next waypoint in meters.
+ *
+ * @param lat_now current position in degrees (47.1234567°, not 471234567°)
+ * @param lon_now current position in degrees (8.1234567°, not 81234567°)
+ * @param lat_next next waypoint position in degrees (47.1234567°, not 471234567°)
+ * @param lon_next next waypoint position in degrees (8.1234567°, not 81234567°)
+ */
 __EXPORT float get_distance_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);

+/**
+ * Returns the bearing to the next waypoint in radians.
+ *
+ * @param lat_now current position in degrees (47.1234567°, not 471234567°)
+ * @param lon_now current position in degrees (8.1234567°, not 81234567°)
+ * @param lat_next next waypoint position in degrees (47.1234567°, not 471234567°)
+ * @param lon_next next waypoint position in degrees (8.1234567°, not 81234567°)
+ */
 __EXPORT float get_bearing_to_next_waypoint(double lat_now, double lon_now, double lat_next, double lon_next);

 __EXPORT int get_distance_to_line(struct crosstrack_error_s * crosstrack_error, double lat_now, double lon_now, double lat_start, double lon_start, double lat_end, double lon_end);
--- a/src/systemcmds/mixer/mixer.c
+++ b/src/systemcmds/mixer/mixer.c
@ -88,8 +88,8 @@ load(const char *devname, const char *fname)
 {
 	int		dev;
 	FILE		*fp;
-	char		line[80];
-	char		buf[512];
+	char		line[120];
+	char		buf[2048];

 	/* open the device */
 	if ((dev = open(devname, 0)) < 0)
--- a/src/systemcmds/pwm/pwm.c
+++ b/src/systemcmds/pwm/pwm.c
@ -185,12 +185,18 @@ pwm_main(int argc, char *argv[])
 		const char *arg = argv[0];
 		argv++;
 		if (!strcmp(arg, "arm")) {
+			/* tell IO that its ok to disable its safety with the switch */
+			ret = ioctl(fd, PWM_SERVO_SET_ARM_OK, 0);
+			if (ret != OK)
+				err(1, "PWM_SERVO_SET_ARM_OK");
+			/* tell IO that the system is armed (it will output values if safety is off) */
 			ret = ioctl(fd, PWM_SERVO_ARM, 0);
 			if (ret != OK)
 				err(1, "PWM_SERVO_ARM");
 			continue;
 		}
 		if (!strcmp(arg, "disarm")) {
+			/* disarm, but do not revoke the SET_ARM_OK flag */
 			ret = ioctl(fd, PWM_SERVO_DISARM, 0);
 			if (ret != OK)
 				err(1, "PWM_SERVO_DISARM");