ardupilot/APMrover2/APMrover2.pde

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-

#define THISFIRMWARE "ArduRover v2.42beta2"

/* 
This is the APMrover2 firmware. It was originally derived from
ArduPlane by Jean-Louis Naudin (JLN), and then rewritten after the
AP_HAL merge by Andrew Tridgell

Maintainer: Andrew Tridgell

Authors:    Doug Weibel, Jose Julio, Jordi Munoz, Jason Short, Andrew Tridgell, Randy Mackay, Pat Hickey, John Arne Birkeland, Olivier Adler, Jean-Louis Naudin
Thanks to:  Chris Anderson, Michael Oborne, Paul Mather, Bill Premerlani, James Cohen, JB from rotorFX, Automatik, Fefenin, Peter Meister, Remzibi, Yury Smirnov, Sandro Benigno, Max Levine, Roberto Navoni, Lorenz Meier 
Please contribute your ideas!
APMrover alpha version tester: Franco Borasio, Daniel Chapelat... 

This firmware is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

// Radio setup:
// APM INPUT (Rec = receiver)
// Rec ch1: Steering
// Rec ch2: not used
// Rec ch3: Throttle
// Rec ch4: not used
// Rec ch5: not used
// Rec ch6: not used
// Rec ch7: Option channel to 2 position switch
// Rec ch8: Mode channel to 6 position switch
// APM OUTPUT
// Ch1: Wheel servo (direction)
// Ch2: not used
// Ch3: to the motor ESC
// Ch4: not used
//
*/

////////////////////////////////////////////////////////////////////////////////
// Header includes
////////////////////////////////////////////////////////////////////////////////

#include <math.h>
#include <stdarg.h>
#include <stdio.h>

// Libraries
#include <AP_Common.h>
#include <AP_Progmem.h>
#include <AP_HAL.h>
#include <AP_Menu.h>
#include <AP_Param.h>
#include <AP_GPS.h>         // ArduPilot GPS library
#include <AP_ADC.h>         // ArduPilot Mega Analog to Digital Converter Library
#include <AP_ADC_AnalogSource.h>
#include <AP_Baro.h>
#include <AP_Compass.h>     // ArduPilot Mega Magnetometer Library
#include <AP_Math.h>        // ArduPilot Mega Vector/Matrix math Library
#include <AP_InertialSensor.h> // Inertial Sensor (uncalibated IMU) Library
#include <AP_AHRS.h>         // ArduPilot Mega DCM Library
#include <PID.h>            // PID library
#include <RC_Channel.h>     // RC Channel Library
#include <AP_RangeFinder.h>	// Range finder library
#include <Filter.h>			// Filter library
#include <Butter.h>			// Filter library - butterworth filter
#include <AP_Buffer.h>      // FIFO buffer library
#include <ModeFilter.h>		// Mode Filter from Filter library
#include <AverageFilter.h>	// Mode Filter from Filter library
#include <AP_Relay.h>       // APM relay
#include <AP_Mount.h>		// Camera/Antenna mount
#include <GCS_MAVLink.h>    // MAVLink GCS definitions
#include <AP_Airspeed.h>    // needed for AHRS build
#include <memcheck.h>
#include <DataFlash.h>
#include <AP_RCMapper.h>        // RC input mapping library
#include <SITL.h>
#include <stdarg.h>

#include <AP_HAL_AVR.h>
#include <AP_HAL_AVR_SITL.h>
#include <AP_HAL_PX4.h>
#include <AP_HAL_Empty.h>
#include "compat.h"

// Configuration
#include "config.h"

// Local modules
#include "defines.h"
#include "Parameters.h"
#include "GCS.h"

#include <AP_Declination.h> // ArduPilot Mega Declination Helper Library

AP_HAL::BetterStream* cliSerial;

const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;

// this sets up the parameter table, and sets the default values. This
// must be the first AP_Param variable declared to ensure its
// constructor runs before the constructors of the other AP_Param
// variables
AP_Param param_loader(var_info, WP_START_BYTE);

////////////////////////////////////////////////////////////////////////////////
// the rate we run the main loop at
////////////////////////////////////////////////////////////////////////////////
static const AP_InertialSensor::Sample_rate ins_sample_rate = AP_InertialSensor::RATE_50HZ;

////////////////////////////////////////////////////////////////////////////////
// Parameters
////////////////////////////////////////////////////////////////////////////////
//
// Global parameters are all contained within the 'g' class.
//
static Parameters      g;

// mapping between input channels
static RCMapper rcmap;

// primary control channels
static RC_Channel *channel_steer;
static RC_Channel *channel_throttle;

////////////////////////////////////////////////////////////////////////////////
// prototypes
static void update_events(void);
void gcs_send_text_fmt(const prog_char_t *fmt, ...);
static void print_mode(AP_HAL::BetterStream *port, uint8_t mode);

////////////////////////////////////////////////////////////////////////////////
// DataFlash
////////////////////////////////////////////////////////////////////////////////
#if CONFIG_HAL_BOARD == HAL_BOARD_APM1
static DataFlash_APM1 DataFlash;
#elif CONFIG_HAL_BOARD == HAL_BOARD_APM2
static DataFlash_APM2 DataFlash;
#elif CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL
//static DataFlash_File DataFlash("/tmp/APMlogs");
static DataFlash_SITL DataFlash;
#elif CONFIG_HAL_BOARD == HAL_BOARD_PX4
static DataFlash_File DataFlash("/fs/microsd/APM/logs");
#else
DataFlash_Empty DataFlash;
#endif


////////////////////////////////////////////////////////////////////////////////
// Sensors
////////////////////////////////////////////////////////////////////////////////
//
// There are three basic options related to flight sensor selection.
//
// - Normal driving mode.  Real sensors are used.
// - HIL Attitude mode.  Most sensors are disabled, as the HIL
//   protocol supplies attitude information directly.
// - HIL Sensors mode.  Synthetic sensors are configured that
//   supply data from the simulation.
//

// All GPS access should be through this pointer.
static GPS         *g_gps;

// flight modes convenience array
static AP_Int8		*modes = &g.mode1;

#if CONFIG_ADC == ENABLED
static AP_ADC_ADS7844 adc;
#endif

#if CONFIG_COMPASS == AP_COMPASS_PX4
static AP_Compass_PX4 compass;
#elif CONFIG_COMPASS == AP_COMPASS_HMC5843
static AP_Compass_HMC5843 compass;
#elif CONFIG_COMPASS == AP_COMPASS_HIL
static AP_Compass_HIL compass;
#else
 #error Unrecognized CONFIG_COMPASS setting
#endif

// GPS selection
#if   GPS_PROTOCOL == GPS_PROTOCOL_AUTO
AP_GPS_Auto     g_gps_driver(&g_gps);

#elif GPS_PROTOCOL == GPS_PROTOCOL_NMEA
AP_GPS_NMEA     g_gps_driver;

#elif GPS_PROTOCOL == GPS_PROTOCOL_SIRF
AP_GPS_SIRF     g_gps_driver;

#elif GPS_PROTOCOL == GPS_PROTOCOL_UBLOX
AP_GPS_UBLOX    g_gps_driver;

#elif GPS_PROTOCOL == GPS_PROTOCOL_MTK
AP_GPS_MTK      g_gps_driver;

#elif GPS_PROTOCOL == GPS_PROTOCOL_MTK19
AP_GPS_MTK19    g_gps_driver;

#elif GPS_PROTOCOL == GPS_PROTOCOL_NONE
AP_GPS_None     g_gps_driver;

#elif GPS_PROTOCOL == GPS_PROTOCOL_HIL
AP_GPS_HIL      g_gps_driver;

#else
  #error Unrecognised GPS_PROTOCOL setting.
#endif // GPS PROTOCOL

#if CONFIG_INS_TYPE == CONFIG_INS_MPU6000
AP_InertialSensor_MPU6000 ins;
#elif CONFIG_INS_TYPE == CONFIG_INS_PX4
AP_InertialSensor_PX4 ins;
#elif CONFIG_INS_TYPE == CONFIG_INS_STUB
AP_InertialSensor_Stub ins;
#elif CONFIG_INS_TYPE == CONFIG_INS_OILPAN
AP_InertialSensor_Oilpan ins( &adc );
#else
  #error Unrecognised CONFIG_INS_TYPE setting.
#endif // CONFIG_INS_TYPE

#if HIL_MODE == HIL_MODE_ATTITUDE
AP_AHRS_HIL ahrs(&ins, g_gps);
#else
AP_AHRS_DCM ahrs(&ins, g_gps);
#endif

#if CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL
SITL sitl;
#endif

////////////////////////////////////////////////////////////////////////////////
// GCS selection
////////////////////////////////////////////////////////////////////////////////
//
GCS_MAVLINK	gcs0;
GCS_MAVLINK	gcs3;

// a pin for reading the receiver RSSI voltage. The scaling by 0.25 
// is to take the 0 to 1024 range down to an 8 bit range for MAVLink
AP_HAL::AnalogSource *rssi_analog_source;

AP_HAL::AnalogSource *vcc_pin;

AP_HAL::AnalogSource * batt_volt_pin;
AP_HAL::AnalogSource * batt_curr_pin;

////////////////////////////////////////////////////////////////////////////////
// SONAR selection
////////////////////////////////////////////////////////////////////////////////
//
static AP_RangeFinder_analog sonar;
static AP_RangeFinder_analog sonar2;

// relay support
AP_Relay relay;

// Camera/Antenna mount tracking and stabilisation stuff
// --------------------------------------
#if MOUNT == ENABLED
AP_Mount camera_mount(g_gps, &dcm);
#endif

////////////////////////////////////////////////////////////////////////////////
// Global variables
////////////////////////////////////////////////////////////////////////////////

// APM2 only
#if USB_MUX_PIN > 0
static bool usb_connected;
#endif

/* Radio values
		Channel assignments
			1   Steering
			2   ---
			3   Throttle
			4   ---
			5   Aux5
			6   Aux6
			7   Aux7
			8   Aux8/Mode
		Each Aux channel can be configured to have any of the available auxiliary functions assigned to it.
		See libraries/RC_Channel/RC_Channel_aux.h for more information
*/

////////////////////////////////////////////////////////////////////////////////
// Radio
////////////////////////////////////////////////////////////////////////////////
// This is the state of the flight control system
// There are multiple states defined such as MANUAL, FBW-A, AUTO
enum mode   control_mode        = INITIALISING;
// Used to maintain the state of the previous control switch position
// This is set to -1 when we need to re-read the switch
uint8_t 	oldSwitchPosition;
// These are values received from the GCS if the user is using GCS joystick
// control and are substituted for the values coming from the RC radio
static int16_t rc_override[8] = {0,0,0,0,0,0,0,0};
// A flag if GCS joystick control is in use
static bool rc_override_active = false;

////////////////////////////////////////////////////////////////////////////////
// Failsafe
////////////////////////////////////////////////////////////////////////////////
// A tracking variable for type of failsafe active
// Used for failsafe based on loss of RC signal or GCS signal. See 
// FAILSAFE_EVENT_*
static struct {
    uint8_t bits;
    uint32_t rc_override_timer;
    uint32_t start_time;
    uint8_t triggered;
} failsafe;

////////////////////////////////////////////////////////////////////////////////
// LED output
////////////////////////////////////////////////////////////////////////////////
// state of the GPS light (on/off)
static bool GPS_light;							

////////////////////////////////////////////////////////////////////////////////
// GPS variables
////////////////////////////////////////////////////////////////////////////////
// This is used to scale GPS values for EEPROM storage
// 10^7 times Decimal GPS means 1 == 1cm
// This approximation makes calculations integer and it's easy to read
static const 	float t7			= 10000000.0;	
// We use atan2 and other trig techniques to calaculate angles

// A counter used to count down valid gps fixes to allow the gps estimate to settle
// before recording our home position (and executing a ground start if we booted with an air start)
static uint8_t 	ground_start_count	= 5;
// Used to compute a speed estimate from the first valid gps fixes to decide if we are 
// on the ground or in the air.  Used to decide if a ground start is appropriate if we
// booted with an air start.
static int16_t     ground_start_avg;
static int32_t          gps_base_alt;		

////////////////////////////////////////////////////////////////////////////////
// Location & Navigation
////////////////////////////////////////////////////////////////////////////////
// Constants
const	float radius_of_earth 	= 6378100;	// meters


// true if we have a position estimate from AHRS
static bool have_position;

// This is the currently calculated direction to fly.  
// deg * 100 : 0 to 360
static int32_t nav_bearing;
// This is the direction to the next waypoint
// deg * 100 : 0 to 360
static int32_t target_bearing;	
//This is the direction from the last waypoint to the next waypoint 
// deg * 100 : 0 to 360
static int32_t crosstrack_bearing;
// A gain scaler to account for ground speed/headwind/tailwind
static float	nav_gain_scaler 		= 1.0f;		
static bool rtl_complete = false;

// There may be two active commands in Auto mode.  
// This indicates the active navigation command by index number
static uint8_t	nav_command_index;					
// This indicates the active non-navigation command by index number
static uint8_t	non_nav_command_index;				
// This is the command type (eg navigate to waypoint) of the active navigation command
static uint8_t	nav_command_ID		= NO_COMMAND;	
static uint8_t	non_nav_command_ID	= NO_COMMAND;	

// ground speed error in m/s
static float	groundspeed_error;	
// 0-(throttle_max - throttle_cruise) : throttle nudge in Auto mode using top 1/2 of throttle stick travel
static int16_t     throttle_nudge = 0;

// receiver RSSI
static uint8_t receiver_rssi;

// the time when the last HEARTBEAT message arrived from a GCS
static uint32_t last_heartbeat_ms;

// obstacle detection information
static struct {
    // have we detected an obstacle?
    uint8_t detected_count;
    float turn_angle;
    uint16_t sonar1_distance_cm;
    uint16_t sonar2_distance_cm;

    // time when we last detected an obstacle, in milliseconds
    uint32_t detected_time_ms;
} obstacle;

// this is set to true when auto has been triggered to start
static bool auto_triggered;

////////////////////////////////////////////////////////////////////////////////
// Ground speed
////////////////////////////////////////////////////////////////////////////////
// The amount current ground speed is below min ground speed.  meters per second
static float 	ground_speed = 0;
static int16_t throttle_last = 0, throttle = 500;

////////////////////////////////////////////////////////////////////////////////
// Location Errors
////////////////////////////////////////////////////////////////////////////////
// Difference between current bearing and desired bearing.  in centi-degrees
static int32_t bearing_error_cd;

// Distance perpandicular to the course line that we are off trackline.  Meters 
static float	crosstrack_error;

////////////////////////////////////////////////////////////////////////////////
// CH7 control
////////////////////////////////////////////////////////////////////////////////

// Used to track the CH7 toggle state.
// When CH7 goes LOW PWM from HIGH PWM, this value will have been set true
// This allows advanced functionality to know when to execute
static bool ch7_flag;
// This register tracks the current Mission Command index when writing
// a mission using CH7 in flight
static int8_t CH7_wp_index;
float tuning_value;

////////////////////////////////////////////////////////////////////////////////
// Battery Sensors
////////////////////////////////////////////////////////////////////////////////
// Battery pack 1 voltage.  Initialized above the low voltage threshold to pre-load the filter and prevent low voltage events at startup.
static float 	battery_voltage1 	= LOW_VOLTAGE * 1.05;
// Battery pack 1 instantaneous currrent draw.  Amperes
static float	current_amps1;
// Totalized current (Amp-hours) from battery 1
static float	current_total1;									


////////////////////////////////////////////////////////////////////////////////
// Navigation control variables
////////////////////////////////////////////////////////////////////////////////
// The instantaneous desired steering angle.  Hundredths of a degree
static int32_t nav_steer_cd;

////////////////////////////////////////////////////////////////////////////////
// Waypoint distances
////////////////////////////////////////////////////////////////////////////////
// Distance between rover and next waypoint.  Meters
static float wp_distance;
// Distance between previous and next waypoint.  Meters
static int32_t wp_totalDistance;

////////////////////////////////////////////////////////////////////////////////
// repeating event control
////////////////////////////////////////////////////////////////////////////////
// Flag indicating current event type
static uint8_t 		event_id;
// when the event was started in ms
static int32_t 		event_timer;
// how long to delay the next firing of event in millis
static uint16_t 	event_delay;					
// how many times to cycle : -1 (or -2) = forever, 2 = do one cycle, 4 = do two cycles
static int16_t 		event_repeat = 0;
// per command value, such as PWM for servos
static int16_t 		event_value; 
// the value used to cycle events (alternate value to event_value)
static int16_t 		event_undo_value;

////////////////////////////////////////////////////////////////////////////////
// Conditional command
////////////////////////////////////////////////////////////////////////////////
// A value used in condition commands (eg delay, change alt, etc.)
// For example in a change altitude command, it is the altitude to change to.
static int32_t 	condition_value;
// A starting value used to check the status of a conditional command.
// For example in a delay command the condition_start records that start time for the delay
static int32_t 	condition_start;
// A value used in condition commands.  For example the rate at which to change altitude.
static int16_t 		condition_rate;

////////////////////////////////////////////////////////////////////////////////
// 3D Location vectors
// Location structure defined in AP_Common
////////////////////////////////////////////////////////////////////////////////
// The home location used for RTL.  The location is set when we first get stable GPS lock
static struct 	Location home;
// Flag for if we have g_gps lock and have set the home location
static bool	home_is_set;
// The location of the previous waypoint.  Used for track following and altitude ramp calculations
static struct 	Location prev_WP;
// The rover's current location
static struct 	Location current_loc;
// The location of the current/active waypoint.  Used for track following
static struct 	Location next_WP;
// The location of the active waypoint in Guided mode.
static struct  	Location guided_WP;

// The location structure information from the Nav command being processed
static struct 	Location next_nav_command;	
// The location structure information from the Non-Nav command being processed
static struct 	Location next_nonnav_command;

////////////////////////////////////////////////////////////////////////////////
// IMU variables
////////////////////////////////////////////////////////////////////////////////
// The main loop execution time.  Seconds
//This is the time between calls to the DCM algorithm and is the Integration time for the gyros.
static float G_Dt						= 0.02;		

////////////////////////////////////////////////////////////////////////////////
// Performance monitoring
////////////////////////////////////////////////////////////////////////////////
// Timer used to accrue data and trigger recording of the performanc monitoring log message
static int32_t 	perf_mon_timer;
// The maximum main loop execution time recorded in the current performance monitoring interval
static int16_t 	G_Dt_max = 0;
// The number of gps fixes recorded in the current performance monitoring interval
static uint8_t 	gps_fix_count = 0;
// A variable used by developers to track performanc metrics.
// Currently used to record the number of GCS heartbeat messages received
static int16_t pmTest1 = 0;


////////////////////////////////////////////////////////////////////////////////
// System Timers
////////////////////////////////////////////////////////////////////////////////
// Time in miliseconds of start of main control loop.  Milliseconds
static uint32_t 	fast_loopTimer;
// Time Stamp when fast loop was complete.  Milliseconds
static uint32_t 	fast_loopTimeStamp;
// Number of milliseconds used in last main loop cycle
static uint8_t 		delta_ms_fast_loop;
// Counter of main loop executions.  Used for performance monitoring and failsafe processing
static uint16_t			mainLoop_count;

// Time in miliseconds of start of medium control loop.  Milliseconds
static uint32_t 	medium_loopTimer;
// Counters for branching from main control loop to slower loops
static uint8_t 			medium_loopCounter;	
// Number of milliseconds used in last medium loop cycle
static uint8_t			delta_ms_medium_loop;

// Counters for branching from medium control loop to slower loops
static uint8_t 			slow_loopCounter;
// Counter to trigger execution of very low rate processes
static uint8_t 			superslow_loopCounter;
// Counter to trigger execution of 1 Hz processes
static uint8_t				counter_one_herz;

// % MCU cycles used
static float 			load;

////////////////////////////////////////////////////////////////////////////////
// Top-level logic
////////////////////////////////////////////////////////////////////////////////

void setup() {
	memcheck_init();
    cliSerial = hal.console;

    // load the default values of variables listed in var_info[]
    AP_Param::setup_sketch_defaults();

    rssi_analog_source = hal.analogin->channel(ANALOG_INPUT_NONE);
    vcc_pin = hal.analogin->channel(ANALOG_INPUT_BOARD_VCC);
    batt_volt_pin = hal.analogin->channel(g.battery_volt_pin);
    batt_curr_pin = hal.analogin->channel(g.battery_curr_pin);

	init_ardupilot();
}

void loop()
{
    // We want this to execute at 50Hz, but synchronised with the gyro/accel
    uint16_t num_samples = ins.num_samples_available();
    if (num_samples >= 1) {
		delta_ms_fast_loop	= millis() - fast_loopTimer;
		load                = (float)(fast_loopTimeStamp - fast_loopTimer)/delta_ms_fast_loop;
		G_Dt                = (float)delta_ms_fast_loop / 1000.f;
		fast_loopTimer      = millis();

		mainLoop_count++;

		// Execute the fast loop
		// ---------------------
		fast_loop();

		// Execute the medium loop
		// -----------------------
		medium_loop();

		counter_one_herz++;
		if(counter_one_herz == 50){
			one_second_loop();
			counter_one_herz = 0;
		}

		if (millis() - perf_mon_timer > 20000) {
			if (mainLoop_count != 0) {
				if (g.log_bitmask & MASK_LOG_PM)
					#if HIL_MODE != HIL_MODE_ATTITUDE
					Log_Write_Performance();
					#endif
				resetPerfData();
			}
		}

		fast_loopTimeStamp = millis();
    } else if (millis() - fast_loopTimeStamp < 19) {
        // less than 19ms has passed. We have at least one millisecond
        // of free time. The most useful thing to do with that time is
        // to accumulate some sensor readings, specifically the
        // compass, which is often very noisy but is not interrupt
        // driven, so it can't accumulate readings by itself
        if (g.compass_enabled) {
            compass.accumulate();
        }
    }
}

// Main loop 50Hz
static void fast_loop()
{
	// This is the fast loop - we want it to execute at 50Hz if possible
	// -----------------------------------------------------------------
	if (delta_ms_fast_loop > G_Dt_max)
		G_Dt_max = delta_ms_fast_loop;

	// Read radio
	// ----------
	read_radio();

    // try to send any deferred messages if the serial port now has
    // some space available
    gcs_send_message(MSG_RETRY_DEFERRED);

	#if HIL_MODE == HIL_MODE_SENSORS
		// update hil before dcm update
		gcs_update();
	#endif

	ahrs.update();

    read_sonars();

	// uses the yaw from the DCM to give more accurate turns
	calc_bearing_error();

	# if HIL_MODE == HIL_MODE_DISABLED
		if (g.log_bitmask & MASK_LOG_ATTITUDE_FAST)
			Log_Write_Attitude();

		if (g.log_bitmask & MASK_LOG_IMU)
			DataFlash.Log_Write_IMU(&ins);
	#endif

	// custom code/exceptions for flight modes
	// ---------------------------------------
	update_current_mode();

	// write out the servo PWM values
	// ------------------------------
	set_servos();

    gcs_update();
    gcs_data_stream_send();
}

static void medium_loop()
{
#if MOUNT == ENABLED
	camera_mount.update_mount_position();
#endif

	// This is the start of the medium (10 Hz) loop pieces
	// -----------------------------------------
	switch(medium_loopCounter) {

		// This case deals with the GPS
		//-------------------------------
		case 0:
            failsafe_trigger(FAILSAFE_EVENT_GCS, last_heartbeat_ms != 0 && (millis() - last_heartbeat_ms) > 2000);
			medium_loopCounter++;
            update_GPS();
            
			#if HIL_MODE != HIL_MODE_ATTITUDE
            if (g.compass_enabled && compass.read()) {
                ahrs.set_compass(&compass);
                // Calculate heading
                compass.null_offsets();
                if (g.log_bitmask & MASK_LOG_COMPASS) {
                    Log_Write_Compass();
                }
            } else {
                ahrs.set_compass(NULL);
            }
			#endif
			break;

		// This case performs some navigation computations
		//------------------------------------------------
		case 1:
			medium_loopCounter++;
            navigate();
			break;

		// command processing
		//------------------------------
		case 2:
			medium_loopCounter++;

            read_receiver_rssi();

			// perform next command
			// --------------------
			update_commands();
			break;

		// This case deals with sending high rate telemetry
		//-------------------------------------------------
		case 3:
			medium_loopCounter++;
			#if HIL_MODE != HIL_MODE_ATTITUDE
				if ((g.log_bitmask & MASK_LOG_ATTITUDE_MED) && !(g.log_bitmask & MASK_LOG_ATTITUDE_FAST))
					Log_Write_Attitude();

				if (g.log_bitmask & MASK_LOG_CTUN)
					Log_Write_Control_Tuning();
			#endif

			if (g.log_bitmask & MASK_LOG_NTUN)
				Log_Write_Nav_Tuning();
			break;

		// This case controls the slow loop
		//---------------------------------
		case 4:
			medium_loopCounter = 0;
			delta_ms_medium_loop	= millis() - medium_loopTimer;
			medium_loopTimer      	= millis();

			if (g.battery_monitoring != 0){
				read_battery();
			}

			read_trim_switch();

			slow_loop();
			break;
	}
}

static void slow_loop()
{
	// This is the slow (3 1/3 Hz) loop pieces
	//----------------------------------------
	switch (slow_loopCounter){
		case 0:
			slow_loopCounter++;
			superslow_loopCounter++;
			if(superslow_loopCounter >=200) {				//	200 = Execute every minute
				#if HIL_MODE != HIL_MODE_ATTITUDE
					if(g.compass_enabled) {
						compass.save_offsets();
					}
				#endif
				superslow_loopCounter = 0;
			}
			break;

		case 1:
			slow_loopCounter++;

			// Read 3-position switch on radio
			// -------------------------------
			read_control_switch();

			update_aux_servo_function(&g.rc_2, &g.rc_4, &g.rc_5, &g.rc_6, &g.rc_7, &g.rc_8);

#if MOUNT == ENABLED
			camera_mount.update_mount_type();
#endif
			break;

		case 2:
			slow_loopCounter = 0;
                        
			update_events();

            mavlink_system.sysid = g.sysid_this_mav;		// This is just an ugly hack to keep mavlink_system.sysid sync'd with our parameter

            check_usb_mux();
			break;
	}
}

static void one_second_loop()
{
	if (g.log_bitmask & MASK_LOG_CURRENT)
		Log_Write_Current();
	// send a heartbeat
	gcs_send_message(MSG_HEARTBEAT);

    // allow orientation change at runtime to aid config
    ahrs.set_orientation();

    set_control_channels();
}

static void update_GPS(void)
{        
    static uint32_t last_gps_reading;
	g_gps->update();
	update_GPS_light();

    if (g_gps->last_message_time_ms() != last_gps_reading) {
        last_gps_reading = g_gps->last_message_time_ms();
        if (g.log_bitmask & MASK_LOG_GPS) {
            DataFlash.Log_Write_GPS(g_gps, current_loc.alt);
        }
    }

    have_position = ahrs.get_projected_position(&current_loc);

	if (g_gps->new_data && g_gps->status() >= GPS::GPS_OK_FIX_3D) {
		gps_fix_count++;

		if(ground_start_count > 1){
			ground_start_count--;
			ground_start_avg += g_gps->ground_speed;

		} else if (ground_start_count == 1) {
			// We countdown N number of good GPS fixes
			// so that the altitude is more accurate
			// -------------------------------------
			if (current_loc.lat == 0) {
				ground_start_count = 5;

			} else {
                init_home();
				if (g.compass_enabled) {
					// Set compass declination automatically
					compass.set_initial_location(g_gps->latitude, g_gps->longitude);
				}
				ground_start_count = 0;
			}
		}
        ground_speed   = g_gps->ground_speed * 0.01;
	}
}

static void update_current_mode(void)
{ 
    switch (control_mode){
    case AUTO:
    case RTL:
    case GUIDED:
        calc_nav_steer();
        calc_throttle(g.speed_cruise);
        break;

    case STEERING:
        /*
          in steering mode we control the bearing error, which gives
          the same type of steering control as auto mode. The throttle
          controls the target speed, in proportion to the throttle
         */
        bearing_error_cd = channel_steer->pwm_to_angle();
        calc_nav_steer();

        /* we need to reset the I term or it will build up */
        g.pidNavSteer.reset_I();
        calc_throttle(channel_throttle->pwm_to_angle() * 0.01 * g.speed_cruise);
        break;

    case LEARNING:
    case MANUAL:
        /*
          in both MANUAL and LEARNING we pass through the
          controls. Setting servo_out here actually doesn't matter, as
          we set the exact value in set_servos(), but it helps for
          logging
         */
        channel_throttle->servo_out = channel_throttle->control_in;
        channel_steer->servo_out = channel_steer->pwm_to_angle();
        break;

    case HOLD:
        // hold position - stop motors and center steering
        channel_throttle->servo_out = 0;
        channel_steer->servo_out = 0;
        break;

    case INITIALISING:
        break;
	}
}

static void update_navigation()
{
    switch (control_mode) {
    case MANUAL:
    case HOLD:
    case LEARNING:
    case STEERING:
    case INITIALISING:
        break;

    case AUTO:
		verify_commands();
        break;

    case RTL:
    case GUIDED:
        // no loitering around the wp with the rover, goes direct to the wp position
        calc_nav_steer();
        calc_bearing_error();
        if (verify_RTL()) {  
            channel_throttle->servo_out = g.throttle_min.get();
            set_mode(HOLD);
        }
        break;
	}
}

AP_HAL_MAIN();