ardupilot/ArduPlane/ArduPlane.pde

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

#define THISFIRMWARE "ArduPlane V2.75beta2"
/*
   Lead developer: Andrew Tridgell
 
   Authors:    Doug Weibel, Jose Julio, Jordi Munoz, Jason Short, Randy Mackay, Pat Hickey, John Arne Birkeland, Olivier Adler, Amilcar Lucas, Gregory Fletcher, Paul Riseborough, Brandon Jones, Jon Challinger
   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, Yury MonZon

   Please contribute your ideas! See http://dev.ardupilot.com for details

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

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

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

#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_Baro.h>        // ArduPilot barometer library
#include <AP_Compass.h>     // ArduPilot Mega Magnetometer Library
#include <AP_Math.h>        // ArduPilot Mega Vector/Matrix math Library
#include <AP_ADC.h>         // ArduPilot Mega Analog to Digital Converter Library
#include <AP_ADC_AnalogSource.h>
#include <AP_InertialSensor.h> // Inertial Sensor 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 <AP_Buffer.h>      // APM FIFO Buffer
#include <AP_Relay.h>       // APM relay
#include <AP_Camera.h>          // Photo or video camera
#include <AP_Airspeed.h>
#include <memcheck.h>

#include <APM_OBC.h>
#include <APM_Control.h>
#include <GCS_MAVLink.h>    // MAVLink GCS definitions
#include <AP_Mount.h>           // Camera/Antenna mount
#include <AP_Declination.h> // ArduPilot Mega Declination Helper Library
#include <DataFlash.h>
#include <SITL.h>
#include <AP_Scheduler.h>       // main loop scheduler

#include <AP_Navigation.h>
#include <AP_L1_Control.h>
#include <AP_RCMapper.h>        // RC input mapping library

#include <AP_Vehicle.h>
#include <AP_SpdHgtControl.h>
#include <AP_TECS.h>

#include <AP_Notify.h>      // Notify library

// Pre-AP_HAL compatibility
#include "compat.h"

// Configuration
#include "config.h"

// Local modules
#include "defines.h"

// key aircraft parameters passed to multiple libraries
static AP_Vehicle::FixedWing aparm;

#include "Parameters.h"
#include "GCS.h"

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

AP_HAL::BetterStream* cliSerial;

const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;


////////////////////////////////////////////////////////////////////////////////
// Outback Challenge Failsafe Support
////////////////////////////////////////////////////////////////////////////////
#if OBC_FAILSAFE == ENABLED
APM_OBC obc;
#endif

////////////////////////////////////////////////////////////////////////////////
// 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;

// main loop scheduler
static AP_Scheduler scheduler;
 
// mapping between input channels
static RCMapper rcmap;

// primary control channels
static RC_Channel *channel_roll;
static RC_Channel *channel_pitch;
static RC_Channel *channel_throttle;
static RC_Channel *channel_rudder;

// notification object for LEDs, buzzers etc
static AP_Notify notify;

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


////////////////////////////////////////////////////////////////////////////////
// DataFlash
////////////////////////////////////////////////////////////////////////////////
#if LOGGING_ENABLED == ENABLED
#if CONFIG_HAL_BOARD == HAL_BOARD_APM1
DataFlash_APM1 DataFlash;
#elif CONFIG_HAL_BOARD == HAL_BOARD_APM2
DataFlash_APM2 DataFlash;
#elif CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL
DataFlash_SITL DataFlash;
#elif CONFIG_HAL_BOARD == HAL_BOARD_PX4
static DataFlash_File DataFlash("/fs/microsd/APM/logs");
#else
// no dataflash driver
DataFlash_Empty DataFlash;
#endif
#endif

////////////////////////////////////////////////////////////////////////////////
// Sensors
////////////////////////////////////////////////////////////////////////////////
//
// There are three basic options related to flight sensor selection.
//
// - Normal flight 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          *flight_modes = &g.flight_mode1;

#if CONFIG_HAL_BOARD == HAL_BOARD_APM1
AP_ADC_ADS7844 apm1_adc;
#endif

#if CONFIG_BARO == AP_BARO_BMP085
static AP_Baro_BMP085 barometer;
#elif CONFIG_BARO == AP_BARO_PX4
static AP_Baro_PX4 barometer;
#elif CONFIG_BARO == AP_BARO_HIL
static AP_Baro_HIL barometer;
#elif CONFIG_BARO == AP_BARO_MS5611
 #if CONFIG_MS5611_SERIAL == AP_BARO_MS5611_SPI
 static AP_Baro_MS5611 barometer(&AP_Baro_MS5611::spi);
 #elif CONFIG_MS5611_SERIAL == AP_BARO_MS5611_I2C
 static AP_Baro_MS5611 barometer(&AP_Baro_MS5611::i2c);
 #else
 #error Unrecognized CONFIG_MS5611_SERIAL setting.
 #endif
#else
 #error Unrecognized CONFIG_BARO setting
#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( &apm1_adc );
#else
  #error Unrecognised CONFIG_INS_TYPE setting.
#endif // CONFIG_INS_TYPE

AP_AHRS_DCM ahrs(&ins, g_gps);

static AP_L1_Control L1_controller(ahrs);
static AP_TECS TECS_controller(ahrs, aparm);

// Attitude to servo controllers
static AP_RollController  rollController(ahrs, aparm);
static AP_PitchController pitchController(ahrs, aparm);
static AP_YawController   yawController(ahrs, aparm);


#if CONFIG_HAL_BOARD == HAL_BOARD_AVR_SITL
SITL sitl;
#endif

// Training mode
static bool training_manual_roll;  // user has manual roll control
static bool training_manual_pitch; // user has manual pitch control

// should throttle be pass-thru in guided?
static bool guided_throttle_passthru;

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

// selected navigation controller
static AP_Navigation *nav_controller = &L1_controller;

// selected navigation controller
static AP_SpdHgtControl *SpdHgt_Controller = &TECS_controller;

////////////////////////////////////////////////////////////////////////////////
// Analog Inputs
////////////////////////////////////////////////////////////////////////////////

// a pin for reading the receiver RSSI voltage. 
static AP_HAL::AnalogSource *rssi_analog_source;

static AP_HAL::AnalogSource *vcc_pin;

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

////////////////////////////////////////////////////////////////////////////////
// Relay
////////////////////////////////////////////////////////////////////////////////
static AP_Relay relay;

// Camera
#if CAMERA == ENABLED
static AP_Camera camera(&relay);
#endif

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

// remember if USB is connected, so we can adjust baud rate
static bool usb_connected;

/* Radio values
 *               Channel assignments
 *                       1   Ailerons
 *                       2   Elevator
 *                       3   Throttle
 *                       4   Rudder
 *                       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 FlightMode 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;
// This is used to enable the inverted flight feature
bool inverted_flight     = false;

static struct {
    // These are trim values used for elevon control
    // For elevons radio_in[CH_ROLL] and radio_in[CH_PITCH] are
    // equivalent aileron and elevator, not left and right elevon
    uint16_t trim1;
    uint16_t trim2;
    // These are used in the calculation of elevon1_trim and elevon2_trim
    uint16_t ch1_temp;
    uint16_t ch2_temp;
} elevon = {
	trim1 : 1500,
    trim2 : 1500,
    ch1_temp : 1500,
    ch2_temp : 1500
};


////////////////////////////////////////////////////////////////////////////////
// Failsafe
////////////////////////////////////////////////////////////////////////////////
static struct {
    // A flag if GCS joystick control is in use
    uint8_t rc_override_active:1;

    // Used to track if the value on channel 3 (throtttle) has fallen below the failsafe threshold
    // RC receiver should be set up to output a low throttle value when signal is lost
    uint8_t ch3_failsafe:1;

    // has the saved mode for failsafe been set?
    uint8_t saved_mode_set:1;

    // saved flight mode
    enum FlightMode saved_mode;

    // A tracking variable for type of failsafe active
    // Used for failsafe based on loss of RC signal or GCS signal
    int16_t state;

    // number of low ch3 values
    uint8_t ch3_counter;

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

    // A timer used to track how long we have been in a "short failsafe" condition due to loss of RC signal
    uint32_t ch3_timer_ms;
} failsafe;


////////////////////////////////////////////////////////////////////////////////
// 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;

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

////////////////////////////////////////////////////////////////////////////////
// Location & Navigation
////////////////////////////////////////////////////////////////////////////////

// Direction held during phases of takeoff and landing
// deg * 100 dir of plane,  A value of -1 indicates the course has not been set/is not in use
// this is a 0..36000 value, or -1 for disabled
static int32_t hold_course_cd                 = -1;              // deg * 100 dir of plane

// 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;

////////////////////////////////////////////////////////////////////////////////
// Airspeed
////////////////////////////////////////////////////////////////////////////////
// The calculated airspeed to use in FBW-B.  Also used in higher modes for insuring min ground speed is met.
// Also used for flap deployment criteria.  Centimeters per second.
static int32_t target_airspeed_cm;

// The difference between current and desired airspeed.  Used in the pitch controller.  Centimeters per second.
static float airspeed_error_cm;

// An amount that the airspeed should be increased in auto modes based on the user positioning the
// throttle stick in the top half of the range.  Centimeters per second.
static int16_t airspeed_nudge_cm;

// Similar to airspeed_nudge, but used when no airspeed sensor.
// 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;


////////////////////////////////////////////////////////////////////////////////
// Ground speed
////////////////////////////////////////////////////////////////////////////////
// The amount current ground speed is below min ground speed.  Centimeters per second
static int32_t groundspeed_undershoot = 0;

// Difference between current altitude and desired altitude.  Centimeters
static int32_t altitude_error_cm;

////////////////////////////////////////////////////////////////////////////////
// Battery Sensors
////////////////////////////////////////////////////////////////////////////////
static struct {
    // Battery pack 1 voltage.  Initialized above the low voltage
    // threshold to pre-load the filter and prevent low voltage events
    // at startup.
    float voltage;
    // Battery pack 1 instantaneous currrent draw.  Amperes
    float current_amps;
    // Totalized current (Amp-hours) from battery 1
    float current_total_mah;
    // true when a low battery event has happened
    bool low_batttery;
    // time when current was last read
    uint32_t last_time_ms;
} battery;

////////////////////////////////////////////////////////////////////////////////
// Airspeed Sensors
////////////////////////////////////////////////////////////////////////////////
AP_Airspeed airspeed(aparm);

////////////////////////////////////////////////////////////////////////////////
// ACRO controller state
////////////////////////////////////////////////////////////////////////////////
static struct {
    bool locked_roll;
    bool locked_pitch;
    float locked_roll_err;
    int32_t locked_pitch_cd;
} acro_state;

////////////////////////////////////////////////////////////////////////////////
// CRUISE controller state
////////////////////////////////////////////////////////////////////////////////
static struct {
    bool locked_heading;
    int32_t locked_heading_cd;
    uint32_t lock_timer_ms;
} cruise_state;

////////////////////////////////////////////////////////////////////////////////
// flight mode specific
////////////////////////////////////////////////////////////////////////////////
// Flag for using gps ground course instead of INS yaw.  Set false when takeoff command in process.
static bool takeoff_complete    = true;
// Flag to indicate if we have landed.
//Set land_complete if we are within 2 seconds distance or within 3 meters altitude of touchdown
static bool land_complete;
// Altitude threshold to complete a takeoff command in autonomous modes.  Centimeters
static int32_t takeoff_altitude_cm;

// Minimum pitch to hold during takeoff command execution.  Hundredths of a degree
static int16_t takeoff_pitch_cd;

// true if we are in an auto-throttle mode, which means
// we need to run the speed/height controller
static bool auto_throttle_mode;

// this controls throttle suppression in auto modes
static bool throttle_suppressed;

////////////////////////////////////////////////////////////////////////////////
// Loiter management
////////////////////////////////////////////////////////////////////////////////

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

// The instantaneous desired pitch angle.  Hundredths of a degree
static int32_t nav_pitch_cd;

////////////////////////////////////////////////////////////////////////////////
// Waypoint distances
////////////////////////////////////////////////////////////////////////////////
// Distance between plane and next waypoint.  Meters
static uint32_t wp_distance;

// Distance between previous and next waypoint.  Meters
static uint32_t wp_totalDistance;

/*
  meta data to support counting the number of circles in a loiter
 */
static struct {
    // previous target bearing, used to update sum_cd
    int32_t old_target_bearing_cd;

    // Total desired rotation in a loiter.  Used for Loiter Turns commands. 
    int32_t total_cd;

    // total angle completed in the loiter so far
    int32_t sum_cd;

	// Direction for loiter. 1 for clockwise, -1 for counter-clockwise
    int8_t direction;

	// start time of the loiter.  Milliseconds.
    uint32_t start_time_ms;

	// The amount of time we should stay in a loiter for the Loiter Time command.  Milliseconds.
    uint32_t time_max_ms;
} loiter;


// event control state
enum event_type { 
    EVENT_TYPE_RELAY=0,
    EVENT_TYPE_SERVO=1
};

static struct {
    enum event_type type;

	// when the event was started in ms
    uint32_t start_time_ms;

	// how long to delay the next firing of event in millis
    uint16_t delay_ms;

	// how many times to cycle : -1 (or -2) = forever, 2 = do one cycle, 4 = do two cycles
    int16_t repeat;

    // RC channel for servos
    uint8_t rc_channel;

	// PWM for servos
	uint16_t servo_value;

	// the value used to cycle events (alternate value to event_value)
    uint16_t undo_value;
} event_state;


////////////////////////////////////////////////////////////////////////////////
// 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 uint32_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 plane's current location
static struct   Location current_loc;
// The location of the current/active waypoint.  Used for altitude ramp, track following and loiter calculations.
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;

////////////////////////////////////////////////////////////////////////////////
// Altitude / Climb rate control
////////////////////////////////////////////////////////////////////////////////
// The current desired altitude.  Altitude is linearly ramped between waypoints.  Centimeters
static int32_t target_altitude_cm;
// Altitude difference between previous and current waypoint.  Centimeters
static int32_t offset_altitude_cm;

////////////////////////////////////////////////////////////////////////////////
// INS 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;

////////////////////////////////////////////////////////////////////////////////
// System Timers
////////////////////////////////////////////////////////////////////////////////
// Time in miliseconds of start of main control loop.  Milliseconds
static uint32_t fast_loopTimer_ms;

// 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;

// Camera/Antenna mount tracking and stabilisation stuff
// --------------------------------------
#if MOUNT == ENABLED
// current_loc uses the baro/gps soloution for altitude rather than gps only.
// mabe one could use current_loc for lat/lon too and eliminate g_gps alltogether?
AP_Mount camera_mount(&current_loc, g_gps, &ahrs, 0);
#endif

#if MOUNT2 == ENABLED
// current_loc uses the baro/gps soloution for altitude rather than gps only.
// mabe one could use current_loc for lat/lon too and eliminate g_gps alltogether?
AP_Mount camera_mount2(&current_loc, g_gps, &ahrs, 1);
#endif

#if CAMERA == ENABLED
//pinMode(camtrig, OUTPUT);			// these are free pins PE3(5), PH3(15), PH6(18), PB4(23), PB5(24), PL1(36), PL3(38), PA6(72), PA7(71), PK0(89), PK1(88), PK2(87), PK3(86), PK4(83), PK5(84), PK6(83), PK7(82)
#endif

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

/*
  scheduler table - all regular tasks apart from the fast_loop()
  should be listed here, along with how often they should be called
  (in 20ms units) and the maximum time they are expected to take (in
  microseconds)
 */
static const AP_Scheduler::Task scheduler_tasks[] PROGMEM = {
    { update_speed_height,    1,    900 }, // 0
    { update_flight_mode,     1,   1000 },
    { stabilize,              1,   3200 },
    { set_servos,             1,   1100 },
    { read_control_switch,    7,   1000 },
    { update_GPS,             5,   4000 },
    { navigate,               5,   4800 },
    { update_compass,         5,   1500 },
    { read_airspeed,          5,   1500 },
    { update_alt,             5,   3400 },
    { calc_altitude_error,    5,   1000 }, // 10
    { update_commands,        5,   7000 },
    { obc_fs_check,           5,   1000 },
    { gcs_update,             1,   1700 },
    { gcs_data_stream_send,   1,   3000 },
    { update_mount,           1,   1500 },
    { update_events,		 15,   1500 },
    { check_usb_mux,          5,    200 },
    { read_battery,           5,   1000 },
    { compass_accumulate,     1,   1500 },
    { barometer_accumulate,   1,    900 }, // 20
    { update_notify,          1,    100 },
    { one_second_loop,       50,   3900 },
    { check_long_failsafe,   15,   1000 },
    { airspeed_ratio_update, 50,   1000 },
    { update_logging,         5,   1200 },
    { read_receiver_rssi,     5,   1000 },
};

// setup the var_info table
AP_Param param_loader(var_info, WP_START_BYTE);

void setup() {
    // this needs to be the first call, as it fills memory with
    // sentinel values
    memcheck_init();

    cliSerial = hal.console;

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

    // arduplane does not use arming nor pre-arm checks
    AP_Notify::flags.armed = true;
    AP_Notify::flags.pre_arm_check = true;
    AP_Notify::flags.failsafe_battery = false;

    notify.init();

    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();

    // initialise the main loop scheduler
    scheduler.init(&scheduler_tasks[0], sizeof(scheduler_tasks)/sizeof(scheduler_tasks[0]));
}

void loop()
{
    uint32_t timer = millis();
    // 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      = timer - fast_loopTimer_ms;
        G_Dt                = delta_ms_fast_loop * 0.001f;
        fast_loopTimer_ms   = timer;

        mainLoop_count++;

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

        // tell the scheduler one tick has passed
        scheduler.tick();

        // run all the tasks that are due to run. Note that we only
        // have to call this once per loop, as the tasks are scheduled
        // in multiples of the main loop tick. So if they don't run on
        // the first call to the scheduler they won't run on a later
        // call until scheduler.tick() is called again
        scheduler.run(19000U);
    }
}

// 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);

    // check for loss of control signal failsafe condition
    // ------------------------------------
    check_short_failsafe();

#if HIL_MODE != HIL_MODE_DISABLED
    // update hil before AHRS update
    gcs_update();
#endif

    ahrs.update();

    if (g.log_bitmask & MASK_LOG_ATTITUDE_FAST)
        Log_Write_Attitude();

    if (g.log_bitmask & MASK_LOG_IMU)
        Log_Write_IMU();
}

/*
  update 50Hz speed/height controller
 */
static void update_speed_height(void)
{
    if (auto_throttle_mode) {
	    // Call TECS 50Hz update. Note that we call this regardless of
	    // throttle suppressed, as this needs to be running for
	    // takeoff detection
        SpdHgt_Controller->update_50hz(relative_altitude());
    }
}


/*
  update camera mount
 */
static void update_mount(void)
{
#if MOUNT == ENABLED
    camera_mount.update_mount_position();
#endif

#if MOUNT2 == ENABLED
    camera_mount2.update_mount_position();
#endif

#if CAMERA == ENABLED
    camera.trigger_pic_cleanup();
#endif
}

/*
  read and update compass
 */
static void update_compass(void)
{
    if (g.compass_enabled && compass.read()) {
        ahrs.set_compass(&compass);
        compass.null_offsets();
        if (g.log_bitmask & MASK_LOG_COMPASS) {
            Log_Write_Compass();
        }
    } else {
        ahrs.set_compass(NULL);
    }
}

/*
  if the compass is enabled then try to accumulate a reading
 */
static void compass_accumulate(void)
{
    if (g.compass_enabled) {
        compass.accumulate();
    }    
}

/*
  try to accumulate a baro reading
 */
static void barometer_accumulate(void)
{
    barometer.accumulate();
}

/*
  do 10Hz logging
 */
static void update_logging(void)
{
    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();
    
    if (g.log_bitmask & MASK_LOG_NTUN)
        Log_Write_Nav_Tuning();
}

/*
  check for OBC failsafe check
 */
static void obc_fs_check(void)
{
#if OBC_FAILSAFE == ENABLED
    // perform OBC failsafe checks
    obc.check(OBC_MODE(control_mode),
              failsafe.last_heartbeat_ms,
              g_gps ? g_gps->last_fix_time : 0);
#endif
}


/*
  update aux servo mappings
 */
static void update_aux(void)
{
#if CONFIG_HAL_BOARD == HAL_BOARD_PX4
        update_aux_servo_function(&g.rc_5, &g.rc_6, &g.rc_7, &g.rc_8, &g.rc_9, &g.rc_10, &g.rc_11, &g.rc_12);
#elif CONFIG_HAL_BOARD == HAL_BOARD_APM2
        update_aux_servo_function(&g.rc_5, &g.rc_6, &g.rc_7, &g.rc_8, &g.rc_10, &g.rc_11);
#else
        update_aux_servo_function(&g.rc_5, &g.rc_6, &g.rc_7, &g.rc_8);
#endif
        enable_aux_servos();

#if MOUNT == ENABLED
        camera_mount.update_mount_type();
#endif
#if MOUNT2 == ENABLED
        camera_mount2.update_mount_type();
#endif
}

static void one_second_loop()
{
    if (g.log_bitmask & MASK_LOG_CURRENT)
        Log_Write_Current();

    // send a heartbeat
    gcs_send_message(MSG_HEARTBEAT);

    // make it possible to change control channel ordering at runtime
    set_control_channels();

    // make it possible to change orientation at runtime
    ahrs.set_orientation();

    // sync MAVLink system ID
    mavlink_system.sysid = g.sysid_this_mav;

    update_aux();

    static uint8_t counter;
    counter++;

    if (counter == 20) {
        if (g.log_bitmask & MASK_LOG_PM)
            Log_Write_Performance();
        resetPerfData();
    }

    if (counter >= 60) {                                               
        if(g.compass_enabled) {
            compass.save_offsets();
        }
        counter = 0;
    }
}

/*
  once a second update the airspeed calibration ratio
 */
static void airspeed_ratio_update(void)
{
    if (!airspeed.enabled() ||
        g_gps->status() < GPS::GPS_OK_FIX_3D ||
        g_gps->ground_speed_cm < 400 ||
        airspeed.get_airspeed() < aparm.airspeed_min) {
        // don't calibrate when not moving
        return;
    }
    if (abs(ahrs.roll_sensor) > g.roll_limit_cd ||
        ahrs.pitch_sensor > aparm.pitch_limit_max_cd ||
        ahrs.pitch_sensor < aparm.pitch_limit_min_cd) {
        // don't calibrate when going beyond normal flight envelope
        return;
    }
    Vector3f vg = g_gps->velocity_vector();
    airspeed.update_calibration(vg);
    gcs_send_airspeed_calibration(vg);
}


/*
  read the GPS and update position
 */
static void update_GPS(void)
{
    static uint32_t last_gps_reading;
    g_gps->update();

    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) {
            Log_Write_GPS();
        }
    }

    // get position from AHRS
    have_position = ahrs.get_projected_position(current_loc);

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

        // for performance
        // ---------------
        gps_fix_count++;

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

        } 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;
            }
        }

        // see if we've breached the geo-fence
        geofence_check(false);

#if CAMERA == ENABLED
        if (camera.update_location(current_loc) == true) {
            do_take_picture();
        }
#endif        
    }

    calc_gndspeed_undershoot();
}

/*
  main handling for AUTO mode
 */
static void handle_auto_mode(void)
{
    switch(nav_command_ID) {
    case MAV_CMD_NAV_TAKEOFF:
        if (hold_course_cd == -1) {
            // we don't yet have a heading to hold - just level
            // the wings until we get up enough speed to get a GPS heading
            nav_roll_cd = 0;
        } else {
            calc_nav_roll();
            // during takeoff use the level flight roll limit to
            // prevent large course corrections
            nav_roll_cd = constrain_int32(nav_roll_cd, -g.level_roll_limit*100UL, g.level_roll_limit*100UL);
        }
        
        if (airspeed.use()) {
            calc_nav_pitch();
            if (nav_pitch_cd < takeoff_pitch_cd)
                nav_pitch_cd = takeoff_pitch_cd;
        } else {
            nav_pitch_cd = (g_gps->ground_speed_cm / (float)g.airspeed_cruise_cm) * takeoff_pitch_cd;
            nav_pitch_cd = constrain_int32(nav_pitch_cd, 500, takeoff_pitch_cd);
        }
        
        // max throttle for takeoff
        channel_throttle->servo_out = aparm.throttle_max;
        break;

    case MAV_CMD_NAV_LAND:
        calc_nav_roll();
        
        if (land_complete) {
            // during final approach constrain roll to the range
            // allowed for level flight
            nav_roll_cd = constrain_int32(nav_roll_cd, -g.level_roll_limit*100UL, g.level_roll_limit*100UL);
            
            // hold pitch constant in final approach
            nav_pitch_cd = g.land_pitch_cd;
        } else {
            calc_nav_pitch();
            if (!airspeed.use()) {
                // when not under airspeed control, don't allow
                // down pitch in landing
                nav_pitch_cd = constrain_int32(nav_pitch_cd, 0, nav_pitch_cd);
            }
        }
        calc_throttle();
        
        if (land_complete) {
            // we are in the final stage of a landing - force
            // zero throttle
            channel_throttle->servo_out = 0;
        }
        break;
        
    default:
        // we are doing normal AUTO flight, the special cases
        // are for takeoff and landing
        hold_course_cd = -1;
        land_complete = false;
        calc_nav_roll();
        calc_nav_pitch();
        calc_throttle();
        break;
    }
}

/*
  main flight mode dependent update code 
 */
static void update_flight_mode(void)
{
    enum FlightMode effective_mode = control_mode;
    if (control_mode == AUTO && g.auto_fbw_steer) {
        effective_mode = FLY_BY_WIRE_A;
    }

    if (effective_mode != AUTO) {
        // hold_course is only used in takeoff and landing
        hold_course_cd = -1;
    }

    switch (effective_mode) 
    {
    case AUTO:
        handle_auto_mode();
        break;

    case RTL:
    case LOITER:
    case GUIDED:
        calc_nav_roll();
        calc_nav_pitch();
        calc_throttle();
        break;
        
    case TRAINING: {
        training_manual_roll = false;
        training_manual_pitch = false;
        
        // if the roll is past the set roll limit, then
        // we set target roll to the limit
        if (ahrs.roll_sensor >= g.roll_limit_cd) {
            nav_roll_cd = g.roll_limit_cd;
        } else if (ahrs.roll_sensor <= -g.roll_limit_cd) {
            nav_roll_cd = -g.roll_limit_cd;                
        } else {
            training_manual_roll = true;
            nav_roll_cd = 0;
        }
        
        // if the pitch is past the set pitch limits, then
        // we set target pitch to the limit
        if (ahrs.pitch_sensor >= aparm.pitch_limit_max_cd) {
            nav_pitch_cd = aparm.pitch_limit_max_cd;
        } else if (ahrs.pitch_sensor <= aparm.pitch_limit_min_cd) {
            nav_pitch_cd = aparm.pitch_limit_min_cd;
        } else {
            training_manual_pitch = true;
            nav_pitch_cd = 0;
        }
        if (inverted_flight) {
            nav_pitch_cd = -nav_pitch_cd;
        }
        break;
    }

    case ACRO: {
        // handle locked/unlocked control
        if (acro_state.locked_roll) {
            nav_roll_cd = acro_state.locked_roll_err;
        } else {
            nav_roll_cd = ahrs.roll_sensor;
        }
        if (acro_state.locked_pitch) {
            nav_pitch_cd = acro_state.locked_pitch_cd;
        } else {
            nav_pitch_cd = ahrs.pitch_sensor;
        }
        break;
    }

    case FLY_BY_WIRE_A: {
        // set nav_roll and nav_pitch using sticks
        nav_roll_cd  = channel_roll->norm_input() * g.roll_limit_cd;
        nav_roll_cd = constrain_int32(nav_roll_cd, -g.roll_limit_cd, g.roll_limit_cd);
        float pitch_input = channel_pitch->norm_input();
        if (pitch_input > 0) {
            nav_pitch_cd = pitch_input * aparm.pitch_limit_max_cd;
        } else {
            nav_pitch_cd = -(pitch_input * aparm.pitch_limit_min_cd);
        }
        nav_pitch_cd = constrain_int32(nav_pitch_cd, aparm.pitch_limit_min_cd.get(), aparm.pitch_limit_max_cd.get());
        if (inverted_flight) {
            nav_pitch_cd = -nav_pitch_cd;
        }
        if (failsafe.ch3_failsafe && g.short_fs_action == 2) {
            // FBWA failsafe glide
            nav_roll_cd = 0;
            nav_pitch_cd = 0;
        }
        break;
    }

    case FLY_BY_WIRE_B:
        // Thanks to Yury MonZon for the altitude limit code!
        nav_roll_cd = channel_roll->norm_input() * g.roll_limit_cd;
        update_fbwb_speed_height();
        break;
        
    case CRUISE:
        /*
          in CRUISE mode we use the navigation code to control
          roll when heading is locked. Heading becomes unlocked on
          any aileron or rudder input
        */
        if ((channel_roll->control_in != 0 ||
             channel_rudder->control_in != 0)) {                
            cruise_state.locked_heading = false;
            cruise_state.lock_timer_ms = 0;
        }                 
        
        if (!cruise_state.locked_heading) {
            nav_roll_cd = channel_roll->norm_input() * g.roll_limit_cd;
        } else {
            calc_nav_roll();
        }
        update_fbwb_speed_height();
        break;
        
    case STABILIZE:
        nav_roll_cd        = 0;
        nav_pitch_cd       = 0;
        // throttle is passthrough
        break;
        
    case CIRCLE:
        // we have no GPS installed and have lost radio contact
        // or we just want to fly around in a gentle circle w/o GPS,
        // holding altitude at the altitude we set when we
        // switched into the mode
        nav_roll_cd  = g.roll_limit_cd / 3;
        calc_nav_pitch();
        calc_throttle();
        break;

    case MANUAL:
        // servo_out is for Sim control only
        // ---------------------------------
        channel_roll->servo_out = channel_roll->pwm_to_angle();
        channel_pitch->servo_out = channel_pitch->pwm_to_angle();
        channel_rudder->servo_out = channel_rudder->pwm_to_angle();
        break;
        //roll: -13788.000,  pitch: -13698.000,   thr: 0.000, rud: -13742.000
        
    case INITIALISING:
        // handled elsewhere
        break;
    }
}

static void update_navigation()
{
    // wp_distance is in ACTUAL meters, not the *100 meters we get from the GPS
    // ------------------------------------------------------------------------

    // distance and bearing calcs only
    switch(control_mode) {
    case AUTO:
        verify_commands();
        break;
            
    case LOITER:
    case RTL:
    case GUIDED:
        update_loiter();
        break;

    case CRUISE:
        update_cruise();
        break;

    case MANUAL:
    case STABILIZE:
    case TRAINING:
    case INITIALISING:
    case ACRO:
    case FLY_BY_WIRE_A:
    case FLY_BY_WIRE_B:
    case CIRCLE:
        // nothing to do
        break;
    }
}


static void update_alt()
{
    // this function is in place to potentially add a sonar sensor in the future
    //altitude_sensor = BARO;

    if (barometer.healthy) {
        // alt_MSL centimeters (centimeters)
        current_loc.alt = (1 - g.altitude_mix) * g_gps->altitude_cm;
        current_loc.alt += g.altitude_mix * (read_barometer() + home.alt);
    } else if (g_gps->status() >= GPS::GPS_OK_FIX_3D) {
        // alt_MSL centimeters (centimeters)
        current_loc.alt = g_gps->altitude_cm;
    }

    geofence_check(true);

    // Update the speed & height controller states
    if (auto_throttle_mode && !throttle_suppressed) {
        SpdHgt_Controller->update_pitch_throttle(target_altitude_cm - home.alt + (int32_t(g.alt_offset)*100), 
                                                 target_airspeed_cm,
                                                 (control_mode==AUTO && takeoff_complete == false), 
                                                 takeoff_pitch_cd,
                                                 throttle_nudge,
                                                 relative_altitude());
        if (g.log_bitmask & MASK_LOG_TECS) {
            Log_Write_TECS_Tuning();
        }
    }

    // tell AHRS the airspeed to true airspeed ratio
    airspeed.set_EAS2TAS(barometer.get_EAS2TAS());
}

AP_HAL_MAIN();