Merge remote-tracking branch 'px4/new_state_machine_drton' into fmuv2_bringup_new_state_machine_drton

Conflicts:
	src/drivers/blinkm/blinkm.cpp
	src/drivers/px4io/px4io.cpp
	src/modules/commander/state_machine_helper.c
	src/modules/px4iofirmware/protocol.h
	src/modules/px4iofirmware/registers.c
	src/modules/systemlib/systemlib.h
	src/systemcmds/reboot/reboot.c

1 files changed, 1640 insertions, 0 deletions

diff --git a/src/modules/commander/commander.cpp b/src/modules/commander/commander.cpp
new file mode 100644
index 000000000..41e22d21d
--- /dev/null
+++ b/src/modules/commander/commander.cpp
@@ -0,0 +1,1640 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *   Author: Petri Tanskanen <petri.tanskanen@inf.ethz.ch>
+ *           Lorenz Meier <lm@inf.ethz.ch>
+ *           Thomas Gubler <thomasgubler@student.ethz.ch>
+ *           Julian Oes <joes@student.ethz.ch>
+ *
+ * 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 commander.cpp
+ * Main system state machine implementation.
+ *
+ */
+
+#include <nuttx/config.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <debug.h>
+#include <sys/prctl.h>
+#include <string.h>
+#include <math.h>
+#include <poll.h>
+
+#include <uORB/uORB.h>
+#include <uORB/topics/sensor_combined.h>
+#include <uORB/topics/battery_status.h>
+#include <uORB/topics/manual_control_setpoint.h>
+#include <uORB/topics/offboard_control_setpoint.h>
+#include <uORB/topics/home_position.h>
+#include <uORB/topics/vehicle_global_position.h>
+#include <uORB/topics/vehicle_local_position.h>
+#include <uORB/topics/vehicle_gps_position.h>
+#include <uORB/topics/vehicle_command.h>
+#include <uORB/topics/vehicle_control_mode.h>
+#include <uORB/topics/subsystem_info.h>
+#include <uORB/topics/actuator_controls.h>
+#include <uORB/topics/actuator_armed.h>
+#include <uORB/topics/parameter_update.h>
+#include <uORB/topics/differential_pressure.h>
+#include <uORB/topics/safety.h>
+
+#include <drivers/drv_led.h>
+#include <drivers/drv_hrt.h>
+#include <drivers/drv_tone_alarm.h>
+
+#include <mavlink/mavlink_log.h>
+#include <systemlib/param/param.h>
+#include <systemlib/systemlib.h>
+#include <systemlib/err.h>
+#include <systemlib/cpuload.h>
+
+#include "px4_custom_mode.h"
+#include "commander_helper.h"
+#include "state_machine_helper.h"
+#include "calibration_routines.h"
+#include "accelerometer_calibration.h"
+#include "gyro_calibration.h"
+#include "mag_calibration.h"
+#include "baro_calibration.h"
+#include "rc_calibration.h"
+#include "airspeed_calibration.h"
+
+/* oddly, ERROR is not defined for c++ */
+#ifdef ERROR
+# undef ERROR
+#endif
+static const int ERROR = -1;
+
+extern struct system_load_s system_load;
+
+#define LOW_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS 1000.0f
+#define CRITICAL_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS 100.0f
+
+/* Decouple update interval and hysteris counters, all depends on intervals */
+#define COMMANDER_MONITORING_INTERVAL 50000
+#define COMMANDER_MONITORING_LOOPSPERMSEC (1/(COMMANDER_MONITORING_INTERVAL/1000.0f))
+#define LOW_VOLTAGE_BATTERY_COUNTER_LIMIT (LOW_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
+#define CRITICAL_VOLTAGE_BATTERY_COUNTER_LIMIT (CRITICAL_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
+
+#define STICK_ON_OFF_LIMIT 0.75f
+#define STICK_THRUST_RANGE 1.0f
+#define STICK_ON_OFF_HYSTERESIS_TIME_MS 1000
+#define STICK_ON_OFF_COUNTER_LIMIT (STICK_ON_OFF_HYSTERESIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
+
+#define GPS_FIX_TYPE_2D 2
+#define GPS_FIX_TYPE_3D 3
+#define GPS_QUALITY_GOOD_HYSTERIS_TIME_MS 5000
+#define GPS_QUALITY_GOOD_COUNTER_LIMIT (GPS_QUALITY_GOOD_HYSTERIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
+
+#define LOCAL_POSITION_TIMEOUT 1000000 /**< consider the local position estimate invalid after 1s */
+
+#define PRINT_INTERVAL	5000000
+#define PRINT_MODE_REJECT_INTERVAL	2000000
+
+enum MAV_MODE_FLAG {
+	MAV_MODE_FLAG_CUSTOM_MODE_ENABLED = 1, /* 0b00000001 Reserved for future use. | */
+	MAV_MODE_FLAG_TEST_ENABLED = 2, /* 0b00000010 system has a test mode enabled. This flag is intended for temporary system tests and should not be used for stable implementations. | */
+	MAV_MODE_FLAG_AUTO_ENABLED = 4, /* 0b00000100 autonomous mode enabled, system finds its own goal positions. Guided flag can be set or not, depends on the actual implementation. | */
+	MAV_MODE_FLAG_GUIDED_ENABLED = 8, /* 0b00001000 guided mode enabled, system flies MISSIONs / mission items. | */
+	MAV_MODE_FLAG_STABILIZE_ENABLED = 16, /* 0b00010000 system stabilizes electronically its attitude (and optionally position). It needs however further control inputs to move around. | */
+	MAV_MODE_FLAG_HIL_ENABLED = 32, /* 0b00100000 hardware in the loop simulation. All motors / actuators are blocked, but internal software is full operational. | */
+	MAV_MODE_FLAG_MANUAL_INPUT_ENABLED = 64, /* 0b01000000 remote control input is enabled. | */
+	MAV_MODE_FLAG_SAFETY_ARMED = 128, /* 0b10000000 MAV safety set to armed. Motors are enabled / running / can start. Ready to fly. | */
+	MAV_MODE_FLAG_ENUM_END = 129, /*  | */
+};
+
+/* Mavlink file descriptors */
+static int mavlink_fd;
+
+/* flags */
+static bool commander_initialized = false;
+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 */
+
+/* timout until lowlevel failsafe */
+static unsigned int failsafe_lowlevel_timeout_ms;
+static unsigned int leds_counter;
+/* To remember when last notification was sent */
+static uint64_t last_print_mode_reject_time = 0;
+
+
+/* tasks waiting for low prio thread */
+typedef enum {
+	LOW_PRIO_TASK_NONE = 0,
+	LOW_PRIO_TASK_PARAM_SAVE,
+	LOW_PRIO_TASK_PARAM_LOAD,
+	LOW_PRIO_TASK_GYRO_CALIBRATION,
+	LOW_PRIO_TASK_MAG_CALIBRATION,
+	LOW_PRIO_TASK_ALTITUDE_CALIBRATION,
+	LOW_PRIO_TASK_RC_CALIBRATION,
+	LOW_PRIO_TASK_ACCEL_CALIBRATION,
+	LOW_PRIO_TASK_AIRSPEED_CALIBRATION
+} low_prio_task_t;
+
+static low_prio_task_t low_prio_task = LOW_PRIO_TASK_NONE;
+
+/**
+ * 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().
+ *
+ * @ingroup apps
+ */
+extern "C" __EXPORT int commander_main(int argc, char *argv[]);
+
+/**
+ * Print the correct usage.
+ */
+void usage(const char *reason);
+
+/**
+ * React to commands that are sent e.g. from the mavlink module.
+ */
+void handle_command(struct vehicle_status_s *status, struct vehicle_control_mode_s *control_mode, struct vehicle_command_s *cmd, struct actuator_armed_s *armed);
+
+/**
+ * Mainloop of commander.
+ */
+int commander_thread_main(int argc, char *argv[]);
+
+void toggle_status_leds(vehicle_status_s *status, actuator_armed_s *armed, vehicle_gps_position_s *gps_position);
+
+void check_mode_switches(struct manual_control_setpoint_s *sp_man, struct vehicle_status_s *current_status);
+
+transition_result_t check_main_state_machine(struct vehicle_status_s *current_status);
+
+void print_reject_mode(const char *msg);
+
+transition_result_t check_navigation_state_machine(struct vehicle_status_s *current_status, struct vehicle_control_mode_s *control_mode);
+
+/**
+ * Loop that runs at a lower rate and priority for calibration and parameter tasks.
+ */
+void *commander_low_prio_loop(void *arg);
+
+
+int commander_main(int argc, char *argv[])
+{
+	if (argc < 1)
+		usage("missing command");
+
+	if (!strcmp(argv[1], "start")) {
+
+		if (thread_running) {
+			warnx("commander already running\n");
+			/* this is not an error */
+			exit(0);
+		}
+
+		thread_should_exit = false;
+		daemon_task = task_spawn_cmd("commander",
+					     SCHED_DEFAULT,
+					     SCHED_PRIORITY_MAX - 40,
+					     3000,
+					     commander_thread_main,
+					     (argv) ? (const char **)&argv[2] : (const char **)NULL);
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "stop")) {
+		thread_should_exit = true;
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "status")) {
+		if (thread_running) {
+			warnx("\tcommander is running\n");
+
+		} else {
+			warnx("\tcommander not started\n");
+		}
+
+		exit(0);
+	}
+
+	usage("unrecognized command");
+	exit(1);
+}
+
+void usage(const char *reason)
+{
+	if (reason)
+		fprintf(stderr, "%s\n", reason);
+
+	fprintf(stderr, "usage: daemon {start|stop|status} [-p <additional params>]\n\n");
+	exit(1);
+}
+
+void handle_command(struct vehicle_status_s *status, const struct safety_s *safety, struct vehicle_control_mode_s *control_mode, struct vehicle_command_s *cmd, struct actuator_armed_s *armed)
+{
+	/* result of the command */
+	uint8_t result = VEHICLE_CMD_RESULT_UNSUPPORTED;
+
+	/* request to set different system mode */
+	switch (cmd->command) {
+	case VEHICLE_CMD_DO_SET_MODE: {
+			uint8_t base_mode = (uint8_t) cmd->param1;
+			uint32_t custom_mode = (uint32_t) cmd->param2;
+
+			// TODO remove debug code
+			mavlink_log_critical(mavlink_fd, "[cmd] command setmode: %d %d", base_mode, custom_mode);
+			/* set arming state */
+			transition_result_t arming_res = TRANSITION_NOT_CHANGED;
+
+			if (base_mode & MAV_MODE_FLAG_SAFETY_ARMED) {
+				arming_res = arming_state_transition(status, safety, ARMING_STATE_ARMED, armed);
+
+				if (arming_res == TRANSITION_CHANGED) {
+					mavlink_log_info(mavlink_fd, "[cmd] ARMED by command");
+				}
+
+			} else {
+				if (status->arming_state == ARMING_STATE_ARMED || status->arming_state == ARMING_STATE_ARMED_ERROR) {
+					arming_state_t new_arming_state = (status->arming_state == ARMING_STATE_ARMED ? ARMING_STATE_STANDBY : ARMING_STATE_STANDBY_ERROR);
+					arming_res = arming_state_transition(status, safety, new_arming_state, armed);
+
+					if (arming_res == TRANSITION_CHANGED) {
+						mavlink_log_info(mavlink_fd, "[cmd] DISARMED by command");
+					}
+
+				} else {
+					arming_res = TRANSITION_NOT_CHANGED;
+				}
+			}
+
+			/* set main state */
+			transition_result_t main_res = TRANSITION_DENIED;
+
+			if (base_mode & MAV_MODE_FLAG_CUSTOM_MODE_ENABLED) {
+				/* use autopilot-specific mode */
+				if (custom_mode == PX4_CUSTOM_MODE_MANUAL) {
+					/* MANUAL */
+					main_res = main_state_transition(status, MAIN_STATE_MANUAL);
+
+				} else if (custom_mode == PX4_CUSTOM_MODE_SEATBELT) {
+					/* SEATBELT */
+					main_res = main_state_transition(status, MAIN_STATE_SEATBELT);
+
+				} else if (custom_mode == PX4_CUSTOM_MODE_EASY) {
+					/* EASY */
+					main_res = main_state_transition(status, MAIN_STATE_EASY);
+
+				} else if (custom_mode == PX4_CUSTOM_MODE_AUTO) {
+					/* AUTO */
+					main_res = main_state_transition(status, MAIN_STATE_AUTO);
+				}
+
+			} else {
+				/* use base mode */
+				if (base_mode & MAV_MODE_FLAG_AUTO_ENABLED) {
+					/* AUTO */
+					main_res = main_state_transition(status, MAIN_STATE_AUTO);
+
+				} else if (base_mode & MAV_MODE_FLAG_MANUAL_INPUT_ENABLED) {
+					if (base_mode & MAV_MODE_FLAG_GUIDED_ENABLED) {
+						/* EASY */
+						main_res = main_state_transition(status, MAIN_STATE_EASY);
+
+					} else if (base_mode & MAV_MODE_FLAG_STABILIZE_ENABLED) {
+						/* MANUAL */
+						main_res = main_state_transition(status, MAIN_STATE_MANUAL);
+					}
+				}
+			}
+
+			if (arming_res != TRANSITION_DENIED && main_res != TRANSITION_DENIED) {
+				result = VEHICLE_CMD_RESULT_ACCEPTED;
+
+			} else {
+				result = VEHICLE_CMD_RESULT_TEMPORARILY_REJECTED;
+			}
+
+			break;
+		}
+
+	case VEHICLE_CMD_COMPONENT_ARM_DISARM:
+		break;
+
+	case VEHICLE_CMD_PREFLIGHT_REBOOT_SHUTDOWN:
+			if (is_safe(status, safety, armed)) {
+
+				if (((int)(cmd->param1)) == 1) {
+					/* reboot */
+					systemreset(false);
+				} else if (((int)(cmd->param1)) == 3) {
+					/* reboot to bootloader */
+
+					// XXX implement
+					result = VEHICLE_CMD_RESULT_UNSUPPORTED;
+				} else {
+					result = VEHICLE_CMD_RESULT_DENIED;
+				}
+			
+			} else {
+				result = VEHICLE_CMD_RESULT_DENIED;
+			}
+		break;
+
+	case VEHICLE_CMD_PREFLIGHT_CALIBRATION: {
+			low_prio_task_t new_low_prio_task = LOW_PRIO_TASK_NONE;
+
+			if ((int)(cmd->param1) == 1) {
+				/* gyro calibration */
+				new_low_prio_task = LOW_PRIO_TASK_GYRO_CALIBRATION;
+
+			} else if ((int)(cmd->param2) == 1) {
+				/* magnetometer calibration */
+				new_low_prio_task = LOW_PRIO_TASK_MAG_CALIBRATION;
+
+			} else if ((int)(cmd->param3) == 1) {
+				/* zero-altitude pressure calibration */
+				//new_low_prio_task = LOW_PRIO_TASK_ALTITUDE_CALIBRATION;
+			} else if ((int)(cmd->param4) == 1) {
+				/* RC calibration */
+				new_low_prio_task = LOW_PRIO_TASK_RC_CALIBRATION;
+
+			} else if ((int)(cmd->param5) == 1) {
+				/* accelerometer calibration */
+				new_low_prio_task = LOW_PRIO_TASK_ACCEL_CALIBRATION;
+
+			} else if ((int)(cmd->param6) == 1) {
+				/* airspeed calibration */
+				new_low_prio_task = LOW_PRIO_TASK_AIRSPEED_CALIBRATION;
+			}
+
+			/* check if we have new task and no other task is scheduled */
+			if (low_prio_task == LOW_PRIO_TASK_NONE && new_low_prio_task != LOW_PRIO_TASK_NONE) {
+				/* try to go to INIT/PREFLIGHT arming state */
+				if (TRANSITION_DENIED != arming_state_transition(status, safety, ARMING_STATE_INIT, armed)) {
+					result = VEHICLE_CMD_RESULT_ACCEPTED;
+					low_prio_task = new_low_prio_task;
+
+				} else {
+					result = VEHICLE_CMD_RESULT_DENIED;
+				}
+
+			} else {
+				result = VEHICLE_CMD_RESULT_TEMPORARILY_REJECTED;
+			}
+
+			break;
+		}
+
+	case VEHICLE_CMD_PREFLIGHT_STORAGE: {
+			low_prio_task_t new_low_prio_task = LOW_PRIO_TASK_NONE;
+
+			if (((int)(cmd->param1)) == 0) {
+				new_low_prio_task = LOW_PRIO_TASK_PARAM_LOAD;
+
+			} else if (((int)(cmd->param1)) == 1) {
+				new_low_prio_task = LOW_PRIO_TASK_PARAM_SAVE;
+			}
+
+			/* check if we have new task and no other task is scheduled */
+			if (low_prio_task == LOW_PRIO_TASK_NONE && new_low_prio_task != LOW_PRIO_TASK_NONE) {
+				result = VEHICLE_CMD_RESULT_ACCEPTED;
+				low_prio_task = new_low_prio_task;
+
+			} else {
+				result = VEHICLE_CMD_RESULT_TEMPORARILY_REJECTED;
+			}
+
+			break;
+		}
+
+	default:
+		break;
+	}
+
+	/* supported command handling stop */
+	if (result == VEHICLE_CMD_RESULT_ACCEPTED) {
+		tune_positive();
+
+	} else {
+		tune_negative();
+
+		if (result == VEHICLE_CMD_RESULT_DENIED) {
+			mavlink_log_critical(mavlink_fd, "[cmd] command denied: %u", cmd->command);
+
+		} else if (result == VEHICLE_CMD_RESULT_FAILED) {
+			mavlink_log_critical(mavlink_fd, "[cmd] command failed: %u", cmd->command);
+
+		} else if (result == VEHICLE_CMD_RESULT_TEMPORARILY_REJECTED) {
+			mavlink_log_critical(mavlink_fd, "[cmd] command temporarily rejected: %u", cmd->command);
+
+		} else if (result == VEHICLE_CMD_RESULT_UNSUPPORTED) {
+			mavlink_log_critical(mavlink_fd, "[cmd] command unsupported: %u", cmd->command);
+		}
+	}
+
+	/* send any requested ACKs */
+	if (cmd->confirmation > 0) {
+		/* send acknowledge command */
+		// XXX TODO
+	}
+
+}
+
+int commander_thread_main(int argc, char *argv[])
+{
+	/* not yet initialized */
+	commander_initialized = false;
+	bool home_position_set = false;
+
+	bool battery_tune_played = false;
+	bool arm_tune_played = false;
+
+	/* set parameters */
+	failsafe_lowlevel_timeout_ms = 0;
+	param_get(param_find("SYS_FAILSAVE_LL"), &failsafe_lowlevel_timeout_ms);
+
+	param_t _param_sys_type = param_find("MAV_TYPE");
+	param_t _param_system_id = param_find("MAV_SYS_ID");
+	param_t _param_component_id = param_find("MAV_COMP_ID");
+
+	/* welcome user */
+	warnx("[commander] starting");
+
+	/* pthread for slow low prio thread */
+	pthread_t commander_low_prio_thread;
+
+	/* initialize */
+	if (led_init() != 0) {
+		warnx("ERROR: Failed to initialize leds");
+	}
+
+	if (buzzer_init() != OK) {
+		warnx("ERROR: Failed to initialize buzzer");
+	}
+
+	mavlink_fd = open(MAVLINK_LOG_DEVICE, 0);
+
+	if (mavlink_fd < 0) {
+		warnx("ERROR: Failed to open MAVLink log stream, start mavlink app first.");
+	}
+
+	/* Main state machine */
+	struct vehicle_status_s status;
+	orb_advert_t status_pub;
+	/* make sure we are in preflight state */
+	memset(&status, 0, sizeof(status));
+
+	/* armed topic */
+	struct actuator_armed_s armed;
+	orb_advert_t armed_pub;
+	/* Initialize armed with all false */
+	memset(&armed, 0, sizeof(armed));
+
+	/* flags for control apps */
+	struct vehicle_control_mode_s control_mode;
+	orb_advert_t control_mode_pub;
+
+	/* Initialize all flags to false */
+	memset(&control_mode, 0, sizeof(control_mode));
+
+	status.main_state = MAIN_STATE_MANUAL;
+	status.navigation_state = NAVIGATION_STATE_STANDBY;
+	status.arming_state = ARMING_STATE_INIT;
+	status.hil_state = HIL_STATE_OFF;
+
+	/* neither manual nor offboard control commands have been received */
+	status.offboard_control_signal_found_once = false;
+	status.rc_signal_found_once = false;
+
+	/* mark all signals lost as long as they haven't been found */
+	status.rc_signal_lost = true;
+	status.offboard_control_signal_lost = true;
+
+	/* allow manual override initially */
+	control_mode.flag_external_manual_override_ok = true;
+
+	/* set battery warning flag */
+	status.battery_warning = VEHICLE_BATTERY_WARNING_NONE;
+
+	// XXX for now just set sensors as initialized
+	status.condition_system_sensors_initialized = true;
+
+	// XXX just disable offboard control for now
+	control_mode.flag_control_offboard_enabled = false;
+
+	/* advertise to ORB */
+	status_pub = orb_advertise(ORB_ID(vehicle_status), &status);
+	/* publish current state machine */
+
+	/* publish initial state */
+	status.counter++;
+	status.timestamp = hrt_absolute_time();
+	orb_publish(ORB_ID(vehicle_status), status_pub, &status);
+
+	armed_pub = orb_advertise(ORB_ID(actuator_armed), &armed);
+
+	control_mode_pub = orb_advertise(ORB_ID(vehicle_control_mode), &control_mode);
+
+	/* home position */
+	orb_advert_t home_pub = -1;
+	struct home_position_s home;
+	memset(&home, 0, sizeof(home));
+
+	if (status_pub < 0) {
+		warnx("ERROR: orb_advertise for topic vehicle_status failed (uorb app running?).\n");
+		warnx("exiting.");
+		exit(ERROR);
+	}
+
+	mavlink_log_info(mavlink_fd, "[cmd] started");
+
+	pthread_attr_t commander_low_prio_attr;
+	pthread_attr_init(&commander_low_prio_attr);
+	pthread_attr_setstacksize(&commander_low_prio_attr, 2048);
+
+	struct sched_param param;
+	/* low priority */
+	param.sched_priority = SCHED_PRIORITY_DEFAULT - 50;
+	(void)pthread_attr_setschedparam(&commander_low_prio_attr, &param);
+	pthread_create(&commander_low_prio_thread, &commander_low_prio_attr, commander_low_prio_loop, NULL);
+
+	/* Start monitoring loop */
+	unsigned counter = 0;
+	unsigned low_voltage_counter = 0;
+	unsigned critical_voltage_counter = 0;
+	unsigned stick_off_counter = 0;
+	unsigned stick_on_counter = 0;
+
+	/* To remember when last notification was sent */
+	uint64_t last_print_control_time = 0;
+
+	enum VEHICLE_BATTERY_WARNING battery_warning_previous = VEHICLE_BATTERY_WARNING_NONE;
+	bool armed_previous = false;
+
+	bool low_battery_voltage_actions_done;
+	bool critical_battery_voltage_actions_done;
+
+	uint64_t last_idle_time = 0;
+
+	uint64_t start_time = 0;
+
+	bool status_changed = true;
+	bool param_init_forced = true;
+
+	bool updated = false;
+
+	/* Subscribe to safety topic */
+	int safety_sub = orb_subscribe(ORB_ID(safety));
+	struct safety_s safety;
+	memset(&safety, 0, sizeof(safety));
+	safety.safety_switch_available = false;
+	safety.safety_off = false;
+
+	/* Subscribe to manual control data */
+	int sp_man_sub = orb_subscribe(ORB_ID(manual_control_setpoint));
+	struct manual_control_setpoint_s sp_man;
+	memset(&sp_man, 0, sizeof(sp_man));
+
+	/* Subscribe to offboard control data */
+	int sp_offboard_sub = orb_subscribe(ORB_ID(offboard_control_setpoint));
+	struct offboard_control_setpoint_s sp_offboard;
+	memset(&sp_offboard, 0, sizeof(sp_offboard));
+
+	/* Subscribe to global position */
+	int global_position_sub = orb_subscribe(ORB_ID(vehicle_global_position));
+	struct vehicle_global_position_s global_position;
+	memset(&global_position, 0, sizeof(global_position));
+
+	/* Subscribe to local position data */
+	int local_position_sub = orb_subscribe(ORB_ID(vehicle_local_position));
+	struct vehicle_local_position_s local_position;
+	memset(&local_position, 0, sizeof(local_position));
+
+	/*
+	 * The home position is set based on GPS only, to prevent a dependency between
+	 * position estimator and commander. RAW GPS is more than good enough for a
+	 * non-flying vehicle.
+	 */
+
+	/* Subscribe to GPS topic */
+	int gps_sub = orb_subscribe(ORB_ID(vehicle_gps_position));
+	struct vehicle_gps_position_s gps_position;
+	memset(&gps_position, 0, sizeof(gps_position));
+
+	/* Subscribe to sensor topic */
+	int sensor_sub = orb_subscribe(ORB_ID(sensor_combined));
+	struct sensor_combined_s sensors;
+	memset(&sensors, 0, sizeof(sensors));
+
+	/* Subscribe to differential pressure topic */
+	int diff_pres_sub = orb_subscribe(ORB_ID(differential_pressure));
+	struct differential_pressure_s diff_pres;
+	memset(&diff_pres, 0, sizeof(diff_pres));
+	uint64_t last_diff_pres_time = 0;
+
+	/* Subscribe to command topic */
+	int cmd_sub = orb_subscribe(ORB_ID(vehicle_command));
+	struct vehicle_command_s cmd;
+	memset(&cmd, 0, sizeof(cmd));
+
+	/* Subscribe to parameters changed topic */
+	int param_changed_sub = orb_subscribe(ORB_ID(parameter_update));
+	struct parameter_update_s param_changed;
+	memset(&param_changed, 0, sizeof(param_changed));
+
+	/* Subscribe to battery topic */
+	int battery_sub = orb_subscribe(ORB_ID(battery_status));
+	struct battery_status_s battery;
+	memset(&battery, 0, sizeof(battery));
+	battery.voltage_v = 0.0f;
+
+	/* Subscribe to subsystem info topic */
+	int subsys_sub = orb_subscribe(ORB_ID(subsystem_info));
+	struct subsystem_info_s info;
+	memset(&info, 0, sizeof(info));
+
+	/* now initialized */
+	commander_initialized = true;
+	thread_running = true;
+
+	start_time = hrt_absolute_time();
+
+	while (!thread_should_exit) {
+		hrt_abstime t = hrt_absolute_time();
+
+		/* update parameters */
+		orb_check(param_changed_sub, &updated);
+
+		if (updated || param_init_forced) {
+			param_init_forced = false;
+			/* parameters changed */
+			orb_copy(ORB_ID(parameter_update), param_changed_sub, &param_changed);
+
+			/* update parameters */
+			if (!armed.armed) {
+				if (param_get(_param_sys_type, &(status.system_type)) != OK) {
+					warnx("failed getting new system type");
+				}
+
+				/* disable manual override for all systems that rely on electronic stabilization */
+				if (status.system_type == VEHICLE_TYPE_COAXIAL ||
+				    status.system_type == VEHICLE_TYPE_HELICOPTER ||
+				    status.system_type == VEHICLE_TYPE_TRICOPTER ||
+				    status.system_type == VEHICLE_TYPE_QUADROTOR ||
+				    status.system_type == VEHICLE_TYPE_HEXAROTOR ||
+				    status.system_type == VEHICLE_TYPE_OCTOROTOR) {
+					control_mode.flag_external_manual_override_ok = false;
+					status.is_rotary_wing = true;
+
+				} else {
+					control_mode.flag_external_manual_override_ok = true;
+					status.is_rotary_wing = false;
+				}
+
+				/* check and update system / component ID */
+				param_get(_param_system_id, &(status.system_id));
+				param_get(_param_component_id, &(status.component_id));
+				status_changed = true;
+			}
+		}
+
+		orb_check(sp_man_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(manual_control_setpoint), sp_man_sub, &sp_man);
+		}
+
+		orb_check(sp_offboard_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(offboard_control_setpoint), sp_offboard_sub, &sp_offboard);
+		}
+
+		orb_check(sensor_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(sensor_combined), sensor_sub, &sensors);
+		}
+
+		orb_check(diff_pres_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(differential_pressure), diff_pres_sub, &diff_pres);
+			last_diff_pres_time = diff_pres.timestamp;
+		}
+
+		orb_check(cmd_sub, &updated);
+
+		if (updated) {
+			/* got command */
+			orb_copy(ORB_ID(vehicle_command), cmd_sub, &cmd);
+
+			/* handle it */
+			handle_command(&status, &safety, &control_mode, &cmd, &armed);
+		}
+
+		/* update safety topic */
+		orb_check(safety_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(safety), safety_sub, &safety);
+		}
+
+		/* update global position estimate */
+		orb_check(global_position_sub, &updated);
+
+		if (updated) {
+			/* position changed */
+			orb_copy(ORB_ID(vehicle_global_position), global_position_sub, &global_position);
+		}
+
+		/* update local position estimate */
+		orb_check(local_position_sub, &updated);
+
+		if (updated) {
+			/* position changed */
+			orb_copy(ORB_ID(vehicle_local_position), local_position_sub, &local_position);
+		}
+
+		/* set the condition to valid if there has recently been a local position estimate */
+		if (t - local_position.timestamp < LOCAL_POSITION_TIMEOUT) {
+			if (!status.condition_local_position_valid) {
+				status.condition_local_position_valid = true;
+				status_changed = true;
+			}
+
+		} else {
+			if (status.condition_local_position_valid) {
+				status.condition_local_position_valid = false;
+				status_changed = true;
+			}
+		}
+
+		/* update battery status */
+		orb_check(battery_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(battery_status), battery_sub, &battery);
+			status.battery_voltage = battery.voltage_v;
+			status.condition_battery_voltage_valid = true;
+		}
+
+		/*
+		 * Only update battery voltage estimate if system has
+		 * been running for two and a half seconds.
+		 */
+		if (t - start_time > 2500000 && status.condition_battery_voltage_valid) {
+			status.battery_remaining = battery_remaining_estimate_voltage(status.battery_voltage);
+
+		} else {
+			status.battery_voltage = 0.0f;
+		}
+
+		/* update subsystem */
+		orb_check(subsys_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(subsystem_info), subsys_sub, &info);
+
+			warnx("subsystem changed: %d\n", (int)info.subsystem_type);
+
+			/* mark / unmark as present */
+			if (info.present) {
+				status.onboard_control_sensors_present |= info.subsystem_type;
+
+			} else {
+				status.onboard_control_sensors_present &= ~info.subsystem_type;
+			}
+
+			/* mark / unmark as enabled */
+			if (info.enabled) {
+				status.onboard_control_sensors_enabled |= info.subsystem_type;
+
+			} else {
+				status.onboard_control_sensors_enabled &= ~info.subsystem_type;
+			}
+
+			/* mark / unmark as ok */
+			if (info.ok) {
+				status.onboard_control_sensors_health |= info.subsystem_type;
+
+			} else {
+				status.onboard_control_sensors_health &= ~info.subsystem_type;
+			}
+
+			status_changed = true;
+		}
+
+		toggle_status_leds(&status, &armed, &gps_position);
+
+		if (counter % (1000000 / COMMANDER_MONITORING_INTERVAL) == 0) {
+			/* compute system load */
+			uint64_t interval_runtime = system_load.tasks[0].total_runtime - last_idle_time;
+
+			if (last_idle_time > 0)
+				status.load = 1000 - (interval_runtime / 1000);	//system load is time spent in non-idle
+
+			last_idle_time = system_load.tasks[0].total_runtime;
+		}
+
+		/* if battery voltage is getting lower, warn using buzzer, etc. */
+		if (status.condition_battery_voltage_valid && status.battery_remaining < 0.15f && !low_battery_voltage_actions_done) {
+			//TODO: add filter, or call emergency after n measurements < VOLTAGE_BATTERY_MINIMAL_MILLIVOLTS
+			if (low_voltage_counter > LOW_VOLTAGE_BATTERY_COUNTER_LIMIT) {
+				low_battery_voltage_actions_done = true;
+				mavlink_log_critical(mavlink_fd, "[cmd] WARNING: LOW BATTERY");
+				status.battery_warning = VEHICLE_BATTERY_WARNING_WARNING;
+				status_changed = true;
+			}
+
+			low_voltage_counter++;
+
+		} else if (status.condition_battery_voltage_valid && status.battery_remaining < 0.1f && !critical_battery_voltage_actions_done && low_battery_voltage_actions_done) {
+			/* critical battery voltage, this is rather an emergency, change state machine */
+			if (critical_voltage_counter > CRITICAL_VOLTAGE_BATTERY_COUNTER_LIMIT) {
+				critical_battery_voltage_actions_done = true;
+				mavlink_log_critical(mavlink_fd, "[cmd] EMERGENCY: CRITICAL BATTERY");
+				status.battery_warning = VEHICLE_BATTERY_WARNING_ALERT;
+				arming_state_transition(&status, &safety, ARMING_STATE_ARMED_ERROR, &armed);
+				status_changed = true;
+			}
+
+			critical_voltage_counter++;
+
+		} else {
+			low_voltage_counter = 0;
+			critical_voltage_counter = 0;
+		}
+
+		/* End battery voltage check */
+
+		/* If in INIT state, try to proceed to STANDBY state */
+		if (status.arming_state == ARMING_STATE_INIT && low_prio_task == LOW_PRIO_TASK_NONE) {
+			// XXX check for sensors
+			arming_state_transition(&status, &safety, ARMING_STATE_STANDBY, &armed);
+
+		} else {
+			// XXX: Add emergency stuff if sensors are lost
+		}
+
+
+		/*
+		 * Check for valid position information.
+		 *
+		 * If the system has a valid position source from an onboard
+		 * position estimator, it is safe to operate it autonomously.
+		 * The flag_vector_flight_mode_ok flag indicates that a minimum
+		 * set of position measurements is available.
+		 */
+
+		/* store current state to reason later about a state change */
+		// bool vector_flight_mode_ok = current_status.flag_vector_flight_mode_ok;
+		bool global_pos_valid = status.condition_global_position_valid;
+		bool local_pos_valid = status.condition_local_position_valid;
+		bool airspeed_valid = status.condition_airspeed_valid;
+
+
+		/* check for global or local position updates, set a timeout of 2s */
+		if (t - global_position.timestamp < 2000000 && t > 2000000 && global_position.valid) {
+			status.condition_global_position_valid = true;
+
+		} else {
+			status.condition_global_position_valid = false;
+		}
+
+		if (t - local_position.timestamp < 2000000 && t > 2000000 && local_position.valid) {
+			status.condition_local_position_valid = true;
+
+		} else {
+			status.condition_local_position_valid = false;
+		}
+
+		/* Check for valid airspeed/differential pressure measurements */
+		if (t - last_diff_pres_time < 2000000 && t > 2000000) {
+			status.condition_airspeed_valid = true;
+
+		} else {
+			status.condition_airspeed_valid = false;
+		}
+
+		orb_check(gps_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(vehicle_gps_position), gps_sub, &gps_position);
+
+			/* check for first, long-term and valid GPS lock -> set home position */
+			float hdop_m = gps_position.eph_m;
+			float vdop_m = gps_position.epv_m;
+
+			/* check if GPS fix is ok */
+			float hdop_threshold_m = 4.0f;
+			float vdop_threshold_m = 8.0f;
+
+			/*
+			 * If horizontal dilution of precision (hdop / eph)
+			 * and vertical diluation of precision (vdop / epv)
+			 * are below a certain threshold (e.g. 4 m), AND
+			 * home position is not yet set AND the last GPS
+			 * GPS measurement is not older than two seconds AND
+			 * the system is currently not armed, set home
+			 * position to the current position.
+			 */
+
+			if (!home_position_set && gps_position.fix_type == GPS_FIX_TYPE_3D &&
+			    (hdop_m < hdop_threshold_m) && (vdop_m < vdop_threshold_m) &&	// XXX note that vdop is 0 for mtk
+			    (t - gps_position.timestamp_position < 2000000)
+			    && !armed.armed) {
+				/* copy position data to uORB home message, store it locally as well */
+				// TODO use global position estimate
+				home.lat = gps_position.lat;
+				home.lon = gps_position.lon;
+				home.alt = gps_position.alt;
+
+				home.eph_m = gps_position.eph_m;
+				home.epv_m = gps_position.epv_m;
+
+				home.s_variance_m_s = gps_position.s_variance_m_s;
+				home.p_variance_m = gps_position.p_variance_m;
+
+				double home_lat_d = home.lat * 1e-7;
+				double home_lon_d = home.lon * 1e-7;
+				warnx("home: lat = %.7f, lon = %.7f", home_lat_d, home_lon_d);
+				mavlink_log_info(mavlink_fd, "[cmd] home: %.7f, %.7f", home_lat_d, home_lon_d);
+
+				/* announce new home position */
+				if (home_pub > 0) {
+					orb_publish(ORB_ID(home_position), home_pub, &home);
+
+				} else {
+					home_pub = orb_advertise(ORB_ID(home_position), &home);
+				}
+
+				/* mark home position as set */
+				home_position_set = true;
+				tune_positive();
+			}
+		}
+
+		/* ignore RC signals if in offboard control mode */
+		if (!status.offboard_control_signal_found_once && sp_man.timestamp != 0) {
+			/* start RC input check */
+			if ((t - sp_man.timestamp) < 100000) {
+				/* handle the case where RC signal was regained */
+				if (!status.rc_signal_found_once) {
+					status.rc_signal_found_once = true;
+					mavlink_log_critical(mavlink_fd, "[cmd] detected RC signal first time");
+					status_changed = true;
+
+				} else {
+					if (status.rc_signal_lost) {
+						mavlink_log_critical(mavlink_fd, "[cmd] RC signal regained");
+						status_changed = true;
+					}
+				}
+
+				status.rc_signal_cutting_off = false;
+				status.rc_signal_lost = false;
+				status.rc_signal_lost_interval = 0;
+
+				transition_result_t res;	// store all transitions results here
+
+				/* arm/disarm by RC */
+				res = TRANSITION_NOT_CHANGED;
+
+				/* check if left stick is in lower left position and we are in MANUAL or AUTO mode -> disarm
+				 * do it only for rotary wings */
+				if (status.is_rotary_wing &&
+				    (status.arming_state == ARMING_STATE_ARMED || status.arming_state == ARMING_STATE_ARMED_ERROR) &&
+				    (status.main_state == MAIN_STATE_MANUAL || status.navigation_state == NAVIGATION_STATE_AUTO_READY)) {
+					if (sp_man.yaw < -STICK_ON_OFF_LIMIT && sp_man.throttle < STICK_THRUST_RANGE * 0.1f) {
+						if (stick_off_counter > STICK_ON_OFF_COUNTER_LIMIT) {
+							/* disarm to STANDBY if ARMED or to STANDBY_ERROR if ARMED_ERROR */
+							arming_state_t new_arming_state = (status.arming_state == ARMING_STATE_ARMED ? ARMING_STATE_STANDBY : ARMING_STATE_STANDBY_ERROR);
+							res = arming_state_transition(&status, &safety, new_arming_state, &armed);
+							stick_off_counter = 0;
+
+						} else {
+							stick_off_counter++;
+						}
+
+						stick_on_counter = 0;
+
+					} else {
+						stick_off_counter = 0;
+					}
+				}
+
+				/* check if left stick is in lower right position and we're in manual mode -> arm */
+				if (status.arming_state == ARMING_STATE_STANDBY &&
+				    status.main_state == MAIN_STATE_MANUAL) {
+					if (sp_man.yaw > STICK_ON_OFF_LIMIT && sp_man.throttle < STICK_THRUST_RANGE * 0.1f) {
+						if (stick_on_counter > STICK_ON_OFF_COUNTER_LIMIT) {
+							res = arming_state_transition(&status, &safety, ARMING_STATE_ARMED, &armed);
+							stick_on_counter = 0;
+
+						} else {
+							stick_on_counter++;
+						}
+
+						stick_off_counter = 0;
+
+					} else {
+						stick_on_counter = 0;
+					}
+				}
+
+				if (res == TRANSITION_CHANGED) {
+					if (status.arming_state == ARMING_STATE_ARMED) {
+						mavlink_log_info(mavlink_fd, "[cmd] ARMED by RC");
+
+					} else {
+						mavlink_log_info(mavlink_fd, "[cmd] DISARMED by RC");
+					}
+				}
+
+				/* fill current_status according to mode switches */
+				check_mode_switches(&sp_man, &status);
+
+				/* evaluate the main state machine */
+				res = check_main_state_machine(&status);
+
+				if (res == TRANSITION_CHANGED) {
+					mavlink_log_info(mavlink_fd, "[cmd] main state: %d", status.main_state);
+					tune_positive();
+
+				} else if (res == TRANSITION_DENIED) {
+					/* DENIED here indicates bug in the commander */
+					warnx("ERROR: main denied: arm %d main %d mode_sw %d", status.arming_state, status.main_state, status.mode_switch);
+					mavlink_log_critical(mavlink_fd, "[cmd] ERROR: main denied: arm %d main %d mode_sw %d", status.arming_state, status.main_state, status.mode_switch);
+				}
+
+			} else {
+
+				/* print error message for first RC glitch and then every 5s */
+				if (!status.rc_signal_cutting_off || (t - last_print_control_time) > PRINT_INTERVAL) {
+					// TODO remove debug code
+					if (!status.rc_signal_cutting_off) {
+						warnx("Reason: not rc_signal_cutting_off\n");
+
+					} else {
+						warnx("last print time: %llu\n", last_print_control_time);
+					}
+
+					/* only complain if the offboard control is NOT active */
+					status.rc_signal_cutting_off = true;
+					mavlink_log_critical(mavlink_fd, "[cmd] CRITICAL: NO RC CONTROL");
+
+					last_print_control_time = t;
+				}
+
+				/* flag as lost and update interval since when the signal was lost (to initiate RTL after some time) */
+				status.rc_signal_lost_interval = t - sp_man.timestamp;
+
+				/* if the RC signal is gone for a full second, consider it lost */
+				if (status.rc_signal_lost_interval > 1000000) {
+					status.rc_signal_lost = true;
+					status.failsave_lowlevel = true;
+					status_changed = true;
+				}
+			}
+		}
+
+		/* END mode switch */
+		/* END RC state check */
+
+		// TODO check this
+		/* state machine update for offboard control */
+		if (!status.rc_signal_found_once && sp_offboard.timestamp != 0) {
+			if ((t - sp_offboard.timestamp) < 5000000) {	// TODO 5s is too long ?
+
+				// /* decide about attitude control flag, enable in att/pos/vel */
+				// bool attitude_ctrl_enabled = (sp_offboard.mode == OFFBOARD_CONTROL_MODE_DIRECT_ATTITUDE ||
+				// 				  sp_offboard.mode == OFFBOARD_CONTROL_MODE_DIRECT_VELOCITY ||
+				// 				  sp_offboard.mode == OFFBOARD_CONTROL_MODE_DIRECT_POSITION);
+
+				// /* decide about rate control flag, enable it always XXX (for now) */
+				// bool rates_ctrl_enabled = true;
+
+				// /* set up control mode */
+				// if (current_status.flag_control_attitude_enabled != attitude_ctrl_enabled) {
+				// 	current_status.flag_control_attitude_enabled = attitude_ctrl_enabled;
+				// 	state_changed = true;
+				// }
+
+				// if (current_status.flag_control_rates_enabled != rates_ctrl_enabled) {
+				// 	current_status.flag_control_rates_enabled = rates_ctrl_enabled;
+				// 	state_changed = true;
+				// }
+
+				// /* handle the case where offboard control signal was regained */
+				// if (!current_status.offboard_control_signal_found_once) {
+				// 	current_status.offboard_control_signal_found_once = true;
+				// 	/* enable offboard control, disable manual input */
+				// 	current_status.flag_control_manual_enabled = false;
+				// 	current_status.flag_control_offboard_enabled = true;
+				// 	state_changed = true;
+				// 	tune_positive();
+
+				// 	mavlink_log_critical(mavlink_fd, "DETECTED OFFBOARD SIGNAL FIRST");
+
+				// } else {
+				// 	if (current_status.offboard_control_signal_lost) {
+				// 		mavlink_log_critical(mavlink_fd, "RECOVERY OFFBOARD CONTROL");
+				// 		state_changed = true;
+				// 		tune_positive();
+				// 	}
+				// }
+
+				status.offboard_control_signal_weak = false;
+				status.offboard_control_signal_lost = false;
+				status.offboard_control_signal_lost_interval = 0;
+
+				// XXX check if this is correct
+				/* arm / disarm on request */
+				if (sp_offboard.armed && !armed.armed) {
+					arming_state_transition(&status, &safety, ARMING_STATE_ARMED, &armed);
+
+				} else if (!sp_offboard.armed && armed.armed) {
+					arming_state_transition(&status, &safety, ARMING_STATE_STANDBY, &armed);
+				}
+
+			} else {
+
+				/* print error message for first offboard signal glitch and then every 5s */
+				if (!status.offboard_control_signal_weak || ((t - last_print_control_time) > PRINT_INTERVAL)) {
+					status.offboard_control_signal_weak = true;
+					mavlink_log_critical(mavlink_fd, "[cmd] CRITICAL: NO OFFBOARD CONTROL");
+					last_print_control_time = t;
+				}
+
+				/* flag as lost and update interval since when the signal was lost (to initiate RTL after some time) */
+				status.offboard_control_signal_lost_interval = t - sp_offboard.timestamp;
+
+				/* if the signal is gone for 0.1 seconds, consider it lost */
+				if (status.offboard_control_signal_lost_interval > 100000) {
+					status.offboard_control_signal_lost = true;
+					status.failsave_lowlevel_start_time = t;
+					tune_positive();
+
+					/* kill motors after timeout */
+					if (t - status.failsave_lowlevel_start_time > failsafe_lowlevel_timeout_ms * 1000) {
+						status.failsave_lowlevel = true;
+						status_changed = true;
+					}
+				}
+			}
+		}
+
+		/* evaluate the navigation state machine */
+		transition_result_t res = check_navigation_state_machine(&status, &control_mode);
+
+		if (res == TRANSITION_DENIED) {
+			/* DENIED here indicates bug in the commander */
+			warnx("ERROR: nav denied: arm %d main %d nav %d", status.arming_state, status.main_state, status.navigation_state);
+			mavlink_log_critical(mavlink_fd, "[cmd] ERROR: nav denied: arm %d main %d nav %d", status.arming_state, status.main_state, status.navigation_state);
+		}
+
+		/* check which state machines for changes, clear "changed" flag */
+		bool arming_state_changed = check_arming_state_changed();
+		bool main_state_changed = check_main_state_changed();
+		bool navigation_state_changed = check_navigation_state_changed();
+
+		if (arming_state_changed || main_state_changed || navigation_state_changed) {
+			mavlink_log_info(mavlink_fd, "[cmd] state: arm %d, main %d, nav %d", status.arming_state, status.main_state, status.navigation_state);
+			status_changed = true;
+		}
+
+		/* publish arming state */
+		if (arming_state_changed) {
+			armed.timestamp = t;
+			orb_publish(ORB_ID(actuator_armed), armed_pub, &armed);
+		}
+
+		/* publish control mode */
+		if (navigation_state_changed) {
+			/* publish new navigation state */
+			control_mode.counter++;
+			control_mode.timestamp = t;
+			orb_publish(ORB_ID(vehicle_control_mode), control_mode_pub, &control_mode);
+		}
+
+		/* publish vehicle status at least with 1 Hz */
+		if (counter % (1000000 / COMMANDER_MONITORING_INTERVAL) == 0 || status_changed) {
+			status.counter++;
+			status.timestamp = t;
+			orb_publish(ORB_ID(vehicle_status), status_pub, &status);
+			status_changed = false;
+		}
+
+		/* play arming and battery warning tunes */
+		if (!arm_tune_played && armed.armed) {
+			/* play tune when armed */
+			if (tune_arm() == OK)
+				arm_tune_played = true;
+
+		} else if (status.battery_warning == VEHICLE_BATTERY_WARNING_WARNING) {
+			/* play tune on battery warning */
+			if (tune_low_bat() == OK)
+				battery_tune_played = true;
+
+		} else if (status.battery_remaining == VEHICLE_BATTERY_WARNING_ALERT) {
+			/* play tune on battery critical */
+			if (tune_critical_bat() == OK)
+				battery_tune_played = true;
+
+		} else if (battery_tune_played) {
+			tune_stop();
+			battery_tune_played = false;
+		}
+
+		/* reset arm_tune_played when disarmed */
+		if (!(armed.armed && (!safety.safety_switch_available || (safety.safety_off && safety.safety_switch_available)))) {
+			arm_tune_played = false;
+		}
+
+		/* store old modes to detect and act on state transitions */
+		battery_warning_previous = status.battery_warning;
+		armed_previous = armed.armed;
+
+		fflush(stdout);
+		counter++;
+		usleep(COMMANDER_MONITORING_INTERVAL);
+	}
+
+	/* wait for threads to complete */
+	pthread_join(commander_low_prio_thread, NULL);
+
+	/* close fds */
+	led_deinit();
+	buzzer_deinit();
+	close(sp_man_sub);
+	close(sp_offboard_sub);
+	close(local_position_sub);
+	close(global_position_sub);
+	close(gps_sub);
+	close(sensor_sub);
+	close(safety_sub);
+	close(cmd_sub);
+	close(subsys_sub);
+	close(diff_pres_sub);
+	close(param_changed_sub);
+	close(battery_sub);
+
+	warnx("exiting");
+	fflush(stdout);
+
+	thread_running = false;
+
+	return 0;
+}
+
+void
+toggle_status_leds(vehicle_status_s *status, actuator_armed_s *armed, vehicle_gps_position_s *gps_position)
+{
+	if (leds_counter % 2 == 0) {
+		/* run at 10Hz, full cycle is 16 ticks = 10/16Hz */
+		if (armed->armed) {
+			/* armed, solid */
+			led_on(LED_AMBER);
+
+		} else if (armed->ready_to_arm) {
+			/* ready to arm, blink at 2.5Hz */
+			if (leds_counter & 8) {
+				led_on(LED_AMBER);
+
+			} else {
+				led_off(LED_AMBER);
+			}
+
+		} else {
+			/* not ready to arm, blink at 10Hz */
+			led_toggle(LED_AMBER);
+		}
+
+		if (status->condition_global_position_valid) {
+			/* position estimated, solid */
+			led_on(LED_BLUE);
+
+		} else if (leds_counter == 0) {
+			/* waiting for position estimate, short blink at 1.25Hz */
+			led_on(LED_BLUE);
+
+		} else {
+			/* no position estimator available, off */
+			led_off(LED_BLUE);
+		}
+	}
+
+	leds_counter++;
+
+	if (leds_counter >= 16)
+		leds_counter = 0;
+}
+
+void
+check_mode_switches(struct manual_control_setpoint_s *sp_man, struct vehicle_status_s *current_status)
+{
+	/* main mode switch */
+	if (!isfinite(sp_man->mode_switch)) {
+		warnx("mode sw not finite");
+		current_status->mode_switch = MODE_SWITCH_MANUAL;
+
+	} else if (sp_man->mode_switch > STICK_ON_OFF_LIMIT) {
+		current_status->mode_switch = MODE_SWITCH_AUTO;
+
+	} else if (sp_man->mode_switch < -STICK_ON_OFF_LIMIT) {
+		current_status->mode_switch = MODE_SWITCH_MANUAL;
+
+	} else {
+		current_status->mode_switch = MODE_SWITCH_ASSISTED;
+	}
+
+	/* land switch */
+	if (!isfinite(sp_man->return_switch)) {
+		current_status->return_switch = RETURN_SWITCH_NONE;
+
+	} else if (sp_man->return_switch > STICK_ON_OFF_LIMIT) {
+		current_status->return_switch = RETURN_SWITCH_RETURN;
+
+	} else {
+		current_status->return_switch = RETURN_SWITCH_NONE;
+	}
+
+	/* assisted switch */
+	if (!isfinite(sp_man->assisted_switch)) {
+		current_status->assisted_switch = ASSISTED_SWITCH_SEATBELT;
+
+	} else if (sp_man->assisted_switch > STICK_ON_OFF_LIMIT) {
+		current_status->assisted_switch = ASSISTED_SWITCH_EASY;
+
+	} else {
+		current_status->assisted_switch = ASSISTED_SWITCH_SEATBELT;
+	}
+
+	/* mission switch  */
+	if (!isfinite(sp_man->mission_switch)) {
+		current_status->mission_switch = MISSION_SWITCH_MISSION;
+
+	} else if (sp_man->mission_switch > STICK_ON_OFF_LIMIT) {
+		current_status->mission_switch = MISSION_SWITCH_NONE;
+
+	} else {
+		current_status->mission_switch = MISSION_SWITCH_MISSION;
+	}
+}
+
+transition_result_t
+check_main_state_machine(struct vehicle_status_s *current_status)
+{
+	/* evaluate the main state machine */
+	transition_result_t res = TRANSITION_DENIED;
+
+	switch (current_status->mode_switch) {
+	case MODE_SWITCH_MANUAL:
+		res = main_state_transition(current_status, MAIN_STATE_MANUAL);
+		// TRANSITION_DENIED is not possible here
+		break;
+
+	case MODE_SWITCH_ASSISTED:
+		if (current_status->assisted_switch == ASSISTED_SWITCH_EASY) {
+			res = main_state_transition(current_status, MAIN_STATE_EASY);
+
+			if (res != TRANSITION_DENIED)
+				break;	// changed successfully or already in this state
+
+			// else fallback to SEATBELT
+			print_reject_mode("EASY");
+		}
+
+		res = main_state_transition(current_status, MAIN_STATE_SEATBELT);
+
+		if (res != TRANSITION_DENIED)
+			break;	// changed successfully or already in this mode
+
+		if (current_status->assisted_switch != ASSISTED_SWITCH_EASY)	// don't print both messages
+			print_reject_mode("SEATBELT");
+
+		// else fallback to MANUAL
+		res = main_state_transition(current_status, MAIN_STATE_MANUAL);
+		// TRANSITION_DENIED is not possible here
+		break;
+
+	case MODE_SWITCH_AUTO:
+		res = main_state_transition(current_status, MAIN_STATE_AUTO);
+
+		if (res != TRANSITION_DENIED)
+			break;	// changed successfully or already in this state
+
+		// else fallback to SEATBELT (EASY likely will not work too)
+		print_reject_mode("AUTO");
+		res = main_state_transition(current_status, MAIN_STATE_SEATBELT);
+
+		if (res != TRANSITION_DENIED)
+			break;	// changed successfully or already in this state
+
+		// else fallback to MANUAL
+		res = main_state_transition(current_status, MAIN_STATE_MANUAL);
+		// TRANSITION_DENIED is not possible here
+		break;
+
+	default:
+		break;
+	}
+
+	return res;
+}
+
+void
+print_reject_mode(const char *msg)
+{
+	hrt_abstime t = hrt_absolute_time();
+
+	if (t - last_print_mode_reject_time > PRINT_MODE_REJECT_INTERVAL) {
+		last_print_mode_reject_time = t;
+		char s[80];
+		sprintf(s, "[cmd] WARNING: reject %s", msg);
+		mavlink_log_critical(mavlink_fd, s);
+		tune_negative();
+	}
+}
+
+transition_result_t
+check_navigation_state_machine(struct vehicle_status_s *current_status, struct vehicle_control_mode_s *control_mode)
+{
+	transition_result_t res = TRANSITION_DENIED;
+
+	if (current_status->arming_state == ARMING_STATE_ARMED || current_status->arming_state == ARMING_STATE_ARMED_ERROR) {
+		/* ARMED */
+		switch (current_status->main_state) {
+		case MAIN_STATE_MANUAL:
+			res = navigation_state_transition(current_status, current_status->is_rotary_wing ? NAVIGATION_STATE_STABILIZE : NAVIGATION_STATE_DIRECT, control_mode);
+			break;
+
+		case MAIN_STATE_SEATBELT:
+			res = navigation_state_transition(current_status, NAVIGATION_STATE_ALTHOLD, control_mode);
+			break;
+
+		case MAIN_STATE_EASY:
+			res = navigation_state_transition(current_status, NAVIGATION_STATE_VECTOR, control_mode);
+			break;
+
+		case MAIN_STATE_AUTO:
+			if (current_status->navigation_state != NAVIGATION_STATE_AUTO_TAKEOFF) {
+				/* don't act while taking off */
+				if (current_status->condition_landed) {
+					/* if landed: transitions only to AUTO_READY are allowed */
+					res = navigation_state_transition(current_status, NAVIGATION_STATE_AUTO_READY, control_mode);
+					// TRANSITION_DENIED is not possible here
+					break;
+
+				} else {
+					/* if not landed: act depending on switches */
+					if (current_status->return_switch == RETURN_SWITCH_RETURN) {
+						/* RTL */
+						res = navigation_state_transition(current_status, NAVIGATION_STATE_AUTO_RTL, control_mode);
+
+					} else {
+						if (current_status->mission_switch == MISSION_SWITCH_MISSION) {
+							/* MISSION */
+							res = navigation_state_transition(current_status, NAVIGATION_STATE_AUTO_MISSION, control_mode);
+
+						} else {
+							/* LOITER */
+							res = navigation_state_transition(current_status, NAVIGATION_STATE_AUTO_LOITER, control_mode);
+						}
+					}
+				}
+			}
+
+			break;
+
+		default:
+			break;
+		}
+
+	} else {
+		/* DISARMED */
+		res = navigation_state_transition(current_status, NAVIGATION_STATE_STANDBY, control_mode);
+	}
+
+	return res;
+}
+
+void *commander_low_prio_loop(void *arg)
+{
+	/* Set thread name */
+	prctl(PR_SET_NAME, "commander_low_prio", getpid());
+
+	low_prio_task = LOW_PRIO_TASK_NONE;
+
+	while (!thread_should_exit) {
+
+		switch (low_prio_task) {
+		case LOW_PRIO_TASK_PARAM_LOAD:
+
+			if (0 == param_load_default()) {
+				mavlink_log_info(mavlink_fd, "[cmd] parameters loaded");
+
+			} else {
+				mavlink_log_critical(mavlink_fd, "[cmd] parameters load ERROR");
+				tune_error();
+			}
+
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_PARAM_SAVE:
+
+			if (0 == param_save_default()) {
+				mavlink_log_info(mavlink_fd, "[cmd] parameters saved");
+
+			} else {
+				mavlink_log_critical(mavlink_fd, "[cmd] parameters save error");
+				tune_error();
+			}
+
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_GYRO_CALIBRATION:
+
+			do_gyro_calibration(mavlink_fd);
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_MAG_CALIBRATION:
+
+			do_mag_calibration(mavlink_fd);
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_ALTITUDE_CALIBRATION:
+
+			// do_baro_calibration(mavlink_fd);
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_RC_CALIBRATION:
+
+			// do_rc_calibration(mavlink_fd);
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_ACCEL_CALIBRATION:
+
+			do_accel_calibration(mavlink_fd);
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_AIRSPEED_CALIBRATION:
+
+			do_airspeed_calibration(mavlink_fd);
+			low_prio_task = LOW_PRIO_TASK_NONE;
+			break;
+
+		case LOW_PRIO_TASK_NONE:
+		default:
+			/* slow down to 10Hz */
+			usleep(100000);
+			break;
+		}
+
+	}
+
+	return 0;
+}