Merge commit 'bd808ccf3a825ac1304a72dcede12478fda76857' into mavlinkrates2

44 files changed, 1771 insertions, 43 deletions

diff --git a/.gitmodules b/.gitmodules
index 8436b398e..4b84afac2 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -4,3 +4,6 @@
 [submodule "NuttX"]
 	path = NuttX
 	url = git://github.com/PX4/NuttX.git
+[submodule "uavcan"]
+	path = uavcan
+	url = git://github.com/pavel-kirienko/uavcan.git
diff --git a/Makefile b/Makefile
index 7b7c00704..809f54dd3 100644
--- a/Makefile
+++ b/Makefile
@@ -212,6 +212,9 @@ endif
 $(NUTTX_SRC):
 	$(Q) ($(PX4_BASE)/Tools/check_submodules.sh)
 
+$(UAVCAN_DIR):
+	$(Q) (./Tools/check_submodules.sh)
+
 .PHONY: checksubmodules
 checksubmodules:
 	$(Q) ($(PX4_BASE)/Tools/check_submodules.sh)
diff --git a/NuttX b/NuttX
-Subproject 7e1b97bcf10d8495169eec355988ca5890bfd5d
+Subproject 088146b90eee5b614ea6386a64dae343a49a517
diff --git a/ROMFS/px4fmu_common/init.d/4012_quad_x_can b/ROMFS/px4fmu_common/init.d/4012_quad_x_can
new file mode 100644
index 000000000..8c5a4fbf2
--- /dev/null
+++ b/ROMFS/px4fmu_common/init.d/4012_quad_x_can
@@ -0,0 +1,27 @@
+#!nsh
+#
+# F450-sized quadrotor with CAN
+#
+# Lorenz Meier <lm@inf.ethz.ch>
+#
+
+sh /etc/init.d/4001_quad_x
+
+if [ $DO_AUTOCONFIG == yes ]
+then
+	# TODO REVIEW
+	param set MC_ROLL_P 7.0
+	param set MC_ROLLRATE_P 0.1
+	param set MC_ROLLRATE_I 0.0
+	param set MC_ROLLRATE_D 0.003
+	param set MC_PITCH_P 7.0
+	param set MC_PITCHRATE_P 0.1
+	param set MC_PITCHRATE_I 0.0
+	param set MC_PITCHRATE_D 0.003
+	param set MC_YAW_P 2.8
+	param set MC_YAWRATE_P 0.2
+	param set MC_YAWRATE_I 0.0
+	param set MC_YAWRATE_D 0.0
+fi
+
+set OUTPUT_MODE uavcan_esc
diff --git a/ROMFS/px4fmu_common/init.d/rc.autostart b/ROMFS/px4fmu_common/init.d/rc.autostart
index 5d9e9502c..17541e680 100644
--- a/ROMFS/px4fmu_common/init.d/rc.autostart
+++ b/ROMFS/px4fmu_common/init.d/rc.autostart
@@ -136,6 +136,11 @@ then
 	sh /etc/init.d/4011_dji_f450
 fi
 
+if param compare SYS_AUTOSTART 4012
+then
+	sh /etc/init.d/4012_quad_x_can
+fi
+
 if param compare SYS_AUTOSTART 4020
 then
 	sh /etc/init.d/4020_hk_micro_pcb
diff --git a/ROMFS/px4fmu_common/init.d/rc.interface b/ROMFS/px4fmu_common/init.d/rc.interface
index 7f793b219..1de0abb58 100644
--- a/ROMFS/px4fmu_common/init.d/rc.interface
+++ b/ROMFS/px4fmu_common/init.d/rc.interface
@@ -24,6 +24,11 @@ then
 	else
 		set OUTPUT_DEV /dev/pwm_output
 	fi
+
+	if [ $OUTPUT_MODE == uavcan_esc ]
+	then
+		set OUTPUT_DEV /dev/uavcan/esc
+	fi
 	
 	if mixer load $OUTPUT_DEV $MIXER_FILE
 	then
diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index 8855539fe..24b2a299a 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -297,7 +297,17 @@ then
 	# If OUTPUT_MODE == none then something is wrong with setup and we shouldn't try to enable output
 	if [ $OUTPUT_MODE != none ]
 	then
-		if [ $OUTPUT_MODE == io ]
+		if [ $OUTPUT_MODE == uavcan_esc ]
+		then
+			if uavcan start 1
+			then
+				echo "CAN UP"
+			else
+				echo "CAN ERR"
+			fi
+		fi
+
+		if [ $OUTPUT_MODE == io -o $OUTPUT_MODE == uavcan_esc ]
 		then
 			echo "[init] Use PX4IO PWM as primary output"
 			if px4io start
diff --git a/Tools/check_submodules.sh b/Tools/check_submodules.sh
index 8adc6b6c7..3904a2775 100755
--- a/Tools/check_submodules.sh
+++ b/Tools/check_submodules.sh
@@ -53,4 +53,28 @@ else
 	git submodule update;
 fi
 
+
+if [ -d uavcan ]
+then
+	STATUSRETVAL=$(git submodule summary | grep -A20 -i uavcan | grep "<")
+	if [ -z "$STATUSRETVAL" ]
+	then
+		echo "Checked uavcan submodule, correct version found"
+	else
+		echo ""
+		echo ""
+		echo "uavcan sub repo not at correct version. Try 'git submodule update'"
+		echo "or follow instructions on http://pixhawk.org/dev/git/submodules"
+		echo ""
+		echo ""
+		echo "New commits required:"
+		echo "$(git submodule summary)"
+		echo ""
+		exit 1
+	fi
+else
+	git submodule init;
+	git submodule update;
+fi
+
 exit 0
diff --git a/Tools/tests-host/data/fit_linear_voltage.m b/Tools/tests-host/data/fit_linear_voltage.m
new file mode 100644
index 000000000..7d0c2c27f
--- /dev/null
+++ b/Tools/tests-host/data/fit_linear_voltage.m
@@ -0,0 +1,14 @@
+close all;
+clear all;
+M = importdata('px4io_v1.3.csv');
+voltage = M.data(:, 1);
+counts = M.data(:, 2);
+plot(counts, voltage, 'b*-', 'LineWidth', 2, 'MarkerSize', 15);
+coeffs = polyfit(counts, voltage, 1);
+fittedC = linspace(min(counts), max(counts), 500);
+fittedV = polyval(coeffs, fittedC);
+hold on
+plot(fittedC, fittedV, 'r-', 'LineWidth', 3);
+
+slope = coeffs(1)
+y_intersection = coeffs(2)
diff --git a/Tools/tests-host/data/px4io_v1.3.csv b/Tools/tests-host/data/px4io_v1.3.csv
new file mode 100644
index 000000000..b41ee8f1f
--- /dev/null
+++ b/Tools/tests-host/data/px4io_v1.3.csv
@@ -0,0 +1,70 @@
+voltage, counts
+4.3, 950
+4.4, 964
+4.5, 986
+4.6, 1009
+4.7, 1032
+4.8, 1055
+4.9, 1078
+5.0, 1101
+5.2, 1124
+5.3, 1148
+5.4, 1171
+5.5, 1195
+6.0, 1304
+6.1, 1329
+6.2, 1352
+7.0, 1517
+7.1, 1540
+7.2, 1564
+7.3, 1585
+7.4, 1610
+7.5, 1636
+8.0, 1728
+8.1, 1752
+8.2, 1755
+8.3, 1798
+8.4, 1821
+9.0, 1963
+9.1, 1987
+9.3, 2010
+9.4, 2033
+10.0, 2174
+10.1, 2198
+10.2, 2221
+10.3, 2245
+10.4, 2268
+11.0, 2385
+11.1, 2409
+11.2, 2432
+11.3, 2456
+11.4, 2480
+11.5, 2502
+11.6, 2526
+11.7, 2550
+11.8, 2573
+11.9, 2597
+12.0, 2621
+12.1, 2644
+12.3, 2668
+12.4, 2692
+12.5, 2716
+12.6, 2737
+12.7, 2761
+13.0, 2832
+13.5, 2950
+13.6, 2973
+14.1, 3068
+14.2, 3091
+14.7, 3209
+15.0, 3280
+15.1, 3304
+15.5, 3374
+15.6, 3397
+15.7, 3420
+16.0, 3492
+16.1, 3514
+16.2, 3538
+16.9, 3680
+17.0, 3704
+17.1, 3728
diff --git a/makefiles/config_px4fmu-v2_default.mk b/makefiles/config_px4fmu-v2_default.mk
index adfbc2b7d..a498a1b40 100644
--- a/makefiles/config_px4fmu-v2_default.mk
+++ b/makefiles/config_px4fmu-v2_default.mk
@@ -74,6 +74,7 @@ MODULES		+= modules/commander
 MODULES		+= modules/navigator
 MODULES		+= modules/mavlink
 MODULES		+= modules/gpio_led
+MODULES		+= modules/uavcan
 
 #
 # Estimation modules (EKF/ SO3 / other filters)
diff --git a/makefiles/nuttx.mk b/makefiles/nuttx.mk
index d283096b2..bf0744140 100644
--- a/makefiles/nuttx.mk
+++ b/makefiles/nuttx.mk
@@ -64,6 +64,7 @@ LDSCRIPT		+= $(NUTTX_EXPORT_DIR)build/ld.script
 # Add directories from the NuttX export to the relevant search paths
 #
 INCLUDE_DIRS		+= $(NUTTX_EXPORT_DIR)include \
+			   $(NUTTX_EXPORT_DIR)include/cxx \
 			   $(NUTTX_EXPORT_DIR)arch/chip \
 			   $(NUTTX_EXPORT_DIR)arch/common
 
diff --git a/makefiles/setup.mk b/makefiles/setup.mk
index 6a092ef6b..4bfa7a087 100644
--- a/makefiles/setup.mk
+++ b/makefiles/setup.mk
@@ -49,6 +49,7 @@ export NUTTX_SRC	 = $(abspath $(PX4_BASE)/NuttX/nuttx)/
 export MAVLINK_SRC	 = $(abspath $(PX4_BASE)/mavlink/include/mavlink/v1.0)/
 export NUTTX_APP_SRC	 = $(abspath $(PX4_BASE)/NuttX/apps)/
 export MAVLINK_SRC	 = $(abspath $(PX4_BASE)/mavlink)/
+export UAVCAN_DIR	 = $(abspath $(PX4_BASE)/uavcan)/
 export ROMFS_SRC	 = $(abspath $(PX4_BASE)/ROMFS)/
 export IMAGE_DIR	 = $(abspath $(PX4_BASE)/Images)/
 export BUILD_DIR	 = $(abspath $(PX4_BASE)/Build)/
diff --git a/makefiles/toolchain_gnu-arm-eabi.mk b/makefiles/toolchain_gnu-arm-eabi.mk
index d8d45d34e..71c7fb49f 100644
--- a/makefiles/toolchain_gnu-arm-eabi.mk
+++ b/makefiles/toolchain_gnu-arm-eabi.mk
@@ -121,7 +121,7 @@ INSTRUMENTATIONDEFINES	 = $(ARCHINSTRUMENTATIONDEFINES_$(CONFIG_ARCH))
 # Language-specific flags
 #
 ARCHCFLAGS		 = -std=gnu99
-ARCHCXXFLAGS		 = -fno-exceptions -fno-rtti -std=gnu++0x
+ARCHCXXFLAGS		 = -fno-exceptions -fno-rtti -std=gnu++0x -fno-threadsafe-statics
 
 # Generic warnings
 #
diff --git a/src/drivers/airspeed/module.mk b/src/drivers/airspeed/module.mk
index 4eef06161..5fbc75309 100644
--- a/src/drivers/airspeed/module.mk
+++ b/src/drivers/airspeed/module.mk
@@ -36,3 +36,5 @@
 #
 
 SRCS			= airspeed.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/bma180/module.mk b/src/drivers/bma180/module.mk
index 4c60ee082..33433307a 100644
--- a/src/drivers/bma180/module.mk
+++ b/src/drivers/bma180/module.mk
@@ -38,3 +38,5 @@
 MODULE_COMMAND	= bma180
 
 SRCS		= bma180.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/drv_tone_alarm.h b/src/drivers/drv_tone_alarm.h
index b7981e9c4..19f792d19 100644
--- a/src/drivers/drv_tone_alarm.h
+++ b/src/drivers/drv_tone_alarm.h
@@ -149,6 +149,7 @@ enum {
 	TONE_GPS_WARNING_TUNE,
 	TONE_ARMING_FAILURE_TUNE,
 	TONE_PARACHUTE_RELEASE_TUNE,
+	TONE_EKF_WARNING_TUNE,
 	TONE_NUMBER_OF_TUNES
 };
 
diff --git a/src/drivers/ets_airspeed/module.mk b/src/drivers/ets_airspeed/module.mk
index 966a5b819..8aaaf0ebb 100644
--- a/src/drivers/ets_airspeed/module.mk
+++ b/src/drivers/ets_airspeed/module.mk
@@ -40,3 +40,5 @@ MODULE_COMMAND		= ets_airspeed
 SRCS			= ets_airspeed.cpp
 
 MODULE_STACKSIZE	= 1200
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/hil/module.mk b/src/drivers/hil/module.mk
index f8895f5d5..f1fc49fb3 100644
--- a/src/drivers/hil/module.mk
+++ b/src/drivers/hil/module.mk
@@ -38,3 +38,5 @@
 MODULE_COMMAND	= hil
 
 SRCS		= hil.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/led/module.mk b/src/drivers/led/module.mk
index 777f3e442..5b7b4491b 100644
--- a/src/drivers/led/module.mk
+++ b/src/drivers/led/module.mk
@@ -36,3 +36,5 @@
 #
 
 SRCS		= led.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/md25/module.mk b/src/drivers/md25/module.mk
index 13821a6b5..3f9cf2d89 100644
--- a/src/drivers/md25/module.mk
+++ b/src/drivers/md25/module.mk
@@ -40,3 +40,5 @@ MODULE_COMMAND		= md25
 
 SRCS			= md25.cpp \
 			  md25_main.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/meas_airspeed/module.mk b/src/drivers/meas_airspeed/module.mk
index 2a15b669f..6f5909978 100644
--- a/src/drivers/meas_airspeed/module.mk
+++ b/src/drivers/meas_airspeed/module.mk
@@ -42,3 +42,5 @@ SRCS			= meas_airspeed.cpp
 MODULE_STACKSIZE	= 1200
 
 EXTRACXXFLAGS	= -Weffc++
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/ms5611/module.mk b/src/drivers/ms5611/module.mk
index 20f8aa173..ee74058fc 100644
--- a/src/drivers/ms5611/module.mk
+++ b/src/drivers/ms5611/module.mk
@@ -38,3 +38,5 @@
 MODULE_COMMAND	= ms5611
 
 SRCS		= ms5611.cpp ms5611_spi.cpp ms5611_i2c.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/px4flow/module.mk b/src/drivers/px4flow/module.mk
index d3062e457..460bec7b9 100644
--- a/src/drivers/px4flow/module.mk
+++ b/src/drivers/px4flow/module.mk
@@ -38,3 +38,5 @@
 MODULE_COMMAND	= px4flow
 
 SRCS		= px4flow.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/roboclaw/module.mk b/src/drivers/roboclaw/module.mk
index 1abecf198..c5e55bdc3 100644
--- a/src/drivers/roboclaw/module.mk
+++ b/src/drivers/roboclaw/module.mk
@@ -39,3 +39,5 @@ MODULE_COMMAND		= roboclaw
 
 SRCS			= roboclaw_main.cpp \
 			  RoboClaw.cpp
+
+MAXOPTIMIZATION	 = -Os
diff --git a/src/drivers/stm32/tone_alarm/tone_alarm.cpp b/src/drivers/stm32/tone_alarm/tone_alarm.cpp
index 810f4aacc..03c7bd399 100644
--- a/src/drivers/stm32/tone_alarm/tone_alarm.cpp
+++ b/src/drivers/stm32/tone_alarm/tone_alarm.cpp
@@ -336,6 +336,7 @@ ToneAlarm::ToneAlarm() :
 	_default_tunes[TONE_GPS_WARNING_TUNE] = "MFT255L4AAAL1F#";					//gps warning slow
 	_default_tunes[TONE_ARMING_FAILURE_TUNE] = "MFT255L4<<<BAP";
 	_default_tunes[TONE_PARACHUTE_RELEASE_TUNE] = "MFT255L16agagagag";			// parachute release
+	_default_tunes[TONE_EKF_WARNING_TUNE] = "MFT255L8ddd#d#eeff";				// ekf warning
 
 	_tune_names[TONE_STARTUP_TUNE] = "startup";			// startup tune
 	_tune_names[TONE_ERROR_TUNE] = "error";				// ERROR tone
@@ -348,6 +349,7 @@ ToneAlarm::ToneAlarm() :
 	_tune_names[TONE_GPS_WARNING_TUNE] = "gps_warning";	            // gps warning
 	_tune_names[TONE_ARMING_FAILURE_TUNE] = "arming_failure";            //fail to arm
 	_tune_names[TONE_PARACHUTE_RELEASE_TUNE] = "parachute_release";	// parachute release
+	_tune_names[TONE_EKF_WARNING_TUNE] = "ekf_warning";				// ekf warning
 }
 
 ToneAlarm::~ToneAlarm()
diff --git a/src/modules/commander/commander.cpp b/src/modules/commander/commander.cpp
index 04450a44f..a0c896178 100644
--- a/src/modules/commander/commander.cpp
+++ b/src/modules/commander/commander.cpp
@@ -913,6 +913,11 @@ int commander_thread_main(int argc, char *argv[])
 	struct system_power_s system_power;
 	memset(&system_power, 0, sizeof(system_power));
 
+	/* Subscribe to actuator controls (outputs) */
+	int actuator_controls_sub = orb_subscribe(ORB_ID_VEHICLE_ATTITUDE_CONTROLS);
+	struct actuator_controls_s actuator_controls;
+	memset(&actuator_controls, 0, sizeof(actuator_controls));
+
 	control_status_leds(&status, &armed, true);
 
 	/* now initialized */
@@ -1194,13 +1199,17 @@ int commander_thread_main(int argc, char *argv[])
 
 		if (updated) {
 			orb_copy(ORB_ID(battery_status), battery_sub, &battery);
+			orb_copy(ORB_ID_VEHICLE_ATTITUDE_CONTROLS, actuator_controls_sub, &actuator_controls);
 
 			/* only consider battery voltage if system has been running 2s and battery voltage is valid */
 			if (hrt_absolute_time() > start_time + 2000000 && battery.voltage_filtered_v > 0.0f) {
 				status.battery_voltage = battery.voltage_filtered_v;
 				status.battery_current = battery.current_a;
 				status.condition_battery_voltage_valid = true;
-				status.battery_remaining = battery_remaining_estimate_voltage(battery.voltage_filtered_v, battery.discharged_mah);
+
+				/* get throttle (if armed), as we only care about energy negative throttle also counts */
+				float throttle = (armed.armed) ? fabsf(actuator_controls.control[3]) : 0.0f;
+				status.battery_remaining = battery_remaining_estimate_voltage(battery.voltage_filtered_v, battery.discharged_mah, throttle);
 			}
 		}
 
@@ -1262,13 +1271,13 @@ int commander_thread_main(int argc, char *argv[])
 		}
 
 		/* if battery voltage is getting lower, warn using buzzer, etc. */
-		if (status.condition_battery_voltage_valid && status.battery_remaining < 0.25f && !low_battery_voltage_actions_done) {
+		if (status.condition_battery_voltage_valid && status.battery_remaining < 0.18f && !low_battery_voltage_actions_done) {
 			low_battery_voltage_actions_done = true;
 			mavlink_log_critical(mavlink_fd, "LOW BATTERY, RETURN TO LAND ADVISED");
 			status.battery_warning = VEHICLE_BATTERY_WARNING_LOW;
 			status_changed = true;
 
-		} else if (status.condition_battery_voltage_valid && status.battery_remaining < 0.1f && !critical_battery_voltage_actions_done && low_battery_voltage_actions_done) {
+		} else if (status.condition_battery_voltage_valid && status.battery_remaining < 0.09f && !critical_battery_voltage_actions_done && low_battery_voltage_actions_done) {
 			/* critical battery voltage, this is rather an emergency, change state machine */
 			critical_battery_voltage_actions_done = true;
 			mavlink_log_emergency(mavlink_fd, "CRITICAL BATTERY, LAND IMMEDIATELY");
@@ -1407,8 +1416,12 @@ int commander_thread_main(int argc, char *argv[])
 				arming_state_changed = true;
 
 			} else if (arming_ret == TRANSITION_DENIED) {
-				/* DENIED here indicates bug in the commander */
-				mavlink_log_critical(mavlink_fd, "arming state transition denied");
+				/*
+				 * the arming transition can be denied to a number of reasons:
+				 *  - pre-flight check failed (sensors not ok or not calibrated)
+				 *  - safety not disabled
+				 *  - system not in manual mode
+				 */
 				tune_negative(true);
 			}
 
diff --git a/src/modules/commander/commander_helper.cpp b/src/modules/commander/commander_helper.cpp
index d5fe122cb..2022e99fb 100644
--- a/src/modules/commander/commander_helper.cpp
+++ b/src/modules/commander/commander_helper.cpp
@@ -281,15 +281,17 @@ void rgbled_set_pattern(rgbled_pattern_t *pattern)
 	}
 }
 
-float battery_remaining_estimate_voltage(float voltage, float discharged)
+float battery_remaining_estimate_voltage(float voltage, float discharged, float throttle_normalized)
 {
 	float ret = 0;
 	static param_t bat_v_empty_h;
 	static param_t bat_v_full_h;
 	static param_t bat_n_cells_h;
 	static param_t bat_capacity_h;
-	static float bat_v_empty = 3.2f;
-	static float bat_v_full = 4.0f;
+	static param_t bat_v_load_drop_h;
+	static float bat_v_empty = 3.4f;
+	static float bat_v_full = 4.2f;
+	static float bat_v_load_drop = 0.06f;
 	static int bat_n_cells = 3;
 	static float bat_capacity = -1.0f;
 	static bool initialized = false;
@@ -297,23 +299,26 @@ float battery_remaining_estimate_voltage(float voltage, float discharged)
 
 	if (!initialized) {
 		bat_v_empty_h = param_find("BAT_V_EMPTY");
-		bat_v_full_h = param_find("BAT_V_FULL");
+		bat_v_full_h = param_find("BAT_V_CHARGED");
 		bat_n_cells_h = param_find("BAT_N_CELLS");
 		bat_capacity_h = param_find("BAT_CAPACITY");
+		bat_v_load_drop_h = param_find("BAT_V_LOAD_DROP");
 		initialized = true;
 	}
 
 	if (counter % 100 == 0) {
 		param_get(bat_v_empty_h, &bat_v_empty);
 		param_get(bat_v_full_h, &bat_v_full);
+		param_get(bat_v_load_drop_h, &bat_v_load_drop);
 		param_get(bat_n_cells_h, &bat_n_cells);
 		param_get(bat_capacity_h, &bat_capacity);
 	}
 
 	counter++;
 
-	/* remaining charge estimate based on voltage */
-	float remaining_voltage = (voltage - bat_n_cells * bat_v_empty) / (bat_n_cells * (bat_v_full - bat_v_empty));
+	/* remaining charge estimate based on voltage and internal resistance (drop under load) */
+	float bat_v_full_dynamic = bat_v_full - (bat_v_load_drop * throttle_normalized);
+	float remaining_voltage = (voltage - (bat_n_cells * bat_v_empty)) / (bat_n_cells * (bat_v_full_dynamic - bat_v_empty));
 
 	if (bat_capacity > 0.0f) {
 		/* if battery capacity is known, use discharged current for estimate, but don't show more than voltage estimate */
diff --git a/src/modules/commander/commander_helper.h b/src/modules/commander/commander_helper.h
index a49c9e263..4a77fe487 100644
--- a/src/modules/commander/commander_helper.h
+++ b/src/modules/commander/commander_helper.h
@@ -80,8 +80,9 @@ void rgbled_set_pattern(rgbled_pattern_t *pattern);
  *
  * @param voltage the current battery voltage
  * @param discharged the discharged capacity
+ * @param throttle_normalized the normalized throttle magnitude from 0 to 1. Negative throttle should be converted to this range as well, as it consumes energy.
  * @return the estimated remaining capacity in 0..1
  */
-float battery_remaining_estimate_voltage(float voltage, float discharged);
+float battery_remaining_estimate_voltage(float voltage, float discharged, float throttle_normalized);
 
 #endif /* COMMANDER_HELPER_H_ */
diff --git a/src/modules/commander/commander_params.c b/src/modules/commander/commander_params.c
index 4750f9d5c..dba68700b 100644
--- a/src/modules/commander/commander_params.c
+++ b/src/modules/commander/commander_params.c
@@ -65,7 +65,17 @@ PARAM_DEFINE_FLOAT(BAT_V_EMPTY, 3.4f);
  *
  * @group Battery Calibration
  */
-PARAM_DEFINE_FLOAT(BAT_V_FULL, 3.9f);
+PARAM_DEFINE_FLOAT(BAT_V_CHARGED, 4.2f);
+
+/**
+ * Voltage drop per cell on 100% load
+ *
+ * This implicitely defines the internal resistance
+ * to maximum current ratio and assumes linearity.
+ *
+ * @group Battery Calibration
+ */
+PARAM_DEFINE_FLOAT(BAT_V_LOAD_DROP, 0.07f);
 
 /**
  * Number of cells.
diff --git a/src/modules/commander/state_machine_helper.cpp b/src/modules/commander/state_machine_helper.cpp
index 372ba9d7d..7b26e3e8c 100644
--- a/src/modules/commander/state_machine_helper.cpp
+++ b/src/modules/commander/state_machine_helper.cpp
@@ -110,8 +110,8 @@ arming_state_transition(struct vehicle_status_s *status,            /// current
 	ASSERT(ARMING_STATE_IN_AIR_RESTORE == ARMING_STATE_MAX - 1);
 
 	transition_result_t ret = TRANSITION_DENIED;
-
 	arming_state_t current_arming_state = status->arming_state;
+	bool feedback_provided = false;
 
 	/* only check transition if the new state is actually different from the current one */
 	if (new_arming_state == current_arming_state) {
@@ -156,13 +156,15 @@ arming_state_transition(struct vehicle_status_s *status,            /// current
 
 					// Fail transition if pre-arm check fails
 					if (prearm_ret) {
+						/* the prearm check already prints the reject reason */
+						feedback_provided = true;
 						valid_transition = false;
 
 					// Fail transition if we need safety switch press
 					} else if (safety->safety_switch_available && !safety->safety_off) {
 
-						mavlink_log_critical(mavlink_fd, "NOT ARMING: Press safety switch!");
-
+						mavlink_log_critical(mavlink_fd, "NOT ARMING: Press safety switch first!");
+						feedback_provided = true;
 						valid_transition = false;
 					}
 
@@ -173,6 +175,7 @@ arming_state_transition(struct vehicle_status_s *status,            /// current
 						if (!status->condition_power_input_valid) {
 
 							mavlink_log_critical(mavlink_fd, "NOT ARMING: Connect power module.");
+							feedback_provided = true;
 							valid_transition = false;
 						}
 
@@ -182,6 +185,7 @@ arming_state_transition(struct vehicle_status_s *status,            /// current
 							(status->avionics_power_rail_voltage < 4.9f))) {
 
 							mavlink_log_critical(mavlink_fd, "NOT ARMING: Avionics power low: %6.2f V.", (double)status->avionics_power_rail_voltage);
+							feedback_provided = true;
 							valid_transition = false;
 						}
 					}
@@ -200,6 +204,8 @@ arming_state_transition(struct vehicle_status_s *status,            /// current
 
 		/* Sensors need to be initialized for STANDBY state */
 		if (new_arming_state == ARMING_STATE_STANDBY && !status->condition_system_sensors_initialized) {
+			mavlink_log_critical(mavlink_fd, "NOT ARMING: Sensors not operational.");
+			feedback_provided = true;
 			valid_transition = false;
 		}
 
@@ -216,11 +222,14 @@ arming_state_transition(struct vehicle_status_s *status,            /// current
 	}
 
 	if (ret == TRANSITION_DENIED) {
-		static const char *errMsg = "INVAL: %s - %s";
+		const char * str = "INVAL: %s - %s";
+		/* only print to console here by default as this is too technical to be useful during operation */
+		warnx(str, state_names[status->arming_state], state_names[new_arming_state]);
 
-		mavlink_log_critical(mavlink_fd, errMsg, state_names[status->arming_state], state_names[new_arming_state]);
-
-		warnx(errMsg, state_names[status->arming_state], state_names[new_arming_state]);
+		/* print to MAVLink if we didn't provide any feedback yet */
+		if (!feedback_provided) {
+			mavlink_log_critical(mavlink_fd, str, state_names[status->arming_state], state_names[new_arming_state]);
+		}
 	}
 
 	return ret;
@@ -648,8 +657,7 @@ int prearm_check(const struct vehicle_status_s *status, const int mavlink_fd)
 		float accel_magnitude = sqrtf(acc.x * acc.x + acc.y * acc.y + acc.z * acc.z);
 
 		if (accel_magnitude < 4.0f || accel_magnitude > 15.0f /* m/s^2 */) {
-			mavlink_log_critical(mavlink_fd, "ARM FAIL: ACCEL RANGE");
-			mavlink_log_critical(mavlink_fd, "hold still while arming");
+			mavlink_log_critical(mavlink_fd, "ARM FAIL: ACCEL RANGE, hold still");
 			/* this is frickin' fatal */
 			failed = true;
 			goto system_eval;
diff --git a/src/modules/position_estimator_inav/position_estimator_inav_params.c b/src/modules/position_estimator_inav/position_estimator_inav_params.c
index 0581f8236..98b31d17b 100644
--- a/src/modules/position_estimator_inav/position_estimator_inav_params.c
+++ b/src/modules/position_estimator_inav/position_estimator_inav_params.c
@@ -40,22 +40,196 @@
 
 #include "position_estimator_inav_params.h"
 
+/**
+ * Z axis weight for barometer
+ *
+ * Weight (cutoff frequency) for barometer altitude measurements.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_Z_BARO, 0.5f);
+
+/**
+ * Z axis weight for GPS
+ *
+ * Weight (cutoff frequency) for GPS altitude measurements. GPS altitude data is very noisy and should be used only as slow correction for baro offset.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_Z_GPS_P, 0.005f);
+
+/**
+ * Z axis weight for sonar
+ *
+ * Weight (cutoff frequency) for sonar measurements.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_Z_SONAR, 3.0f);
+
+/**
+ * XY axis weight for GPS position
+ *
+ * Weight (cutoff frequency) for GPS position measurements.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_XY_GPS_P, 1.0f);
+
+/**
+ * XY axis weight for GPS velocity
+ *
+ * Weight (cutoff frequency) for GPS velocity measurements.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_XY_GPS_V, 2.0f);
+
+/**
+ * XY axis weight for optical flow
+ *
+ * Weight (cutoff frequency) for optical flow (velocity) measurements.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_XY_FLOW, 5.0f);
+
+/**
+ * XY axis weight for resetting velocity
+ *
+ * When velocity sources lost slowly decrease estimated horizontal velocity with this weight.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_XY_RES_V, 0.5f);
+
+/**
+ * XY axis weight factor for GPS when optical flow available
+ *
+ * When optical flow data available, multiply GPS weights (for position and velocity) by this factor.
+ *
+ * @min 0.0
+ * @max 1.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_GPS_FLOW, 0.1f);
+
+/**
+ * Accelerometer bias estimation weight
+ *
+ * Weight (cutoff frequency) for accelerometer bias estimation. 0 to disable.
+ *
+ * @min 0.0
+ * @max 0.1
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_W_ACC_BIAS, 0.05f);
+
+/**
+ * Optical flow scale factor
+ *
+ * Factor to convert raw optical flow (in pixels) to radians [rad/px].
+ *
+ * @min 0.0
+ * @max 1.0
+ * @unit rad/px
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_FLOW_K, 0.15f);
+
+/**
+ * Minimal acceptable optical flow quality
+ *
+ * 0 - lowest quality, 1 - best quality.
+ *
+ * @min 0.0
+ * @max 1.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_FLOW_Q_MIN, 0.5f);
+
+/**
+ * Weight for sonar filter
+ *
+ * Sonar filter detects spikes on sonar measurements and used to detect new surface level.
+ *
+ * @min 0.0
+ * @max 1.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_SONAR_FILT, 0.05f);
+
+/**
+ * Sonar maximal error for new surface
+ *
+ * If sonar measurement error is larger than this value it skiped (spike) or accepted as new surface level (if offset is stable).
+ *
+ * @min 0.0
+ * @max 1.0
+ * @unit m
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_SONAR_ERR, 0.5f);
+
+/**
+ * Land detector time
+ *
+ * Vehicle assumed landed if no altitude changes happened during this time on low throttle.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @unit s
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_LAND_T, 3.0f);
+
+/**
+ * Land detector altitude dispersion threshold
+ *
+ * Dispersion threshold for triggering land detector.
+ *
+ * @min 0.0
+ * @max 10.0
+ * @unit m
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_LAND_DISP, 0.7f);
+
+/**
+ * Land detector throttle threshold
+ *
+ * Value should be lower than minimal hovering thrust. Half of it is good choice.
+ *
+ * @min 0.0
+ * @max 1.0
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_LAND_THR, 0.2f);
+
+/**
+ * GPS delay
+ *
+ * GPS delay compensation
+ *
+ * @min 0.0
+ * @max 1.0
+ * @unit s
+ * @group Position Estimator INAV
+ */
 PARAM_DEFINE_FLOAT(INAV_DELAY_GPS, 0.2f);
 
 int parameters_init(struct position_estimator_inav_param_handles *h)
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index fcd53f1f1..43161aa70 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -739,30 +739,19 @@ registers_get(uint8_t page, uint8_t offset, uint16_t **values, unsigned *num_val
 		{
 			/*
 			 * Coefficients here derived by measurement of the 5-16V
-			 * range on one unit:
+			 * range on one unit, validated on sample points of another unit
 			 *
-			 * V   counts
-			 *  5  1001
-			 *  6  1219
-			 *  7  1436
-			 *  8  1653
-			 *  9  1870
-			 * 10  2086
-			 * 11  2303
-			 * 12  2522
-			 * 13  2738
-			 * 14  2956
-			 * 15  3172
-			 * 16  3389
+			 * Data in Tools/tests-host/data folder.
 			 *
-			 * slope = 0.0046067
-			 * intercept = 0.3863
+			 * measured slope = 0.004585267878277 (int: 4585)
+			 * nominal theoretic slope: 0.00459340659 (int: 4593)
+			 * intercept = 0.016646394188076 (int: 16646)
+			 * nominal theoretic intercept: 0.00 (int: 0)
 			 *
-			 * Intercept corrected for best results @ 12V.
 			 */
 			unsigned counts = adc_measure(ADC_VBATT);
 			if (counts != 0xffff) {
-				unsigned mV = (4150 + (counts * 46)) / 10 - 200;
+				unsigned mV = (166460 + (counts * 45934)) / 10000;
 				unsigned corrected = (mV * r_page_setup[PX4IO_P_SETUP_VBATT_SCALE]) / 10000;
 
 				r_page_status[PX4IO_P_STATUS_VBATT] = corrected;
diff --git a/src/modules/uORB/topics/vehicle_status.h b/src/modules/uORB/topics/vehicle_status.h
index b46c00b75..cbb148eda 100644
--- a/src/modules/uORB/topics/vehicle_status.h
+++ b/src/modules/uORB/topics/vehicle_status.h
@@ -186,7 +186,7 @@ struct vehicle_status_s {
 	bool condition_system_sensors_initialized;
 	bool condition_system_returned_to_home;
 	bool condition_auto_mission_available;
-	bool condition_global_position_valid;		/**< set to true by the commander app if the quality of the gps signal is good enough to use it in the position estimator */
+	bool condition_global_position_valid;		/**< set to true by the commander app if the quality of the position estimate is good enough to use it for navigation */
 	bool condition_launch_position_valid;		/**< indicates a valid launch position */
 	bool condition_home_position_valid;		/**< indicates a valid home position (a valid home position is not always a valid launch) */
 	bool condition_local_position_valid;
diff --git a/src/modules/uavcan/.gitignore b/src/modules/uavcan/.gitignore
new file mode 100644
index 000000000..24fbf171f
--- /dev/null
+++ b/src/modules/uavcan/.gitignore
@@ -0,0 +1 @@
+./dsdlc_generated/
diff --git a/src/modules/uavcan/esc_controller.cpp b/src/modules/uavcan/esc_controller.cpp
new file mode 100644
index 000000000..406eba88c
--- /dev/null
+++ b/src/modules/uavcan/esc_controller.cpp
@@ -0,0 +1,138 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file esc_controller.cpp
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#include "esc_controller.hpp"
+#include <systemlib/err.h>
+
+UavcanEscController::UavcanEscController(uavcan::INode &node) :
+	_node(node),
+	_uavcan_pub_raw_cmd(node),
+	_uavcan_sub_status(node),
+	_orb_timer(node)
+{
+}
+
+UavcanEscController::~UavcanEscController()
+{
+	perf_free(_perfcnt_invalid_input);
+	perf_free(_perfcnt_scaling_error);
+}
+
+int UavcanEscController::init()
+{
+	// ESC status subscription
+	int res = _uavcan_sub_status.start(StatusCbBinder(this, &UavcanEscController::esc_status_sub_cb));
+	if (res < 0)
+	{
+		warnx("ESC status sub failed %i", res);
+		return res;
+	}
+
+	// ESC status will be relayed from UAVCAN bus into ORB at this rate
+	_orb_timer.setCallback(TimerCbBinder(this, &UavcanEscController::orb_pub_timer_cb));
+	_orb_timer.startPeriodic(uavcan::MonotonicDuration::fromMSec(1000 / ESC_STATUS_UPDATE_RATE_HZ));
+
+	return res;
+}
+
+void UavcanEscController::update_outputs(float *outputs, unsigned num_outputs)
+{
+	if ((outputs == nullptr) || (num_outputs > MAX_ESCS)) {
+		perf_count(_perfcnt_invalid_input);
+		return;
+	}
+
+	/*
+	 * Rate limiting - we don't want to congest the bus
+	 */
+	const auto timestamp = _node.getMonotonicTime();
+	if ((timestamp - _prev_cmd_pub).toUSec() < (1000000 / MAX_RATE_HZ)) {
+		return;
+	}
+	_prev_cmd_pub = timestamp;
+
+	/*
+	 * Fill the command message
+	 * If unarmed, we publish an empty message anyway
+	 */
+	uavcan::equipment::esc::RawCommand msg;
+
+	if (_armed) {
+		for (unsigned i = 0; i < num_outputs; i++) {
+
+			float scaled = (outputs[i] + 1.0F) * 0.5F * uavcan::equipment::esc::RawCommand::CMD_MAX;
+			if (scaled < 1.0F) {
+				scaled = 1.0F;  // Since we're armed, we don't want to stop it completely
+			}
+
+			if (scaled < uavcan::equipment::esc::RawCommand::CMD_MIN) {
+				scaled = uavcan::equipment::esc::RawCommand::CMD_MIN;
+				perf_count(_perfcnt_scaling_error);
+			} else if (scaled > uavcan::equipment::esc::RawCommand::CMD_MAX) {
+				scaled = uavcan::equipment::esc::RawCommand::CMD_MAX;
+				perf_count(_perfcnt_scaling_error);
+			} else {
+				; // Correct value
+			}
+
+			msg.cmd.push_back(static_cast<unsigned>(scaled));
+		}
+	}
+
+	/*
+	 * Publish the command message to the bus
+	 * Note that for a quadrotor it takes one CAN frame
+	 */
+	(void)_uavcan_pub_raw_cmd.broadcast(msg);
+}
+
+void UavcanEscController::arm_esc(bool arm)
+{
+	_armed = arm;
+}
+
+void UavcanEscController::esc_status_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::esc::Status> &msg)
+{
+	// TODO save status into a local storage; publish to ORB later from orb_pub_timer_cb()
+}
+
+void UavcanEscController::orb_pub_timer_cb(const uavcan::TimerEvent&)
+{
+	// TODO publish to ORB
+}
diff --git a/src/modules/uavcan/esc_controller.hpp b/src/modules/uavcan/esc_controller.hpp
new file mode 100644
index 000000000..559ede561
--- /dev/null
+++ b/src/modules/uavcan/esc_controller.hpp
@@ -0,0 +1,107 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file esc_controller.hpp
+ *
+ * UAVCAN <--> ORB bridge for ESC messages:
+ *     uavcan.equipment.esc.RawCommand
+ *     uavcan.equipment.esc.RPMCommand
+ *     uavcan.equipment.esc.Status
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#pragma once
+
+#include <uavcan/uavcan.hpp>
+#include <uavcan/equipment/esc/RawCommand.hpp>
+#include <uavcan/equipment/esc/Status.hpp>
+#include <systemlib/perf_counter.h>
+
+class UavcanEscController
+{
+public:
+	UavcanEscController(uavcan::INode& node);
+	~UavcanEscController();
+
+	int init();
+
+	void update_outputs(float *outputs, unsigned num_outputs);
+
+	void arm_esc(bool arm);
+
+private:
+	/**
+	 * ESC status message reception will be reported via this callback.
+	 */
+	void esc_status_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::esc::Status> &msg);
+
+	/**
+	 * ESC status will be published to ORB from this callback (fixed rate).
+	 */
+	void orb_pub_timer_cb(const uavcan::TimerEvent &event);
+
+
+	static constexpr unsigned MAX_RATE_HZ = 100;			///< XXX make this configurable
+	static constexpr unsigned ESC_STATUS_UPDATE_RATE_HZ = 5;
+	static constexpr unsigned MAX_ESCS = uavcan::equipment::esc::RawCommand::FieldTypes::cmd::MaxSize;
+
+	typedef uavcan::MethodBinder<UavcanEscController*,
+		void (UavcanEscController::*)(const uavcan::ReceivedDataStructure<uavcan::equipment::esc::Status>&)>
+		StatusCbBinder;
+
+	typedef uavcan::MethodBinder<UavcanEscController*, void (UavcanEscController::*)(const uavcan::TimerEvent&)>
+		TimerCbBinder;
+
+	/*
+	 * libuavcan related things
+	 */
+	uavcan::MonotonicTime							_prev_cmd_pub;   ///< rate limiting
+	uavcan::INode								&_node;
+	uavcan::Publisher<uavcan::equipment::esc::RawCommand>			_uavcan_pub_raw_cmd;
+	uavcan::Subscriber<uavcan::equipment::esc::Status, StatusCbBinder>	_uavcan_sub_status;
+	uavcan::TimerEventForwarder<TimerCbBinder>				_orb_timer;
+
+	/*
+	 * ESC states
+	 */
+	bool 				_armed = false;
+	uavcan::equipment::esc::Status	_states[MAX_ESCS];
+
+	/*
+	 * Perf counters
+	 */
+	perf_counter_t _perfcnt_invalid_input = perf_alloc(PC_COUNT, "uavcan_esc_invalid_input");
+	perf_counter_t _perfcnt_scaling_error = perf_alloc(PC_COUNT, "uavcan_esc_scaling_error");
+};
diff --git a/src/modules/uavcan/gnss_receiver.cpp b/src/modules/uavcan/gnss_receiver.cpp
new file mode 100644
index 000000000..ba1fe5e49
--- /dev/null
+++ b/src/modules/uavcan/gnss_receiver.cpp
@@ -0,0 +1,153 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file gnss_receiver.cpp
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ * @author Andrew Chambers <achamber@gmail.com>
+ *
+ */
+
+#include "gnss_receiver.hpp"
+#include <systemlib/err.h>
+#include <mathlib/mathlib.h>
+
+#define MM_PER_CM 			10	// Millimeters per centimeter
+
+UavcanGnssReceiver::UavcanGnssReceiver(uavcan::INode &node) :
+_node(node),
+_uavcan_sub_status(node),
+_report_pub(-1)
+{
+}
+
+int UavcanGnssReceiver::init()
+{
+	int res = -1;
+
+	// GNSS fix subscription
+	res = _uavcan_sub_status.start(FixCbBinder(this, &UavcanGnssReceiver::gnss_fix_sub_cb));
+	if (res < 0)
+	{
+		warnx("GNSS fix sub failed %i", res);
+		return res;
+	}
+
+	// Clear the uORB GPS report
+	memset(&_report, 0, sizeof(_report));
+
+	return res;
+}
+
+void UavcanGnssReceiver::gnss_fix_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::gnss::Fix> &msg)
+{
+	_report.timestamp_position = hrt_absolute_time();
+	_report.lat = msg.lat_1e7;
+	_report.lon = msg.lon_1e7;
+	_report.alt = msg.alt_1e2 * MM_PER_CM;	// Convert from centimeter (1e2) to millimeters (1e3)
+
+	_report.timestamp_variance = _report.timestamp_position;
+
+
+	// Check if the msg contains valid covariance information
+	const bool valid_position_covariance = !msg.position_covariance.empty();
+	const bool valid_velocity_covariance = !msg.velocity_covariance.empty();
+
+	if (valid_position_covariance) {
+		float pos_cov[9];
+		msg.position_covariance.unpackSquareMatrix(pos_cov);
+
+		// Horizontal position uncertainty
+		const float horizontal_pos_variance = math::max(pos_cov[0], pos_cov[4]);
+		_report.eph = (horizontal_pos_variance > 0) ? sqrtf(horizontal_pos_variance) : -1.0F;
+
+		// Vertical position uncertainty
+		_report.epv = (pos_cov[8] > 0) ? sqrtf(pos_cov[8]) : -1.0F;
+	} else {
+		_report.eph = -1.0F;
+		_report.epv = -1.0F;
+	}
+
+	if (valid_velocity_covariance) {
+	    float vel_cov[9];
+	    msg.velocity_covariance.unpackSquareMatrix(vel_cov);
+		_report.s_variance_m_s = math::max(math::max(vel_cov[0], vel_cov[4]), vel_cov[8]);
+
+		/* There is a nonlinear relationship between the velocity vector and the heading.
+		 * Use Jacobian to transform velocity covariance to heading covariance
+		 *
+		 * Nonlinear equation:
+		 * heading = atan2(vel_e_m_s, vel_n_m_s)
+		 * For math, see http://en.wikipedia.org/wiki/Atan2#Derivative
+		 *
+		 * To calculate the variance of heading from the variance of velocity,
+		 * cov(heading) = J(velocity)*cov(velocity)*J(velocity)^T
+		 */
+		float vel_n = msg.ned_velocity[0];
+		float vel_e = msg.ned_velocity[1];
+		float vel_n_sq = vel_n * vel_n;
+		float vel_e_sq = vel_e * vel_e;
+		_report.c_variance_rad =
+				(vel_e_sq * vel_cov[0] +
+						-2 * vel_n * vel_e * vel_cov[1] +	// Covariance matrix is symmetric
+						vel_n_sq* vel_cov[4]) / ((vel_n_sq + vel_e_sq) * (vel_n_sq + vel_e_sq));
+
+	} else {
+		_report.s_variance_m_s = -1.0F;
+		_report.c_variance_rad = -1.0F;
+	}
+
+	_report.fix_type = msg.status;
+
+	_report.timestamp_velocity = _report.timestamp_position;
+	_report.vel_n_m_s = msg.ned_velocity[0];
+	_report.vel_e_m_s = msg.ned_velocity[1];
+	_report.vel_d_m_s = msg.ned_velocity[2];
+	_report.vel_m_s = sqrtf(_report.vel_n_m_s * _report.vel_n_m_s + _report.vel_e_m_s * _report.vel_e_m_s + _report.vel_d_m_s * _report.vel_d_m_s);
+	_report.cog_rad = atan2f(_report.vel_e_m_s, _report.vel_n_m_s);
+	_report.vel_ned_valid = true;
+
+	_report.timestamp_time = _report.timestamp_position;
+	_report.time_gps_usec = uavcan::UtcTime(msg.gnss_timestamp).toUSec();	// Convert to microseconds
+
+	_report.satellites_used = msg.sats_used;
+
+	if (_report_pub > 0) {
+		orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &_report);
+
+	} else {
+		_report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &_report);
+	}
+
+}
diff --git a/src/modules/uavcan/gnss_receiver.hpp b/src/modules/uavcan/gnss_receiver.hpp
new file mode 100644
index 000000000..18df8da2f
--- /dev/null
+++ b/src/modules/uavcan/gnss_receiver.hpp
@@ -0,0 +1,84 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file gnss_receiver.hpp
+ *
+ * UAVCAN --> ORB bridge for GNSS messages:
+ *     uavcan.equipment.gnss.Fix
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ * @author Andrew Chambers <achamber@gmail.com>
+ */
+
+#pragma once
+
+#include <drivers/drv_hrt.h>
+
+#include <uORB/uORB.h>
+#include <uORB/topics/vehicle_gps_position.h>
+
+#include <uavcan/uavcan.hpp>
+#include <uavcan/equipment/gnss/Fix.hpp>
+
+class UavcanGnssReceiver
+{
+public:
+	UavcanGnssReceiver(uavcan::INode& node);
+
+	int init();
+
+private:
+	/**
+	 * GNSS fix message will be reported via this callback.
+	 */
+	void gnss_fix_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::gnss::Fix> &msg);
+
+
+	typedef uavcan::MethodBinder<UavcanGnssReceiver*,
+		void (UavcanGnssReceiver::*)(const uavcan::ReceivedDataStructure<uavcan::equipment::gnss::Fix>&)>
+		FixCbBinder;
+
+	/*
+	 * libuavcan related things
+	 */
+	uavcan::INode													&_node;
+	uavcan::Subscriber<uavcan::equipment::gnss::Fix, FixCbBinder>	_uavcan_sub_status;
+
+	/*
+	 * uORB
+	 */
+	struct vehicle_gps_position_s 	_report;					///< uORB topic for gnss position
+	orb_advert_t			_report_pub;					///< uORB pub for gnss position
+
+};
diff --git a/src/modules/uavcan/module.mk b/src/modules/uavcan/module.mk
new file mode 100644
index 000000000..1ef6f0cfa
--- /dev/null
+++ b/src/modules/uavcan/module.mk
@@ -0,0 +1,74 @@
+############################################################################
+#
+#   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+#   Author: Pavel Kirienko <pavel.kirienko@gmail.com>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+#
+# UAVCAN <--> uORB bridge
+#
+
+MODULE_COMMAND = uavcan
+
+MAXOPTIMIZATION = -Os
+
+SRCS += uavcan_main.cpp         \
+        uavcan_clock.cpp        \
+        esc_controller.cpp      \
+        gnss_receiver.cpp
+
+#
+# libuavcan
+#
+include $(UAVCAN_DIR)/libuavcan/include.mk
+SRCS += $(LIBUAVCAN_SRC)
+INCLUDE_DIRS += $(LIBUAVCAN_INC)
+# Since actual compiler mode is C++11, the library will default to UAVCAN_CPP11, but it will fail to compile
+# because this platform lacks most of the standard library and STL. Hence we need to force C++03 mode.
+override EXTRADEFINES := $(EXTRADEFINES) -DUAVCAN_CPP_VERSION=UAVCAN_CPP03 -DUAVCAN_NO_ASSERTIONS
+
+#
+# libuavcan drivers for STM32
+#
+include $(UAVCAN_DIR)/libuavcan_drivers/stm32/driver/include.mk
+SRCS += $(LIBUAVCAN_STM32_SRC)
+INCLUDE_DIRS += $(LIBUAVCAN_STM32_INC)
+override EXTRADEFINES := $(EXTRADEFINES) -DUAVCAN_STM32_NUTTX -DUAVCAN_STM32_NUM_IFACES=2
+
+#
+# Invoke DSDL compiler
+# TODO: Add make target for this, or invoke dsdlc manually.
+#       The second option assumes that the generated headers shall be saved
+#       under the version control, which may be undesirable.
+#       The first option requires any Python and the Python Mako library for the sources to be built.
+#
+$(info $(shell $(LIBUAVCAN_DSDLC) $(UAVCAN_DSDL_DIR)))
+INCLUDE_DIRS += dsdlc_generated
diff --git a/src/modules/uavcan/uavcan_clock.cpp b/src/modules/uavcan/uavcan_clock.cpp
new file mode 100644
index 000000000..e41d5f953
--- /dev/null
+++ b/src/modules/uavcan/uavcan_clock.cpp
@@ -0,0 +1,79 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include <uavcan_stm32/uavcan_stm32.hpp>
+#include <drivers/drv_hrt.h>
+
+/**
+ * @file uavcan_clock.cpp
+ *
+ * Implements a clock for the CAN node.
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+namespace uavcan_stm32
+{
+namespace clock
+{
+
+uavcan::MonotonicTime getMonotonic()
+{
+	return uavcan::MonotonicTime::fromUSec(hrt_absolute_time());
+}
+
+uavcan::UtcTime getUtc()
+{
+	return uavcan::UtcTime();
+}
+
+void adjustUtc(uavcan::UtcDuration adjustment)
+{
+	(void)adjustment;
+}
+
+uavcan::uint64_t getUtcUSecFromCanInterrupt()
+{
+	return 0;
+}
+
+} // namespace clock
+
+SystemClock &SystemClock::instance()
+{
+	static SystemClock inst;
+	return inst;
+}
+
+}
+
diff --git a/src/modules/uavcan/uavcan_main.cpp b/src/modules/uavcan/uavcan_main.cpp
new file mode 100644
index 000000000..27e77e9c5
--- /dev/null
+++ b/src/modules/uavcan/uavcan_main.cpp
@@ -0,0 +1,582 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <cstdlib>
+#include <cstring>
+#include <fcntl.h>
+#include <systemlib/err.h>
+#include <systemlib/systemlib.h>
+#include <systemlib/mixer/mixer.h>
+#include <arch/board/board.h>
+#include <arch/chip/chip.h>
+
+#include <drivers/drv_hrt.h>
+#include <drivers/drv_pwm_output.h>
+
+#include "uavcan_main.hpp"
+
+/**
+ * @file uavcan_main.cpp
+ *
+ * Implements basic functinality of UAVCAN node.
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+/*
+ * UavcanNode
+ */
+UavcanNode *UavcanNode::_instance;
+
+UavcanNode::UavcanNode(uavcan::ICanDriver &can_driver, uavcan::ISystemClock &system_clock) :
+	CDev("uavcan", UAVCAN_DEVICE_PATH),
+	_node(can_driver, system_clock),
+	_esc_controller(_node),
+	_gnss_receiver(_node)
+{
+	_control_topics[0] = ORB_ID(actuator_controls_0);
+	_control_topics[1] = ORB_ID(actuator_controls_1);
+	_control_topics[2] = ORB_ID(actuator_controls_2);
+	_control_topics[3] = ORB_ID(actuator_controls_3);
+
+	// memset(_controls, 0, sizeof(_controls));
+	// memset(_poll_fds, 0, sizeof(_poll_fds));
+}
+
+UavcanNode::~UavcanNode()
+{
+	if (_task != -1) {
+		/* tell the task we want it to go away */
+		_task_should_exit = true;
+
+		unsigned i = 10;
+
+		do {
+			/* wait 5ms - it should wake every 10ms or so worst-case */
+			usleep(5000);
+
+			/* if we have given up, kill it */
+			if (--i == 0) {
+				task_delete(_task);
+				break;
+			}
+
+		} while (_task != -1);
+	}
+
+	/* clean up the alternate device node */
+		// unregister_driver(PWM_OUTPUT_DEVICE_PATH);
+
+	::close(_armed_sub);
+
+	_instance = nullptr;
+}
+
+int UavcanNode::start(uavcan::NodeID node_id, uint32_t bitrate)
+{
+	if (_instance != nullptr) {
+		warnx("Already started");
+		return -1;
+	}
+
+	/*
+	 * GPIO config.
+	 * Forced pull up on CAN2 is required for Pixhawk v1 where the second interface lacks a transceiver.
+	 * If no transceiver is connected, the RX pin will float, occasionally causing CAN controller to
+	 * fail during initialization.
+	 */
+	stm32_configgpio(GPIO_CAN1_RX);
+	stm32_configgpio(GPIO_CAN1_TX);
+	stm32_configgpio(GPIO_CAN2_RX | GPIO_PULLUP);
+	stm32_configgpio(GPIO_CAN2_TX);
+
+	/*
+	 * CAN driver init
+	 */
+	static CanInitHelper can;
+	static bool can_initialized = false;
+
+	if (!can_initialized) {
+		const int can_init_res = can.init(bitrate);
+
+		if (can_init_res < 0) {
+			warnx("CAN driver init failed %i", can_init_res);
+			return can_init_res;
+		}
+
+		can_initialized = true;
+	}
+
+	/*
+	 * Node init
+	 */
+	_instance = new UavcanNode(can.driver, uavcan_stm32::SystemClock::instance());
+
+	if (_instance == nullptr) {
+		warnx("Out of memory");
+		return -1;
+	}
+
+	const int node_init_res = _instance->init(node_id);
+
+	if (node_init_res < 0) {
+		delete _instance;
+		_instance = nullptr;
+		warnx("Node init failed %i", node_init_res);
+		return node_init_res;
+	}
+
+	/*
+	 * Start the task. Normally it should never exit.
+	 */
+	static auto run_trampoline = [](int, char *[]) {return UavcanNode::_instance->run();};
+	_instance->_task = task_spawn_cmd("uavcan", SCHED_DEFAULT, SCHED_PRIORITY_DEFAULT, StackSize,
+			      static_cast<main_t>(run_trampoline), nullptr);
+
+	if (_instance->_task < 0) {
+		warnx("start failed: %d", errno);
+		return -errno;
+	}
+
+	return OK;
+}
+
+int UavcanNode::init(uavcan::NodeID node_id)
+{
+	int ret = -1;
+
+	/* do regular cdev init */
+	ret = CDev::init();
+
+	if (ret != OK)
+		return ret;
+
+	ret = _esc_controller.init();
+	if (ret < 0)
+		return ret;
+
+	ret = _gnss_receiver.init();
+	if (ret < 0)
+		return ret;
+
+	uavcan::protocol::SoftwareVersion swver;
+	swver.major = 12;                        // TODO fill version info
+	swver.minor = 34;
+	_node.setSoftwareVersion(swver);
+
+	uavcan::protocol::HardwareVersion hwver;
+	hwver.major = 42;                        // TODO fill version info
+	hwver.minor = 42;
+	_node.setHardwareVersion(hwver);
+
+	_node.setName("org.pixhawk"); // Huh?
+
+	_node.setNodeID(node_id);
+
+	return _node.start();
+}
+
+void UavcanNode::node_spin_once()
+{
+	const int spin_res = _node.spin(uavcan::MonotonicTime());
+	if (spin_res < 0) {
+		warnx("node spin error %i", spin_res);
+	}
+}
+
+int UavcanNode::run()
+{
+	const unsigned PollTimeoutMs = 50;
+
+	// XXX figure out the output count
+	_output_count = 2;
+
+
+	_armed_sub = orb_subscribe(ORB_ID(actuator_armed));
+
+	actuator_outputs_s outputs;
+	memset(&outputs, 0, sizeof(outputs));
+
+	const int busevent_fd = ::open(uavcan_stm32::BusEvent::DevName, 0);
+	if (busevent_fd < 0)
+	{
+		warnx("Failed to open %s", uavcan_stm32::BusEvent::DevName);
+		_task_should_exit = true;
+	}
+
+	/*
+	 * XXX Mixing logic/subscriptions shall be moved into UavcanEscController::update();
+	 *     IO multiplexing shall be done here.
+	 */
+
+	_node.setStatusOk();
+
+	while (!_task_should_exit) {
+
+		if (_groups_subscribed != _groups_required) {
+			subscribe();
+			_groups_subscribed = _groups_required;
+			/*
+			 * This event is needed to wake up the thread on CAN bus activity (RX/TX/Error).
+			 * Please note that with such multiplexing it is no longer possible to rely only on
+			 * the value returned from poll() to detect whether actuator control has timed out or not.
+			 * Instead, all ORB events need to be checked individually (see below).
+			 */
+			_poll_fds[_poll_fds_num] = ::pollfd();
+			_poll_fds[_poll_fds_num].fd = busevent_fd;
+			_poll_fds[_poll_fds_num].events = POLLIN;
+			_poll_fds_num += 1;
+		}
+
+		const int poll_ret = ::poll(_poll_fds, _poll_fds_num, PollTimeoutMs);
+
+		node_spin_once();  // Non-blocking
+
+		// this would be bad...
+		if (poll_ret < 0) {
+			log("poll error %d", errno);
+			continue;
+		} else {
+			// get controls for required topics
+			bool controls_updated = false;
+			unsigned poll_id = 0;
+			for (unsigned i = 0; i < NUM_ACTUATOR_CONTROL_GROUPS; i++) {
+				if (_control_subs[i] > 0) {
+					if (_poll_fds[poll_id].revents & POLLIN) {
+						controls_updated = true;
+						orb_copy(_control_topics[i], _control_subs[i], &_controls[i]);
+					}
+					poll_id++;
+				}
+			}
+
+			if (!controls_updated) {
+				// timeout: no control data, switch to failsafe values
+				// XXX trigger failsafe
+			}
+
+			//can we mix?
+			if (controls_updated && (_mixers != nullptr)) {
+
+				// XXX one output group has 8 outputs max,
+				// but this driver could well serve multiple groups.
+				unsigned num_outputs_max = 8;
+
+				// Do mixing
+				outputs.noutputs = _mixers->mix(&outputs.output[0], num_outputs_max);
+				outputs.timestamp = hrt_absolute_time();
+
+				// iterate actuators
+				for (unsigned i = 0; i < outputs.noutputs; i++) {
+					// last resort: catch NaN, INF and out-of-band errors
+					if (!isfinite(outputs.output[i])) {
+						/*
+						 * Value is NaN, INF or out of band - set to the minimum value.
+						 * This will be clearly visible on the servo status and will limit the risk of accidentally
+						 * spinning motors. It would be deadly in flight.
+						 */
+						outputs.output[i] = -1.0f;
+					}
+
+					// limit outputs to valid range
+
+					// never go below min
+					if (outputs.output[i] < -1.0f) {
+						outputs.output[i] = -1.0f;
+					}
+
+					// never go below max
+					if (outputs.output[i] > 1.0f) {
+						outputs.output[i] = 1.0f;
+					}
+				}
+
+				// Output to the bus
+				_esc_controller.update_outputs(outputs.output, outputs.noutputs);
+			}
+
+		}
+
+		// Check arming state
+		bool updated = false;
+		orb_check(_armed_sub, &updated);
+
+		if (updated) {
+			orb_copy(ORB_ID(actuator_armed), _armed_sub, &_armed);
+
+			// Update the armed status and check that we're not locked down
+			bool set_armed = _armed.armed && !_armed.lockdown;
+
+			arm_actuators(set_armed);
+		}
+	}
+
+	teardown();
+	warnx("exiting.");
+
+	exit(0);
+}
+
+int
+UavcanNode::control_callback(uintptr_t handle,
+			 uint8_t control_group,
+			 uint8_t control_index,
+			 float &input)
+{
+	const actuator_controls_s *controls = (actuator_controls_s *)handle;
+
+	input = controls[control_group].control[control_index];
+	return 0;
+}
+
+int
+UavcanNode::teardown()
+{
+	for (unsigned i = 0; i < NUM_ACTUATOR_CONTROL_GROUPS; i++) {
+		if (_control_subs[i] > 0) {
+			::close(_control_subs[i]);
+			_control_subs[i] = -1;
+		}
+	}
+	return ::close(_armed_sub);
+}
+
+int
+UavcanNode::arm_actuators(bool arm)
+{
+	_is_armed = arm;
+	_esc_controller.arm_esc(arm);
+	return OK;
+}
+
+void
+UavcanNode::subscribe()
+{
+	// Subscribe/unsubscribe to required actuator control groups
+	uint32_t sub_groups = _groups_required & ~_groups_subscribed;
+	uint32_t unsub_groups = _groups_subscribed & ~_groups_required;
+	_poll_fds_num = 0;
+	for (unsigned i = 0; i < NUM_ACTUATOR_CONTROL_GROUPS; i++) {
+		if (sub_groups & (1 << i)) {
+			warnx("subscribe to actuator_controls_%d", i);
+			_control_subs[i] = orb_subscribe(_control_topics[i]);
+		}
+		if (unsub_groups & (1 << i)) {
+			warnx("unsubscribe from actuator_controls_%d", i);
+			::close(_control_subs[i]);
+			_control_subs[i] = -1;
+		}
+
+		if (_control_subs[i] > 0) {
+			_poll_fds[_poll_fds_num].fd = _control_subs[i];
+			_poll_fds[_poll_fds_num].events = POLLIN;
+			_poll_fds_num++;
+		}
+	}
+}
+
+int
+UavcanNode::ioctl(file *filp, int cmd, unsigned long arg)
+{
+	int ret = OK;
+
+	lock();
+
+	switch (cmd) {
+	case PWM_SERVO_ARM:
+		arm_actuators(true);
+		break;
+
+	case PWM_SERVO_SET_ARM_OK:
+	case PWM_SERVO_CLEAR_ARM_OK:
+	case PWM_SERVO_SET_FORCE_SAFETY_OFF:
+		// these are no-ops, as no safety switch
+		break;
+
+	case PWM_SERVO_DISARM:
+		arm_actuators(false);
+		break;
+
+	case MIXERIOCGETOUTPUTCOUNT:
+		*(unsigned *)arg = _output_count;
+		break;
+
+	case MIXERIOCRESET:
+		if (_mixers != nullptr) {
+			delete _mixers;
+			_mixers = nullptr;
+			_groups_required = 0;
+		}
+
+		break;
+
+	case MIXERIOCLOADBUF: {
+			const char *buf = (const char *)arg;
+			unsigned buflen = strnlen(buf, 1024);
+
+			if (_mixers == nullptr)
+				_mixers = new MixerGroup(control_callback, (uintptr_t)_controls);
+
+			if (_mixers == nullptr) {
+				_groups_required = 0;
+				ret = -ENOMEM;
+
+			} else {
+
+				ret = _mixers->load_from_buf(buf, buflen);
+
+				if (ret != 0) {
+					warnx("mixer load failed with %d", ret);
+					delete _mixers;
+					_mixers = nullptr;
+					_groups_required = 0;
+					ret = -EINVAL;
+				} else {
+
+					_mixers->groups_required(_groups_required);
+				}
+			}
+
+			break;
+		}
+
+	default:
+		ret = -ENOTTY;
+		break;
+	}
+
+	unlock();
+
+	if (ret == -ENOTTY) {
+		ret = CDev::ioctl(filp, cmd, arg);
+	}
+
+	return ret;
+}
+
+void
+UavcanNode::print_info()
+{
+	if (!_instance) {
+		warnx("not running, start first");
+	}
+
+	warnx("groups: sub: %u / req: %u / fds: %u", (unsigned)_groups_subscribed, (unsigned)_groups_required, _poll_fds_num);
+	warnx("mixer: %s", (_mixers == nullptr) ? "FAIL" : "OK");
+}
+
+/*
+ * App entry point
+ */
+static void print_usage()
+{
+	warnx("usage: uavcan start <node_id> [can_bitrate]");
+}
+
+extern "C" __EXPORT int uavcan_main(int argc, char *argv[]);
+
+int uavcan_main(int argc, char *argv[])
+{
+	constexpr unsigned DEFAULT_CAN_BITRATE = 1000000;
+
+	if (argc < 2) {
+		print_usage();
+		::exit(1);
+	}
+
+	if (!std::strcmp(argv[1], "start")) {
+		if (argc < 3) {
+			print_usage();
+			::exit(1);
+		}
+
+		/*
+		 * Node ID
+		 */
+		const int node_id = atoi(argv[2]);
+
+		if (node_id < 0 || node_id > uavcan::NodeID::Max || !uavcan::NodeID(node_id).isUnicast()) {
+			warnx("Invalid Node ID %i", node_id);
+			::exit(1);
+		}
+
+		/*
+		 * CAN bitrate
+		 */
+		unsigned bitrate = 0;
+
+		if (argc > 3) {
+			bitrate = atol(argv[3]);
+		}
+
+		if (bitrate <= 0) {
+			bitrate = DEFAULT_CAN_BITRATE;
+		}
+
+		if (UavcanNode::instance()) {
+			errx(1, "already started");
+		}
+
+		/*
+		 * Start
+		 */
+		warnx("Node ID %u, bitrate %u", node_id, bitrate);
+		return UavcanNode::start(node_id, bitrate);
+
+	}
+
+	/* commands below require the app to be started */
+	UavcanNode *inst = UavcanNode::instance();
+
+	if (!inst) {
+		errx(1, "application not running");
+	}
+
+	if (!std::strcmp(argv[1], "status") || !std::strcmp(argv[1], "info")) {
+		
+			inst->print_info();
+			return OK;
+	}
+
+	if (!std::strcmp(argv[1], "stop")) {
+		
+			delete inst;
+			inst = nullptr;
+			return OK;
+	}
+
+	print_usage();
+	::exit(1);
+}
diff --git a/src/modules/uavcan/uavcan_main.hpp b/src/modules/uavcan/uavcan_main.hpp
new file mode 100644
index 000000000..443525379
--- /dev/null
+++ b/src/modules/uavcan/uavcan_main.hpp
@@ -0,0 +1,123 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2014 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+#pragma once
+
+#include <nuttx/config.h>
+
+#include <uavcan_stm32/uavcan_stm32.hpp>
+#include <drivers/device/device.h>
+
+#include <uORB/topics/actuator_controls.h>
+#include <uORB/topics/actuator_outputs.h>
+#include <uORB/topics/actuator_armed.h>
+
+#include "esc_controller.hpp"
+#include "gnss_receiver.hpp"
+
+/**
+ * @file uavcan_main.hpp
+ *
+ * Defines basic functinality of UAVCAN node.
+ *
+ * @author Pavel Kirienko <pavel.kirienko@gmail.com>
+ */
+
+#define NUM_ACTUATOR_CONTROL_GROUPS_UAVCAN	4
+#define UAVCAN_DEVICE_PATH	"/dev/uavcan/esc"
+
+/**
+ * A UAVCAN node.
+ */
+class UavcanNode : public device::CDev
+{
+	static constexpr unsigned MemPoolSize        = 10752;
+	static constexpr unsigned RxQueueLenPerIface = 64;
+	static constexpr unsigned StackSize          = 3000;
+
+public:
+	typedef uavcan::Node<MemPoolSize> Node;
+	typedef uavcan_stm32::CanInitHelper<RxQueueLenPerIface> CanInitHelper;
+
+	UavcanNode(uavcan::ICanDriver &can_driver, uavcan::ISystemClock &system_clock);
+
+	virtual		~UavcanNode();
+
+	virtual int	ioctl(file *filp, int cmd, unsigned long arg);
+
+	static int	start(uavcan::NodeID node_id, uint32_t bitrate);
+
+	Node&		getNode() { return _node; }
+
+	static int	control_callback(uintptr_t handle,
+					 uint8_t control_group,
+					 uint8_t control_index,
+					 float &input);
+
+	void		subscribe();
+
+	int		teardown();
+	int		arm_actuators(bool arm);
+
+	void		print_info();
+
+	static UavcanNode* instance() { return _instance; }
+
+private:
+	int		init(uavcan::NodeID node_id);
+	void		node_spin_once();
+	int		run();
+
+	int			_task = -1;			///< handle to the OS task
+	bool			_task_should_exit = false;	///< flag to indicate to tear down the CAN driver
+	int			_armed_sub = -1;		///< uORB subscription of the arming status
+	actuator_armed_s	_armed;				///< the arming request of the system
+	bool			_is_armed = false;		///< the arming status of the actuators on the bus
+
+	unsigned		_output_count = 0;		///< number of actuators currently available
+
+	static UavcanNode	*_instance;			///< singleton pointer
+	Node			_node;				///< library instance
+	UavcanEscController	_esc_controller;
+	UavcanGnssReceiver 	_gnss_receiver;
+
+	MixerGroup		*_mixers = nullptr;
+
+	uint32_t		_groups_required = 0;
+	uint32_t		_groups_subscribed = 0;
+	int			_control_subs[NUM_ACTUATOR_CONTROL_GROUPS_UAVCAN] = {};
+	actuator_controls_s 	_controls[NUM_ACTUATOR_CONTROL_GROUPS_UAVCAN] = {};
+	orb_id_t		_control_topics[NUM_ACTUATOR_CONTROL_GROUPS_UAVCAN] = {};
+	pollfd			_poll_fds[NUM_ACTUATOR_CONTROL_GROUPS_UAVCAN + 1] = {};	///< +1 for /dev/uavcan/busevent
+	unsigned		_poll_fds_num = 0;
+};
diff --git a/uavcan b/uavcan
new file mode 160000
+Subproject d84fc8a84678d93f97f93b240c81472797ca588