INAV blackbox variables

Overview

Blackbox is a valuable tool for analyzing the flight dynamics of our airborne vehicles and as such it can be useful for troubleshooting and debugging purposes.

In INAV we use a set of specific variables, each variable may contain multiple arrays, for example - navPos[0-2].

navPos, navVel, navTgtPos and navTgtVel each hold arrays [0-2], which represent distances due North [0], due East [1] and straight Up [2], all relative to the "point of origin". North and East are fused from accelerometer and GPS data, while Up is fused from accelerometer + barometer for multicopters and accelerometer + gps for airplanes if no barometer is available. Read the Inertial position estimator|Inertial-position-estimator-(INAV) section in the Developer info page for detailed explanation.

"Point of origin" might be different from "Home". "Home" is defined as position at the time of arming. While "Point of origin" is recorded after a valid GPS fix is aquired.

For further information about the coordinate system used please read the Coordinate systems|Coordinate-systems section on the Developer info page.

#INAV Variables

Variables listed below with a short description of each:

• navMode (navState in newer code): current mode of operation from INAV's point of view. Might be different from flight mode. Meaning vary by version, but navMode=0 and navState=1 means idle.

• navFlags: binary flags of INAV internal state: new data availability for altitude, position and heading, validity of altitude, surface distance and position, flags to indicate if pilot is adjusting altitude and position via rc input.

• navTgtPos: represents the desired position as used/calculated by INAV. When you are in PH, navTgtPos will be set to hold position coordinates.

• navPos: array of latest NEU coordinates as provided by inertial estimator. Will be slightly different from GPS/baro readings for 99% of time. Units - cm.

• navVel: same as navPos, but for estimated velocity. Units - cm/s

• navTgtVel: represents the desired velocity as used/calculated by INAV. When you are in PH, navTgtVel will be set to calculated desired velocity to reach the target position.

• navDebug: as the name suggests it is used for debugging. Meaning of these values differ all the time depending on what part of the code is currently being debugged.

Blackbox can log data either via serial port or into internal dataflash. In order to log the data into the internal flash at the moment is possible via CLI: set blackbox_device = SPIFLASH # instead of SERIAL set blackbox_rate_num = 1 set blackbox_rate_denom = 2 This will make it work and store every second value.

INAV Logging Intervals

Blackbox logs several types of frames - flight behaviour is written using I- and P-frames. I-frames are fairly big and contain absolute values, P-frames are delta-encoded to save space. Blackbox denominator only reduces P-frame rate, the I-frame rate is constant.

Originally I-frames were logged every 32 iterations, P-frame is logged every blackbox_rate_denom after I-frame. This doesn't give you exactly 1 / blackbox_rate_denom rate, i.e. for 1/16 - 1/31 rates it's going to be c. 16 iterations between frames on average.

For INAV 1.6 and later, the I-frame interval is set dynamically at 1/32, 1/64, 1/128 and 1/256 based on the blackbox_rate_denom chosen.

For example, if a blackbox_rate_denom of 50 is used, INav will select 64 as the I-frame interval, meaning c. 1/32 actual logging rate.

Note

Due to the complexity of the tasks being performed in later INAV releases. e.g. 2K_looptime, lower Dshot values, Control Profiles, Programming framework, OSD etc. It is advisable to run blackbox_rate_denom at the lowest value (32 - 3%) to start with. Otherwise higher rates may cause breaks in the log, or inability to record any log data. This will vary based on the hardware logging type (FLASH, SDCARD, SDIO)

Some fields that are logged, are not yet accessible with Blackbox Explorer. Instead try using MWPtools.

Explanation of all the parameters

Name of field in txt file	Name in Blackbox Log Viewer	Explanation	.	..
loopIteration	not used	counter from main loop
time (us)	x-axis of diagram	real time in micoseconds
axisRate[0]	gyros[roll] (.. deg/s)	rotation rate	roll	deg/sec
axisRate[1]	gyros[pitch] (.. deg/s)	rotation rate	pitch	deg/sec
axisRate[2]	gyros[yaw] (.. deg/s)	rotation rate	yaw	deg/sec
axisP[0]	PID_P[roll]	PID controller	roll	P
axisP[1]	PID_P[pitch]	PID controller	pitch	P
axisP[2]	PID_P[yaw]	PID controller	yaw	P
axisI[0]	PID_I[roll]	PID controller	roll	I
axisI[1]	PID_I[pitch]	PID controller	pitch	I
axisI[2]	PID_I[yaw]	PID controller	yaw	I
axisD[0]	PID_D[roll]	PID controller	roll	D
axisD[1]	PID_D[pitch]	PID controller	pitch	D
axisD[2]	PID_D[yaw]	PID controller	yaw	D
mcPosAxisP[0]	mcPosAxisP[0]	multicopter position	north	cm
mcPosAxisP[1]	mcPosAxisP[1]	multicopter position	east	cm
mcPosAxisP[2]	mcPosAxisP[2]	multicopter position	vertical	cm
mcVelAxisP[0]	mcVelAxisP[0]	multicopter velocity	north	cm/sec
mcVelAxisP[1]	mcVelAxisP[1]	multicopter velocity	east	cm/sec
mcVelAxisP[2]	mcVelAxisP[2]	multicopter velocity	vertical	cm/sec
mcVelAxisI[0]	mcVelAxisI[0]	multicopter velocity	north	cm/sec
mcVelAxisI[1]	mcVelAxisI[1]	multicopter velocity	east	cm/sec
mcVelAxisI[2]	mcVelAxisI[2]	multicopter velocity	vertical	cm/sec
mcVelAxisD[0]	mcVelAxisD[0]	multicopter velocity	north	cm/sec
mcVelAxisD[1]	mcVelAxisD[1]	multicopter velocity	east	cm/sec
mcVelAxisD[2]	mcVelAxisD[2]	multicopter velocity	vertical	cm/sec
mcVelAxisOut[0]	mcVelAxisOut[0]	multicopter velocity	north	cm/sec
mcVelAxisOut[1]	mcVelAxisOut[1]	multicopter velocity	east	cm/sec
mcVelAxisOut[2]	mcVelAxisOut[2]	multicopter velocity	vertical	cm/sec
mcSurfaceP	mcSurfaceP	multicopter surface mode		P
mcSurfaceI	mcSurfaceI	multicopter surface mode		I
mcSurfaceD	mcSurfaceD	multicopter surface mode		D
mcSurfaceOut	mcSurfaceOut	multicopter surface mode
fwAltP	fwAltP	fixedwing altitude position		P
fwAltI	fwAltI	fixedwing altitude position		I
fwAltD	fwAltD	fixedwing altitude position		D
fwAltOut	fwAltOut	fixedwing altitude position output
fwPosP	fwPosP	fixedwing horizontal position		P
fwPosI	fwPosI	fixedwing horizontal position		I
fwPosD	fwPosD	fixedwing horizontal position		D
fwPosOut	fwPosOut	fixedwing horizontal position output
rcData[0]	rcData[0]	received rc signal	roll	1000-2000 µs
rcData[1]	rcData[1]	received rc signal	pitch	1000-2000 µs
rcData[2]	rcData[2]	received rc signal	yaw	1000-2000 µs
rcData[3]	rcData[3]	received rc signal	throttle	1000-2000 µs
rcCommand[0]	rcCommand[0]	stabilization controller command	roll	1000-2000 µs
rcCommand[1]	rcCommand[1]	stabilization controller command	pitch	1000-2000 µs
rcCommand[2]	rcCommand[2]	stabilization controller command	yaw	1000-2000 µs
rcCommand[3]	rcCommand[3]	stabilization controller command	throttle	1000-2000 µs
vbat	vbat	voltage of flight battery		volts
sagCompensatedVBat		load compensated battery voltage		volts
powerSupplyImpedance		flight battery internal resistance		mΩ
amperage		system current drain		amps
magADC[0]	mag[x]	compass	north
magADC[1]	mag[y]	compass	east
magADC[2]	mag[z]	compass	vertical
BaroAlt	Baro	altitude(barometric)		m
gyroADC[0]	gyro[0]	rotation(gyro)	roll	deg/sec
gyroADC[1]	gyro[1]	rotation(gyro)	pitch	deg/sec
gyroADC[2]	gyro[2]	rotation(gyro)	yaw	deg/sec
gyroRaw[0]	gyroRaw[0]	rotation(gyro before filtering)	roll	deg/sec
gyroRaw[1]	gyroRaw[1]	rotation(gyro before filtering)	pitch	deg/sec
gyroRaw[2]	gyroRaw[2]	rotation(gyro before filtering)	yaw	deg/sec
accSmooth[0]	acc[x]	acceleration	north	ADC * normalised 1g
accSmooth[1]	acc[y]	acceleration	east	ADC * normalised 1g
accSmooth[2]	acc[z]	acceleration	vertical	ADC * normalised 1g
accVib	accVib	accelerometer vibration level	frequency	Hz
attitude[0]	attitude[0]	heading	roll	0-3600 deg/10
attitude[1]	attitude[1]	heading	pitch	0-3600 deg/10
attitude[2]	attitude[2]	heading	yaw	0-3600 deg/10
debug[0-7]	debug[0-7]	CLI debug_mode		0 - 7
motor[0]	motor[0]	output to motor ESC	0	1000-2000 µs
motor[1]	motor[1]	output to motor ESC	1	1000-2000 µs
motor[2]	motor[2]	output to motor ESC	2	1000-2000 µs
motor[3]	motor[3]	output to motor ESC	3	1000-2000 µs
navState		navigation control mode state
navFlags		navigation data trusted
navPos[0]	navPos[0]	position of vehicle	north	cm
navPos[1]	navPos[1]	position of vehicle	east	cm
navPos[2]	navPos[2]	position of vehicle	vertical	cm
navVel[0]	navVel[0]	velocity of vehicle	north	cm/s
navVel[1]	navVel[1]	velocity of vehicle	east	cm/s
navVel[2]	navVel[2]	velocity of vehicle	vertical	cm/s
navAcc[0]	navAcc[0]	acceleration of vehicle	north	cm/s/s
navAcc[1]	navAcc[1]	acceleration of vehicle	east	cm/s/s
navAcc[2]	navAcc[2]	acceleration of vehicle	vertical	cm/s/s
navTgtVel[0]	navTgtVel[0]	target value: velocity	north	cm/s
navTgtVel[1]	navTgtVel[1]	target value: velocity	east	cm/s
navTgtVel[2]	navTgtVel[2]	target value: velocity	vertical	cm/s
navTgtPos[0]	navTgtPos[0]	target value: position	north	cm
navTgtPos[1]	navTgtPos[1]	target value: position	east	cm
navTgtPos[2]	navTgtPos[2]	target value: position	vertical	cm
navTgtHdg		active heading computation	horizontal
navSurf[0]	navSurf[0]	requires surface mode
flightModeFlags (flags)		active modes
stateFlags (flags)		active control states
failsafePhase (flags)	failsafePhase	idle/active (RTH/Land)	boolean	0/1
rxSignalReceived		active RX link	boolean	0/1
rxFlightChannelsValid
hwHealthStatus		active sensor communication
waypoint	activeWPNumber	current flight waypoint		decimal
rpm	escRPM	ESC telemetry motor revolutions/min		RPM
escTemperature	escTemperature	ESC telemetry temperature		decidegrees C
IMUTemperature	IMUTemperature	Gyro/Acc device temperature		degrees C
baroTemperature	baroTemperature	barometer device temperature		degrees C
sensTemp	Sens 0-7 Temp	user dedicated temperature sensors	0-7	degrees C
	windHeading	direction		degrees
	windVelocity	speed		m/s
wind[0]	windVelocity	wind X axis velocity	north	m/s
wind[1]	windVelocity	wind Y axis velocity	east	m/s
wind[2]	windVelocity	wind Z axis velocity	vertical	m/s
AirSpeed	AirSpeed	Pitot or Virtual		cm/s
GPS_home[0]		latitude		degrees
GPS_home[1]		longitude		degrees
GPS_fixType		positional lock accuracy		None - 2D - 3D
GPS_numSat		number of satellites acquired		decimal
GPS_coord[0]		latitude		deg : min : sec
GPS_coord[1]		longitude		deg : min : sec
GPS_altitude		GPS_altitude		m
GPS_speed		velocity		cm/s
GPS ground course		ground course heading		degrees
GPS_hdop		quality of GPS fix		10 down to 0.5
navEPH		Std deviation horizontal position error		meters
navEPV		Std deviation of vertical position error		meters
GPS_velned[0]		CoG X axis velocity	north	m/s
GPS_velned[1]		CoG Y axis velocity	east	m/s
GPS_velned[2]		CoG Z axis velocity	down	m/s