ANavS® Binary Solution Output Format

The sensor fusion solution provides two different output-streams for the position, attitude, velocity and many more states of solution and quality of solution.
By default it’s possible to configure the hardware to write to a file and/or to broadcast the solution per TCP on a customizable port (standardt-port: 6001). To stream the solution per WLAN or Ethernet, you need additionally to the defined port-number the IP-adress of your MSRTK Module, which is by default 192.168.42.1 (in case you are connected with WLAN-AP “ANavS_MSRTK_AP”).

The ANavS® sensor fusion framework provides two different protocols for the solution output, the standardized NMEA-Format and the proprietary binary protocol. In the following, the proprietary ANavS® binary protocol is described.

ANavS® Binary Protocol

The Binary Protocol is defined as follows:

Structure:	Sync Char 1	Sync Char 2	Class	ID	Length	Payload	ChecksumA	ChecksumB
Bytes:	1 Byte	1 Byte	1 Byte	1 Byte	2 Byte	Length-Byte	1 Byte	1Byte

The endianness of Length and the following Payload is little endian. The payload is of Length. The checksum is calculated with the 16-Bit Fletcher algorithm over Class, ID, Length and Payload with modulo 256. The ANavS® binary protocol message can be identified by Sync Char 1 = 0xB5 (dec 181), Sync Char 2 = 0x62 (dec 98), Class = 0x02 (dec 2) and Id = 0xE0 (dec 224). In the following, the type double has 8 bytes. If a variable in the Payload is given in the NED frame, the variable has three components (hence 3 times the data type, e.g. 3*double), where the components are north, east and down. This also holds for the body frame, which is the fixed frame of the rover, and where the components are given in x, y and z.

The Payload is given as:

			Size	Scaling	Name	Unit	Description

			uint8	–	id	–	Identifier of the system/the ANavS Position and Attitude Determination (PAD) solution.
			uint16	–	resCode	–	Result code bitfield, which keeps the system status and information.
			uint16	–	week	–	Week number of the current epoch (epoch means Kalman filter state-update with GNSS, IMU or another sensor data).
			double	–	tow	s	Time of Week of the current epoch.
			uint16	–	weekInit	–	Week number of the epoch when the system was started.
			double	–	towInit	s	Time of Week of the epoch when the system was started.
			int16	–	–	–	Reserved
			double	–	lat	deg	Latitude in WGS84.
			double	–	lon	deg	Longitude in WGS84.
			double	–	height	m	Height in WGS84 with geoid EGM96
			double	–	ECEF-X	m	X-position in ECEF-coordinate frame (WGS84).
			double	–	ECEF-Y	m	Y-position in ECEF-coordinate frame (WGS84).
			double		ECEF-Z	m	Z-position in ECEF-coordinate frame (WGS84).
			3*double	–	b	m	Baseline in NED frame spanned by the position given by lat, lon and height, and by the position of the reference station.
			3*double	–	bStdDev	m	Standard deviation of the baseline.
			3*double	–	vel	m/s	Velocity in NED frame.
			3*double	–	velStdDev	m/s	Standard deviation of the velocity.
			3*double	–	acc	m/s²	Acceleration in body frame.
			3*double	–	accStdDev	m/s²	Standard deviation of the acceleration.
			3*double	–	att	deg	Attitude/Euler angles (heading, pitch, roll).
			3*double	–	attStdDev	deg	Standard deviation of the attitude.
			double	–	accuracy	m	Estimated accuracy of the baseline.
			double	–	systemTime	s	System time of solution data output packet
			5*double	–	timingInfo	s	CPU-Load of used sensors. The sum (green line in the GUI) of elapsed time should not over 1 second (–> to slow processor). First double: Elapsed time GNSS; Second double: Elapsed time IMU; Third double: Elapsed time Baro; Fourth double: Elapsed time Odometry; Fifth double: Overall elapsed time
			5*double	–	–	–	Reserved
			double	–	gnssReception	–	Scalar, which indicates the GNSS signal reception. The value is between 0 and 20, where 20 is the best, i.e. very good conditions.
			uint8	–	numSats	–	Number of satellites.
		Loop	uint8	–	gnssId	–	Identifier of the GNSS (GPS = 1, SBAS = 2, GLONASS = 4, Galileo = 8).
			uint8	–	svId	–	Identifier of the satellite (“PRN”)
			double	–	elev	deg	Elevation angle of the satellite.
			double	–	azim	deg	Azimuth angle of the satellite.
			uint8	–	numRcv	–	Number of GNSS receivers.
	Loop		uint8	–	rcvId	–	Identifier of the receiver (unqiue within this system).
			char[11]	–	serial	–	Serial number of the receiver (unique).
			bool	–	isRefStation	–	Is true, if this receiver is a reference station (stationary).
			uint16	–	week	–	Week number of the current epoch for this receiver. If the following tow is NaN, the weeknumber is not valid!
			double	–	tow	s	Time of week of the current epoch for this receiver. Can be NaN, if there are no measurements at this epoch (e.g. commonly for reference station).
			double	–	lat	deg	Latitude of this receiver. Only given if the receiver is a reference station, otherwise it is NaN.
			double	–	lon	deg	Longitude of this receiver. Only given if the receiver is a reference station, otherwise it is NaN.
			double	–	height	m	Height of this receiver. Only given if the receiver is a reference station, otherwise it is NaN.
			3*double	–	bodyPos	m	Receiver position in x, y and z (body frame).
			3*double	–	bodyMisalign	m	Misalignment of the receiver in x, y and z (body frame).
			uint8	–	–	–	Reserved.
			5*double	–	sensorBufFillLvl	%	Sensor buffer filling level: First double: GNSS Second: IMU Third: BARO Fourth: ODO Fifth: Raw
			uint8	–	numSatsMeas	–	Number of satellites for which measurements are available for this receiver.
		Loop	uint8	–	gnssId	–	Identifier of the GNSS.
			uint8	–	svId	–	Identifier of the satellite.
			uint8	–	freq	–	Frequency band (currently that is 1 L1)).
			uint16	–	locktime	ms	Carrier phase locktime counter (maximum 64500ms).
			uint8	–	cno	dBHz	Carrier-to-noise density ratio (signal strength) [dB-Hz].
			uint8	0.01*2^n	prStdDev	m	Standard deviation of the pseudorange measurement.
			uint8	0.004	cpStdDev	cycles	Standard deviation of the carrier phase measurement.
			uint8	0.002*2^n	doStdDev	Hz	Standard deviation of the Doppler frequency.
			uint8	–	trkStat	–	Status bitfield of the tracking (see graphic below).
			uint8	–	numBl	–	Number of baselines spanned by a receiver pair.
		Loop	uint8	–	rcvId1	–	Identifier of the receiver the baseline is pointing to.
			uint8	–	rcvId2	–	Identifier of the receiver the baseline is pointing from.
			bool	–	isFixed	–	Is true, if the ambiguities of the phase measurements are fixed for this baseline.
			uint8	–	gnssIdJointRefSat	–	GNSS identifier of the joint reference satellite for the single and double differenced measurements.
			uint8	–	svIdJointRefSat	–	Identifier of the reference satellite.
			uint8	–	svIdGloRefSat	–	Identifier of the GLONASS reference satellite.
			uint8	–	svIdUnlSat	–	Identifier of the GLONASS ultra narrowlane satellite.
			3*double	–	aprioriBl	m	A priori baseline.
			3*double	–	stdDevAprioriBl	m	Standard deviation of the a priori baseline.
			double	–	aprioriLen	m	A priori baseline length.
			double	–	stdDevAprioriLen	m	Standard deviation of the a priori baseline length.
			uint8	–	numFilter	–	Number of filters.
Loop			uint8	–	nameLen	Bytes	Length of the filtername.
			char[nameLen]	–	name	–	Filtername.
			uint32	–	params	–	Bitfield of parameters (states, residuals), which are transmitted by the filter.
			bool	–	isActive	–	Is true, if the filter is active.
	Conditioned on Bit 0, i.e. if Bit 0 is not set, this shall not be considered (no pointer increment, just leave out!).		6*double	–	absPos	deg and m	Absolute position in latitude, longitude (both in deg) and height (in m) (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 1		2*double	–	clkErr	s	Receiver clock error (first double) and its standard deviation (latter double).
	Bit 2		uint8	–	rcvId1	–	Identifier of the receiver the baseline is pointing to.
			uint8	–	rcvId2	–	Identifier of the receiver the baseline is pointing from.
			6*double	–	baseline	m	Baseline in NED frame (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 3		6*double	–	vel	m/s	Velocity in NED frame (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 4		6*double	–	acc	m/s²	Acceleration in body frame (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 5		6*double	–	accBias	m/s²	Accelerometer bias in body frame (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 6		6*double	–	eulerAng	deg	Euler angles in heading, pitch and roll (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 7		6*double	–	angRate	deg/s	Angular rate in heading, pitch and roll (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 8		6*double	–	gyroBias	deg/s	Gyroscope bias (first 3 doubles) and its standard deviation (latter 3 doubles).
	Bit 9		2*double	–	tropoZenDel	m	Tropospheric zenith delay (first double) and its standard deviation (latter double). Currently not in use (Bit 9 is always 0).
	Bit 10		2*double	–	Accuracy	m	Accuracy of the baseline (first double) and its standard deviation (latter double). Currently not in use (Bit 10 is always 0).
	Bit 11-17		7*double	–	Reserved	–	–
			uint8	–	numPhase	–	Number of phase measurements.
		Loop	uint8	–	gnssId	–	Identifier of the GNSS.
			uint8	–	svId	–	Identifier of the satellite.
			uint8	–	freq	–	Frequency band (currently that is 1 (L1)).
	Bit 18		2*double	–	ambiguities	cycles	Double difference ambiguities and std. dev.
	Bit 19		2*double	–	phaseMp	m	Phase multipath and std. dev.
	Bit 20		2*double	–	phaseRes	m	Phase residuals and std. dev.
			uint8	–	numCode	–	Number of code measurements.
		Loop	uint8	–	gnssId	–	Identifier of the GNSS.
			uint8	–	svId	–	Identifier of the satellite.
			uint8	–	freq	–	Frequency band (currently that is 1 (L1)).
	Bit 21		2*double	–	codeMp	m	First double is code multipath, second its standard deviation.
	Bit 22		2*double	–	codeRes	m	First double is code residual, second its standard deviation.
			uint8	–	numDoppler	–	Number of Doppler measurements.
		Loop	uint8	–	gnssId	–	Identifier of the GNSS.
			uint8	–	svId	–	Identifier of the satellite.
			uint8	–	freq	–	Frequency band (currently that is 1 (L1)).
	Bit 23		2*double	–	doRes	Hz	First double is Doppler residual, second is its standard deviation.

The payload contains loops and conditions. The number of loop iterations and the conditions depends on other payload data. For example, the number of satellites determines, how often the following color-coded data is repeated. For numSats = 2 and p being a pointer to numSats, the following data is given as

Address	Type	Name
p+1	uint8	gnssId1
p+2	uint8	svId1
p+3	double	elev1
p+11	double	azim1
p+19	uint8	gnssId2
p+20	uint8	svId2
p+21	double	elev2
p+29	double	azim2
p+37	uint8	numRcv

For numSats = 0, no satellite position data is transmitted and the next variable would be numRcv. If a condition is fulfilled the following color-coded data is transmitted. For example, if isActive is true, then at least the variables numPhase, numCode and numDoppler are transmitted. If isActive is false, then the end of the UBX message is reached. The bitfield params is also a condition, whose bits determine, whether the following data is transmitted.
Example: Let p being a pointer to isActive with isActive = true, Bit 0 of params is false and Bit 1 is true. Then, p+1 points to the receiver clock error clkErr and not to the absolute position absPos since Bit 0 is false.

The resCode bitfield is defined as

Bit	Definition
0	Is set for GNSS update-epochs processed in the PAD-Software
1	Is set for IMU update-epochs processed in the PAD-Software
2	Is set for Barometer update-epochs processed in the PAD-Software
3	Is set for Odometrie update-epochs processed in the PAD-Software
4	Is set for Camera update-epochs processed in the PAD-Software
5	Is set for Steering update-epochs processed in the PAD-Software
6	Is set if the IMU is initialized/calibrated
7	Is set if the Multi-Sensor RTK-Filter is reset in the current epoch
8	Is set if RTK correction were received initially
9 to 10	State-definition for the Attitude Kalman-Filter: 00 -> No solution 01 -> Least-Squares solution 10 -> Float solution 11 -> Fixed solution
11 to 12	State-definition for the RTK-Position Kalman-Filter: 00 -> No solution 01 -> Least-Squares solution 10 -> Float solution 11 -> Fixed solution




13	Is set if the RTK-Position Kalman-Filter has only a float-solution accuracy but enough satellites in view to try a RTK-refix (the vehicle must be stationary for this try!)
14	Is set if state update is only a prediction step (without sensor data) in our sensor fusion filter. In this case, Bit 0-5 is set to zero.
15	Reserved

Extended Integrity Information

To extend the existing binary format with more integrity information, ANavS provides since version 5.1.72 an additional message with the following header:
Sync Char 1 = 0xB5 (dec 181), Sync Char 2 = 0x62 (dec 98), Class = 0x02 (dec 2) and Id = 0xE5 (dec 229).
The Message is activated via customer-code 10.

The Payload is given as:

Size	Scaling	Name	Unit	Description
uint16	–	week	–	Week number of the current epoch
double	–	tow	s	Time of Week of the current epoch
double	–	cov_b_xx		Covariance matrix of RTK solution (value xx)
double	–	cov_b_xy		Covariance matrix of RTK solution (value xy)
double	–	cov_b_xz		Covariance matrix of RTK solution (value xz)
double	–	cov_b_yx		Covariance matrix of RTK solution (value yx)
double	–	cov_b_yy		Covariance matrix of RTK solution (value yy)
double	–	cov_b_yz		Covariance matrix of RTK solution (value yz)
double	–	cov_b_zx		Covariance matrix of RTK solution (value zx)
double	–	cov_b_zy		Covariance matrix of RTK solution (value zy)
double	–	cov_b_zz		Covariance matrix of RTK solution (value zz)
double	–	GDOP		Dilution of Precision: GDOP
double	–	PDOP		Dilution of Precision: PDOP
double	–	HDOP		Dilution of Precision: HDOP
double	–	VDOP		Dilution of Precision: VDOP
double	–	TDOP		Dilution of Precision: TDOP
bool	–	Flag No Movement		True: Rover stand still, no movement detected with IMU –> RTK- and Attitude Fix is triggert, bias estimation of IMU also. False: Rover is moving –> NO RTK- and Attitude Fix is triggert, NO bias estimation of IMU
double	–	RTK-Fix Validation		Difference of successfully fixed RTK-baseline to the next best candidate. Only if “Flag No Movement” is true, this value is relevant for integrity information of RTK baseline.
double	–	Correction-Outage		Time since last RTK correction-data arrived.