GSOF message: Attitude Info

This message describes attitude information relating to the vector between the Heading antenna and the Moving Base antenna. It contains the following data:

Tilt or vertical angle, in radians, from the Heading antenna to the Moving Base antenna relative to a horizontal plane through the Heading antenna
Heading or yaw, in radians, relative to True North
Range or slope distance between the Heading antenna and the Moving Base antenna

The heading computation in this message is computed from the moving baseline vector, which requires a two-antenna system.

Attitude (Type 27 record)

Field	Item	Type	Value	Meaning
0	Output record type	Char	1Bh	Attitude information
1	Record length	Char		Bytes in record
2 to 5	GPS time	Long	msecs	GPS time in milliseconds of GPS week
6	Flags	Char	See Attitude flags	Flag bits indicating validity of attitude components
7	Number of SVs used	Char		Number of satellites used to calculate attitude
8	Calculation mode	Char	See Attitude calculation flags	Positioning mode
9	Reserved			Reserved (unused)
10 to 17	Pitch	Double	radians	The forward dive/climb angle
18 to 25	Yaw	Double	radians	Rotation about the vertical axis relative to True North (i.e. horizontal turn left or right)
26 to 33	Roll	Double	radians	Side-to-side roll angle
34 to 41	Master-Slave range	Double	meters	Distance between master and slave antennas
42 to 43	PDOP	Short	0.1	Position Dilution of Precision of current position
44 to 47	Pitch variance	Float	radians ¹	Expected variance of error of the pitch estimate
48 to 51	Yaw variance	Float	radians ¹	Expected variance of error of the yaw estimate
52 to 55	Roll variance	Float	radians ¹	Expected variance of error of the roll estimate
56 to 59	Pitch-Yaw covariance	Float	radians ¹	Expected covariance of errors of the pitch and yaw estimates
60 to 63	Pitch-Roll covariance	Float	radians ¹	Expected covariance of errors of the pitch and roll estimates
64 to 67	Yaw-Roll covariance	Float	radians ¹	Expected covariance of errors of the yaw and roll estimates
68 to 71	Master-Slave range variance	Float	meters ¹	Expected variance of error of the master-slave range estimates

1. Subsequent elements are not implemented in firmware versions before GNSS version 4.20 firmware. The error stats valid flag is not set when these elements are implemented, because the error stats flag refers to specific position statistics, and not to the attitude statistics provided here. The presence of these additional elements should be detected based on the record length.