Ouster OS1 - lidar-data; lidar-data-format

(continuedfrompreviouspage)
]
}
Whichcorrespondsto thefollowingmatrix
M_imu_to_sensor =








1 0 0 6.253
0 1 0 −11.775
0 0 1 7.645
0 0 0 1








9 LidarData
9.1 Lidar Data Format
Note: The calculations and illustrations of the lidar data in this section presupposes the use of the
latest firmware v1.14.0 or v2.0.0. Previous firmware did not scale lidar data packet size with number
ofchannelsinasensor. Pleasecontactsupport@ouster.ioifyouneedanolderversionoftheguideto
lidardata format.
Lidardatapacketsconsistof16azimuthblocksandvariesinlengthrelativetothenumberofchannels
inthesensor. Thepacketrateisdependentontheoutputmode. Wordsare32bitsinlengthandlittle
endian. Bydefault, lidarUDP dataisforwardedtoPort7502.
Eachazimuth blockcontains:
Timestamp [64 bitunsignedint] -timestamp ofthemeasurement innanoseconds.
Measurement ID [16 bit unsigned int] - a sequentially incrementing azimuth measurement
countingup from0 to511,or 0to 1023, or0to2047dependingon lidar_mode.
FrameID [16 bitunsigned int] -index of thelidar scan. Incrementsevery timethe sensor com-
pletesarotation, crossingthe zeropointof theencoder.
EncoderCount [32bitunsignedint]-an azimuthangleasarawencoder count,starting from0
withamaxvalueof90,111-incrementing44tickseveryazimuthanglein2048mode,88ticksin
1024mode,and 176ticksin 512mode.
DataBlock [96bits]- 3datawordsforeach pixel,each containing:
Range [32 bit unsigned int - only 20 bits used] - range in millimeters, discretized to the
nearest3millimeters.
SignalPhotons[16bitunsignedint]-signalintensityphotonsinthesignalreturnmeasure-
mentarereported.
16