Ouster OS1 - time-synchronization-nmea-message-format

EXAMPLECOMMANDS:Hereareexamplecommandsandtheireffectonoutputpulsewhenlidar_mode
is1024x10, andassuming sync_pulse_out_pulse_width is10 ms.
→
Command Response
set_config_param multipurpose_io_mode
OUTPUT_FROM_SYNC_PULSE_IN
set_config_param sync_pulse_out_pulse_width 10
set_config_param sync_pulse_out_frequency 1
reinitialize
The output pulse frequency is 1 Hz. Each pulse
is 10 ms wide. sync_pulse_out_pulse_width and
sync_pulse_out_frequency commands are optionalbe-
causethey justre-command thedefaultvalues
set_config_param multipurpose_io_mode
OUTPUT_FROM_SYNC_PULSE_IN
set_config_param sync_pulse_out_frequency 50
reinitialize
Theoutputpulsefrequencyis50Hz. Eachpulseis10
mswide.
set_config_param multipurpose_io_mode
OUTPUT_FROM_ENCODER_ANGLE
set_config_param sync_pulse_out_angle 360
reinitialize
Theoutputpulsefrequencyis10Hz,sincethesensor
is in 10 Hz mode (10 rotations / sec) andthe angleis
setto360º, a fullrotation. Eachpulseis 10ms wide.
set_config_param multipurpose_io_mode
OUTPUT_FROM_ENCODER_ANGLE
set_config_param sync_pulse_out_angle 45
reinitialize
Theoutputpulsefrequencyis80Hz,sincethesensor
is in 10 Hz mode (10 rotations / sec) andthe angleis
set to 45º. Each full rotation will have8 pulses. Each
pulseis 10ms wide.
25.5 NMEAMessageFormat
The OusterSensor expectsa standard NMEA$GPRMC UART message. Data (calleda sentence) isa
simpleASCIIstringstartingwitha‘$’ characterand endingwitha returncharacter. Fieldsofthesen-
tenceareseparatedwitha‘,’character,andthelastfield(achecksum)isseparatedbya‘*’character.
The max character length of a standard message is 80 characters; however, the Ouster Sensor can
support non-standardmessages upto 85characters(seeExample2 below).
TheOusterSensorwilldelivertimeintheUDPpacketbycalculatingsecondssince00:00:00Thursday,
1 January 1970. nmea_leap_seconds by default is 0, meaning this calculation will not take into account
anyleapseconds. Ifnmea_leap_seconds is0 thenthereported timeis UnixEpochtime. As ofFebruary,
2019CoordinatedUniversalTime(UTC)lagsbehindInternationalAtomicTime(TAI)byanoffsetof37
85