gps-wizard

SBP - SiRF Binary (Packed)

Geodetic Navigation Data - Message ID 41

This format is generated by the Locosys GT-11, GT-31, GW-52 and GW-60.

The packed SiRF binary format consists of 32 byte messages which originate from the Geodetic Navigation Data.

SiRF Name Raw Name Type Name Type Units Resolution
HDOP hdop u1 hdop float32 - 2 x 10-1
Number of SVs in Fix sv_count u1 sat uint8 - -
UTC Milliseconds utc_millisecs <u2 ts float64 s 1 x 10-3
UTC Packed Datetime 1 utc_packed_datetime <u4 ts float64 s 1 x 10-3
Satellite ID List sv_ids <u4 svids uint32 - -
Latitude latitude <i4 lat float64 deg 1 x 10-7
Longitude longitude <i4 lon float64 deg 1 x 10-7
Altitude from MSL altitude_msl <i4 ele float64 m 1 x 10-2
Speed Over Ground (SOG) sog <u2 sog float32 m/s 1 x 10-2
Course Over Ground (COG, True) cog <u2 cog float32 deg 1 x 10-2
Climb Rate climb_rate <i2 roc float32 m/s 1 x 10-2
Speed Dilution of Precision sdop u1 ehve float32 m/s 1 x 10-2
Vertical Speed Dilution of Precision vsdop u1 evve float32 m/s 1 x 10-2

Notes:

  1. Two digit years in the packed datetime are since 2000.

SDOP and VSDOP

During the testing of the GPS Wizard modules, it was observed that GPSResults does not handle SDOP and VSDOP being unavailable in SBP files. This results in +/- figures of 0.000 being reported by GPSResults for SBP tracks missing SDOP and VSDOP which is incorrect / misleading.

GPS Wizard will ignore the last 2 bytes of the SBP files when SDOP and VSDOP are unpopulated; e.g. GT-11 tracks.