Trimble Standard Interface Protocol

A

0x27

0x28

0x29

0x2A

Command Packet 27

Signal Levels Request

This packet requests signal levels for all satellites currently being tracked. This packet contains no data. The GPS receiver returns packet 47.

Command Packet 28

GPS System Message Request

This packet requests the GPS system ASCII message sent with the navigation data by each satellite. This packet contains no data. The GPS receiver returns packet 48.

Command Packet 29

Almanac Health Page Request

This packet requests the health page from the almanac. This packet contains no data. The GPS receiver returns packet 49.

Command Packet 2A

Altitude for 2-D Mode Command

This packet provides the altitude to be used for Manual 2-dimensional navigation mode. This altitude is also used for Auto 2-D mode. This packet contains one SINGLE number (4 bytes) specifying the altitude in meters, using the WGS-84 model of the earth or MSL geoid altitude, depending on I/O options (set by packet 35). The GPS receiver returns packet 4A. It is recommended that the user upload the reference altitude before the receiver starts doing position fixes.

If an altitude is not provided, the receiver will use the altitude of the previous 3-D fix (altitude-hold mode). Sending packet 2A with one data byte equal to 0xFF will cancel altitude-set mode and return the reference altitude to 0. The altitude setting is stored in non-volatile memory. Packet 0x8E-26 can be used to write receiver configuration to EEPROM.

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Acutime 2000 Synchronization Kit User Guide

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Trimble Outdoors Part Number 45005-00-ENG manual 0x27 0x28 0x29 0x2A, Signal Levels Request, GPS System Message Request