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0x31, 0x32, 0x35 – Trimble Outdoors SK8 User Manual

Page 88

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A-24

Lassen-SK8 Embedded GPS Module

Trimble Standard Interface Protocol

A.17.15 Command Packet 0x31

This packet is identical in content to Packet

0x

23. This packet provides an initial position

to the GPS receiver in XYZ coordinates. However, the GPS receiver assumes the position
provided in this packet to be accurate. This packet is used for satellite acquisition aiding in
systems where another source of position is available and in time transfer (one-satellite
mode) applications. For acquisition aiding, the position provided by the user to the GPS
receiver in this packet should be accurate to a few kilometers. For high-accuracy time
transfer, position should be accurate to a few meters.

A.17.16 Command Packet 0x32

This packet is identical in content to Packet

0x

2B. This packet provides the GPS receiver

with an approximate initial position in latitude, longitude, and altitude coordinates.
However, the GPS receiver assumes the position provided in this packet to be accurate.
This packet is used for satellite acquisition aiding in systems where another source of
position is available and in time transfer (one-satellite mode) applications. For acquisition
aiding, the position provided by the user to the GPS receiver in this packet should be
accurate to a few kilometers. For high-accuracy time transfer, position should be accurate
to a few meters.

A.17.17 Command Packet 0x35

This packet requests the current I/O option states and optionally allows the I/O option
states to be set as desired.

To request the option states without changing them, the user sends the packet with no data
bytes included. To change any option states, the user includes 4 data bytes with the values.
The I/O options, their default states, and the byte values for all possible states are shown
below. These option states are held in battery-backed memory and can be set into non-
volatile RAM (EEPROM) with the

0x

8E-26 command. The GPS receiver returns Packet

0x

55. See A.3 for information on saving the settings to non-volatile memory.

These abbreviations apply to the following table: ALT (Altitude), ECEF (Earth-centered,
Earth-fixed), XYZ (Cartesian coordinates), LLA (latitude, longitude, altitude), HAE
(height above ellipsoid), WGS-84 (Earth model (ellipsoid)), MSL geoid (mean sea level),
and UTC (coordinated universal time).