GLOBALSAT ET-314 GPS Engine Board User Manual

Page 19

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ET-314AC
High Performance GPS Engine Board

2010/4/1

- 19 -

Table B-8 LLA Navigation Initialization Data Format

Name

Example

Unit

Description

Message ID

$PSRF104

PSRF104 protocol header

Lat

37.3875111

degrees

Latitude + = North (Range 90 to -90)

Lon

-121.97232

degrees

Longitude + = East (Range 180 to -180)

Alt 0 meters

Altitude

position

ClkDrift

96000

Hz

Clock Drift of the Receiver1

TimeOfWeek

237759

sec

GPS Time Of Week

WeekNo

1946

Extended GPS Week Number

ChannelCount 12

Range 1 to 12

ResetCfg 1

See

Table

B-9

Checksum *07

<CR> <LF>

End of message termination

Use 0 for last saved value if available. If this is unavailable, a default value of 96,250 Hz is used.

Table B-9 Reset Configuration Bit Map

Bit Description

0☆

Data valid flag: 1 = Use data in ECEF X, Y, Z, Clock Offset, Time of Week and Week
number to initialize the receiver; 0 = Ignore data fields

1

Clear ephemeris from memory: blocks Snap or Hot Start from occurring

2

Clear all history (except clock drift) from memory: blocks Snap, Hot, and Warm Starts

3

Factory Reset: clears all GPS memory including clock drift. Also clears almanac stored
in flash memory

4

Enable Nav Lib data (YES = 1, NO = 0) ★

For software that does not support initialized data (GSW3, GSWLT3, SiRFXTrac) setting this
bit may cause unpredictable results. Do not attempt to use initializing data.

If Nav Lib data are enabled, the resulting messages are enabled: Clock Status (Message ID 7),
50BPS (Message ID 8), Raw DGPS (Message ID 17), NL Measurement Data (Message ID 28),
DGPS Data (Message ID 29), SV State Data (Message ID 30), and NL Initialized Data
(Message ID 31). All messages sent at 1 Hz. If SiRFDemo is used to enable Nav Lib data, the
bit rate is automatically set to 57600 by SiRFDemo.

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