A

Trimble Standard Interface Protocol

0x84 Report Packet 84

Double-precision LLA Position Fix and Bias

Information

This packet provides current GPS position fix in LLA coordinates. If the I/O "position" option is set to "LLA" and the double-precision option is selected (packet 35), the receiver sends this packet each time a fix is computed. The data format is shown in the table below.

Table A-66 Report Packet 84

Byte

Item

Type

Units

0-7

latitude

DOUBLE

radians;

 

 

 

+ for north, for south

 

 

 

 

8-15

longitude

DOUBLE

radians;

 

 

 

+ for east, for west

 

 

 

 

16-23

altitude

DOUBLE

meters

 

 

 

 

24-31

clock bias

DOUBLE

meters

 

 

 

 

32-35

time of fix

SINGLE

seconds

 

 

 

 

The time-of-fix is in GPS time or UTC, as selected by the I/O "timing" option "packet 35." At start-up, this packet is also sent with a negative time-of-fix to report the current stored position.

Packet 4A provides a single-precision version of this information.

"Caution – When converting from radians to degrees, using an insufficiently precise approximation for the constant π (Pi) introduces significant and readily visible errors. The value of π as specified in ICD-GPS-200 is 3.1415926535898.

Acutime 2000 Synchronization Kit User Guide

A-77

Page 183
Image 183
Trimble Outdoors AcutimeTM2000 Synchronization Kit manual Double-precision LLA Position Fix and Bias Information