Trimble Outdoors R7 - Manual (Page 182)

A NMEA-0183 Output
1 7 0 Trimble R7/R8 GPS Receiver User Guide
Tr
imble R7 and R8
A.1
Introduction
This appendix describes the formats of the subset of NMEA-0183
messages that are available for output by the receivers. For a copy of
the NMEA-0183 Standard, visit the National Marine Electronics
Association website at www.nmea.org.
A.2
NMEA-0183 Outputs
When NMEA-0183 output is enabled, a subset of NMEA-0183
messages can be output to external instruments and equipment
connected to the Trimble R7 serial ports. These NMEA-0183
messages let external devices use selected data collected or computed
by the GPS receiver.
All messages conform to the NMEA-0183 Version 3.01 format. All
begin with $ and end with a carriage return and a line feed. Data fields
follow comma (,) delimiters and are variable in length. Null fields still
follow comma (,) delimiters but contain no information.
An asterisk ( *) delimiter and checksum value follow the last field of
data contained in an NMEA-0183 message. The checksum is the 8-bit
exclusive OR of all characters in the message, including the commas
between fields, but not including the $ and asterisk delimiters. The
hexadecimal result is converted to two ASCII characters (0–9, A–F).
The most significant character appears first.
Table A.1 summarizes the set of NMEA messages supported by the
Trimble R7 receiver, and shows the page where detailed information
about each message can be found.
Table A.1 NMEA message summary
Message Function Page
AVR Time, yaw, tilt, range, mode, PDOP, and
number of SVs for Moving Baseline RTK 174
GGA Time, position, and fix related data 175
GSA GNSS DOP and active satellites 176