SXBlue II GPS Series Technical Reference Manual
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Note - If you require different data types to be output from the SXBlue II GPS
simultaneously (such as NMEA and binary or NMEA and RTCM), ensure that the software
used for logging and processing of the data has been designed to correctly parse the
different data types from the single stream of data. Alternatively, you may also use any
two ports to separate the different data types and set at different output rates.
3.2.1 NMEA 0183 Interface
NMEA 0183 is a communications standard established by the National Marine Electronics
Association (NMEA) and provides data definitions for a variety of navigation and related
equipment. Such instruments supported include gyrocompasses, Loran receivers, echo
sounders, GPS receivers, and more. NMEA functionality is virtually standard on all GPS
equipment available. NMEA has an ASCII character format that allows you to read the data via
terminal software on the receiving device (if possible). One second of example NMEA data
from the SXBlue II GPS follows:
$GPGGA,141823.00,4536.79732,N,07333.95861,W,2,09,1.0,49.6,M,-32.4,M,5.4,0313*4E
$GPVTG,151.61,T,,M,0.08,N,0.15,K,D*36
$GPZDA,141823.00,9,7,2004,00,00*63
$GPGSA,M,3,06,08,10,17,18,21,24,26,29,,,,1.7,1.0,1.3*31
$GPGSV,3,1,11,06,40,234,48,08,18,056,42,10,43,066,45,16,00,319,*7F
$GPGSV,3,2,11,17,43,121,45,18,21,264,45,21,39,304,45,24,10,125,45*7E
$GPGSV,3,3,11,26,69,160,48,27,07,031,39,29,73,109,45,,,,*45
The SXBlue II GPS supports a variety of standard and proprietary NMEA messages. These
messages are used to configure the receiver and also contain the required information from the
SXBlue II GPS. You may configure a selection of NMEA 0183 data messages on one port at
various update rates (each message has a maximum update rate) and a different selection of
NMEA 0183 messages with different rates on the other port.
Chapter 4 presents information relating to the NMEA interface of the SXBlue II GPS. Appendix
D - Resources provides contact information, should you wish to purchase a copy of the NMEA
0183 standard.
3.2.2 Binary Interface
Binary messages may be output from the SXBlue II GPS simultaneously as NMEA 0183 data.
Binary messages have a proprietary definition and would likely require custom software support
if you wish to use them. Binary messages are inherently more efficient than NMEA 0183 and
would be used when you require maximum communication efficiency. Use of binary messages
for most users is not recommended - the NMEA interface allows you to control the operation of
the SXBlue II GPS and also receive most types of information regarding status and positioning
information.
Note – If you wish to log binary data, please ensure that your logging software has
opened the file as a binary file, otherwise you may lose data.
3.2.3 RTCM SC-104 Protocol
RTCM SC-104 is a standard that defines the data structure for differential correction information
for a variety of differential correction applications. It has been developed by the Radio
Technical Commission for Maritime services (RTCM) and has become an industry standard for
communication of correction information. RTCM is a binary data protocol and is not readable
