SXBlue II GPS Series Technical Reference Manual
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$>JSHOW,ASC,GPGSA,1.0,OTHER
$>JSHOW,ASC,GPZDA,1.0,OTHER
Q – How can I be sure that the configuration will be saved for the subsequent power
cycle?
A – The surest method is to query the receiver to make sure you’re satisfied with the
current configuration, by issuing a $JSHOW<CR><LF> command (if not, make the
necessary changes and repeat). If the current configuration is acceptable, issue a
$JSAVE<CR><LF> command. Wait for the receiver to indicate that the save is
complete. You may power the receiver down and issue another $JSAVE if you feel it’s
necessary; however, it is not required.
Q - What is the best software tool to use to communicate with the SXBlue II GPS and
how to configure it?
A - We use two different software applications at Geneq for this application:
•
PocketMAX - Available from Geneq. This application is a very useful tool for graphically
viewing tracking performance, positioning accuracy, and more on a Pocket PC.
•
HyperTerminal – Available on all Windows 95, 98, ME, 2000 and XP. This tool is useful as
it allows you to easily configure the SXBlue II GPS by directly typing commands into the
terminal window. The output from the SXBlue II GPS is shown simultaneously. Ensure
that when using HyperTerminal that it is configured to use the correct PC communication
port, baud rate, and that the local echo feature is on (see section 3.3).
6.5 GPS Reception and Performance
Q - How do I know what the SXBlue II GPS is doing?
A - The SXBlue II GPS supports standard NMEA data
messages. The $GPGSV data
message contains satellite tracking information. Since the GPS automatically tracks
GPS satellites when powered, this will give you information on the tracking status. If
your receiver has computed a position, this will be contained within the $GPGGA data
message. Additionally, the SXBlue II GPS module has LEDs that give indication of
receiver status.
Q - Do I have to be careful when using the SXBlue II GPS to ensure that it tracks
properly?
A – For best performance, you have to be careful such that the hemisphere above the
SXBlue II GPS’s antenna is unobstructed for satellite tracking. The SXBlue II GPS is
tolerable of a certain amount of signal blockage due to the availability of redundant
satellites (only four are required for a position). However, as more satellites are blocked,
the more impact this could have on your positioning accuracy.
6.6 SBAS Reception and Performance
Q - How do I know if I can receive a SBAS signal in my area?
A - Refer to Appendix C that contains approximate coverage maps for both WAAS (for
Central and North America) and EGNOS (for Europe). It’s important to have both signal
