A GPS connection is the main issue between your GNSS receiver and our land survey apps.
We tested a lot GNSS receivers. While testing we could make a GPS connection with GNSS receivers of the following brands.
Our GIS mapping apps and land surveying apps are using Bluetooth to make a connection between the GNSS receiver and the GPS software. This is a great connection method, because it is easy for the user to make this connection. The distance between the GNSS receiver and the Android device where our GPS software is installed is usually small. That is ideal to make a Bluetooth connection.
There are two parts of communication between our survey software and the GNSS receiver. The first one is the messages going from the GNSS receiver to our GPS apps.
Most of the time this direction of communication is done with NMEA 0183. Our GPS apps support this messages. NMEA 0183 exists of many different strings. There are strings for many different kind of information.
Our GPS apps needs the following NMEA 0183 strings to get all the information they need:
- GGA – Fix information
- GST – GPS Pseudorange Noise Statistics
Some of our land survey apps use some other NMEA 0183 strings, like GSA – Overall Satellite data.
There are also other protocols to send information from the GNSS receiver to our land survey apps. If needed we can add this to our applications.
Our GPS apps are like a messenger of RTCM messages. You can compare them with a mailman. Our land survey apps connect as a NTRIP client to a certain NTRIP caster. Our GPS forward the RTCM messages, that are send from the NTRIP caster, to the GNSS receiver.
The messages that our land survey apps forward can be any messages that are send from the NTRIP caster. This can be RTCM 2.x or RTCM 3.x. Our GIS mapping apps don’t adapt any messages that it forwards to the GNSS receiver. So if your GNSS receiver use any other messages from NTRIP then it won’t be a problem for our apps.
This is the second part of the GPS connection.