Corrections via radio modem and base station
- Ensure the GNSS2 is using the supplied dual frequency GPS+GLONASS antenna.
- Fit 4G LTE antenna to the GNSS2
- Attach radio modem receiver to second serial port using breakout lead. On GNSS2, with serial comms configured at 38400 baud.
- Attach radio modem transmitter to a base station, configured to use the same radio frequency as the radio modem receiver attached to the GNSS2.
- Ensure the base station transmits RTCM v3.x corrections.
No configuration is required on the GNSS2 to use corrections from a radio modem. If present they will be used. It will expect to receive RTCM v3 corrections on serial port 2 at 38400 baud. Connection to serial port will require the supplied breakout cable.
Any radio modem capable of sending data at 38400baud can be used, Satel units are very popular for this purpose:
Whichever radio modems are used, they must be used in matched pairs as they are rarely compatible between manufacturers.
Note: This configuration can also be used to receive corrections from another GNSS2 that has been configured to receive corrections over the internet, A GNSS2 that has been configured to receive internet based corrections will automatically re-transmit them at 38400 baud, and in this way a single server connection can be shared. The remainder of this page will simply consider the base station case, but the setup for using shared corrections from an additional GPS2 RTK receiver is conceptually the same.
Setup the system as shown in the diagram below. The GNSS2 will work with any base station capable of transmitting RTCM v3.x corrections. Ensure that the radio modem attached to the base station and the radio modem attached to the GNSS2 are transmitting and receiving on the same frequency, and will work together. Ensure that the radio modem attached to the GNSS2 is configured to use a serial connection at 38400 baud, and attach to the 2nd RS232 port on the rear of the GNSS2 using a null modem cable and the supplied breakout cable. Ensure that the GNSS2 is using the supplied dual frequency GPS+GLONASS antenna; use of a GPS only or a single frequency antenna will result in substandard operation. The 4G LTE antenna must also be fitted.
Following these steps, the GNSS2 should achieve integer RTK differential lock (full accuracy) as long as the base station is transmitting corrections and the GNSS2 has a clear view of the sky and is using the supplied dual frequency GPS+GLONASS antenna. To verify correct operation, check on Screens 4 and 6 of the LCD status data to see correction age and traffic on serial port 2.