RTCM Message rates?

Hi Guys,

A few questions related to RTCM packets if I may:

Can you please let me know what the relative rates used are used for each of the RTCM messages generated by the Base? (does the Rover expect the Ephemeris Data every nth observation packet or each time the Ephemeris is new for example) The reason I ask is that when using a Reach module as the base station, it all works very smoothly, when I generate the RTCM packets from a different GPS (Novatel OEM6) I see that the grey bars periodically disappear, I assume that this is related to not supplying the observations and/or ephemeris packets at the correct rate.

Does the RTCM 1008 packet (Antenna Type) get used by the Reach Rover currently?

Thanks again for an excellent product and the rapid functionality expansion.

Best Regards,

My suggestion is 1004 at 1 sec, 1012 at 1 sec , 1019 at 5 sec and 1020 at 5 sec with 1104 at 1 sec. We noticed that Trimble needed base station position at 1 Hz while Leica SpiderNET was setup to 15" and in that case a Trimble GNSS RTK rover was longer to first fix. Not sure RTK-LIB is supporting antenna type but you can use ADV NULL ANTENNA where the calibration values of the antenna are incorporated into the observations.

Hi Paul,

Currently the RTCM rate is tied to the GPS update rate, so if you have base at 5Hz it will be sending RTCM at 5 Hz. Maybe there is issue with the communication link?

Thanks Joel, have you used the Reach modules in any of the testing you’re referring to? I’d made similar assumptions do to previous usage of Novatel system.


Hi Igor,

So to be clear, you send all of the RTCM at this rate from the base station?
I had assumed this would be the case for the raw observations but possibly not for the antenna position and ephemeris data?

Do you use/know of any useful software tools that can examine these packets?

Best Regards,