Trimble R10 as a Base Station for Emlid Reach RS4 Pro Using UHF Radio and RTCM 3.x

Reach RS4 / RS4 Pro RTK / PPK configuration
1

Hi everyone,

Has anyone tried using a Trimble R10 as a GNSS base station for an Emlid Reach RS4 Pro rover using a direct UHF radio connection with RTCM 3.x corrections?

I would like to know if this setup is possible without using NTRIP or an internet connection.

If anyone has successfully configured this setup, could you please share the following?

  • Recommended RTCM 3.x message types and settings on the Trimble R10.

  • Compatible UHF radio protocol and configuration.

  • How to connect and configure the RS4 Pro to receive corrections.

  • Any known compatibility issues or limitations.

Any advice or field experience would be greatly appreciated. Thank you!

5

Hi @eulogio.idl ,

Welcome to our Community Forum!

The setup using TrimbleR10 as a base and a Reach RS4 Pro as a rover is possible without using an NTRIP or an Internet connection while using UHF radio.

Just make sure you’re using RTCM3 corrections over TRIMTALK 450S protocol in the 410.0–475.0 MHz range. I’ve attached this guide on using a third-party base over UHF radio which can walk you through the setup.

I’d also encourage anyone in the community who is actively running this combo to chime in with their experience on this setup!

6

Daniela covered the protocol. A few more things that usually trip people up:

  • On the R10 base, set the output to RTCM 3 with MSM messages, not CMR or CMR+. Emlid reads RTCM 3.
  • Messages you want: 1005 or 1006 (base position), plus MSM for each constellation (1074 GPS, 1084 GLONASS, 1094 Galileo, 1124 BeiDou). MSM4 is enough and keeps the data small.
  • Radio: the RS4 uses TRIMTALK 450S, so set the R10 radio to TRIMTALK 450S too. Use the same frequency and the same bandwidth on both. On the RS4 the over the air rate follows the bandwidth: 25 kHz gives 9600 bit/s, 12.5 kHz gives 4800 bit/s. Match the R10 to that.
  • At 4800 bit/s, 4 constellations can be too much data. If the rover keeps dropping to float, use MSM4 or turn off a constellation on the base.
  • Check that the base coordinates on the R10 are on the same datum as your rover project.

Once it’s up, watch the corrections age on the rover. If it keeps climbing past a couple seconds, it’s the radio link, not the receiver.