RS2 can no longer achieve float or fix

I have an RS2 base and rover and have conducted 3-4 surveys, setting the base over a known point. No CORS or NTRIP available. Baselines maximum 500m in peri urban areas. The last survey, while collecting points with the rover, I lost the connection with the base about 250m away. I thought it had shut off because I had forgotten to recharge it but when arriving at the base it was still functioning but still wouldnt connect or achieve a fix.
Since then I can no longer obtain float or fix on the base unit even setting up at home with units adjacent to each other. When reversing roles of base and rover, the rover unit functions fine in base mode. In addition, the base unit has consistently had more problems than the rover in maintaining a connection, showing lower signal strength and dropping the connection even when just a few meters away.
I must be msissing something but it is strange that the connection suddenlydropped and the base can no longer achieve a fix. Any suggestions as to the cause?

What firmware are you running?

RS2 are running firmware v2.24.2

Hi @itenviro,

Did I get correctly that you use LoRa to set up an RTK connection? If so, may I ask you to try Emlid Caster and check if the issue persists?

thats correct. RTK / lora. I will check out emlid caster and get back to you.

I set up emlid caster on the base and rover. Not sure I have made the proper connections as both base and rover are “waiting for corrections” . Still no fix though. Just single solution.

Can you post process the same observation and get a fix?

i made a 3 hour observation in static mode over a known point and submitted to NRCan for ppp. The obs file was valid and received virtually identical results to a previous 3 hour observation about a month ago. seems to be a connection or software issue.
I am tempted to do a hard reset and to reinstall ReachView3. Maybe reinstall firmware also.

Just to update. I used the Reach flash tool for both RS2 units and reinstalled Reachview. I can now achieve a fix. Performed a survey although range / baseline doesnt seem as great as before but maybe just different environment…

Hi @itenviro,

Could you conduct a 10-15 minutes test and record the following logs:

  • Raw data log on both the base and rover
  • Position log on the rover
  • Base corrections log on the rover

Please share them with me. It will help me to understand the possible reason for such issues. You can send the logs in PM if it contains sensitive info.


I recently experience a similar loss of RTK connections. Really bad Lora, flakey Caster, and pretty much useless RTK between base & rover. My fix (after 4 full days of trying every test procedure in these numerous threads about poor RTK) was to re-flash the GPS units and all is well. I was on the latest Beta firmware (from Dec. 2020) and connection problems were getting worse by the day. I ReFlashed to latest stable release and RTK works much, much better in both Lora and Caster mode.

For now, the ReFlash tool is my best friend. Based upon reading every post about poor RTK corrections between base & rover, its my suggestion to get the ReFlash tool out and give it a try FIRST. Most of these threads end with the suggestion to ReFlash, and then we don’t hear back from the O.P.

Still lovin’ my Reach RS2s after about a year. The caster function is a big help.

Keep up the good work EMLID.

P.S. I told my son (who owns a 25 man engineering and surveying firm) about the Reach RS2s and they are now the GO TO instruments for his field crews. The RS2s work every day, while the Trimble & Topcon units gather dust.

P.P.S. During my recent RTK Lora issues, I dug out one of my Ubiquiti M900 (nano bridge m-9) wireless network radios. As part of the $200 radio, it comes with a software package which is called “AirView”. Its a 900 Mhz Spectrum Analyzer and I was able to determine the noise floor over the entire 900mhz band by letting the AirView program run. By selecting the frequency with the lowest noise floor, I’m able to get 6 db less noise at 914.8 mhz versus the rest of the band. As noise varies due to local conditions, I’ll be keeping the Ubiquiti M900 in my tool box for when long distance Lora is the only way to get RTK corrections.

Radio (Lora) is all about Signal to Noise Ratio. To get better reception, either increase your signal strength by 6db (which requires 4 times more power at the transmitter), or select a frequency which has a lower average noise level by 6db at the receiver.

Great Job Emlid - atta boy!


1 Like

Hi Tom,

Thanks for your kind words and for promoting our devices to surveying companies :slightly_smiling_face:

I suppose it was dev v2.25.1. We indeed had issues with getting a fix on that version. I just wanted to let you know that we’ve fixed this behavior in v2.25.2. So, if you’d like to be subscribed to the dev branch, you can do it now.

However, as you’ve mentioned, the stable v2.24.2 works without any issues as well.

A post was split to a new topic: Add a LoRa RF scan/survey function

This topic was automatically closed 100 days after the last reply. New replies are no longer allowed.