RS+ FIX Issues and Consistency

Hi all,

I am based in Auckland, New Zealand and using Reach RS+ with ReachView 3 and the latest updates.

I have been having issues with consistency and FIX times. I was originally getting corrections from a free national service LINZ, but have recently started using a local provider for base stations.

I have been getting issues with FIX for the last few months. Previously I would go out and it would take a minute or two to sort itself out and then I would get a FIX with 14/10 horiz/ vert accuracy and this would stay firm. From what I understand this as a constant give the best accuracy.

I am not sure what has happened but in the last couple of months I have really struggled to get anything reliable/ consistent. There would be the odd day where I would get a 14/10 FIX pretty quickly, but this would start to bounce around when I pick the unit up and move it say 100m to the next mark to ping. This simple movement would cause the unit to go back to FLOAT and then it would take sometimes up to 15 minutes for it to find FIX again. Not the greatest as you ant to do a quick efficient site visit.

I am mostly working around suburban/ rural areas with great coverage and not lot of large obstructions.

More recently the unit can’t find a 14/10 FIX - its seem to get down to 09/20 ish and I haven’t been able to get a solid stable fix. This is throwing the accuracy of the unit and I have no idea what is going on or what has changed in the last 2 months for it to stop getting to 14/10.

The measurements I am getting a hugely varied now and I can’t trust it even when it says FIX. Had multiple shots on the same site visit within a half an hour period and they varied up to 800mm in height and 3/400mm in position - not good.

If anyone could shed some light on this irritating issue that would be much appreciated.

Thanks,
Jason

What is your baseline?

Have you also checked in GNSS settings if the solution is calculated as static or kinematic? A receiver set to static that keeps moving will lose and struggle to regain fix much more.

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Hi Jason,

Welcome to our community forum!

Came up with the same questions as Christian and Gabriel while reading about your situation. Did you get a chance to check the baseline and RTK settings?

As for the Fix solution accuracy, both measurements of the same point can have some centimeter-level shift to the point’s actual position. To check the accuracy, I’d suggest collecting a known benchmark in the same coordinate system. If you have such a point nearby, you can calculate the difference between its known coordinates and the ones collected with Reach.

Hi Christian - sorry for the late reply. Not sure what your term baseline relates to - haven’t heard that exact term here in NZ.

I am using the Reach as a Rover getting corrections from local base stations - the network setup is automatically connected to the nearest station at any one time depending on where I am - usually under 10km distance.

Hi Gabriel - yes it is always set to Kinematic.

Hi Kseniia,

As stated above - I am using the Reach as a Rover getting corrections from local base stations - the network setup is automatically connected to the nearest station at any one time depending on where I am - usually under 10km distance.

I am using Kinematic not Static.

Whenever I do a survey I always ping at least 3 local survey marks. I also cross check against survey from other registered surveyors (quite often existing info from jobs we are doing)

This is where I find the issues - my work is for photo locations and tie-in points to math with the photos for commercial/ residential projects. This is how I get survey background info to compare with.

Has anything changed with the software in the last few months? It is only really in this time that I have found massive changes and issues with speed/ consistency. When I set up the rover over a point to survey it and I am sitting in the open waiting 15 minutes later for a FIX, it gets quite frustrating!

What normal speeds ona good day would you expect to see for a FIX?

Baseline is the length of the “vector” from your correction-source (your base) to your rover.

Hi Jason,

The time to Fix depends on the environment and settings, but it’s usually several minutes for Reach RS+. As for the baseline, Reach RS+ supports up to 10 km in RTK. So, the remote bases you use should work well. Since you’re in an open area, the setup looks pretty good overall.

I’ll need to see the receiver’s data quality to check what can be wrong. Please check that your unit is on the latest stable firmware (28.4), record these logs for at least 10-15 minutes, and share them here or via support@emlid.com:

Please enable logging right after turning Reach on so that we can see how long it takes to calculate a Fix solution. During the test, collect some known points with ReachView 3 and share their known and measured coordinates with us.

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