FLOAT RMS Error Accuracy and Estimation?

Let’s say I have a FLOAT connection using NTRIP with a base 10 km away, clear skies, at least 8 GPS/GLONASS satellites on the rover and base. Are the RMS error values indicated in the Reachview app after collecting for 5 minutes a good estimate of the FLOAT coordinates accuracy? If not, is there a general rule of thumb to use just to get an approximate RMS error estimate (1 m versus 5 dm versus 1 dm ?)

It seems in most cases the longer you collect in FLOAT the higher the RMS error inches up. Would you just have to collect longer until a point the RMS error either plateaus or starts going down to have confidence in the RMS value?

Typically if I have to work in a float condition I am logging for PPK at the same time. A trick you can use though is occupy the point for a minute, back off about 10 meters, reoccupy the point for a minute and then start your collection. If you start your collection immediately after the occupation then you will get high RMS as the receiver continues to realign.

If you get a FIX do you keep the unit on when moving between collection points and so if you PPK it you just look at the collection time range, or do you always power the unit off between collection points in order to create separate discrete logs that you know the unit was only logging when it was level and stationary? I guess if you back off 10m then you might as well just leave the unit on the entire time, especially if you get a FIX as powering it down would mean you might not get a FIX very quickly when powering back up at the next location.

Personally in this scenario I log as if I was shooting the point.

  1. Occupy the point for 1 minute
  2. Turn on logging
  3. Shoot the point for an appropriate amount of time
  4. Turn logging off

This method allows me to PPK each point independently. If the exported points report a Fix then I don’t worry about it and any points that report a Float are then PPK’d.

If you experience this allot and are shooting allot of points then I would recommend you checkout THIS solution and always PPK.

That link is a great resource. Thanks. So basically you leave the unit on the whole time? When you say “turn on logging” is that a separate function then in Reachview from starting ‘collecting’ ?

Correct, you can traditionally collect and log at the same time. It’s just a few extra seconds on a separate screen to log as a point as I refer to it.


For doing PPK, would all I need to log is RAW Data in Rinex?

I do the raw UBX and then use the RTKLIB package to post-process. Mainly RTKCONV to create the correct RINEX and RTKPOST to get the positions. All in all I can do an entire drone track or about 10-15 points in less than 15 minutes.

A post was split to a new topic: PPK setup with Reach device

Hi guys,

I agree with Michael’s point. Just want to additionally share the post-processing guide if it might be useful and @jazee hasn’t seen it before :slightly_smiling_face:

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