Hi all,
The chances of catching a False Fix on a typical survey site are pretty low. Such situations usually occur in challenging surveying conditions. Most of the time you can rely on the solution status you see in the software.
However, how do you determine which conditions may potentially lead to wrong calculations?
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If you work under the dense foliage
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If you are tightly surrounded by high-raised buildings
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Near any other obstacle that blocks 80-90% of the sky. You can check the Satellite SNR chart. There should be at least 5-7 sats with SNR higher than 30
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If you receive corrections via NTRIP and work in an area with unstable Internet coverage
What parameters need to be additionally checked in the cases mentioned above?
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DOP value. We do not recommend collecting points with DOP higher than 2
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Age of differential. If the time is more than 2 seconds, there is a chance of connectivity issues
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Point observation time. As I’ve already said, I’d suggest increasing observation time in harsh conditions. It might help to capture the Fix instability
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RMS value
Reach RS+ and Reach RS2 calculate the solution differently. Also, we conducted some Fix-and-Hols vs. Continuous comparing tests and found no proof that one mode works better than the other. The results are described in this thread.
It is not always possible to provide the receiver with an absolutely clear sky view without any obstacles. I understand that you would rather avoid even a rare opportunity of catching a false fix. However, this is a common challenge for all GNSS receivers, not only for Reach.