Hi,
we’re planning to use two reach units for surveying, using postprocessing.
We would like estimate in the field if the recorded data will likely suffice for a fix. Assumption is that the base station has very good satellite view, so we only have to look at rover data. (There is no way to look at the base data, we have no link)
I’m now using the following metrics:
- average number of sats in view
- average number of sats with SNR > 45 or, 40 …
- average snr
But I can’t get a clear relationship with fix status, some observations with average more than 5 sats with snr > 45 stay float even when recording data for 2-3 min, while others with <5 sats above 45 snr get fix in 1 minute…
Any suggestions on other metrics to use?
DOP/HDOP? (Any tip how to get this from Rinex / RTKRCV status?)
longest time span with n sats > 45 snr …
For example I tested the reaches against a reference (Topcon hiper L1/L2 using RTK from a external NTRIP caster).
I good fixes for most points, but especially when there is some obtrusion there is no or short fixes some time quite off:
This graph shows the relationship between mean number of sats. with SNR > 40 vs the distance (m, log scale) to the point measured with the Topcon.