I have some questions regarding the csv files that are written when raw logging is enabled.
In the raw logging files, there are a few columns which are not described in the Skydel documentation.
First of all, could you confirm that the following ECEF coordinates describe the satellites position at the times displayed in either the column “Elapsed Time” or “GPS TOW, Week Number” and not the coordinates of the satellite at signal transmission time.
Furthermore, is it correct that the column “PSR satellite time (ms)” indicates the simulation time at which the signal was transmitted? If this is the case, there seems to be an inconsistency in the calculation of the “Range”. To my understanding, the column “range” described the true geometric distance between satellite and receiver at transmission time. The “range” column should then be equal to the difference of:
- the receiver position at the time indicated in the column “elapsed time” and
- the GNSS satellite position at transmission time indicated in the column “PSR satellite time”
However, if the GNSS satellite position is calculated through interpolation from the coordinates provided in “ECEF”, it is not equal to the “range” value. There seems to be a difference of around 50m.
Could you provide further information to clarify this issue?