Assuming that demodulator is already enabled and that the dongle has sufficient days remaining (see Help > Dongle > View), the most important task is to check the predicted satellite count and DOP values during the critical period.
Click View > GNSS > DOP to open the window. Right click and adjust the time scale as necessary.
Depending upon the system configuration, the DOP window may display GLONASS data.
If using Ultra, or any other non-GLONASS calculation, right-click in the window and click “Hide GLONASS”. The window will then display the satellite count and DOP values which are applicable for GPS-only calculations.
Any problem periods will be evident as indicated by a low number of satellites and high DOP value allowing the operator to plan for these periods.
Note: It is worth checking any recent NANU’s (Notice Advisory to Navstar Users) issued by NAVCEN (http://www.navcen.uscg.gov) to ensure that no satellites are scheduled to become unhealthy during the critical period.