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GSM19 Series Magnetometers - Version 7
GEM Systems, Inc. Advanced Magnetometers
For more technical information, visit www.gemsys.ca
After setting display mode, cycling rate and the other parameters as it has been explained before for
the mobile mode (see sections 5.3.3 to 5.3.9), press
A-start
to start the base file.
5.7.2 Stopping a Base Station Reading
The only way of stopping a Base survey is by pressing
1 C
to force the return to main menu. If the
base is re-started, a new file is created.
NOTE:
Optionally, v7.0 GEM Systems magnetometers may be equipped with a
Programmable Base Station feature. The programmable base allows you to enter
and store up to 30 base station survey programs or schedules that determine the
date and time to start and stop the base. The schedules can be entered using the
keypad or transferred from a file on a PC using GEMLinkW.
5.8 SYNCHRONIZING ROVER AND BASE STATION UNITS (ALL MODELS)
If you intend to use two or more GSM-19s (for example, a Rover unit such as a GSM-19 in mobile,
gradiometer, walking or walking gradiometer mode and a Base Station unit) in the survey to later
perform diurnal correction, you must synchronize their times.
5.8.1 Setting the Time on the First Magnetometer
First, you have to set the right time on one of the mags. (Refer to 5.3.3 Setting Time) and then
transfer it to the other units using the synchronization cable and the procedure described below.
IMPORTANT NOTES:
Units equipped with built-in GPS overwrites the local time with UTC when GPS
is active.
•
If ALL units are equipped with GPS they all automatically synchronize to
UTC and the GPS timing controls their cycling. This is the optimum
synchronization and in this case there is no need to transfer the time from one
unit to another.
•
If only ONE unit is equipped with GPS, you should synchronize that unit to
UTC (see Appendix D) and then use the synchronization cable to transfer the
UTC time to the other.
•
Also note that in this case, the cycling of one unit is synchronized to GPS time
every reading taken. The other unit runs on its internal timer with no further
GPS synchronization. Therefore, there may be a time discrepancy between the
two units. This time discrepancy only becomes significant after very long
surveys or in the case of unattended base stations without GPS.