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GSM19 Series Magnetometers - Version 7
GEM Systems, Inc. Advanced Magnetometers
For more technical information, visit www.gemsys.ca
NOTE:
This is NOT a permanent selection. Even when the upper channel is selected for
single channel modes, the unit defaults to the lower channel after a grad mode is
used.
5.6 WORKING WITH WALKING MODES (19W, 19WG & 19GFW)
GEM’s unique “Walking” Magnetometer/Gradiometer enables acquisition of nearly continuous
data on survey lines. Thanks to the Overhauser effect enhancement exclusive of GEM Systems,
sampling rates that could otherwise be obtained only with optically pumped systems, can be
achieved with excellent results.
Similar to an airborne survey in principle, data is recorded at discrete time intervals (normally up to
2 and optionally up to 5 readings per second) as the instrument travels along the line. At each
survey picket the operator presses the designated key. The “Walking Mag” records the coordinates
of the picket and automatically assigns linearly interpolated coordinates to all intervening readings
(see section 6.2.3).
NOTE:
When a Walking Mag or Grad is used with GPS coordinates, the system does not
perform interpolation at pickets; instead it uses the actual GPS position at each
designated time (as specified through the survey cycle time).