BARTINGTON INSTRUMENTS
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the second traverse line. A dual sensor gradiometer will be carried with one sensor at 0.5m and
the other at 1.5m for the first traverse.
When the first two traverses have been recorded, the trapeze is moved to the next mark on the
edge lines and the next two traverses are recorded. This process is repeated until the Grid has
been completed. Using a dual sensor gradiometer with a trapeze, as described above, the last
traverse for a 10 or 30m Grid will be completed with the centre of the trapeze in line with the
edge of the Grid.
The edge lines are then moved to the adjacent Grid, and the next Grid is surveyed in the same
manner. In this way a complete row of Grids can be covered quickly.
A.10. Other Methods
The equipment described above is suitable for single or dual sensor operation.
For the highest spatial accuracy, the operator should walk relatively slowly and ensure the
sensor is held upright at all times. The movement should be smooth and well synchronised with
the bleeps from the data logger. With experience, and where the spatial accuracy is less critical,
it is possible to walk at a constant pace without the aid of the 1m marks on the trapeze lines and
the trapeze may then be abandoned. The operator may then mark only the end of the traverse
lines with canes, count the bleeps during each traverse, and aim to reach the end of the traverse
at the last double bleep. This procedure minimises the number of operators required.
If required, Bartington Instruments also sells a cart to mount the sensors upon during GPS
surveys. The cart is non-magnetic and specially designed to minimise any shock and vibration
that may occur to the sensor during a survey.
