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Laser Rangefinders I
Calibration of the compass is quick and extremely simple. Follow the
instructions below:
1. Press the compass calibration control option on the HUD
(Heads Up Display).
You are prompted in the head-up display to point the Advantage
in approximate directions starting at 0° (due North),
2. Press Start.
3. In a clockwise direction moving in a 360° turn, adjust the pitch
and roll of the Advantage for 60 seconds. After this, a number
should appear (from 0 to 9) in the display. The higher the
number, the better the calibration. If this value is below 5,
perform the calibration again.
Note – The calibration procedure does not modify the compass’s idea
of where magnetic north is. It simply distributes local distortion of the
earth’s magnetic field evenly through a 360° circle. This is important
as it makes sure that compass readings are locally consistent. If you
want to account for an error in the compass’s determination of
magnetic north, do this by entering a new value for the Magnetic
declination field in the Asset Surveyor software’s Units and display
configuration form.
I.4.4 Using the Advantage with the Asset Surveyor Software
As mentioned previously, the practical accuracy of the fluxgate
compass in typical field use is around ±1°. This yields a steady
reduction in accuracy as the distance between the laser and a target
point increases. At a distance of 100–200 m, the average positional
error when using the Advantage is approximately 1 m (in addition to
the error of your GPS measurement).
TSC1 Asset Surveyor Operation Manual 351