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First of all, to get the best possible accuracy, make sure the compass is calibrated and that the camera is pointed at the object/target for 1-3 seconds (more time is even better) to give the electronic compass a chance to settle on the most accurate heading/azimuth. Imagine a liquid filled Lensatic Compass settling down on its heading as the electronic compass acts in a similar fashion.
The TruPulse laser has an accuracy of +/- 1 foot on a highly reflective target so this error is probably insignificant for most applications. However, the compass, with an accuracy of +/- 1.5 degrees can have a very significant effect on the accuracy of the GPS position of the target/object. The further out the object is, the greater the right or left possible error.
Trigonometry is used to calculate the possible right or left error. Picture a right triangle where the possible compass error (1.5 degrees) is the angle at the camera. The distance to the object is the adjacent leg, and possible error (right or left) is the opposite leg. The tangent of the possible error angle of 1.5 degrees is equal to the opposite side of the angle (possible error distance) divided by the adjacent side (laser distance to object). Solving this algebraic equation will tell us that the possible right or left error is equal to the Tangent of 1.5 degrees (.0262) times the distance to the object.
So, for a distance to the object of 1000m, we could have a right or left error of as much as 26.2m.
So as a rule of thumb, we can say that for every 100 meters to the object, we could have an error in the GPS position of the object of as much as 2.6 meters right or left.
Obviously, if you are using extended optics to photograph and determine the GPS position of distant objects, a tripod that holds the camera motionless will aid tremendously in obtaining the most accurate position.
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