Lorn writes: <<<
Now if we take a look at the circumference of the
Earth at the NP, we get, again according to Wikipedia, sin( 90° - 82.7°
) = .127. .127 * 21,600 nm = 2,743 nm. In other words the NP has done
more than 2/3 of a complete circle at its' latitude. In other words,
Detroit should be back to a 0° offset in about another 10 years.>>>
The Earths North Pole (actually, magnetically a south pole) meanders.
To calculate the field values in your (or any) area go here:
http://www.ngdc.noaa.gov/geomag/magfield.shtml
We use a magnetic field model to qualify the magnetometer during post
installation setup of the Chelton ADAHRS. When you "spin" your compass
after installation the software compares the triaxial magnetometer
readings to the earth field for your location and date. For the
installation to be valid you need to be within 5% of the anticipated
values.
At our location (North Idaho) the vector that points towards the North
Pole has an elevation angle of 70 degrees below horizontal.
Regards
Brent Regan
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