Hello all, I am an aviator learning about the electronic flight instruments used in modern aircrafts. I am reading on how aircrafts determine their heading through a magnetic flux compass but the explanation is very technical and complex.
I am seeking a simple and clear explanation on how these compasses work in normal operations.
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A fluxgate compass has no moving parts. Instead, it consists of two or three coils of wire wrapped around magnetically permeable cores, which are at right angles to each other. “Flux” refers to change, and as you may or may not be aware, a changing electric field induces a magnetic field, and vise versa. Nothing happens at steady-state. So, the coils are subject to a changing electric current through all of them, but the presence of the earth’s magnetic field has a slight effect on the resistance of the coils. The current flux generates a corresponding magnetic flux, which will have a component of the Earth magnetic field acting with it or against it depending on the orientation of the device. These slight differences in back EMF are measured on each coil, and from that you can calculate the orientation of the device with respect to the prevailing magnetic field at the device location. The device is usually fixed with respect to the vehicle / aircraft, so subject to the effect of external magnetic influences, this generally gives you the direction of the Earth’s magnetic field (direction to the magnetic North pole).
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