Electronic compass working principle and the overall plan

Electronic compass working principle and the overall plan
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Z1 and Z4 for flip coil, Z2 Z3 and for compensation loop. Due to the environmental temperature may affect the system precision, therefore, in high precision system, can through the compensation of the coil compensation. There are two orthogonal inside of the magnetic field sensor? Corresponding to the planar X axis and Y axis. The principle of the magnetic field sensor is using magnetic resistance (MR) composition magnetic type structure, so that it can change the electromagnetic material in the external magnetic field in the electrical resistance coefficient. So in the magnetic field sensors to flip the coil Z1 and Z2 loading flip on electrical signal to change after the magnetic field. Because the changes caused by the magnetic field magnetic resistance changes (Δ R) 0 and translate into change differential voltage output, such, can according to the size of the magnetic field is proportional to the principle of differential output voltage, respectively, the corresponding two axis read signal,
Because KMZ52 output signal of a weak, the signal interference is bigger. In the output amplitude is small position, usually has 300 mV and change a lot about the interference; And in the output amplitude, keep constant value approximate. Two way signal amplitude and the relationship between the Angle as shown in figure 4 shows. To make the ratio of both close to tan α? 0 < α < 90 ° change can be in amplitude and larger numerical changes smaller Angle range, make amplitude keep basic unchanged; And in amplitude lesser and numerical changes greatly Angle range, with a function to change its amplitude change curves. The specific implementation, can according to certain Angle to the curve of the block, and the paragraphs with a function y = ax + b to fitting. This way, you can make amplitude change curve close to tan α. View the fine division, the higher accuracy. ?
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