A method to correct the drift in the phase shift between first and second signals, the first and second signals generated by a signal having frequency Fe, the drift in the phase shift resulting from a drift in the frequency Fe, according to a given relationship. In one embodiment, the method includes...http://www.google.de/patents/US6614396?utm_source=gb-gplus-sharePatent US6614396 - Method and device to correct a variation in bearing measurement
