Patent ID: 6920406
Filing Date: 2005-07-19
Classification: G01C

Abstract:
1. A method of resetting to zero azimuth automatically comprising the steps of: collecting multiple samples with different azimuths in the longitudinal and latitudinal orientations using two orthogonal magnetic sensors, and outputting corresponding first and second sine wave signals; adjusting the amplitudes of one of the first and second sine wave signals such that the amplitudes of the first sine wave signals and the amplitudes of the second sine wave signal are equal; comparing the sample values in each set respectively represented by the first and second sine wave signals to generate the maximum and minimum values; computing the average values based on the maximum and minimum values of the first and second sine wave signals, repectively, and taking each of the average values to be the zero reference value of the first and second sine wave signals, respectively, to produce refererence first and second sine wave signals, whereby the reference first and second sine wave signals have positive and negative sides of equal amplitude.