Data processing method of multi-position strap-down north seeking system based on SVD

With the aim to fit the sin wave curve of a multi position strap-down north seeking system and to calculate the real north angle accurately, the principles of the system and the algorithm of singular value decomposition(SVD) are introduced. The factors influencing the measuring precision are also analyzed. Then, the algorithm is adopted to fit curves. Experimental results indicate that the singular value decomposition is very precise, for its error sum is 1.1 × 10² μV, and the squared error is 2.8mV. Moreover, for phase angle measurement, measured six times in same direction, the squared error is 24" (1σ) . The method based on SVD can satisfy the system precision requirements of curve-fitting north seeking systems.