Comparison of initial alignment methods for SINS

Six standard analytic coarse alignment methods and a direct method are compared via error analyses for strapdown inertial navigation system on stationary base. Although these methods are derived from the same measurements of the local gravity vector and the Earth rate, their error characteristics are not completely identical. The susceptibility of these methods to geographical latitude is examined, and a criterion for the election of an appropriate algorithm is established. Due to its high accuracy, computation efficiency and immunity to latitude uncertainty, the direct method is more suitable for practical applications. The results obtained from both simulation and real data test give a visual demonstration.