Patent ID: 8019543

Claim:
A method for determining A k (a best initial heading estimate) using serial computing for use with an alignment program running in an AINS (aided INS) computer in an AINS system, the method comprising the steps of: A. powering up the AINS system, requesting movement of the AINS system and acknowledging movement when AINS system is moving, B. receiving and recording N (a predetermined number of) time indexed records, each record having a corresponding sub-set of time indexed aiding position data values and a corresponding sub-sets of time indexed in-motion data values in a first array, and advancing to step C as the Nth (last) time indexed record is recorded in the first array, C. assigning a value to an indexed heading ψ k , D. selecting a record from the first array and using the assigned value of the indexed heading ψ k and the AINS algorithm calculating and recording an update for the position data, E. calculating and recording a time indexed horizontal position measurement residual using record from the first array and the value of the indexed heading ψ k in a second array, F. testing to see if all N records in the first array have been processed and if there are records in the first array that have not been processed, return to step D and E and if all N records in the first array have been processed then advance to step G, G. selecting the maximum horizontal position measurement residual norm from those saved in the second array and the corresponding ψ k in a third array, and advance to step H, H. test to see if ψ k is equal to 360 degrees and if not, return to step C, increment the value of ψ k and repeat steps D, E, F, G and if ψ k equals 360 degrees, advance to step I, I. identifying the smallest maximum horizontal position measurement residual norm over the recorded maximum horizontal position measurement residual norms in the third array and designate the initial heading corresponding to the smallest horizontal position measurement residual norm in the third array as A k for subsequent use in alignment.