Grid point search algorithm for fast integer ambiguity resolution

A Grid Point Search Algorithm (GRIPSA) for fast integer ambiguity resolutio n is presented. In the proposed algorithm, after the orthogonal transformat ion of the original ambiguity parameters, the confidence ellipsoid of the n ew parameters is represented by a rectangular polyhedron with its edges par allel to the corresponding axes. A cubic grid covering the whole polyhedron is then identified and transformed back to the original coordinate system. The integer values of the corresponding transformed grid points are obtain ed by rounding off the transformed values to their nearest integer values. These values are then tested as to whether they are located inside the poly hedron. Since the identification of the grid points in the transformed coor dinate system greatly reduces the search region of the integer ambiguities, marked improvements are obtained in the computational effort.