Abstract:With the wide application of the multifrequency of GNSS, Triplefrequency phase can form a lot of longwavelength, weak ionospheric delay and lownoise linear combinations. These features can effectively make the value of ambiguity to be quickly identified and the impact of ionospheric delay to be weakened. As the ambiguity of combination observation is necessary to be an integer, every combination coefficient so as to be an integer. The integer programming algorithm is presented, adopting the wavelength of combination observation as the objective function and weak ionospheric delay and lownoise of observation as the constraint conditions for the establishment of integer programming mathematical model in order to obtain global optimal integer solution. GPS data analysis shows that integer programming algorithm to determine the triplefrequency combination observation is a valuable algorithm.