Abstract:GNSS positioning algorithm based on Doppler shift reconstruction solves the problem of abnormal observation signal by reconstructing Doppler shift. Combined with the cross difference weighting method based on vertical elevation selection, we solve the integer ambiguity under the condition of poor observation signal quality, and obtain a high correct estimation rate of integer ambiguity. The results show that the algorithm can achieve 100% ambiguity fixed rate and cm accuracy in the static case of low satellite redundancy. In the dynamic case, the accuracies of E,N and U directions are 0.679 0 m, 0.052 9 m and 0.022 8 m respectively, which are the same as the traditional RTK Positioning, and the fixed ambiguity is increased by 26.38 percentage points.