Abstract:In GPS short baseline deformation monitoring, the coefficient of single epoch normal equation appears to be ill conditioned regularly, which causes the phase ambiguity of LS solutions inaccurate and the final results are of lower accuracy even distorted. To improve the successful rate of single epoch fixed ambiguity of dualfrequency observation, this contribution adopts two following measures.1)Under the conditions that the single epoch normal matrix is illcondition and LS float solution is undependable, using TIKHONOV regularization matrix to improve the illcondition of the normal matrix, thereby leading the fidelity of float solution to be improved; 2)By using LAMBDA search method based on the improved normal equations, total TEC changes are introduced to check its accuracy. The experiment shows that the new method can significantly improve the fidelity of float solution and increase the successful rate of the fixed ambiguity.