Research on Key Techniques of RTK Algorithm Based on Optimized Ambiguity Fix Method

Aiming at the problems of low fixed rate of ambiguity and low accuracy in urban comprehensive scenes with receiving small number satellites, low CN0 satellite signals and large atmospheric residual errors, a optimize the least-square ambiguity decorrelation adjustment (LAMBDA) ambiguity fix method is proposed. Firstly, the LAMBDA method is used for ambiguity fixing. If the ratio is less than 3, multiple epochs of post residuals, fixed satellite number and DOP value are recorded. If these epochs meet the pre-set conditions, the ambiguity has been correctly fixed and output it as a fixed solution. The experimental results show that using the optimized ambiguity fix method for static accuracy testing and multi scenes in urban comprehensive scene, the testing scenes cover under elevated bridges, urban canyons, under tree shade and other scenes. The ambiguity fix rate of test results in each scene is improved about 10%. This method has been applied in fields such as autonomous driving and high-precision map, which can improve the positioning accuracy in urban comprehensive scene.