Abstract:

To improve the ambiguity resolution success rate and accuracy of realtime kinematic (RTK) positioning for medium baseline, a multi-frequency ambiguity resolution algorithm on the basis of three frequency BeiDou navigation satellite system (BDS) and dual frequency global positioning system is proposed. The three carrier ambiguity resolution (TCAR) algorithm and the leastsquare ambiguity decorrelation adjustment (LAMBDA) algorithm are brought together to fix ambiguities in three steps. To reduce the effects of errors such as ionosphere delay on ambiguities, a search algorithm for combination coefficients is presented. In addition, an adaptive extended Kalman filter is utilized for RTK positioning. In the medium baseline experiment, the success rates of the proposed algorithm, BDS TCAR algorithm and single/dualsystem LAMBDA algorithm are compared. The proposed ambiguity resolution algorithm has the highest success rate, and could fix ambiguities instantaneously. Additionally, it has the best positioning accuracy with the position error at the millimeter level.