Research And Application Of BDS Precise Positioning Technology For Kinematic-to-Kinematic Positioning Of Multiple Stations

In the high precision application of GNSS,the RTK technology based on the ambiguity resolution of carrier phase is widely used in engineering surveying and setting out,petroleum geophysical survey,aircraft precision entering and so on.However,in some applications such as in the air or on the sea,the base station is moving.At this time,the fixed-position mode of the base station cannot meet the requirements of applications.The kinematic-to-kinematic positioning refers to the relative positioning between two rover station.In the moving-base positioning,the absolute coordinates of the rover station are not concerned,since the relative position and attitude information between the base station and the rover station are only needed.Multiple stations dynamic positioning refers to the relative positioning of multiple(two or more)stations at the same time based on kinematic-to-kinematic positioning.In order to get accurate relative positioning results,the on-the-fly of ambiguity resolution is very important to ensure the reliability and continuity of positioning.In view of the complicated observing conditions and the easy to lost lock of the satellite signal,this paper uses the advantages of the triple-frequency combination of the BDS,and uses the single epoch ambiguity resolution of triple-frequency to solve the multi-baseline network,and the feasibility of the algorithm is verified by the measured data.The main research contents and work are as follow:(1)The method status and background of the triple-frequency single epoch ambiguity fixing is introduced in this paper.In view of the short baseline moving-base positioning,the optimal triple-frequency combination observation is selected,and the three step method based on geometric model is used to obtain the ambiguity resolution.(2)The difference of solving model between multi-baseline and single-baseline is analyzed.The multi-baseline solution model of star network is described in detail,and its random model and value method are studied.The float ambiguity solution is solved by the superposition of the normal equation.Using LAMBDA method,partial ambiguity resolution is used to improve the efficiency of searching and fixing.(3)Moving-base positioning experiment data of three targets were collected.The solution of BDS triple-frequency single epoch multi-baseline model is compared with PNW software,and it is also compared with the single-baseline solution.The experimental results show that the solution of multi-baseline model is slightly better than the single-baseline model,but the improvement of positioning accuracy is limited.In multi-target moving-base positioning,the multi-baseline model takes the correlation between stations into consideration.Only the n-1 independent baselines can be used to process the whole network,as well as the network adjustment in the single-baseline solution mode is not needed.The efficiency and reliability of the positioning are improved.