GNSS RTK实时自适应换站方法

在中长基线的GNSS动态相对定位中,随着基线长度的增加,参考站与流动站之间误差的相关性会下降,导致模糊度无法快速固定,定位性能下降。在多GNSS参考站条件下,可以通过自适应选择距离更近的参考站,形成更加合理的基线,以保障RTK定位的精度。为解决换站后重新初始化模糊度所带来的定位结果重新收敛问题,本文提出了一种GNSS RTK实时自适应参考站换站算法,引入原参考站与新参考站之间的双差模糊度作为辅助,从而得到准确的新参考站与流动站之间的双差模糊度先验信息,避免了换站后模糊度的重新初始化,得到了连续的高精度定位结果。该方法可适用于实时定位,能够满足大范围RTK高精度连续定位的需求。利用香港CORS站数据进行验证,结果表明,本文换站算法能够克服换站导致的定位重收敛问题,且能够保障换站前后获得连续的高精度定位结果。

GNSS RTK adaptive reference station switching method

In medium-long baseline GNSS kinematic relative positioning, the correlation of errors between the reference station and the rover station decreases with the increase of the baseline length. Consequently, the ambiguity parameters cannot be fixed instantaneously, which may decrease the precision of positioning. In multiple reference station scenarios, we can adaptively switch the reference station to a closer one to form a more rational baseline to guarantee the precision of RTK positioning. Aiming at solving the re-convergence of positioning results caused by reinitiating ambiguity after switching reference stations, a method of adaptively switching GNSS RTK reference stations in real time is proposed in this paper. By imposing the double-difference ambiguity between the two reference stations before and after switching, the precise prior information of double-difference ambiguity between the new reference station and rover station is derived, thus circumventing the ambiguity re-initialization after switching reference stations and maintaining the continuity of high-precision positioning results. The method described in this paper can be used in real-time positioning and can meet the demand for large-scale RTK high-precision continuous positioning. Numerical examples using data of Hong Kong CORS stations show that the proposed method can solve the re-convergence issue of positioning solutions after switching stations and continuous high-precision positioning results can be obtained after switching reference stations.