基于增强型单频GPS的高精度星间相对定位样条方法

为了实现高精度的分布式SAR星间相对定位,提出了一种基于增强型单频GPS的相对定位样条方法,即在单频GPS测量信息的基础上,增加星间距离观测信息,并结合相对位置参数的连续特性,建立了相对定位的样条模型,最后利用最小二乘法进行参数估计.仿真结果表明,新方法不仅能大大提高相对定位精度,而且还能有效地减少固定整周模糊度所需的历元.最后的理论分析证明了仿真的正确性. 

Spline Method for High-Precision Inter-Satellite Relative Positioning Based on Augmented Single-Frequency GPS

Autonomous formation flying of multiple vehicles is a key technology for both deep space and orbital applications that involve multiple spacecraft. Many future space applications will benefit from using formation flying technologies to perform distributed observations (e.g., Synthetic Aperture Radar, SAR). One of the key requirements of distributed SAR is accurate post-progressing knowledge of the relative positions between the vehicles. In order to realize the high-precision inter-satellite relative positioning of the distributed SAR, an augmented relative positioning method based on the single-frequency GPS is proposed in this paper. With this method inter-satellite pseudo-range measurements based on single-frequency GPS measurements incluing P-code and carrier phase measurements are added, then a spline model of relative positioning based on the continuity of the relative position parameters can be found and, finally the least-square method is used to estimate the parameters. The results of simulation show that this method can not only improve relative positioning precision greatly, but also reduce the epochs needed by fixing the ambiguity. The theoretical analyse proves the correctness of the results of simulations.