载波相位差分相对定位在航天器对接中的应用

将GPS载波相位差分技术应用于航天器自主对接,提出了一种在单频接收机条件下的整周模糊度快速求解方法,首先采用载波相位平滑伪距差分技术进行相对定位,估计模糊度的浮点值,而后通过LAMBDA搜索法求解得到整周模糊度,最后通过最小二乘方法实现相对定位。该方法求解过程简单,并可在基线较长情况下解算模糊度。仿真结果表明,当两航天器相距小于100km时,通常20s即可求解模糊度,最长不超过45s。模糊度确定后,采用整周约束解进行相对定位,相对定位的均方差为0.006m,能很好地满足航天器对接的精度需求。

Application of differential carrier phase relative positioning for spacecrafts docking

DGPS was used for spacecrafts docking. A method was presented to resolve the integer ambiguity when using single frequency receiver. Firstly, the differential technique for carrier phase smoothing pseudo-range was used in relative positioning to estimate the float numbers of integer ambiguities. Secondly, the LAMBDA searching method was used to achieve the solution of integer ambiguity. Finally, a least square method was used to realize the relative navigation. This method can calculate the ambiguity easily with long baseline. The simulation results indicate that the time to acquire ambiguity is normally less than 20 s, and no more than 45 s at worst. The relative positioning error is 0.006 m, which can perfectly meet the precision requirements of spacecraft docking.