INS辅助周跳修复以实现精密单点定位瞬时重新收敛

Instantaneous re-convergence of precise point positioning by using INS-aided cycle-slip correction

GNSS接收机信号极易受外界环境遮挡而完全中断,使得接收机所输出的相位观测值产生周跳,这将引起精密单点定位(PPP)模糊度参数的重新初始化,并需要十几分钟甚至更长时间的重新收敛,限制了PPP的推广应用。针对以上问题,以星间单差PPP/INS紧组合为研究基础,借助INS短期导航精度高的优势,提出一种INS辅助的周跳修复新方法。该新方法使用星间单差相位新息与星间单差电离层残差作为周跳修复量;为提高周跳修复可靠性,新方法对周跳修复量进行了质量控制并设置了多重修复准则。两组车载组合导航实验表明:与不修复相比,周跳修复后可实现PPP瞬时重新收敛,定位精度提升至20 cm以内;但需注意,周跳修复成功率会随着GNSS信号中断时间的延长而降低。

When GNSS signals are obstructed by outside environment,the ambiguity parameters in precise point positioning（PPP） filter have to be reset; and it will take 10 min or more to get re-convergence,which restricts the PPP＇s applications. For the tight integration of single difference（SD） between satellites PPP and INS,even though the ambiguity parameters are reset,the rapid re-convergence of PPP can be achieved aided by the INS over short period. If cycle-slips could be corrected,then the ambiguity parameters will not be reset,which leads to the result that instantaneous re-convergence of PPP can be achieved. In this paper,a new cycle-slip correction method aided by INS is proposed,in which the SD phase innovation and the SD phase ionosphere residual are used as two cycle-slip correction observations. To improve the reliability of cycle-slip correction,the qualities of the two cycle-slip correction observations are checked,and several correction rules are set. Two carborne tests show that instantaneous re-convergence of PPP can be obtained,and the positioning accuracy is improved to less than 20 cm by using INS-aided cycle-slip correction. But it should be noted that the success rate of cycle-slip correction will decline with the increase of GNSS signal blockage time.