北斗/INS紧组合的惯性辅助三频周跳探测和修复

Inertial aided triple-frequency cycle slip detection and repair of BDS/INS tightly-coupled integration

传统的使用伪距和相位组合进行周跳探测的方法受限于伪距精度,在多路径效应严重和载体高动态下不可靠。针对该问题,构建北斗/INS紧组合模型,利用惯性辅助北斗三频信号线性组合构造了周跳探测量,兼顾错探率和漏探率,确定探测阈值系数为2.576 8。基于卫星高度角采用正弦函数模型确定载波噪声,分析了载波噪声和卫地距误差对周跳探测和修复的影响。在此基础上选择组合量(0,-1,1),(1,3,-4),(-3,4,0)联合进行周跳探测和修复。使用车载组合导航实测数据验证周跳探测模型的效果。实验结果表明,对于模拟的密集小周跳,所有卫星错探率低于1.75%,漏探率低于0.11%,除低高度角卫星C05,所有卫星修复错误率低于0.35%。对于北斗信号中断的场景,在75 s部分中断内或18 s完全中断内都能够正确修复所有卫星的所有类型周跳。

Traditional methods of cycle-slip detection using code-phase combination are not reliable in the scenario that the multipath effect is severe or the carrier is high dynamic state, due to limited by pseudorange precision. To solve this problem, a BDS/INS tightly coupled integration model is developed to construct the inertial aided BDS triple-frequency linear combinations for cycle slip detection. The detect threshold is set to be 2.576 8 by taking into consideration both the probabilities of missing detection and the false detection. A sine function model based on elevation angle is put forward to determine the carrier-phase noises. The impacts of carrier-phase noises and INS-predicted position error on the cycle-slip detection and repair are investigated. Based on the above investigation, the combinations（0,–1, 1）,（1, 3, –4）, and（–3, 4, 0） are selected to detect and repair the cycle-slip cooperatively. Land vehicle integrated navigation experiments are conducted to demonstrate the performance of the proposed cycle-slip detection model. The experiment results show that, even in a harsh scenario with simulative small cycle slips on each epoch, the false detection ratios of the satellites can all achieve below 1.75%, and the missing detection ratios do not exceed 0.11% as desirable. Besides, the false correction ratios of the satellites are all below 0.35%, excepting the special low elevation C05. At last, the BDS gap scenarios are simulated, and the results show that the cycle slips of the satellites can all be correctly repaired within 75 s partial outage or 18 s complete outage of Bei Dou signals.