GPS/INS紧组合的INS辅助周跳探测与修复

建立了GPS/INS紧组合定位模型,改正惯性器件误差及电离层折射误差,对不同组合观测量的误差影响进行了分析,构造不同观测值组合,提出了基于惯性信息辅助的GPS周跳自适应探测方法,分析了INS定位误差对周跳探测的影响,给出了周跳探测误报率及修复成功率评价指标,提出了一种周跳检测阈值自适应确定方法。利用实测组合导航试验数据验证本文的算法,文中模拟了不同的单历元多周跳及信号失锁条件,结果表明,在GPS信号完全失锁20 s内,该方法能准确检测和修复所有周跳,中断时间的延长降低了周跳修复的成功率;GPS信号部分失锁时,在模拟的90 s中断时段内仍能修复所有周跳;模拟了170历元的5 s间隔密集周跳,周跳探测成功率为100%,正确修复率为99.41%。

Inertial Aided Kinematic GPS Cycle Slip Detection and Correction for GPS/INS Tightly Coupled System

In order to improve the navigation performance and robustness,a GPS/INS tightly coupled model has been developed,the INS related bias and ionospheric errors were compensated and corrected, the impact of combination observations on cycle slip detection was investigated,and four combinations with the characteristics of longer wavelength,smaller noise and lower ionosphere effect were determined, then an innovative inertial aided adaptive cycle slip detection and correction algorithm based on the selected combination observations was presented,and the impact of INS positioning errors on cycle slip detection has been investigated,the probability of false alarm and success rate of cycle slip correction were utilized to enhance the integrity of cycle slip detection and correction,a new threshold determination criterion was provided to achieve robust cycle slip detection and correction.At last,a field test was utilized to verify and evaluate the performance of the proposed algorithm,multi-cycle slips and GPS gap scenarios were simulated,the results show that the scheme works effectively as long as the complete GPS data outage period is less than 20 second,the performance degrades as the outage period becomes longer;while during the partial data outage durations,the proposed scheme can fix the cycle slips correctly for the simulated 90 second partial outage due to the improved positioning accuracy,a total of 170 dense cycle slips (1 slip per 5 epochs)were introduced,it shows that all introduced cycle slips are successfully detected and the true fixing rate reaches 99.41%.