MEDLL辅助的GNSS/INS系统欺骗信号辨识方法

Spoofing interference identification technique of MEDLL aided GNSS/INS system

受欺骗的卫星导航信息与惯导系统组合滤波,会导致错误的惯性器件误差修正量,最终组合导航系统也会被欺骗干扰影响。针对这一问题,提出了一种基于MEDLL算法的改进的GNSS/INS组合导航模式,能够实现欺骗信号的辨识和抑制,保证组合导航信息的可靠性。GNSS接收机通过MEDLL算法同时估计接收的全部卫星信号参数,当欺骗干扰存在时,MEDLL算法可同时估计出两路信号参数,并判定欺骗干扰存在;MEDLL估计的信号参数生成两组输出伪距信息与惯导系统定位信息提供的参考伪距进行比较,实现欺骗信号的辨识。在200次实验测试中,对于牵引速率大于2 m/s的牵引式欺骗信号,4 s内成功辨识的次数为200次。同时,与传统的GNSS/INS组合导航系统相比,提出的MEDLL辅助的组合导航模式能够有效减小欺骗信号的影响,定位结果稳定在真实位置附近。

Spoofed GNSS navigation information in GNSS/INS integrated filtering would lead to incorrect correction of inertial measurement errors, which means the classical GNSS/INS integrated system would also suffer from spoofing interference. To solve this problem, an improved GNSS/INS integrated system based on multipath estimation delay lock loop（MEDLL） is proposed, which can realize the identification and mitigation of the spoofing signals and ensure the reliability of navigation information. The GNSS receiver uses the MEDLL algorithm to simultaneously estimate all the received satellite signal parameters. Under spoofing attack, two sets of parameters referring to one satellite are estimated by the MEDLL algorithm to determine the existence of spoofing interference. The signal parameters estimated by MEDLL generate two sets of output pseudoranges, and these pseudoranges are then compared with the reference pseudorange provided by the INS positioning information to realize the identification of the spoofing pseudorange and the authentic one. Results of 200 tests show that the number of successful identification is 200 within 4 s under the lift-off-aligned spoofing attack with 2 m/s pseudorange traction speed. In addition, compared with classical GNSS/INS integrated navigation system, the proposed MEDLL aided integration system mitigates the effect of the spoofing interference and the positioning results are stabilized at near the real position.