巨型低轨通信卫星星座的快速发展，为机会信号导航(navigation via signals of opportunity，NAV-SOP)技术提供了大量优质的信号资源。针对现有低轨卫星NAVSOP技术无法提供持续、稳定定位服务的问题，提出一种基于低轨卫星正交频分复用(orthogonal frequency division multiplexing，OFDM)信号侦测的隐蔽定位算法。所提算法可以与基于卫星信标信号的NAVSOP技术互补，提供持续、稳定的位置信息。分析了多普勒效应对低轨卫星系统OFDM信号子载波和带宽的影响，在此基础上对接收端信号进行建模;基于谱图修正的OFDM信号带宽估计算法建立基于瞬时带宽的新型观测定位方程，并利用最小二乘算法得到十米量级精度的实时解。实验结果表明，与经典的多普勒定位算法相比，所提算法在低信噪比条件下具有更高的定位精度。
Research on concealed positioning algorithm based on LEO satellites OFDM signal investigation and detection
The rapid development of huge low Earth orbit(LEO)communication mega-constellation satellites provides lots of high-quality signal resources for navigation via signals of opportunity(NAVSOP).A concealed positioning algorithm based on LEO satellite orthogonal frequency division multiplexing(OFDM)signal detection is proposed to address the issue that the existing LEO satellite NAVSOP technology cannot provide sustained and stable positioning services.The proposed algorithm can complement the NAVSOP technology based on satellite beacon signals and provide sustained and stable position information.The influence of Doppler effect on the subcarrier and bandwidth of OFDM signal is analyzed,and the receiver signal is modeled.A new observation and positioning equation based on instantaneous bandwidth is established based on a bandwidth estimation method for OFDM signals based on spectral correction,and a real-time solution with the precision of 10m scale is obtained by least square algorithm.The experimental results show that the proposed algorithm has higher positioning accuracy under low signal-to-noise ratio(SNR)compared with the classical Doppler positioning algorithm.
navigation via signals of opportunity(NAVSOP)low Earth orbit(LEO)satelliteorthogonal frequency division multiplexing(OFDM)signalinstantaneous bandwidth estimationconcealed positioning
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维普
