微弱GPS信号矢量频率锁定环设计
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摘要
载波跟踪环是传统独立式GPS接收机最脆弱的环节,针对弱信号环境下其比伪码跟踪环路更容易失锁的问题,本文给出一种基于矢量频率锁定环(vector-frequency lock loop,VFLL)的载波跟踪方法。给出VFLL理论推导及实现过程,并以最小二乘估计方法证明VFLL在载波跟踪性能上优于频率锁定环(frequency lock loop,FLL)。静止场景时9颗卫星实验结果显示,本文给出的方法能够实现14 d B/Hz微弱GPS信号的载波跟踪。
In a traditional stand-alone GPS receiver,the carrier-tracking loop is the weakest link that loses lock more easily than the code-tracking loop in a weak signal environment.To solve this problem,a carrier-frequency tracking method based on vector-frequency lock loop(VFLL) is presented.The details of theoretical derivation and implementation of VFLL are given,and the weighted least squares method proves that the tracking performance of VFLL is better than that of a frequency lock loop(FLL).In a static scene,the experimental results by utilizing 9 satellites show that VFLL can maintain lock with C/N_0 values as low as 14 dB/Hz.
In a traditional stand-alone GPS receiver,the carrier-tracking loop is the weakest link that loses lock more easily than the code-tracking loop in a weak signal environment.To solve this problem,a carrier-frequency tracking method based on vector-frequency lock loop(VFLL) is presented.The details of theoretical derivation and implementation of VFLL are given,and the weighted least squares method proves that the tracking performance of VFLL is better than that of a frequency lock loop(FLL).In a static scene,the experimental results by utilizing 9 satellites show that VFLL can maintain lock with C/N_0 values as low as 14 dB/Hz.
引文
[1]RAZAVI A,GEBRE-EGZIABHER D,AKOS D M.Carrier loop architectures for tracking weak GPS signals[J].IEEE transactions on aerospace and electronic systems,2008,44(2):697-710.
[2]刘军良.卫星导航系统中的弱信号跟踪研究[D].北京:中国科学院国家授时中心,2015.LIU Junliang.Research on weak signal tracking in satellite navigation systems[D].Beijing:National Time Service Center,Chinese Academy of Sciences,2015.
[3]KAPLAN E D,HEGARTY C J.Understanding GPS:Principles and Applications[M].London:Artech House,2006:153-241.
[4]沈锋,李伟东,李强.基于I/Q支路相干积分观测滤波的GPS接收机信号跟踪方法[J].电子与信息学报,2015,37(1):37-42.SHEN Feng,LI Weidong,LI Qiang.GPS receiver signal tracking method based on I/Q branch coherent integration measurements filter[J].Jounal of electronics&information technology,2015,37(1):37-42.
[5]PERAL-ROSADO J A D,LOPEZ-SALCEDO J A,SECOGRANADOS G,et al.Kalman filter-based architecture for robust and high-sensitivity tracking in GNSS receivers[C]//2010 5th ESA Workshop on Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing,2010:1-8.
[6]WU F,YU L,ZHAO Y,et al.Performance analysis of typical Kalman filter based GPS tracking loop[C]//IEEE International Conference on Control Science and Systems Engineering.Yantai,China,2014:6-12.
[7]HE Z,PETOVELLO M.Performance comparison of kalman filter and maximum likelihood carrier phase tracking for weak GNSS signals[C]//International Conference on Indoor Positioning and Indoor Navigation.Alberta,Canada,2015:1-8.
[8]BA X,LIU H,ZHENG R,et al.A novel algorithm based on FFT for ultra-high-sensitivity GPS tracking[C]//Proceedings of the 22nd International Technical Meeting of The Satellite Division of the Institute of Navigation.Savannah,USA,2009:1700-1706.
[9]朱珍珍.卫星导航矢量跟踪关键技术研究[D].长沙:国防科学技术大学,2011.ZHU Zhenzhen.Research on key techniques of vector tracking for satellite navigation[D].Changsha:National University of Defense Technology,2011.
[10]PARKINSON B,SPILKER J J.Global positioning system:theory and applications[M].Washington:American Institute of Aeronautics and Astronautics,1996:290-327.
[11]LASHLEY M,BEVLY D M.Vector delay/frequency lock loop implementation and analysis[C]//Proceedings of the2009 International Technical Meeting of The Institute of Navigation.Anaheim,USA,2009:1075-1086.
[12]XU F,GAO Y.A high sensitivity VDFLL utilizing precise satellite orbit/clock and ionospheric products[C]//Proceedings of the 2012 IEEE/ION Position,Location and Navigation Symposium,2012:38-43.
[13]LIU J,CUI X,LU M,et al.Vector tracking loops in GNSS receivers for dynamic weak signals[J].Journal of systems engineering and electronics,2013,24(3):349-364.
[14]TANG X,FALCO G,FALLETTI E,et al.Performance comparison of a KF-based and a KF+VDFLL vector tracking-loop in case of GNSS partial outage and low-dynamic conditions[C]//Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing.Noordwijk,Netherlands,2014:1-8.
[15]SOUSA F M G,NUNES F D.Performance comparison of a VDFLL versus VDLL and scalar GNSS receiver architectures in harsh scenarios[C]//Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing.Noordwijk,Netherlands,2014:1-8.
[16]CHUI C K,CHEN G.Kalman filtering with real-time applications[M].Berlin:Springer,2009:1-2.
[2]刘军良.卫星导航系统中的弱信号跟踪研究[D].北京:中国科学院国家授时中心,2015.LIU Junliang.Research on weak signal tracking in satellite navigation systems[D].Beijing:National Time Service Center,Chinese Academy of Sciences,2015.
[3]KAPLAN E D,HEGARTY C J.Understanding GPS:Principles and Applications[M].London:Artech House,2006:153-241.
[4]沈锋,李伟东,李强.基于I/Q支路相干积分观测滤波的GPS接收机信号跟踪方法[J].电子与信息学报,2015,37(1):37-42.SHEN Feng,LI Weidong,LI Qiang.GPS receiver signal tracking method based on I/Q branch coherent integration measurements filter[J].Jounal of electronics&information technology,2015,37(1):37-42.
[5]PERAL-ROSADO J A D,LOPEZ-SALCEDO J A,SECOGRANADOS G,et al.Kalman filter-based architecture for robust and high-sensitivity tracking in GNSS receivers[C]//2010 5th ESA Workshop on Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing,2010:1-8.
[6]WU F,YU L,ZHAO Y,et al.Performance analysis of typical Kalman filter based GPS tracking loop[C]//IEEE International Conference on Control Science and Systems Engineering.Yantai,China,2014:6-12.
[7]HE Z,PETOVELLO M.Performance comparison of kalman filter and maximum likelihood carrier phase tracking for weak GNSS signals[C]//International Conference on Indoor Positioning and Indoor Navigation.Alberta,Canada,2015:1-8.
[8]BA X,LIU H,ZHENG R,et al.A novel algorithm based on FFT for ultra-high-sensitivity GPS tracking[C]//Proceedings of the 22nd International Technical Meeting of The Satellite Division of the Institute of Navigation.Savannah,USA,2009:1700-1706.
[9]朱珍珍.卫星导航矢量跟踪关键技术研究[D].长沙:国防科学技术大学,2011.ZHU Zhenzhen.Research on key techniques of vector tracking for satellite navigation[D].Changsha:National University of Defense Technology,2011.
[10]PARKINSON B,SPILKER J J.Global positioning system:theory and applications[M].Washington:American Institute of Aeronautics and Astronautics,1996:290-327.
[11]LASHLEY M,BEVLY D M.Vector delay/frequency lock loop implementation and analysis[C]//Proceedings of the2009 International Technical Meeting of The Institute of Navigation.Anaheim,USA,2009:1075-1086.
[12]XU F,GAO Y.A high sensitivity VDFLL utilizing precise satellite orbit/clock and ionospheric products[C]//Proceedings of the 2012 IEEE/ION Position,Location and Navigation Symposium,2012:38-43.
[13]LIU J,CUI X,LU M,et al.Vector tracking loops in GNSS receivers for dynamic weak signals[J].Journal of systems engineering and electronics,2013,24(3):349-364.
[14]TANG X,FALCO G,FALLETTI E,et al.Performance comparison of a KF-based and a KF+VDFLL vector tracking-loop in case of GNSS partial outage and low-dynamic conditions[C]//Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing.Noordwijk,Netherlands,2014:1-8.
[15]SOUSA F M G,NUNES F D.Performance comparison of a VDFLL versus VDLL and scalar GNSS receiver architectures in harsh scenarios[C]//Satellite Navigation Technologies and European Workshop on GNSS Signals and Signal Processing.Noordwijk,Netherlands,2014:1-8.
[16]CHUI C K,CHEN G.Kalman filtering with real-time applications[M].Berlin:Springer,2009:1-2.