一种改进的宽巷引导整周模糊度固定算法
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摘要
一般卫星导航接收机的伪距测量误差大于宽巷波长。根据宽巷引导模型,直接使用双差伪距取整固定双差宽巷整周模糊度有很大概率会产生一周固定错误。基于此,提出了一种改进的宽巷引导整周模糊度固定算法,针对宽巷整周模糊度一周固定错误进行探测和修复。利用整周模糊度为整数的特质构造理论探测量,并将该探测量与载噪比所确定的门限相比较,判断是否出现宽巷整周模糊度一周固定错误;利用双差整周模糊度自由度为3的特点,修复错误宽巷整周模糊度。对该算法在高斯噪声条件下的可行性进行了理论分析,结果表明正常载噪比的观测数据均可分辨出一周宽巷整周模糊度的估计错误。同时,分析了考虑多径等误差后该算法所能接受的载波相位最大误差。计算了不同伪距误差下宽巷整周模糊度一周固定错误出现的概率。使用GPS实测短基线数据对算法进行验证,该算法可将基于宽巷引导的整周模糊度固定算法的固定率从原来的只有不到1/3提升至接近100%。
In most GPS(Global Positioning System)receivers,the pseudo-range measurement error is bigger than the wavelength of WL(Wide Lane)carrier phase measurement.It will probably cause one cycle WL integer ambiguity resolution error in case the DD(Double Differenced)WL integer ambiguity is rounded by DD pseudo-range measurement according to the WL integer bootstrapping model.In this view of,we propose a modified WL bootstrapping ambiguity resolution algorithm.The proposed algorithm mainly aims at detecting and repairing one cycle WL integer ambiguity error.The WL integer ambiguity error detector is designed according to the characteristic that the integer ambiguity is an integer.The designed detector is compared with the theoretical threshold calculated by the Carrier Noise Ratio(CNR)to judge whether the WL integer ambiguity is wrong.There are only 3 degrees of freedom in all the ambiguities,therefore we fix the wrong ambiguities by the right ambiguities.We analyze the feasibility of the proposed algorithm in Gaussian noise environment.The results show all the carrier phase measurement in normal CNR environment can judge whether the WL integer ambiguity has one cycle error.The maximum carrier phase error is calculated in case we consider the multipath and other carrier phase measurement error.The probability of one cycle WL integer ambiguity error is analyzed with pseudo-range measurement error in different orders of magnitude.Field tests were carried out by using GPS short baseline data.The proposed algorithm increases the success rate of the WL integer bootstrapping ambiguity resolution algorithm from less than 1/3 to nearly 100%.
In most GPS(Global Positioning System)receivers,the pseudo-range measurement error is bigger than the wavelength of WL(Wide Lane)carrier phase measurement.It will probably cause one cycle WL integer ambiguity resolution error in case the DD(Double Differenced)WL integer ambiguity is rounded by DD pseudo-range measurement according to the WL integer bootstrapping model.In this view of,we propose a modified WL bootstrapping ambiguity resolution algorithm.The proposed algorithm mainly aims at detecting and repairing one cycle WL integer ambiguity error.The WL integer ambiguity error detector is designed according to the characteristic that the integer ambiguity is an integer.The designed detector is compared with the theoretical threshold calculated by the Carrier Noise Ratio(CNR)to judge whether the WL integer ambiguity is wrong.There are only 3 degrees of freedom in all the ambiguities,therefore we fix the wrong ambiguities by the right ambiguities.We analyze the feasibility of the proposed algorithm in Gaussian noise environment.The results show all the carrier phase measurement in normal CNR environment can judge whether the WL integer ambiguity has one cycle error.The maximum carrier phase error is calculated in case we consider the multipath and other carrier phase measurement error.The probability of one cycle WL integer ambiguity error is analyzed with pseudo-range measurement error in different orders of magnitude.Field tests were carried out by using GPS short baseline data.The proposed algorithm increases the success rate of the WL integer bootstrapping ambiguity resolution algorithm from less than 1/3 to nearly 100%.
引文
[1]Li J,Yang Y,Xu J,et al.GNSS Multi-carrier Fast Partial Ambiguity Resolution Strategy Tested with Real BDS/GPS Dual-and Triple-frequency Observations[J].GPS Solut.,2015(19):5-13
[2]He Jun,Liu Wanke,Zhang Xiaohong.Single Epoch Ambiguity Resolution of BDS Triple Frequency Measured Data Under Short Baseline[J].Geomatics and Information Science of Wuhan University,2015,40(3):361-365(何俊,刘万科,张小红.北斗短基线三频实测数据单历元模糊度固定[J].武汉大学学报·信息科学版,2015,40(3):361-365)
[3]Kaplan E D,Hegarty C.Understanding GPS:Principles and Applications[M].2nd Edition.USA:Artech House,2006
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[6]Wu Yue.The Theory and Application on Multi-frequency Data Processing of GNSS2[D].Wuhan:Wuhan University,2005(伍岳.第二代导航卫星系统多频数据处理理论及应用[D].武汉:武汉大学,2005)
[7]Xie Gang.Principle of GPS and Receiver Design[M].Beijing:Publishing House of Electronics Industry,2009(谢刚.GPS原理与接收机设计[M].北京:电子工业出版社,2009)
[8]Zhu Huizhong,Gao Xingwei,Bei Jinzhong,et al.An Algorithm of GPS Ambiguity Resolution on Single-Epoch[J].Science of Surveying and Mapping,2011,36(4):9-11(祝会忠,高星伟,秘金钟,等.一种GPS整周模糊度单历元解算方法[J].测绘科学,2011,36(4):9-11)
[9]Wu Yue,Fu Xiaolin,Li Haijun,et al.Application of TCAR/MCAR Method in Different Baseline Ambiguity Resolution[J].Geomatics and Information Science of Wuhan University,2007,37(2):172-175(伍岳,付小林,李海军,等.TCAR/MCAR方法在不同距离基线模糊度求解中的应用[J].武汉大学学报·信息科学版,2007,37(2):172-175)
[10]Feng Y.GNSS Three Carrier Ambiguity Resolution Using Ionosphere-Reduced Virtual Signals[J].J Geod,2008,82(12):847-862
[11]Xue Zhihong.A Study of Key Technology for Dynamic Deformation Monitoring Using GNSS[D].Zhengzhou:Information Engineering University,2012(薛志宏.GNSS动态变形测量关键技术研究[D].郑州:信息工程大学,2012)
[12]Hatch R.Instantaneous Ambiguity Resolution[C].Kinematic System in Geodesy,Surveying,and Remote Sensing,KIS Symposium,Banff,Canada,1990
[13]Chen D,Lachapelle G.A Comparison of the FASF and Least Squares Search Algorithms for on-the-Fly Ambiguity Resolution[J].Navigation,1995(42):371-390
[14]Teunissen P J G.The LAMBDA Method for the GNSS Compass[J].Art Satellites,2007(41):89-103
[2]He Jun,Liu Wanke,Zhang Xiaohong.Single Epoch Ambiguity Resolution of BDS Triple Frequency Measured Data Under Short Baseline[J].Geomatics and Information Science of Wuhan University,2015,40(3):361-365(何俊,刘万科,张小红.北斗短基线三频实测数据单历元模糊度固定[J].武汉大学学报·信息科学版,2015,40(3):361-365)
[3]Kaplan E D,Hegarty C.Understanding GPS:Principles and Applications[M].2nd Edition.USA:Artech House,2006
[4]Tang W,Deng C,Shi C,et al.Triple-Frequency Carrier Ambiguity Resolution for Beidou Navigation Satellite System[J].GPS Solut.,2014(18):335-344
[5]Teunissen P J G.An Optimality Property of the Integer Leastsquares Estimator[J].J.Geodesy,1999(73):587-593
[6]Wu Yue.The Theory and Application on Multi-frequency Data Processing of GNSS2[D].Wuhan:Wuhan University,2005(伍岳.第二代导航卫星系统多频数据处理理论及应用[D].武汉:武汉大学,2005)
[7]Xie Gang.Principle of GPS and Receiver Design[M].Beijing:Publishing House of Electronics Industry,2009(谢刚.GPS原理与接收机设计[M].北京:电子工业出版社,2009)
[8]Zhu Huizhong,Gao Xingwei,Bei Jinzhong,et al.An Algorithm of GPS Ambiguity Resolution on Single-Epoch[J].Science of Surveying and Mapping,2011,36(4):9-11(祝会忠,高星伟,秘金钟,等.一种GPS整周模糊度单历元解算方法[J].测绘科学,2011,36(4):9-11)
[9]Wu Yue,Fu Xiaolin,Li Haijun,et al.Application of TCAR/MCAR Method in Different Baseline Ambiguity Resolution[J].Geomatics and Information Science of Wuhan University,2007,37(2):172-175(伍岳,付小林,李海军,等.TCAR/MCAR方法在不同距离基线模糊度求解中的应用[J].武汉大学学报·信息科学版,2007,37(2):172-175)
[10]Feng Y.GNSS Three Carrier Ambiguity Resolution Using Ionosphere-Reduced Virtual Signals[J].J Geod,2008,82(12):847-862
[11]Xue Zhihong.A Study of Key Technology for Dynamic Deformation Monitoring Using GNSS[D].Zhengzhou:Information Engineering University,2012(薛志宏.GNSS动态变形测量关键技术研究[D].郑州:信息工程大学,2012)
[12]Hatch R.Instantaneous Ambiguity Resolution[C].Kinematic System in Geodesy,Surveying,and Remote Sensing,KIS Symposium,Banff,Canada,1990
[13]Chen D,Lachapelle G.A Comparison of the FASF and Least Squares Search Algorithms for on-the-Fly Ambiguity Resolution[J].Navigation,1995(42):371-390
[14]Teunissen P J G.The LAMBDA Method for the GNSS Compass[J].Art Satellites,2007(41):89-103