利用三频超宽巷/宽巷模糊度波长较长从而易于固定的优势,提出了一种基于北斗三频宽巷组合的网络RTK单历元定位方法。数据处理中心利用基准站实时生成并播发包含双差对流层和电离层延迟改正信息的虚拟观测值;用户站利用载波、伪距组合及分步解算的TCAR方法基于单个卫星对、单历元可靠固定两个超宽巷或宽巷模糊度。最后利用已固定模糊度且噪声最小的宽巷观测值和内插得到的大气延迟改正进行实时动态定位解算。试验结果表明,对于本文提出的网络RTK单历元定位方法,用户站宽巷模糊度单历元解算准确率高于99.9%,统计的定位中误差平面为3～4 cm,高程方向约为5 cm。
Using the advantage that triple-frequency extra-widelane or widelane ambiguities have much longer wavelength and thus are easy to be fixed, a new network RTK (real-time kinematic) single-epoch positioning method based on BDS widelane combinations is proposed. The data processing center uses reference stations to calculate and broadcast the real-time virtual observations including double difference (DD) tropospheric and ionospheric delay correction. Then using single-satellite-pair and single-epoch mode, two extra-widelane or widelane ambiguities are resolved reliably by carrier-pseudo combination and TCAR (three-carrier ambiguity resolution) method at the rover station. Finally, the ambiguity-fixed widelane observations with the minimum observation noise and the broadcast atmospheric correction are used together to calculate the real-time kinematic positioning results. Experimental results show that the correct rates of single-epoch widelane ambiguity resolution at rover stations are larger than 99.9%. The statistical positioning error in plane is 3-4 cm, and the error in up direction is about 5 cm.
[1] LIU Jingnan, LIU Hui. Continuous Operational Reference System: Infrastructure of Urban Spatial Data[J]. Geomatics and Information Science of Wuhan University, 2003, 28(3): 259-264. (刘经南, 刘晖. 连续运行卫星定位服务系统: 城市空间数据的基础设施[J]. 武汉大学学报: 信息科学版, 2003, 28(3): 259-264.)
[2] LI Bofeng, SHEN Yunzhong, FENG Yanming, et al. GNSS Ambiguity Resolution with Controllable Failure Rate for Long Baseline Network RTK[J]. Journal of Geodesy, 2014, 88(2): 99-112.
[3] LANDAU L, VOLLATH U, CHEN X M. Virtual Reference Station System[J]. Journal of Global Positioning Systems, 2002, 1(2): 137-143.
[4] HUANG Dingfa, ZHOU Letao, LI Chenggang, et al. Strategy and Experimental Results of Augmentation Reference Station Network RTK Positioning[J]. Geomatics and Information Science of Wuhan University, 2009, 34(11): 1344-1349. (黄丁发, 周乐韬, 李成钢, 等. 增强参考站网络 RTK 算法模型及其实验研究[J]. 武汉大学学报: 信息科学版, 2009, 34(11): 1344-1349.)
[5] YANG Yang, PAN Shuguo, WANG Denghui, et al. Software of BeiDou Ground Based Augmentation System (Earth Net 2.0) and Its Application[J]. Bulletin of Surveying and Mapping, 2014(10): 46-49. (杨徉, 潘树国, 汪登辉, 等. 北斗地基增强系统软件(Earth Net 2.0)及其应用[J]. 测绘通报, 2014(10): 46-49.)
[6] HU G R, KHOO H S, GOH P C, et al. Development and Assessment of GPS Virtual Reference Stations for RTK Positioning[J]. Journal of Geodesy, 2003, 77(5-6): 292-302.
[7] WANG C, FENG Y M, HIGGINS M, et al. Assessment of Commercial Network RTK User Positioning Performance over Long Inter-station Distances[J]. Journal of Global Positioning Systems, 2010, 9(1): 78-89.
[8] LI J L, YANG Y X, XU J Y, et al. GNSS Multi-carrier Fast Partial Ambiguity Resolution Strategy Tested with Real BDS/GPS Dual and Triple-frequency Observations[J]. GPS Solutions, 2015, 19(1): 5-13.
[9] LI Bofeng, SHEN Yunzhong, FENG Yanming. Long-range Real-time Precise Navigation with Three Frequency GNSS[J]. Geomatics and Information Science of Wuhan University, 2009, 34(7): 782-786. (李博峰, 沈云中, 冯延明. 利用三频GNSS进行长距离实时精密导航[J]. 武汉大学学报:信息科学版, 2009, 34(7): 782-786.)
[10] MELBOURNE W G. The Case for Ranging in GPS-based Geodetic Systems[C]//Proceedings of the 1st International Symposium on Precise Positioning with the Global Positioning System. Rockville, Maryland: [s.n.], 1985: 373-386.
[11] WUBBENA G. Software Developments for Geodetic Positioning with GPS Using TI-4100 Code and Carrier Measurements[C]//GOAD C C. Proceedings of the First International Symposium on Precise Positioning with the Global Positioning System. Rockville, Maryland: [s.n.], 1985: 403-412.
[12] DAI L W. Dual-frequency GPS/GLONASS Real-time Ambiguity Resolution for Medium-range Kinematic Positioning[C]//Proceedings of the 13th International Technical Meeting of the Satellite Division of the US Institute of Navigation. Salt Lake City, Utah: [s.n.], 2000: 19-22.
[13] FORSSELL B, MARTíN-NEIRA M, HARRISZ R A. Carrier Phase Ambiguity Resolution in GNSS-2[C]//Proceedings of the 10th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GPS 1997). [S.l.]: ION,1997: 1727-1736.
[14] JUNG J, ENGE P, PERVAN B. Optimization of Cascade Integer Resolution with Three Civil GPS Frequencies[C]//Proceedings of the ION GPS 2000. Salt Lake City: ION, 2000: 2191-2200.
[15] FENG Y M. GNSS Three Carrier Ambiguity Resolution Using Ionosphere-reduced Virtual Signals[J]. Journal of Geodesy, 2008, 82(12): 847-862.
[16] LI Bofeng, SHEN Yunzhong, ZHOU Zebo. A New Method for Medium and Long Range Three Frequency GNSS Rapid Ambiguity Resolution[J]. Acta Geodaetica et Cartographica Sinica, 2009, 38(4): 296-301. (李博峰, 沈云中, 周泽波. 中长基线三频 GNSS 模糊度的快速算法[J]. 测绘学报, 2009, 38(4): 296-301.)
[17] LI Jinlong, YANG Yuanxi, HE Haibo, et al. Optimal Carrier-phase Combination for Triple-frequency GNSS Derived from an Analytical Method[J]. Acta Geodaetica et Cartographica Sinica, 2012, 41(6): 797-803. (李金龙, 杨元喜, 何海波, 等. 函数极值法求解三频GNSS最优载波相位组合观测量[J]. 测绘学报, 2012, 41(6): 797-803.)
[18] LI Jinlong. Researches on the Algorithms of GNSS Triple Frequency Precise Positioning[D]. Zhengzhou: The PLA Information Engineering University, 2011. (李金龙. GNSS 三频精密定位数据处理方法研究[D]. 郑州: 解放军信息工程大学, 2011.)
[19] TANG W M, DENG C L, SHI C, et al. Triple-frequency Carrier Ambiguity Resolution for Beidou Navigation Satellite System[J]. GPS Solutions, 2014, 18(3): 335-344.
[20] LI Bofeng, FENG Yanming, SHEN Yunzhong. Three Carrier Ambiguity Resolution: Distance-independent Performance Demonstrated Using Semi-generated Triple Frequency GPS Signals[J]. GPS Solutions, 2010, 14(2): 177-184.
[21] WANG K, ROTHACHER M. Ambiguity Resolution for Triple-frequency Geometry-free and Ionosphere-free Combination Tested with Real Data[J]. Journal of Geodesy, 2013, 87(6): 539-553.
[22] TEUNISSEN P J G. Influence of Ambiguity Precision on the Success Rate of GNSS Integer Ambiguity Bootstrapping[J]. Journal of Geodesy, 2007, 81(5): 351-358.
[23] GAO Chengfa, ZHAO Yi, WAN Dejun. The Weight Determination of the Double Difference Observation in GPS Carrier Phase Positioning[J]. Science of Surveying and Mapping, 2005, 30(3): 28-32. (高成发, 赵毅, 万德钧. GPS 载波定位中双差观测值权的合理确定[J]. 测绘科学, 2005, 30(3): 28-32.)
