| 风云三号D星天基BDS实时定位性能分析 |
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| 引用本文： | 吴春俊,孙越强,王先毅,白伟华,孟祥广,杜起飞.风云三号D星天基BDS实时定位性能分析[J].武汉大学学报(信息科学版),2023,48(2):248-259. |
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| 作者姓名： | 吴春俊 孙越强 王先毅 白伟华 孟祥广 杜起飞 |
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| 作者单位： | 1.中国科学院国家空间科学中心, 北京, 100190 |
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| 基金项目： | 国家自然科学基金41505030国家自然科学基金41606206国家自然科学基金41775034中国科学院空间先导专项XDA15007501中国科学院科研装备研制项目YZ201129国家重点研发计划2017YFB0502800国家重点研发计划2017YFB0502802 |
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| 摘 要： | 随着北斗三号卫星导航系统(BeiDou navigation satellite system-3, BDS-3)开始向全球提供导航服务，独立使用BDS为在轨运行的卫星提供全球覆盖、全时段的定位服务成为可能。结合风云三号D星(FengYun-3D, FY-3D)全球卫星导航系统掩星探测仪(global navigation satellite system occultation sounder, GNOS)的真实在轨数据对天基BDS的定位性能进行了详细的分析。首先, 使用BDS真实广播星历计算了在不同轨道高度下的可见卫星数和定位精度因子（position dilution of precision，PDOP），并结合精密星历分析了广播星历的轨道误差、时钟误差及空间信号测距误差(signal-in-space range error, SISRE)。仿真结果表明，在95%的置信水平下，从地面到2 000 km的轨道高度，BDS在全球范围内最小可见卫星数为6，最大PDOP小于5，星座可用性已经达到100%，全球平均可见卫星数BDS比GPS(global positioning system)高50%以上；BDS广播星历的轨道误差为1.5 m，时钟误差为2.4 ns，SISRE达到了0.79 m，BDS-3的卫星时钟精度已达到GPS相当的水平。然后, 使用GNOS在轨数据测试了BDS的可见卫星数、信号强度、伪距测量精度、定位精度等，重点对BDS-2卫星的码偏移进行了详细的分析。在轨数据分析表明，只使用BDS-2信号时在服务区域内可实现100%的定位，三维定位精度为5.53 m；确认了北斗地球同步轨道、倾斜地球同步轨道、中地球轨道卫星均存在随仰角变化的码偏移，其中北斗地球同步轨道卫星在仰角低于40°时的码偏移是直接测量得到；使用BDS双频测量数据获得了836 km轨道高度以上顶部电离层的全球相对分布，电离层对伪距的相对延时在0.6 m左右。研究对于BDS的天基应用有重要意义，为天基BDS接收机的设计奠定基础。
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| 关 键 词： | 北斗卫星导航系统 天基接收机 定位性能 掩星探测仪 风云三号D星 |
| 收稿时间： | 2021-03-01 |
Assessment of Position Performance of BDS for Space Application Based on FY-3D Satellite |
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| Institution: | 1.National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China2.University of Chinese Academy of Sciences, Beijing 100049, China3.Beijing Key Laboratory of Space Environment Exploration, Beijing 100190, China4.Key Laboratory of Environmental Space Situation Awareness Technology, Chinese Academy of Sciences, Beijing 100190, China5.Joint Laboratory on Occultations for Atmosphere and Climate, Beijing 100190, China |
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| Abstract: | Objectives As BeiDou satellite navigation system-3(BDS-3)starts to provide service for global users, it is possible to get global-coverage and all-time positioning service for space application using BDS alone. The performance of space-borne BDS positioning is thoroughly analyzed with the broadcast ephemeris and the in-orbit data of global navigation satellite system occultation sounder (GNOS) aboard FengYun-3D (FY-3D) satellite. Methods Firstly, the visibility and position dilution of precision of BDS satellites in different low-erath-orbit(LEO)are calculated based on broadcast ephemeris. Moreover, the orbit, clock error of broadcast ephemeris and signal-in-space range error (SISRE) are studied. Secondly, the real visible satellite number, signal strength, precision of pseudo range and position accuracy are verified with the measurement data of GNOS. The code biases of BDS-2 satellites are focused on. Finally, the total electron content above 836 km LEO orbit is measured using BDS dual-frequency measurements. Results The results show that the global coverage usability from ground to 2 000 km height orbit has already been 100%. The mean visible BDS satellite number across the world is 50% larger than that of global positioning system(GPS). For BDS broadcast ephemeris, the 3D orbit error is 1.5 m and clock error is 2.4 ns. SISRE is about 0.79 m and the clock accuracy of BDS-3 has reached the same level of GPS. The in-orbit data results show that GNOS in FY-3D could get 100% positioning with BDS-2 signals in service areas, and 3D position accuracy is 5.53 m. All BDS-2 satellites including geosynchronous earth orbit (GEO), inclined geosynchronous orbit and medium earth orbit satellites have code biases. As GEO satellite is static relative to ground users, the code biases of GEO is firstly measured directly, in which the maxium code bias can reach about 0.6 m. The total electron content above 836 km can cause relative pseudo range delay of about 0.6 m. Conclusions The research in this paper verifies the usability and performance of BDS for space-based users. |
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