The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support highe...The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support higher positioning, navigation and timing precision. Experimenting with real data, positioning accuracy is estimated with a 3GEO/4IGSO COMPASS constellation. The results show that with dual-frequency and single-frequency pseudo-range measurements, the positioning errors are respectively 8 and 10 m (RMS) for open service users, while for authorized users, the errors are 4 and 5 m (RMS), respectively. The COMPASS constellation geometry may cause large error to occur in the height component by 7-9 m for dualor single-frequency users, which can be effectively reduced with the differential corrections supplied by the authorized services. Multipath errors are identified and corrected for COMPASS, resulting in 25% positioning accuracy improvement for dual-frequency users and 10% improvement for single-frequency users.展开更多
在传统灰色系统预报模型的基础上,提出了一种自适应双子群改进粒子群算法（improved particle swarm optimization algorithm by two subgroups,TS-IPSO）和灰色系统相结合的预报模型。首先对钟差序列进行平滑性检验,对不满足平滑条件...在传统灰色系统预报模型的基础上,提出了一种自适应双子群改进粒子群算法（improved particle swarm optimization algorithm by two subgroups,TS-IPSO）和灰色系统相结合的预报模型。首先对钟差序列进行平滑性检验,对不满足平滑条件的序列作对数平滑处理;然后对灰色系统模型进行优化,为避免粒子群算法陷入局部最优,建立了主辅子群协同进化,惯性权重非线性递减机制。通过TS-IPSO优化发展灰数和内生控制灰数,增强了灰色系统模型的泛化能力。选取来自4种不同钟型的卫星钟差数据进行计算分析。结果表明,模型对6h和24h的预报精度和稳定性均优于传统模型,特别是对短期稳定性较差的铯钟,实现了6h预报误差小于1.60ns,24h预报误差小于5.71ns。展开更多
北斗导航系统自2018年12月27日提供全球服务以来,其服务性能受到了极大关注.以上海天文台iGMAS (International GNSS Monitoring&Assessment System)分析中心发布的精密轨道、钟差产品作为基准,评估了2019年年积日3-12d的北斗二号...北斗导航系统自2018年12月27日提供全球服务以来,其服务性能受到了极大关注.以上海天文台iGMAS (International GNSS Monitoring&Assessment System)分析中心发布的精密轨道、钟差产品作为基准,评估了2019年年积日3-12d的北斗二号、北斗三号以及GPS广播星历的轨道、钟差和空间信号用户测距误差(Signal in Space User Ranging Error, SISURE,简称为URE),并且对北斗卫星导航系统结果进行了详细的分析.结果表明:在评估时间段内,北斗三号广播星历轨道精度、URE均明显优于北斗二号,且部分结果优于GPS.北斗三号广播星历轨道径向精度最高,优于0.2m.北斗三号全部卫星URE均值优于0.4m, URE RMS (root mean square)优于0.5m.北斗二号每颗卫星URE均值、95%URE (置信度为95%的URE)、URE RMS小于2m,北斗三号每颗卫星URE均值、95%URE、URE RMS小于1m,均达到了系统公开承诺的服务性能标准.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11103064 and 11173049)the Shanghai Committee of Science and Technology, China (Grant No. 11ZR1443500)
文摘The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support higher positioning, navigation and timing precision. Experimenting with real data, positioning accuracy is estimated with a 3GEO/4IGSO COMPASS constellation. The results show that with dual-frequency and single-frequency pseudo-range measurements, the positioning errors are respectively 8 and 10 m (RMS) for open service users, while for authorized users, the errors are 4 and 5 m (RMS), respectively. The COMPASS constellation geometry may cause large error to occur in the height component by 7-9 m for dualor single-frequency users, which can be effectively reduced with the differential corrections supplied by the authorized services. Multipath errors are identified and corrected for COMPASS, resulting in 25% positioning accuracy improvement for dual-frequency users and 10% improvement for single-frequency users.
文摘在传统灰色系统预报模型的基础上,提出了一种自适应双子群改进粒子群算法（improved particle swarm optimization algorithm by two subgroups,TS-IPSO）和灰色系统相结合的预报模型。首先对钟差序列进行平滑性检验,对不满足平滑条件的序列作对数平滑处理;然后对灰色系统模型进行优化,为避免粒子群算法陷入局部最优,建立了主辅子群协同进化,惯性权重非线性递减机制。通过TS-IPSO优化发展灰数和内生控制灰数,增强了灰色系统模型的泛化能力。选取来自4种不同钟型的卫星钟差数据进行计算分析。结果表明,模型对6h和24h的预报精度和稳定性均优于传统模型,特别是对短期稳定性较差的铯钟,实现了6h预报误差小于1.60ns,24h预报误差小于5.71ns。
文摘北斗导航系统自2018年12月27日提供全球服务以来,其服务性能受到了极大关注.以上海天文台iGMAS (International GNSS Monitoring&Assessment System)分析中心发布的精密轨道、钟差产品作为基准,评估了2019年年积日3-12d的北斗二号、北斗三号以及GPS广播星历的轨道、钟差和空间信号用户测距误差(Signal in Space User Ranging Error, SISURE,简称为URE),并且对北斗卫星导航系统结果进行了详细的分析.结果表明:在评估时间段内,北斗三号广播星历轨道精度、URE均明显优于北斗二号,且部分结果优于GPS.北斗三号广播星历轨道径向精度最高,优于0.2m.北斗三号全部卫星URE均值优于0.4m, URE RMS (root mean square)优于0.5m.北斗二号每颗卫星URE均值、95%URE (置信度为95%的URE)、URE RMS小于2m,北斗三号每颗卫星URE均值、95%URE、URE RMS小于1m,均达到了系统公开承诺的服务性能标准.
