Initial assessment of BDS-3 preliminary system signal-in-space range error
Initial assessment of BDS-3 preliminary system signal-in-space range error
复制标题
北斗三号初步系统空间信号距离误差初步评估
DOI：
10.1007/s10291-019-0928-x
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发表时间：
2020-01-01
期刊：
影响因子：
4.9
通讯作者：
Zhou, Renyu
中科院分区：
文献类型：
--
作者：
Lv, Yifei;Geng, Tao;Zhou, Renyu
截至2018年底，北斗全球卫星导航系统（BDS-3）基本星座已成功完成。它包括18颗中地球轨道卫星和1颗地球静止轨道卫星。本文介绍了基于55天广播电文数据的北斗三号广播轨道和时钟精度的初步评估。将广播星历得到的卫星位置和钟差与精确定轨轨道和钟差进行了比较。在此基础上，计算了导航用户最关心的空间信号距离误差（SISRE）。得益于北斗三号卫星新的星间链路有效载荷，数据年龄星历表和数据时钟统计表明，98%以上的星历表和93%的时钟参数仅在1小时内更新。实验结果表明，整个星座广播轨道误差的三维均方根误差小于0.6 m。广播轨道也被卫星激光测距测量评估，给出7.3厘米的均方根。只有轨道的SISRE大约是0.1米。对于时钟误差，消除了两个时钟产品之间的时间标度差异，以评估广播时钟偏移的准确性。0.25 m的标准差值表现良好，但令人遗憾的是，由于非零均值偏差，RMS值接近0.5 m。北斗三号SISRE的均方根误差约为0.5 m，这主要是由于时钟误差造成的。最后，通过定位实验分析了单点定位的精度。在95%置信水平下，水平精度小于5 m，垂直精度接近6 m。考虑到时钟误差中的非零平均偏置会影响SPP的性能，采用卫星特定常数对非零平均值进行校正，分析时钟偏置对SPP性能的影响。结果表明，三维定位精度的提高可达11%，特别是在向上方向。
The basic constellation of the BeiDou global satellite navigation system (BDS-3) had been successfully completed by the end of 2018. It included 18 medium earth orbit satellites and 1 geostationary orbit satellite. An initial assessment of BDS-3 broadcast orbit and clock accuracy based on 55 days of broadcast message data is presented in this contribution. Satellite positions and clock offsets derived from broadcast ephemeris are compared with precise orbit determination orbits and clock offsets. Furthermore, the corresponding signal-in-space range error (SISRE), which is of most interest to navigation users, is computed. Thanks to the new inter-satellite link payloads on BDS-3 satellites, the statistics of age-of-data-ephemeris and age-of-data-clock demonstrate that more than 98% of ephemerides and 93% of clock parameters are updated within only one hour. Experimental results show that the 3D root mean square (RMS) of broadcast orbit errors is less than 0.6 m for the overall constellation. The broadcast orbit is also assessed by satellite laser ranging measurements, giving an RMS of 7.3 cm. The orbit-only SISRE is about 0.1 m. With respect to clock errors, the timescale differences between two clock products are eliminated to assess the accuracy of broadcast clock offsets. The standard deviation value of 0.25 m shows a good performance, but the RMS value is regrettably nearly 0.5 m due to a nonzero mean bias. RMS of BDS-3 SISRE amounts to approximately 0.5 m, which is largely attributed to clock errors. Finally, a positioning experiment is conducted to analyze the accuracy of single point positioning (SPP). With 95% confidence level, the horizontal accuracy is less than 5 m, and the vertical accuracy is close to 6 m. Considering that the nonzero mean bias in clock errors may affect the performance of SPP, we correct the nonzero mean value by a satellite-specific constant to analyze the influence of clock bias on the SPP performance. The results show that improvement in the 3D position accuracy can be up to 11%, especially in the up direction.