Performance Evaluation of GPS in-orbit Satellite Clocks
LEI Yu1,ZHAO Dan-ning2
1. School of Computer Science & Technology,Xi’an University of Posts & Telecommunications, Xi’an, Shaanxi 710121, China
2. School of Electrical & Electronic Engineering, Baoji University of Arts and Sciences, Baoji, Shaanxi 721016, China
Abstract：It plays an key role in system integrity monitoring and satellite clock prediction to evaluate the performance of satellite clocks in orbit. The work is aimed at evaluating the performance of the on-board clocks in the GPS Block IIR, IIR-M, IIF and newest Block IIIA satellites. The final precise GPS satellite clock produces from the International GNSS Service (IGS) are used to calculate the four indexes, namely the frequency accuracy, drift, stability for an average time of ten thousand seconds as well as stability for a 1-day average time. The results show that the magnitudes of frequency accuracy and drift reach the 10-13～10-12 and 10-15～10-14/d level, respectively. As for frequency stability, the in-orbit Rubidium clocks stability for an average time of ten thousand seconds and one day can reach a magnitude at the 10-14 and 10-15 level, respectively. It is illustrated that the stability of the in-orbit Rubidium clocks is noticeably higher than that of the cesium clocks by an order of magnitude both for the short-and long-term average time. The frequency accuracy and drift of the Block IIIA satellite clocks are comparable with those of the other clocks. However, the frequency stability for an one day interval is at a (3～5)×10-15 level and therefore higher than that of the existing satellite clocks in orbit, demonstrating that the on-board clocks equipped in the newest Block IIIA satellite are continually optimized and improved. In addition, It is found that even for the same Block satellites there are certain performance differences between the on-board clocks, which has no significant relationship with the operation time of the satellite clocks in flight.
［1］Jaduszliwer B, Camparo J. Past, present and future of atomic clocks for GNSS ［J］. GPS Solutions, 2021, 25 (1): 27.
［2］潘志兵,谢勇辉,帅涛,等. 小型化星载被动型氢原子钟研制［J］. 仪器仪表学报,2020,41 (3): 105-112.
Pan Z B, Xie Y H, Shuai T, et al. Development of mini space passive hydrogen maser ［J］. Chinese Journal of Scientific Instrument, 2020, 41 (3): 105-112.
［3］赵广东,陈鹏飞,刘杰,等. 一种基于星载氢钟误差信号提取的实现方法［J］. 计量学报,2021,42 (2): 239-244.
Zhao G D, Chen P F, Liu J, et al. One method of the extraction of the error signal based on the onboard Hydrogen maser ［J］. Acta Metrologia Sinica, 2021, 42 (2): 239-244.
［4］Dupuis R T, Lynch T J, Vaccaro J R. Rubidium frequ-ency standard for the GPS IIF program and modifications for the RAFSMOD program ［C］//Proceedings of the 2008 IEEE International Frequency Control Symposium. 2008: 655-660.
［5］Lee S W, KIM J K, Jeong M S, et al. Monitoring atomic clocks on board GNSS satellites ［J］. Advances in Space Research, 2011, 47 (10): 1654-1663.
［6］伍贻威. 基于钟差预测的铯原子钟频率异常检测算法及性能分析 ［J］. 测绘学报,2021,50 (1): 52-60.
Wu Y W. A cesium atomic clock frequency anomaly detection algorithm based on clock prediction and its per-formance analyses ［J］. Acta Geodaetica et Cartographica Sinica, 2021, 50 (1): 52-60.
［7］Bian L, Liu X, Liu W S, et al. Satellite autonomous integrity monitoring of BDS and onboard performance eva-luation ［J］. Aerospace China, 2020, 21 (4): 42-49.
［8］刘伟平,郝金明,吕志伟,等. 北斗三号空间信号测距误差评估与对比分析 ［J］. 测绘学报,2020,49 (9): 1213-1221.
Liu W P, Hao J M, Lv Z W, et al. Evaluation and comparative analysis of BDS-3 signal-in-space range error ［J］. Acta Geodaetica et Cartographica Sinica, 2020, 49 (9): 1213-1221.
［9］于超,陈俊平,陈倩,等. 北斗系统长期空间信号测距精度评估及精度提升分析 ［J］. 东南大学学报 (自然科学版),2019,49(6): 1064-1071.
Yu C, Chen J P, Chen Q, et al. Assessment of long-term BDS signal-in-space range error and its improvement ［J］. Journal of Southeast University (Natural Science Edition), 2019, 49 (6): 1064-1071.
［10］李浩军,叶珍. 随机模型在GPS卫星钟差估计中的应用 ［J］. 同济大学学报 (自然科学版),2021,49 (4): 554-560.
Li H J, Ye Z. Application of Stochastic model in GPS satellite clock estimation ［J］. Journal of Tongji University (Natural Science), 2021, 49 (4): 554-560.
［11］朱江淼,王星,高源,等. 综合多家实验室的原子时标发布系统设计［J］. 计量学报,2020,41(2): 238-242.
Zhu J M, Wang X, Gao Y, et al. Design of Atomic Time Scale Publication System for Multiple Laboratories［J］. Acta Metrologia Sinica, 2020,41(2): 238-242.
［12］巩秀强,袁俊军,胡小工,等. 北斗广播电文钟差模型精度评估及改善策略 ［J］. 测绘学报,2021,50 (2): 181-188.
Gong X Q, Yuan J J, Hu X G, et al. Accuracy evaluation and improvement strategies of Beidou broadcast clock error model ［J］. Acta Geodaetica et Cartographica Sinica, 2021, 50 (2): 181-188.
［13］王宇谱,吕志平,李林阳,等. GPS BLOCK IIF星载原子钟长期性能分析 ［J］. 天文学报,2017,58 (3): 11-21.
Wang Y P, Lv Z P, Li L Y, et al. Analysis of the long-term performance of GPS BLOCK IIF satellite atomic clocks ［J］. Acta Astronomica Sinica, 2017, 58 (3): 11-21.
［14］Huang G, Zhang Q, Li H, et al. Quality variation of GPS satellite clocks on-orbit using IGS clock products ［J］. Advances in Space Research, 2013, 51 (6): 978-987.
［15］贾小林,冯来平,毛悦,等. GPS 星载原子钟性能评估 ［J］. 时间频率学报,2010,33 (2): 115-120.
Jiao X L, Feng L P, Mao Y, et al. Performance evaluation of GPS on-board clock ［J］. Journal of Time and Frequency, 2010, 33 (2): 115-120.
［16］沈婷梅,杨同敏,阎栋梁. 高性能铷原子钟频率长期特性参量估值算法研究 ［J］. 计量学报,2019,40 (5): 900-903.
Shen T M, Yang T M, Yan D L. Long-term parameter estimation of high performance rubidium atomic clocks ［J］. Acta Metrologia Sinica, 2019, 40 (5): 900-903.
2022, Vol. 43 
