PPP-B2b实时精密钟差短期性能评估及更新频度研究  

Research on Short-term Performance and Update Frequency of PPP-B2b Real-time Precise Clock Difference

作　　者：刘金获 唐成盼[1] 周善石[1] 胡小工[1] 杨宇飞 杨建华 刘宇宸 LIU Jin-huo;TANG Cheng-pan;ZHOU Shan-shi;HU Xiao-gong;YANG Yu-fei;YANG Jian-hua;LIU Yu-chen(Shanghai Astronomical Observatory,Chinese Academy of Science,Shanghai 200030,China;University of Chinese Academy of Sciences,Beijing 100049,China;Beijing Satellite Navigation Center,Beijing 100094,China)

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院大学,北京100049 [3]北京卫星导航中心,北京100094

出　　处：《天文学进展》2022年第4期614-627,共14页Progress In Astronomy

基　　金：国家自然科学基金(12173072)。

摘　　要：研究了PPP-B2b精密钟差的短期特征及预报性能,讨论放宽精密钟差改正数播发间隔的可行性。结果表明,BDS-3卫星星载钟和GPS BLOCK IIF星载铷钟具有良好的短期频率稳定度,其钟差120 s预报误差在1 cm左右,预报误差对精密单点定位收敛速度和收敛后精度几乎无影响。而GPS BLOCK IIR卫星星载钟及星载铯钟卫星的短期性能较差,30 s预报误差已经达到4~6 cm,需要较高的解算和更新频度才能保证用户的使用需求。研究发现,对于部分搭载高性能原子钟的卫星,可以在不增加用户信息获取时间的情况下(该时间会随着播发信息增多而增加),适当延长钟差改正数的更新周期至1 min以内,从而节约下行资源,以播发更多系统产品、大气改正等信息,实现服务性能的提升。With precise point position technology,a user can achieve precise coordinates without reference stations.The real-time precise orbit and clock offset products are the premise and guarantee of the real-time PPP application.In order to meet the real-time and precision requirements of users,the precise clock offset of PPP-B2b updates in seconds,which is the same as others institutions.However,according to the statistics of PPPB2b messages,the high-frequency updating satellite clock offset occupies a large amount of downlink resources of PPP-B2b,which delays the first positioning time of users and limits the further performance improvement of PPP-B2b.This paper evaluates the short-term variation characteristics and prediction error of PPP-B2b precision clock offset,and discusses the possibility to reduce clock offset update frequency.Thanks for their new type of atomic clock,the clock offset of BDS-3 satellites and GPS satellites with RAFS show high short-term frequency stability,and the 120 s prediction error of which is only about 1 cm and has little influence on the convergence speed and precision of PPP.However,the clock offset of the GPS old type satellites and Block IIF satellites with Cs clock have low short-term performance,of which the 30 s prediction error has reached 4 to 6 cm,which need high-frequency updating to meet the users’ accuracy demand.Therefore,we suggest that the clock offset broadcast strategy of high-performance satellites could be transformed into a more flexible style to save downlink resource.On the premise that TTDR will not be extended,the updating period can be prolonged within 1 minutes.The saved downlink resource of PPP-B2b can be used to broadcast more augmentation information such as precise products of others system or atmospheric correction so as to improve service performance further.

关 键 词：北斗卫星导航系统 卫星精密钟差 PPP-B2b服务 

分 类 号：P228[天文地球—大地测量学与测量工程]