大气折射导致的激光北斗单向授时偏差  

Unidirectional Timing Deviation Caused by Atmospheric Refraction in Laser Link Based Beidou Time Transfer

作　　者：邢子轩 卢麟 项鹏 戴卫恒 郑吉林 徐荣 Xing Zixuan;Lu Lin;Xiang Peng;Dai Weiheng;Zheng Jilin;Xu Rong(Institute of Communication Engineering,Army Engineering University of PLA,Nanjing 210007,Jiangsu,China)

机构地区：[1]中国人民解放军陆军工程大学通信工程学院,江苏南京210007

出　　处：《光学学报》2024年第12期156-163,共8页Acta Optica Sinica

基　　金：国家自然科学基金(62273355,61974165);国家重点研发计划(2020YFB2205804)。

摘　　要：为满足大多数位置不定用户高精度、机动灵活的授时需求,充分发挥空间激光授时的优势,提出了激光北斗单向授时体制下由大气折射导致的授时偏差的解算方法。分别利用国家气象数据中心的累月平均和每日实测气象数据进行大气折射率分层建模,并以此为基础仿真研究大气折射导致的激光北斗四星对地单向授时偏差的波动范围。结果表明:在北斗中地球轨道条件下,大气折射导致的激光北斗单向授时偏差在几十ns量级,使用累月平均和每日实测气象数据建立的大气折射率分层模型计算得到的授时偏差整体差异在100 ps量级,有望采用大气模型预测校消方法将大气折射导致的授时偏差降低到ps量级。Objective Compared with traditional global satellite navigation systems and fiber-optic time transfer techniques,satellite time transfer based on free-space laser links has higher accuracy and better flexibility,making them widely applicable.However,they are not capable of meeting the timing needs of a large number of users with uncertain positions and lacking precise bi-directional alignment abilities in real life.In this article,we propose a unidirectional Beidou time transfer scheme based on laser links which adopts the terminal user unidirectional timing scheme in the Beidou/GPS navigation system.The proposed scheme combines the flexibility of a unidirectional timing mechanism and the high-precision of laser link based satellite timing systems.However,one of the factors that restrict the performance of this laser link based Beidou unidirectional time transfer is the timing deviation introduced by atmospheric refraction experienced by the laser transmission.Our study focuses on the influence of atmospheric refraction on the laser link,which causes unidirectional timing deviation.The results can pave the way for our future research in correcting the timing deviation and improving the time transfer accuracy and,in turn,promote the development of satellite-to-earth laser link based unidirectional time transfer.Methods In our study,several typical climate representative cities are chosen and the atmospheric refractive index models are established using the monthly average and daily basic observation meteorological data provided by the China Meteorological Data Service Centre(CMDC).Then,with the help of the precise ephemeris data from the International GNSS Service(IGS)data center of Wuhan University,the Beidou satellites are screened,and then the timing deviation caused by atmospheric refraction is computed using the laser signal transmission model and pseudo-range measurement equations.Using this method,the influence of satellite orbit parameters on the unidirectional timing deviation caused by the atmospheric re

关 键 词：大气光学 大气折射 激光北斗 单向授时偏差 

分 类 号：TN929.12[电子电信—通信与信息系统]