本文選題：地球重力測量 + 星間精密測距�。� 參考：《國防科學(xué)技術(shù)大學(xué)》2013年博士論文

【摘要】：通過測量同軌道面上兩顆近距離低軌衛(wèi)星之間的微小距離變化,可以精確反演出地球重力場。為實現(xiàn)地球重力場的高精度測量,星間測距的精度需求為微米量級。星間精密測距的基本測量方法是雙向單程測距(Dual One-Way Ranging,DOWR)方法,它的一個制約性基礎(chǔ)條件是要求雙星對測量信號的采樣時刻之間保持同步。由于雙星的時鐘不同源,星間時標(biāo)不能完全同步,會導(dǎo)致測距誤差。由此產(chǎn)生了本文研究的基本問題——如何降低星間精密測距中與時標(biāo)有關(guān)的測距誤差,為此,論文重點(diǎn)研究了以下四個關(guān)鍵技術(shù)問題:1.測距誤差模型問題。星間精密測距中涉及的誤差源非常復(fù)雜,部分誤差源之間還存在相互耦合的關(guān)系。要有效降低星間測距誤差,必須給出一個定量描述誤差與其影響要素之間的函數(shù)關(guān)系——測距誤差模型。因此,如何確定測距誤差模型成為星間精密測距的關(guān)鍵問題。2.雙星時標(biāo)統(tǒng)一問題。全球重力場測量需要高度的時空統(tǒng)一,星間精密測距需要兩星時標(biāo)精確同步,重力測量結(jié)果的地球坐標(biāo)賦值需要空間位置同步,二者統(tǒng)一歸結(jié)為將衛(wèi)星時標(biāo)統(tǒng)一到某個參考時間系統(tǒng)。在得不到GPS P(Y)碼的支持,且我國的北斗區(qū)域?qū)Ш较到y(tǒng)目前僅能提供局域溯源的條件下,要自主實現(xiàn)雙星時標(biāo)的統(tǒng)一成為瓶頸難題。3.時標(biāo)偏差修正問題。衛(wèi)星重力測量中的星間精密測距,需要的是地球經(jīng)緯度坐標(biāo)上的距離測量值,根據(jù)衛(wèi)星軌道,對應(yīng)于參考時間系統(tǒng)中某一時刻nt上的量值。由于存在時標(biāo)偏差n?,衛(wèi)星的測量數(shù)據(jù)是時刻n nt??上的量值。必須對測量數(shù)據(jù)中的時標(biāo)偏差進(jìn)行有效修正,才能得到精密的星間距離。因此,時標(biāo)偏差修正問題是星間精密測距的關(guān)鍵問題。4.測距信號優(yōu)化設(shè)計問題。星間精密測距的誤差與測距信號的結(jié)構(gòu)參數(shù)有直接的關(guān)系。在測距信號的結(jié)構(gòu)組成中,頻率設(shè)計值容許一定的選擇范圍。對于采用雙頻測距信號的星間精密測距而言,通過優(yōu)化設(shè)置測距信號的頻點(diǎn)可以進(jìn)一步降低測距誤差,有必要研究最佳的頻率組合以及實現(xiàn)最佳頻率的方法。因此,測距信號的優(yōu)化設(shè)計是星間精密測距的關(guān)鍵問題。為解決上述關(guān)鍵技術(shù)問題,論文建立了雙星時標(biāo)統(tǒng)一的非相對論測距誤差模型,提出了一種基于雙向時間傳遞和北斗時局域溯源的時標(biāo)統(tǒng)一方法,提出了一種基于插值擬合的時標(biāo)偏差分步修正方法,提出了一種DOWR信號的頻率優(yōu)化組合方法。這些技術(shù)方法作為上述四個關(guān)鍵技術(shù)問題的解決方案,均通過理論分析和仿真驗證了其有效性,并在測距系統(tǒng)中得到了實現(xiàn),通過實驗驗證了其技術(shù)可行性。
[Abstract]:By measuring the small distance variation between two low-orbit satellites in the same orbit, the Earth's gravity field can be accurately reversed. In order to realize the high precision measurement of the earth gravity field, the precision of the ranging between satellites is of the order of micron. The basic measurement method of intersatellite precision ranging is the dual One-Way ranging DOWR method. One of its restrictive conditions is that the sampling time of the measured signal is required to be synchronized between the two satellites. Because the binary clock is not homologous, the time scale can not be fully synchronized, which will lead to ranging error. Therefore, the basic problem of this paper is how to reduce the ranging error related to time scale in the intersatellite precision ranging. For this reason, this paper focuses on the following four key technical problems: 1. The problem of ranging error model. The error sources involved in the intersatellite precision ranging are very complex, and some of the error sources are coupled with each other. In order to effectively reduce the ranging error between satellites, a functional relationship between the quantitative description error and its influencing factors must be given, that is, the ranging error model. Therefore, how to determine the ranging error model has become the key problem of intersatellite precision ranging. The unification of double star time scale. The global gravity field measurement needs high spatial and temporal unity, the precise ranging between satellites needs the precise synchronization of two satellite time scales, and the earth coordinate assignment of gravity measurement results needs space position synchronization. The unification of the two comes down to the unification of the satellite time scale into a reference time system. Without the support of GPS Pian YC code and the fact that the Beidou regional navigation system in China can only provide local traceability at present, it is a bottleneck problem to realize the unification of dual star time scale independently. Correction of time scale deviation. In the satellite gravimetry, the distance measurement value in the coordinates of longitude and latitude of the earth is required. According to the satellite orbit, it corresponds to the value of NT at a certain time in the reference time system. Due to the existence of time scale deviation, the measured data of the satellite is the time n NT? The amount of value on. The time scale deviation in the measured data must be corrected effectively in order to obtain the precise inter-satellite distance. Therefore, the correction of time scale deviation is the key problem of intersatellite precision ranging. Optimal design of ranging signal. The error of intersatellite precision ranging is directly related to the structural parameters of ranging signal. In the structure composition of ranging signal, the frequency design value allows a certain range of selection. For the intersatellite precision ranging with dual-frequency ranging signal, the ranging error can be further reduced by optimizing the frequency point of ranging signal. It is necessary to study the best frequency combination and the method of realizing the best frequency. Therefore, the optimal design of ranging signal is the key problem of inter-satellite precision ranging. In order to solve the above key technical problems, a unified non-relativistic ranging error model of double star time scale is established, and a unified method based on bidirectional time transfer and local traceability of Beidou time scale is proposed. In this paper, a time scale deviation step correction method based on interpolation fitting is proposed, and a frequency optimal combination method of DOWR signal is proposed. As the solutions of the four key technical problems mentioned above, these technical methods are proved to be effective by theoretical analysis and simulation, and implemented in the ranging system. The technical feasibility is verified by experiments.
【學(xué)位授予單位】：國防科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：P223.4

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本文編號：1854842