地基GPS反演大氣水汽關(guān)鍵問題的理論與方法研究
發(fā)布時(shí)間：2018-09-19 17:15
【摘要】：研究利用地基GPS反演大氣水汽不僅對天氣變化的預(yù)報(bào)有重要意義,而且可以促進(jìn)GPS定位精度的提高,從而發(fā)揮GPS在應(yīng)用方面的潛力�；诖�,本文對地基GPS反演大氣水汽所涉及的主要問題進(jìn)行了系統(tǒng)的研究,整個(gè)論文的主要研究內(nèi)容和創(chuàng)新點(diǎn)概括如下： 1.概述了影響GPS反演大氣水汽各主要問題的研究現(xiàn)狀,并指出了本文的研究目標(biāo),對GPS的觀測模型及估計(jì)方法進(jìn)行了詳細(xì)的介紹,從而為本文后續(xù)數(shù)據(jù)處理奠定基礎(chǔ)。 2.分析了廣播星歷外推衛(wèi)星軌道的精度,并給出了Lagrange插值、Neville插值、Chebyshev多項(xiàng)式擬合和Legendre多項(xiàng)式擬合進(jìn)行精密星歷加密的方法,通過對實(shí)際精密星歷數(shù)據(jù)的計(jì)算,分別從內(nèi)插和擬合的階數(shù)、計(jì)算精度、計(jì)算效率進(jìn)行了比較分析,并給出了最佳階數(shù)插值算法和擬合算法計(jì)算衛(wèi)星軌道的點(diǎn)位誤差對比圖、所有衛(wèi)星軌道的精度對比效果圖。隨后,分別以實(shí)例對衛(wèi)星信號發(fā)射時(shí)刻的兩種計(jì)算方法與影響衛(wèi)星軌道的地球自轉(zhuǎn)誤差進(jìn)行了探討分析。 3.基于TurboEdit方法對GPS觀測數(shù)據(jù)進(jìn)行周跳探測的特點(diǎn),設(shè)計(jì)了固定弧段長度的滑動(dòng)窗口擬合模型,對其中的Geometry-Free組合法進(jìn)行改進(jìn),在探測出周跳后,提出利用最小二乘Chebyshev多項(xiàng)式擬合來修復(fù)周跳。實(shí)驗(yàn)結(jié)果表明：改進(jìn)后的TurboEdit算法可以探測出等周的1周小周跳、等周的大周跳和連續(xù)的小周跳、大周跳,同時(shí),最小二乘Chebyshev多項(xiàng)式擬合可以精確修復(fù)以上周跳對。 4.根據(jù)雙差相位觀測序列在相鄰歷元間求差后,周跳能真實(shí)地以粗差形式反映出來的特點(diǎn),在利用Chebyshev多項(xiàng)式擬合雙差觀測量時(shí),顧及抗差估計(jì)的思想、Chebyshev多項(xiàng)式擬合階數(shù)、擬合弧段長度,提出基于移動(dòng)窗口的抗差Chebyshev多項(xiàng)式擬合算法來探測與修復(fù)周跳,應(yīng)用采樣間隔為60s和15s的L1頻率的載波相位數(shù)據(jù)測試表明,該算法可有效的探測多歷元間隔周跳及連續(xù)周跳,能對周跳進(jìn)行準(zhǔn)確的修復(fù)。 5.針對不存在先驗(yàn)信息時(shí)常規(guī)GPS單歷元數(shù)據(jù)處理中存在的問題,提出了一種新的GPS整周模糊度單歷元算法。該算法先采用一個(gè)歷元的碼觀測值進(jìn)行最小二乘定位,求取初始模糊度,并根據(jù)解的中誤差來構(gòu)造模糊度原始搜索空間。再采用兩種不同線性組合的擴(kuò)波方法進(jìn)行模糊度變換,使原模糊度的搜索空間變小。在模糊度的新搜索空間確定后,通過線性組合的逆變換求取模糊度N1及N2,并以模糊度函數(shù)法進(jìn)行真值的搜索,實(shí)現(xiàn)單歷元解算。采用基線長度不同的兩組數(shù)據(jù)作為實(shí)例進(jìn)行測試,試驗(yàn)結(jié)果表明了本文方法的可行性和正確性。 6.針對單頻GPS動(dòng)態(tài)定位中常用模糊度求解方法存在的問題,提出了一種新的整周模糊度快速解算方法。該方法先通過對雙差觀測方程中坐標(biāo)參數(shù)的系數(shù)陣進(jìn)行QR分解變換以消除坐標(biāo)參數(shù),從而僅對模糊度參數(shù)建立Kalman濾波方程進(jìn)行估計(jì),然后利用排序和雙Cholesky分解對濾波得到的模糊度進(jìn)行降相關(guān)處理,并結(jié)合收縮模糊度搜索空間的思想來搜索固定整周模糊度。以實(shí)測的動(dòng)態(tài)數(shù)據(jù)為例對該方法進(jìn)行測試,其分析結(jié)果表明,該方法不但可以改善模糊度浮點(diǎn)解精度,而且具有良好的模糊度降相關(guān)效果,可正確有效地實(shí)現(xiàn)整周模糊度的快速解算。 7.通過考慮模糊度的整數(shù)特性及相位波長與基線非參考站初始坐標(biāo)誤差之間的約束條件,提出了一種基于梯級遞推的無模糊度基線解算方法。該方法不受周跳的影響,并且在基線求解過程中不用考慮模糊度參數(shù)。分別以單個(gè)歷元和移動(dòng)窗口的多歷元兩種求解方案驗(yàn)證了該方法的可行性和正確性,并且基線解算結(jié)果具有較高的精度。 8.利用參考站坐標(biāo)已知的先驗(yàn)信息,基于組合后的超快星歷,提出了一種參考站對流層濕延遲近實(shí)時(shí)估計(jì)的三步Kalman濾波算法,該方法先利用Kalman濾波分離寬巷模糊度與偽距多路徑誤差,再基于電離層無關(guān)組合模型,啟動(dòng)Kalman濾波器進(jìn)行L1模糊度與相對對流層濕延遲的分離,然后利用將正確固定的L1雙差模糊度進(jìn)行回代的方法,重新構(gòu)建Kalman濾波器來估計(jì)準(zhǔn)確的相對對流層濕延遲參數(shù),通過實(shí)例驗(yàn)證了該方法的可行性和正確性。隨后,利用該方法獲取的近實(shí)時(shí)對流層濕延遲計(jì)算了相應(yīng)的近實(shí)時(shí)可降水量,并與GAMIT解算的可降水量結(jié)果進(jìn)行了比較分析。
[Abstract]:The research on the retrieval of atmospheric water vapor by ground-based GPS is not only of great significance to the forecast of weather changes, but also can promote the improvement of GPS positioning accuracy, so as to bring into play the potential of GPS in application. Based on this, the main problems involved in the retrieval of atmospheric water vapor by ground-based GPS are systematically studied in this paper, and the main contents and contents of the whole paper are The innovations are summarized as follows:
1. The main problems affecting the retrieval of atmospheric water vapor by GPS are summarized, and the research objectives of this paper are pointed out. The GPS observation model and estimation method are introduced in detail, so as to lay a foundation for subsequent data processing in this paper.
2. The precision of extrapolating satellite orbit from broadcast ephemeris is analyzed. The methods of precise ephemeris encryption by Lagrange interpolation, Neville interpolation, Chebyshev polynomial fitting and Legendre polynomial fitting are given. By calculating the actual precise ephemeris data, the order of interpolation and fitting, the calculating precision and the calculating efficiency are compared and analyzed. Then, the comparisons between the best order interpolation algorithm and the fitting algorithm for calculating the position error of the satellite orbit and the precision comparison results of all the satellite orbit are given.
3. Based on the characteristics of Turbo Edit method in detecting cycle slip of GPS observation data, a sliding window fitting model with fixed arc length is designed, and the Geometry-Free combination method is improved. After detecting cycle slip, the least square Chebyshev polynomial fitting is proposed to repair cycle slip. The algorithm can detect the small cycle slip, the large cycle slip and the continuous small cycle slip. At the same time, the least square Chebyshev polynomial fitting can accurately repair the above cycle slip pairs.
4. According to the characteristic that the cycle slip can be truly reflected in the form of gross error after the difference between adjacent epochs of the double-difference phase observation sequence is calculated, the robust Chebyshev polynomial fitting order and arc length based on the moving window are proposed when the Chebyshev polynomial is used to fit the double-difference observation. Combined algorithm is used to detect and repair cycle slips. Carrier phase data of L1 frequency with sampling intervals of 60 s and 15 s are tested. The results show that this algorithm can detect multi-epoch interval cycle slips and continuous cycle slips effectively and can repair cycle slips accurately.
5. Aiming at the problem of conventional GPS epoch metadata processing without prior information, a new GPS integer ambiguity single epoch algorithm is proposed. Firstly, an epoch code observation is used to locate the GPS integer ambiguity single epoch, and the initial ambiguity is obtained. Then, the original search space of ambiguity is constructed according to the median error of the solution. The ambiguity N1 and N2 are obtained by the inverse transformation of the linear combination, and the true value is searched by the ambiguity function method to realize the single epoch resolution. As an example, the test results show that the method is feasible and correct.
6. Aiming at the problems of ambiguity resolution in single-frequency GPS dynamic positioning, a new method for fast ambiguity resolution is proposed. The method first eliminates the coordinate parameters by QR decomposition transformation of the coefficient matrix of coordinate parameters in the double-difference observation equation, and then establishes Kalman filter equation to estimate only the ambiguity parameters. Then, the fuzzy degree is reduced by ranking and double Cholesky decomposition, and the fixed ambiguity is searched by using the idea of contraction ambiguity search space. Moreover, it has good ambiguity reduction correlation effect, and can effectively and effectively achieve integer ambiguity resolution.
7. Considering the integer characteristic of ambiguity and the constraint condition between phase wavelength and the initial coordinate error of baseline non-reference station, a new method of ambiguity-free baseline solution based on cascade recursion is proposed. The feasibility and validity of the method are verified by the two solutions of multi-epoch with moving window, and the results of baseline calculation have high precision.
8. A three-step Kalman filtering algorithm for near-real-time estimation of tropospheric wet delay at reference stations is proposed based on the combined ultrafast ephemeris and the priori information of reference station coordinates. Firstly, the wide lane ambiguity and pseudo-range multipath error are separated by Kalman filtering, and then the Kalman filter advance is started based on the ionospheric independent combination model. After separating the L1 ambiguity from the relative tropospheric wet delay, the Kalman filter is reconstructed to estimate the accurate relative tropospheric wet delay parameters by using the method of regenerating the correctly fixed L1 ambiguity. The feasibility and correctness of the method are verified by an example. The near-real-time precipitable water is calculated by layer wet delay and compared with the results calculated by GAMIT.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：P228.4;P412.27
本文編號：2250790
[Abstract]:The research on the retrieval of atmospheric water vapor by ground-based GPS is not only of great significance to the forecast of weather changes, but also can promote the improvement of GPS positioning accuracy, so as to bring into play the potential of GPS in application. Based on this, the main problems involved in the retrieval of atmospheric water vapor by ground-based GPS are systematically studied in this paper, and the main contents and contents of the whole paper are The innovations are summarized as follows:
1. The main problems affecting the retrieval of atmospheric water vapor by GPS are summarized, and the research objectives of this paper are pointed out. The GPS observation model and estimation method are introduced in detail, so as to lay a foundation for subsequent data processing in this paper.
2. The precision of extrapolating satellite orbit from broadcast ephemeris is analyzed. The methods of precise ephemeris encryption by Lagrange interpolation, Neville interpolation, Chebyshev polynomial fitting and Legendre polynomial fitting are given. By calculating the actual precise ephemeris data, the order of interpolation and fitting, the calculating precision and the calculating efficiency are compared and analyzed. Then, the comparisons between the best order interpolation algorithm and the fitting algorithm for calculating the position error of the satellite orbit and the precision comparison results of all the satellite orbit are given.
3. Based on the characteristics of Turbo Edit method in detecting cycle slip of GPS observation data, a sliding window fitting model with fixed arc length is designed, and the Geometry-Free combination method is improved. After detecting cycle slip, the least square Chebyshev polynomial fitting is proposed to repair cycle slip. The algorithm can detect the small cycle slip, the large cycle slip and the continuous small cycle slip. At the same time, the least square Chebyshev polynomial fitting can accurately repair the above cycle slip pairs.
4. According to the characteristic that the cycle slip can be truly reflected in the form of gross error after the difference between adjacent epochs of the double-difference phase observation sequence is calculated, the robust Chebyshev polynomial fitting order and arc length based on the moving window are proposed when the Chebyshev polynomial is used to fit the double-difference observation. Combined algorithm is used to detect and repair cycle slips. Carrier phase data of L1 frequency with sampling intervals of 60 s and 15 s are tested. The results show that this algorithm can detect multi-epoch interval cycle slips and continuous cycle slips effectively and can repair cycle slips accurately.
5. Aiming at the problem of conventional GPS epoch metadata processing without prior information, a new GPS integer ambiguity single epoch algorithm is proposed. Firstly, an epoch code observation is used to locate the GPS integer ambiguity single epoch, and the initial ambiguity is obtained. Then, the original search space of ambiguity is constructed according to the median error of the solution. The ambiguity N1 and N2 are obtained by the inverse transformation of the linear combination, and the true value is searched by the ambiguity function method to realize the single epoch resolution. As an example, the test results show that the method is feasible and correct.
6. Aiming at the problems of ambiguity resolution in single-frequency GPS dynamic positioning, a new method for fast ambiguity resolution is proposed. The method first eliminates the coordinate parameters by QR decomposition transformation of the coefficient matrix of coordinate parameters in the double-difference observation equation, and then establishes Kalman filter equation to estimate only the ambiguity parameters. Then, the fuzzy degree is reduced by ranking and double Cholesky decomposition, and the fixed ambiguity is searched by using the idea of contraction ambiguity search space. Moreover, it has good ambiguity reduction correlation effect, and can effectively and effectively achieve integer ambiguity resolution.
7. Considering the integer characteristic of ambiguity and the constraint condition between phase wavelength and the initial coordinate error of baseline non-reference station, a new method of ambiguity-free baseline solution based on cascade recursion is proposed. The feasibility and validity of the method are verified by the two solutions of multi-epoch with moving window, and the results of baseline calculation have high precision.
8. A three-step Kalman filtering algorithm for near-real-time estimation of tropospheric wet delay at reference stations is proposed based on the combined ultrafast ephemeris and the priori information of reference station coordinates. Firstly, the wide lane ambiguity and pseudo-range multipath error are separated by Kalman filtering, and then the Kalman filter advance is started based on the ionospheric independent combination model. After separating the L1 ambiguity from the relative tropospheric wet delay, the Kalman filter is reconstructed to estimate the accurate relative tropospheric wet delay parameters by using the method of regenerating the correctly fixed L1 ambiguity. The feasibility and correctness of the method are verified by an example. The near-real-time precipitable water is calculated by layer wet delay and compared with the results calculated by GAMIT.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：P228.4;P412.27
【參考文獻(xiàn)】
相關(guān)博士學(xué)位論文 前1條
1 張紹成;基于GPS/GLONASS集成的CORS網(wǎng)絡(luò)大氣建模與RTK算法實(shí)現(xiàn)[D];武漢大學(xué);2010年
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