本文選題：POS + 空中三角測量　； 參考：《西南交通大學》2013年碩士論文

【摘要】：長期以來,航空攝影測量中影像的定向都需要借助于地面控制點進行傳統(tǒng)的空中三角測量。近年來,隨著傳感器、空間定位技術以及計算機技術的迅速發(fā)展,非攝影測量信息正逐步取代傳統(tǒng)的地面控制,在航空攝影測量中的應用得到快速發(fā)展。POS輔助空中三角測量作為POS與航空攝影測量最有效的集成方式,逐步成為航空攝影測量的研究熱點和今后發(fā)展的趨勢,如何提高其定位精度則成為研究的關鍵。 與傳統(tǒng)的空三加密方法相比,POS輔助空中三角測量在一定程度上可以減少甚至免去地面控制,這樣既降低了生產(chǎn)成本,縮短了成圖周期,同時提高了生產(chǎn)效率。然而,在研究POS系統(tǒng)穩(wěn)定度和可靠性的同時,如何保證POS輔助空中三角測量的定位精度則顯得尤為重要。 目前對該問題的專注度主要集中在系統(tǒng)誤差的影響上,往往是通過改變平差函數(shù)模型達到誤差補償?shù)哪康摹５?POS輔助空中三角測量是非攝影測量觀測值與攝影測量觀測值進行聯(lián)合平差,參與平差的觀測值不再是單一的像點坐標,還包括GPS(全球定位系統(tǒng))所測得的線元素和IMU(慣性測量單元)所測得的角元素。所以如何合理地確定各種類型觀測值的權,將直接影響平差結果的質(zhì)量。因此,面對觀測值類型的多樣化,需要對POS輔助空三的隨機模型進行正確合理的確定。 本文針對經(jīng)系統(tǒng)誤差校正后的POS系統(tǒng)觀測值和攝影測量像點坐標觀測值,分別采用傳統(tǒng)定權方法和驗后方差分量估計方法,基于.NET平臺編制了POS數(shù)據(jù)輔助光束法空三聯(lián)合平差程序,并在某測區(qū)開展了實驗研究,重點分析了不同的定權方法對平差結果精度的影響規(guī)律。 實驗結果表明,采用傳統(tǒng)定權方法中的單位權定權和以常規(guī)的量測精度定權,加密點精度差異不大；采用驗后方差分量估計方法進行平差,解算的加密點精度比傳統(tǒng)定權方法有大幅度的提高；不過,采用同一驗后方差分量估計方法,但取不同的初始權時會影響迭代計算的收斂速度；采用3種不同驗后估計方法時,加密點精度稍有差異,但因Helmert估計始終無偏,而Fostner估計和Ebner估計過程均為從有偏至無偏,導致迭代次數(shù)有所差別,Helmert估計、Fostner估計和Ebner估計分別迭代了8次、11次和15次；同時,在平差過程中無論采用哪種定權方法,得到的加密點的Z向精度始終比X、Y方向的精度低。實驗驗證了驗后方差分量估計在POS輔助光束法區(qū)域網(wǎng)空中三角測量中的必要性和有效性。
[Abstract]:For a long time, the orientation of aerial photogrammetry requires the help of ground control points to carry out traditional aerial triangulation. In recent years, with the rapid development of sensors, space positioning technology and computer technology, non-photogrammetric information is gradually replacing the traditional ground control. As the most effective integration method between POS and aerial photogrammetry, the application in aerial photogrammetry has gradually become the research hotspot of aerial photogrammetry and the development trend in the future. How to improve its positioning accuracy is the key to the research. Compared with the traditional air triangulation method, POS aided aerial triangulation can reduce or even eliminate ground control to a certain extent, which not only reduces the production cost, shortens the mapping period, but also improves the production efficiency. However, while studying the stability and reliability of POS system, it is very important to ensure the positioning accuracy of POS aided aerial triangulation. At present, the focus of this problem is mainly on the influence of system error, and the purpose of error compensation is usually achieved by changing the adjustment function model. However, POS assisted aerial triangulation is a joint adjustment between non-photogrammetric observations and photogrammetric observations, and the observed values involved in the adjustment are no longer a single image point coordinate. Also includes GPS (Global Positioning system) measured line elements and IMU (Inertial Measurement Unit) measured angular elements. Therefore, how to reasonably determine the weights of various types of observations will directly affect the quality of the adjustment results. Therefore, in the face of the diversity of observation value types, it is necessary to correctly and reasonably determine the random model of POS auxiliary space three. In this paper, the traditional weight determination method and the posterior variance component estimation method are used for the POS system observation values and the photogrammetric image point coordinate observations after the system error correction, respectively. Based on. Net platform, the program of POS data aided beam normal space triple-adjustment is compiled, and the experimental research is carried out in a certain area. The influence of different weight setting methods on the accuracy of adjustment results is analyzed. The experimental results show that there is little difference in the accuracy of the encryption point between the traditional weight determination method and the conventional measurement precision method, and the posterior variance component estimation method is used to adjust the error. The precision of the solution is much higher than that of the traditional weight determination method. However, using the same posterior variance component estimation method, but taking different initial weights will affect the convergence rate of the iterative calculation; when three different posteriori estimation methods are used, the convergence rate of the iterative calculation will be affected by using the same posteriori variance component estimation method. The precision of encryption point is slightly different, but because the Helmert estimation is always unbiased, and the process of Fostner estimation and Ebner estimation is from biased to unbiased, the number of iterations is different. The Helmert estimate and Ebner estimate iterate 8 times 11 times and 15 times, respectively. No matter which weight determination method is used in the adjustment process, the Z direction accuracy of the obtained encryption point is always lower than that of the XY direction. The necessity and validity of posterior variance component estimation in POS assisted beam method are verified by experiments.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：P231.5

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