外文翻譯---一種確定大氣垂直折光系數(shù)的新方法

1、<p><b>　　附錄</b></p><p>　　A VERTICAL ATMOSPHERIC REFRACTION COEFFICIENT TO DETERMINE NEW WAYS OF</p><p>　　FRIST. interoduction</p><p>　　A long time, trigonometric le

2、veling observations in many types of geodetic measurement concept is considered a class of low precision, the reason for this is because of the vast numbers of measurements so far have not found work well to eliminate th

3、e impact of a trigonometric leveling a major factor in the accuracy of the methods and measures, thus limiting this approach in the elevation measurement. We know that, in addition to observational error, the impact of t

4、rigonometric leveling is a majo</p><p>　　SECOND, atmospheric vertical refraction coefficient</p><p>　　We know that the density of light through the medium non-uniform refraction will occur, so t

5、hat light into a complex of both curvature and torsion of space curves. In the survey, because the temperature in time and space changes in the density of the atmosphere have also taken place in time and space changes, s

6、o the speed of light waves, amplitude, phase and propagation direction are randomly generated impact. In light of such properties, it is difficult to even make it almost impossible to use </p><p>　　Third, de

7、termine the atmospheric vertical refraction coefficient method</p><p>　　At present, the determination of atmospheric refraction coefficient vertical approach more, past and present, many scholars have conduc

8、ted research, given</p><p>　　Refraction correction model for many, but these formulas are basically the use of meteorological elements measured refraction coefficient calculation, requiring a high degree of&

9、lt;/p><p>　　Angle measured at the same time observing a large number of meteorological data, it cost more, in practical work, using less. In this paper, the vertical atmospheric refraction coefficient as random

10、 parameters, in the adjustment together with the solution of the main parameters. The selection of the parameters measured in accordance with the geographical area the case may be, you can set up a parameter region can a

11、lso be set up district election. The adjustment in this model, each station used t</p><p>　　FOURH. Example</p><p>　　An example is a triangle with 13-point elevation of the triangular control net

12、 (Network Tulio), in the surveyed area, O is known to its point, the set of the points of vertical deflection relative to zero, that is the point of gravity direction and the corresponding ellipsoid of the normal surface

13、 direction. In the example, because of the distance has reached the mm-level observations, we assume that there being no error in the adjustment does not consider its impact. The example of field work i</p><p&

14、gt;　　Vertical angle measurement using four back, observing the 9 hours of 17:00 a.</p><p>　　1. Atmospheric refraction coefficient of the approximation used to identify examples of this type to determine the

15、refractive index of each side of the approximation coefficients (rounded down to the nearest K negative value), and then calculated for each of the approximate average station.</p><p>　　2. Observing the righ

16、t to determine the elevation difference</p><p>　　Determined by trigonometric leveling the elevation, the accuracy with the side length varies, the longer the length, the greater the error, the lower accuracy

17、, and secondly, to the observation of one-way observation elevation and elevation difference accuracy is not the same . In the network adjustment, in order to distinguish between the accuracy of elevation differences, on

18、 the need to determine the elevation of the right of observation.</p><p>　　SIXTH. Conclusion</p><p>　　By atmospheric refraction on the vertical impact of trigonometric leveling is always include

19、d in the zenith distance or vertical angle observations will refraction coefficient as random parameters and solving together the main parameters, obtained by atmospheric refraction coefficient thus reflecting its on the

20、 impact of observations. An example of this side of 39, some side of the river due to the impact of its large coefficient of atmospheric refraction, in 14 points, K value of 0.08 between o</p><p>　　一種確定大氣垂直折

21、光系數(shù)的新方法</p><p><b>　　一、引言</b></p><p>　　長期以來，三角高程測量的觀測值在大地測量諸多類觀測量中被認(rèn)為是低精度的一類，之所以如此，是由于廣大測量工作者迄今還沒有找到一種能很好消除影響三角高程測量精度的主要因素的方法和措施，因而限制了這一方法在高程測量中的應(yīng)用。我們知道，除觀測誤差外，影響三角高程測量精度的主要因素是大氣垂直折光和

22、垂線偏差，當(dāng)距離較長時，三角高程測量的精度主要受大氣垂直折光的影響。所以，眾多測量工作者長期以來一直在研究、探討確定大氣垂直折光系數(shù)的方法。長期的研究表明，由于大氣折射場隨時間和空間的瞬息變化，特別是近地面溫度梯度的變化非常大，要想建立一個普遍實(shí)用的模型來消除或精確改正大氣垂直折光的影響是很困難的，甚至幾乎是不可能的。近幾年來，隨著測量儀器的不斷發(fā)展和更新，特別是精密測距儀在三角高程測量中的應(yīng)用，引起了眾多學(xué)者對大地測量折光的更深入的研

23、究。</p><p>　　二、大氣垂直折光系數(shù)</p><p>　　我們知道，光線通過密度不均勻的介質(zhì)時會發(fā)生折射，從而使光線成為一條復(fù)雜的既有曲率又有撓率的空間曲線。在測量工作中，由于溫度在時間和空間上的變化，使大氣的密度也發(fā)生時間和空間上的變化，從而對光波的光速、振幅、相位和傳播方向都產(chǎn)生隨機(jī)影響。于光波的這種屬性，使得我們很難甚至幾乎不可能用一種普遍實(shí)用的模型來描述光波在大氣中的這種

24、屬性。就某一地區(qū)而言，大氣密度在各種不同條件下產(chǎn)生的不同差異，需要用統(tǒng)計(jì)規(guī)律來描述，同理，大氣垂直折光系數(shù)也需用統(tǒng)計(jì)規(guī)律來確定。折光現(xiàn)象的產(chǎn)生，主要是由于光線所通過的大氣密度不均勻的緣故，其不均勻性主要分布在垂直方向上，同一種波長的光波的大氣折射，歸根到底是由大氣密度的狀況決定的。大氣折射對三角高程的影響，可以歸結(jié)為大氣垂直折光對垂直角或天頂距觀測值的影響，大氣垂直折光的影響總是實(shí)時實(shí)地不可避免地包含在垂直角或天頂距的實(shí)際觀測值中。所以

25、該影響總是在垂直角或天頂距觀測值的大小與變化中直接反映出來，并以同樣的函數(shù)形式參與計(jì)算，從而產(chǎn)生影響。</p><p>　　三、確定大氣垂直折光系數(shù)的方法</p><p>　　目前求定大氣垂直折光系數(shù)的方法較多，過去和現(xiàn)在都有許多學(xué)者進(jìn)行過研究，給出的折射改正模型甚多，但這些公式基本上都是利用測得的氣象元素推求折光系數(shù)，要求在高精度角觀測的同時測定大量的氣象數(shù)據(jù)，因此耗費(fèi)較大，在實(shí)際工作中

26、較少采用。本文將大氣垂直折光系數(shù)作為隨機(jī)參數(shù)，在平差中與主參數(shù)一并求解。參數(shù)的選取依測區(qū)的地理情況而定，可以全區(qū)設(shè)一個參數(shù)，也可以分區(qū)選設(shè)。在本文的平差模型中，采用每個測站設(shè)定一個參數(shù)的方法來確定整個測區(qū)的平均折光系數(shù)。</p><p><b>　　四、算例</b></p><p>　　算例是一個含13個三角點(diǎn)的三角高程控制網(wǎng)(網(wǎng)圖略)，在該測區(qū)，O號點(diǎn)為已知點(diǎn)，設(shè)該

27、點(diǎn)的相對垂線偏差為零，亦即該點(diǎn)的重力方向和相應(yīng)的橢球面上的法線方向一致。在該算例中，由于距離的觀測已達(dá)到mm級，所以，我們假設(shè)距離沒有誤差，在平差時不考慮其影響。該算例的野外作業(yè)是在六月份進(jìn)行的，測量儀器是T3經(jīng)緯儀，照準(zhǔn)目標(biāo)是橫基尺，儀器和橫基尺均放于1.20m高的水泥柱上。一共13個特定點(diǎn)，39條邊，每條邊均同時進(jìn)行了對向觀測，垂直角采用了4個測回，觀測時間為每天的9-17時。</p><p>　　1.大氣折

28、光系數(shù)近似值的確定本算例采用下式來確定每條邊折光系數(shù)的近似值(舍去負(fù)的K值)，然后再求出每個測站的近似平均值。</p><p>　　2.觀測高差權(quán)的確定</p><p>　　三角高程測量所決定的高差，其精度隨邊長的不同而不同，邊長越長，誤差愈大、精度愈低，其次，對向觀測高差和單向觀測高差的精度也不相同。在網(wǎng)平差中，為了區(qū)別高差精度的差異，就需要確定觀測高差的權(quán)。</p>&l

29、t;p><b>　　五、結(jié)語</b></p><p>　　由大氣垂直折光對三角高程的影響，總是包含在天頂距或垂直角的觀測值中，將折光系數(shù)作為隨機(jī)參數(shù)與主參數(shù)一并求解，所得到的大氣折光系數(shù)因此如實(shí)地反映了其對觀測值的影響程度。在本算例的39條邊中，部分邊因受河流影響，其大氣折光系數(shù)偏大，在14個點(diǎn)中，K值在0.08-0.11之間的有11個，整個測區(qū)的平均折光系數(shù)K=0.092，與我國的統(tǒng)