天文经纬度和天文方位角测定的基本原理

大地天文测量无论在基础科学,还是在国民经济和国防建设中都具有重要的意义。随着空间大地测量技术(VLB、ILLR、SLR和GPS等)的发展,虽然天文测量在应用上有所减少,但在大地测量的绝对定位和中远程武器的发射等领域中仍然是不可替代的技术。本文详细地介绍了天文经纬度和天文方位角测量的基本原理和方法,综述了天文测量目前的发展状况和存在的问题。本文的工作可为天文大地测量的研究提供一定的参考和依据。     

Method of simultaneous determination of astronomic latitude,azimuth and longitude by observing only time and horizontal angles between a pair of stars near elongation and a south star near meridian

Summary This paper endeavours to evolve a method of simultaneous determination of astronomic latitude, azimuth and longitude from observations of a star-pair near their times of east and west elongations and a south star near its time of meridian transit. The star-pair of observation being within a short distance of elongation, either east or west, their motion in azimuth then is extremely slow and the small error in time has therefore insignificant effect on their azimuth, and in addition, the south star with its azimuth known from observations of the previous star-pair, being very fast-moving, the method is especially suitable for determining the astronomic latitude, azimuth and longitude by observing only the time and horizontal angees between them, and also a reference mark for ensuring the orientation of the horizontal circle side by side.     

Estimability of astronomical longitude and latitude only from theodolite observations within three-dimensional networks of terrestrial type

Summary From a two-dimensional network adjustment it is well understood that the one orientation unknown of a theodolite frame is estimable, once the orientation datum parameter, e.g., one azimuth, is fixed. In three-dimensional networks the problem of estimability of three orientation unknowns inherent in a theodolite frame is more complex. Here we prove that not only the classical horizontal orientation unknown is estimable (up to the datum degrees of freedom), but also astronomical longitude and astronomical latitude which can be considered as two additional orientation unknowns of the theodolite frame moving with respect to an earth-fixed equatorial frame of reference. Thus the theodolite instrument can be considered—at least theoretically—a gradiometer measuring the variation of the directional parameters of the gravity vector from one point to another. Or up to the datum degrees of freedom astronomical longitude and astronomical latitude can be determined from only theodolite observations between exclusively terrestrial points. M?nicke (1982), has shown that despite the refraction problem the method works sufficiently well in practice.     

天文经纬度归心实用算式推证

文中分析天文经纬度归心公式中各变量的特点,推导基于2000国家大地坐标系统简单实用的归心计算公式,进一步给出由已确定变量推求归心元素测量精度的数学关系式。验证实用公式计算的归心改正数满足专用工程天文经纬度的计算精度需求。     

基于LightGBM的全球海洋次表层温盐遥感预测

随着卫星遥感技术的发展,越来越多的卫星观测数据被应用于预测海洋内部温盐结构信息,而如何有效提高海洋内部温盐信息的预测精度仍是一个挑战。本文应用LightGBM算法结合随机森林算法构建全球海洋次表层（0—1000 m）温度异常（STA）与盐度异常（SSA）的预测模型,模型使用海表卫星观测数据（海表高度异常（SSHA）、海表温度异常（SSTA）、海表盐度异常（SSSA）和海表风场异常水平和垂直分量（USSWA、VSSWA）,结合经纬度信息（LON、LAT）作为预测变量,使用Argo次表层温盐数据作为模型训练与测试标记。本文使用五参数模型（SSTA、SSHA、SSSA、USSWA、VSSWA）、带纬度六参数模型（LAT、SSTA、SSHA、SSSA、USSWA、VSSWA）、带经度六参数模型（LON、SSTA、SSHA、SSSA、USSWA、VSSWA）与带经纬度七参数模型（LON、LAT、SSTA、SSHA、SSSA、USSWA、VSSWA）来着重分析LON与LAT在STA、SSA遥感预测中发挥的作用。结果表明LON与LAT在STA、SSA各自预测中发挥不同的作用。在单时相和时序预测STA中LON与LAT对模型的贡献随着深度的增加逐渐增大,而在单时相和时序预测SSA中LON与LAT对不同深度预测模型始终保持较大的贡献。在单时相预测STA与SSA中LON较LAT对模型贡献更大,而在时序预测STA与SSA中LAT较LON对模型贡献更大。经纬度信息是全球海洋次表层温盐机器学习预测的重要参数,可以提高模型的预测精度。同时,LightGBM较随机森林在预测海洋次表层温盐异常时精度更高鲁棒性更强。     

Simple and highly accurate formulas for the computation of Transverse Mercator coordinates from longitude and isometric latitude

A conformal approximation to the Transverse Mercator (TM) map projection, global in longitude λ and isometric latitude q, is constructed. New formulas for the point scale factor and grid convergence are also shown. Assuming that the true values of the TM coordinates are given by conveniently truncated Gauss–Krüger series expansions, we use the maximum norm of the absolute error to measure globally the accuracy of the approximation. For a Universal Transverse Mercator (UTM) zone the accuracy equals 0.21  mm, whereas for the region of the ellipsoid bounded by the meridians  ±20° the accuracy is equal to 0.3  mm. Our approach is based on a four-term perturbation series approximation to the radius r(q) of the parallel q, with a maximum absolute deviation of 0.43  mm. The small parameter of the power series expansion is the square of the eccentricity of the ellipsoid. This closed approximation to r(q) is obtained by solving a regularly perturbed Cauchy problem with the Poincaré method of the small parameter. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

地图中国界线与经纬线关系表示方法探究

国界线是地图中的重要内容。经纬线不仅用于确定位置和方向,也用于国家之间划分国界线。地图上绘制国界线不仅要遵循相关法规、条约及标准,还应当正确处理好国界线与经纬线的关系。本文通过介绍地图中绘制国界线的依据,重点梳理国界线与经纬线关系容易出错的几个重点区域,对相关地图编制和地图审查部门起到一定的借鉴作用。     

Simultaneous determination of gravitational acceleration and ground vibrations by free fall experiments

We investigated how well we can simultaneously determine the gravitational acceleration and ground vibrations with many free falls at short intervals by using synthetic data which contain quadratic functions, sinusoids and white noise in order to improve the accuracy of absolute gravimetry and to realize the measurements without a seismometer. As a result of simulations, lower white noise, longer dropping time and longer duration of a series of free falls improve the accuracy in determination of g. The sampling internvals and the dropping intervals, on the other hand, hardly affect the accuracy so long as they are shorter than Nyquist intervals. Both the gravitational acceleration and the waveform of the long period vibrations can be well determined with a series of free falls of about only 2 cm dropping distance without deterioration in the accuracy with this procedure.     

导线加测陀螺方位角的过程简化探讨

针对地下陀螺定向时间较长、作业强度大、陀螺仪电量等问题,现就陀螺仪传统测量过程（主要是逆转点法）提出简化.通过已知坐标反算操作获得粗北方向的方法取代传统的粗定向过程,可以大大提高定向效率和经济效益,并且能够节省电池电量、节省作业人员体力.文中对比新旧方法在寻找粗北方向的测量结果,从而分析方法的可行性.     

THE THEORY AND APPLICATION OF THE STRUCTURE LIGHT ENGINEERING SURVEYING BASED ON A LASER THEODOLITE WITH THREE FREEDOMS OF ROTATION

1　ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｏｕｒｃｏｕｎｔｒｙ ,ｔｈｅｓｕｒｖｅｙｉｎｇｗｏｒｋｏｎｉｎｄｕｓｔｒｉａｌｏｂｊｅｃｔｓｈａｖｅ ｇｒａｄｕａｌｌｙｉｎｃｒｅａｓｅｄ .Ｔｈｏｓｅｉｎｄｕｓｔｒｉａｌｏｂｊｅｃｔｓｉｎｃｌｕｄｅｒａｉｌｗａｙａｎｄｈｉｇｈｗａｙｔｕｎｎｅｌｓ,ｖａｒｉ ｏｕｓｏｉｌａｎｄｇａｓｃａｎｓ ,ｖａｒｉｏｕｓａｉｒｃｒａｆｔ,ｓｈｅｌｌｏｆｃａｒｓ,ｌａｒｇｅｍｉｌｉｔａｒｙａｎｔｅｎｎａｕｓｅｄｆｏｒｓｃｏｕｔｉｎｇｓｔｅａｌｔｈｐｌａｎｅ ,ｓｈｉｐ ,ｉｎｔｅｒｎａｌｓｔ…     

The theory and application of the structure light engineering surveying based on a laser theodolite with three freedoms of rotation

The concepts of “confining structure” and structure light are illuminated in this paper. A laser theodolite with three freedoms of rotation, which is aimed at “confining structure”, is developed. Various scanning modes and their mathematical models based on laser theodolite with three freedoms of rotation are discussed. According to the features of a huge object the structure light engineering surveying based on laser theodolite with three freedoms of rotation is determined as the main method in an actual application. The observation of four sound concrete posts and forced centering plates. Subsequently, it is transformed into the huge object coordinate system. The scanning mode with plumb plane is selected as the main mode in the whole work. And other assistant methods, such as close range photogrammetry and the method of using reflection sheet, are applied to the work of “scanning dead angle”. At last, a surveying accuracy estimation of this method is done and a surveying accuracy test is finished. It can be concluded that the structure light engineering surveying based on laser theodolite with three freedoms of rotation is considered to be an effective and applied method, and has many superiority to some other surveying methods in the work of surveying “confining structure”.     

提高陀螺经纬仪定向效率的方法

采用室内经常检测仪器常数,使用AGT-1高精度自动陀螺经纬仪,将GAK-1等仪器改造成高精度自动陀螺经纬仪以及修订定向测量规程等方法,可以大大提高定向效率和经济效益。     

Calibrating the GOCE accelerations with star sensor data and a global gravity field model

A reliable and accurate gradiometer calibration is essential for the scientific return of the gravity field and steady-state ocean circulation explorer (GOCE) mission. This paper describes a new method for external calibration of the GOCE gradiometer accelerations. A global gravity field model in combination with star sensor quaternions is used to compute reference differential accelerations, which may be used to estimate various combinations of gradiometer scale factors, internal gradiometer misalignments and misalignments between star sensor and gradiometer. In many aspects, the new method is complementary to the GOCE in-flight calibration. In contrast to the in-flight calibration, which requires a satellite-shaking phase, the new method uses data from the nominal measurement phases. The results of a simulation study show that gradiometer scale factors can be estimated on a weekly basis with accuracies better than 2 × 10⁻³ for the ultrasensitive and 10⁻² for the less sensitive axes, which is compatible with the requirements of the gravity gradient error. Based on a 58-day data set, scale factors are found that can reduce the errors of the in-flight-calibrated measurements. The elements of the complete inverse calibration matrix, representing both the internal gradiometer misalignments and scale factors, can be estimated with accuracies in general better than 10⁻³.     

辅助纬度与大地纬度间的无穷展开

利用无穷级数理论和拉格朗日反演定理,详细推导了大地测量和制图学中常用的辅助纬度与大地纬度间的无穷展开,主要表现为参考椭球第一偏心率的幂级数形式。通过建立一系列严格的系数递推公式,得到了等量纬度反解展开式和等角纬度反解展开式;同时,推导了古德曼函数的泰勒展开式,进而得到了等角纬度正解展开式;利用级数除法公式,得到了等距离纬度正解展开式系数的行列式表示。通过比较本文方法与计算机代数系统Mathematica直接推导求得的辅助纬度正反解展开式e^0～e⁴⁰阶系数和相应的程序用时,表明本文算法是正确的、快速的。以CGCS2000参考椭球为例,对辅助纬度正反解进行了算例分析,也进一步验证了本文公式的正确性。