1988 Vol. 13, No. 3
In order to meet the requirements in practical work, this paper proposes a laser traverse system, which can be used to measure the displacements of arch dams or curved structures. The paper discusses in much detail the principles of the system, the design concept of bend-angle prisms, the effect of the errom in installation of the prisms on the accuracy of determining variation of angles of bend, the observation method of the system, and the computation of the displacements of arch dams.
In this paper, the main errors of gyrotheodolite observation data are analyzed. The variance component models of gyrotheodolite observation errors are discussed in the light of Markov stochastic process theory. Finally the practical examples are computed.
This paper discusses the fundamental and data preparation in digital geometric rectification for Spacelab images by using colinearity equations, the determination of the parameters in the calculation of the exterior elements, the flexibility and rectification accuracy of the "Anchor Points Rectification Approach", and several important steps in the rectification procedure for higher accuracy and the shorter CPU time.This paper also introduces the composition of the software package concerning the rectification.
This paper first introduces three basic models——the ARMA model, the AR model and the MA model in the time series analysis and their statistical properties. Taking the absolute displacements of a large dam in the western of China as an example, the paper puts the emphasis on the procedure of the establishment of the model for deformation analysis of the large dam, An AR(2) model has been built and used in the prediction of deformations.The result shows good prediction accuracy. Compared with the stepwise regression analysis, it is of better accuracy. Therefore, if the regression factors have not been observed, the method mentioned in this paper will show its advantages in deformation. analysis.
This paper derives a formula of adjustment computation and precision estimation in the condition group adjustment with constraints. From these methods, it derives the formulas of adjustment computation and precision estimation in other group adjustment methods——the condition group adjustment with parameters, the condition group adjustment without parameters, the parameter group adjustment with constraints, and parameter adjustment in phases.
The paper discusses the periodicity the computation formulas and the range of values relating to the effects of new astronomical constants and system on the star apparent positions. The effects of new astronomical constants and system on astronomical latitude, longitude and azimuth for one class astronomical determination have been estimated. The conclusion is that the effects conld be neglected for the abservations make at any time of year.
This paper presents an algorithm for the automation of cartographic construction of equidistance lines. The organizational structure of the digital data and unique characteristics of the application program are highlighted. Some working cases are provided to illustrate the results of this pioneering effort.
Fabric inspection plays a significant part in the textile industry, but it can not be done automatically yet, because the full number of defect fault is large and the defect cannot be inspected easily.In this paper, the defect fault information has been transformed by an optical system, sampled by a wedge/ring detector and then classified by a computer by using the pattern recognition theory. We have obtained a good result in our experiment.
It has been proved very effective to calculate the non-coaxial optical system by using coordinate system transformation, The paper discusses the essentials in calculating the Optical Transfer Funetion (OTF) of the non-coaxial optical system and gives the calculation method for the Optical Transfer Function of the collimated beam. The Optical Transfer Function of an afocal optical system is also calculated.
On the basis of reference, the paper presents a linear biased estimation, which is called the corrective estimation of pseudo-inverse adjustment of rank-defect net of unknown parameter vectors in the model of rank-defect surveying adjustment with weight. It also discusses in great detail the superiority, admissibility and new bias of the estimation in improving the results of least squares adjustment in terms of the mean squared error. Finally, the results mentioned above are tested by an example.
This paper first introduces the principle of the algorithm——orthogonal-Trhngular Decomposition (OTD). Then it discusses some problems encountered when using OTD in bundIe adjustment with special reference to the characteristics of the design matrix. One of the obvious advantages of OTD is the good solution of the problem "strict and fast calculation of redundancy bunrbers", which has hitherto aroused much attention. OTD has greatly simplified the calculation of Qⅴⅴ elements. It is superior to the other algorithms in numerical stability and calculation time. The results of a set of tests show that the OTD is a valuable algorithm.