1991 Vol. 16, No. 1
There are more and more data available to physical geodesy,e.g.,gravimetric data,satellite altimetric data,satellite gradiometric data,GPS data and data of the deflection of the vertical.Thus arises the overdetermined boundary value problem.In view of this situation,the authors have made an investigation into the difference method for the overdetermined boundary value problem in this paper.
This paper introduces the laser alignment measurement applied to the installation of the Linac of Beijing Electron-Positron Collider(BEPC),and describes nylon line alignment measurement and precision level measurement used for checking and adjusting the results of the laser alignment measurement.In addition,the accuracy for the above-described measurement is also discused.
This system,by making use of the digitizing table and the sterocomparator for data input,designs a simple structure for the topographic data,and solves such problems as blunder detection,on-line editing,and graphic monitoring.So,this system can provide the Digital Mapping System with correct and integrated data.
This paper,by analysing the maps of physical conditions,studies the theories and methods of the combined analysis of isoline maps and quality feature maps.Deep researches have been made into the samplins methods and size and arrangement of samples of simulating geographycal phenomena on the maps of different properties and expressions.Especially,the fuzzy evaluation and fuzzy cluster have been introduced into the information acquisition and processing.Trial for regions of agricultural climate types has proved the result is correct and is able to be used in practice also.It shows that fuzzy mathematics has a unique advantage in the combined analysis of maps of different properties and expressions.
According to the reliability theory of control networks,this paper discusses the reliability design of networks.On the basis of the consideration of precision Reliability and cost,the general mathematical model of Second-Order Design for linear-angular networks is given here by linear programming method.Finally,by three design examples,the general method of Second-Order Design is illustrated in detail for the distance network direction network and combined linear-angular network.
In this paper,the State-Space method is used in the study of recursive Adaptive Digital Filter(ADF).The coefficient sensitivity is introduced to evaluate the performance of ADF,and the balanced structure and symmetric structure ADF are proposed from the viewpoint of low sensitivity.The computer simulation is also presented.
In this paper,factor analysis,when being used for classification,is compared with classification analysis under four situations.Some connections and differences between the two methods are found out and three inequalities which restrict the differences are deduced.Theroretical proof is given here to some facts which were felt true.
The synthetic fracture criteria is based on the normal-stress,shearing-stress and the impact of plastic area.The new fracture criteria is proposed here to replace the one where only the singular term is considered.The conditions of application of the synthetic fracture criteria to the mixed mode crack problems have been given by the analysis and comparison between the theoretical solutions and experiment results.The result that is used in conjunction with the synthetic fracture criteria for problem of I-I mixed mode state is satisfying.
Methods for GPS data processing with carrier phase observations are dealt with in this paper.There are some relationships existing among these processing methods.The equivalent conditions for eliminating nuisance parameters are further extended to fit centralized undifferential method as well as various differential methods.Based on these conditions,the equivalence is proved among original undifferential method,differential method centralized undifferential method and Goad undifferential method.Finally,after a review of GPS data processing method,some conclusions are made and they should be useful to various GPS applications for selecting suitable method in data processing.
This paper,after revealing the problems existing in polynomial adjustment introduces the polynomial adjustment with collinearity condition(PACC) to improve the method used,and analyses the mathematic model of PACC,the structure and solution of its normal equation in detail.Finally,the experiment is undertaken by using this method with a group of practical data.The result shows that the method not only has the advantages of being simple in computation and requiring less memory,but also offers higher adjustment accuracy.
This paper takes the application study of remote sensing and GIS in the comprehensive development planning in Hongshan district,Wuhan city,as an example to describe the characteristics of being complicated and dynamic in an urban system.The use and the advantage of aerial remote sensing for urban survey and the applications of GIS for diagnosis,analysis,evaluation,planning and management of an urban system are also discussed.The emphasis is put on the spatial planning based on system engineering and the rationality of land use.
To improve the precision of terrestrial networks by using high precision results of GPS positioning,it is at first necessary to choose an appropriate model for the transformation between different coordinate systems.A planimetric rectangular coordinate system is usually used for engineering surveying(e.g.city and mine control survey etc.) starating from the fundamental formulae of Gauss comformal projection,therefore,the transformation relation between satellite and terrestrial networks is established to provide a necessary mathematical relation for the combined adjustment of satellite and terretrial networks in Gauss planimetric coordinate system.