1983 Vol. 8, No. 2
Das Ziel der vorliegenden Arbeit besteht darin,dass die wahre Genauigkeit der Nivellementslinie I.O.mit Hilfe von den zahlreichen Daien des wiederholungsnivellements durch Statistik untersucht wird.Man findet heraus,dass die Genauigkeit des Nivellemenis I.O.nicht nur von der Lvnge der Nivellementslinie L,sondern auch von dem Höhenunterschied H abhängt.Bei den Gewichtsannahmen müssen deshalb die zwei Faktoren L,H in Betracht ziehen.Im Hinblick auf die Schwierigkeiten,die Gunstigkeit der Gewichtsannahmen durch den Vergleich von Ausgleichungsergebnissen zu beurteilen,empfiehlt der Autor,die Gewichismatrix der Beobachtungsgrosse anhand der vorhandenen Kenntnise der Nivellementsfehler zu bestimmen.
In den vielen Ländern,z.B.in China,Sowjetunion,Spanien,Portugal,Schweden and Finnland usw.,Sind die Hauptdreiecksnetze erster Orjnung von den Dreiecksketten gebildet.Deshalb ist es von groβer Bedeutung,dieser bestehenden Dreiecksketten durch die Kombination verschiedenartiger geodätischer Daten zu optimieren.In der vorliegenden Arbeit werden numerisch die Einflüsse,die durch die Änderung der Beobachtungsgenauigkeit and Dichte der zusätzlichen gemessenen Strecken,Azimute and Doppler-Punkte entstanden Bind,auf die Genauigkeit der ausgeglichenen Dreieckskette untersucht.Daraus sind einige für die Optimierung einer Dreieckskette wichtige Schlüsse gezogen.
A new software package of Doppler positioning using semi-short-arc method is introduced in this paper.It is composed of two parts,which are pre-processing program DPPPP and adjustment program AODPP,with a series of new functions.This package is to be applied to the data processing of Doppler positioning for higher efficiency and better results.
The estimation of the correlation coefficient between the adjacent misclosures in an extensive triangulation chain is firstly discussed.Then the effect of the centring errors on triangle misclosure is investigated,and the result is applied to the Jst order triangulation chain in China.The following conclusions are drawn:1) Under the general condition,for the practical purposes,the correlation coefficient ρ△ between adjacent misclosures can be estimated by using the formula rp=(wiwi+i)/m/(wi2)/n,in which wi is the triangle misclosure,m is the number of products of all adjacent triangle misclosures and n the number of wi.2) The effect of the centring errors is usually very small and can be neglected.
In this Paper,an experiment on a small computer for making orthophoto maps by the method of digital rectification is described.The main characteristics of this experiment are:1,the fiducial marks are searched automatically by the computer for the inner orientation;2,the terrestrial coordinate system has been turned with an angle k,thus the requirement for the computer memory is reduced;3,measure are taken to considerably simplify the computation of the collinear equation and the bilinear interpolation formula.Experimental results have shown that digital rectification can be used for producing high quality large scall orthophoto maps in mountainous area.
In this paper the experimental planimetric accuracy through performing geometric processing of three strips of Synthetic Aperture Side-looking Radar(SAR) imagery is reported,and the prospects for mapping medium and small scale maps are analyzed.The proposed method of solution has been procceeded in two stages,In the first stage,coordinates of the imagery of SAR are reduced to ground coordinates,they include the corrections of slant-to-ground rang reduction,along-track coordinates,relief displacements and earth curvature.Then,the reduced coordinates are transformed to geodetic coordinates with the help of a well distributed control points.The RMS errors in position at imagery scale computed from 158 check points are mx=0.09mm my=0.08mm ms=0.12mm The accuracy meets with the requirements of maps at a scale of 1:50000,also with ones of 1:25000 for remote areas.The results obtained herein are also tested by the author by using Derenyi and Leberl's high power polynomials.But the best one occures when the polynomials are limited to the second power without y2 term.Hence the second power polynomial is taken to represent the law of radar systematic distortion.From the exprimental results and the theoretical analysis it is shown that the removal of the adverse effect of relief displacement can increase the accuracy remarkably.This is specially important for radar imagery.It is recommended that dividing the strip imagery into sections is a way to improve its accuracy.
This paper mainly investigates the theoretical problem of all-symmetric system with respect to its magnification change ratio,ideal optical formulas and computational techniques of reduction and enlargment ratio.Half of the all-symmetric system is a three-element structure with the arrangment of"-.+.-".The commutative principle of the object and image is adopted in the variable magnification lens group.This theory is applicable to the design of the zoom for the all-symmetric type and apochromatic reproduction camera objective lens,the transversal magnification of which is -1x.This paper mainly discusses the distribution of power and gives a numerical example of power distribution of the apochromatic reproduction camera objective lens with second-order zoom,which can satisfy the field-flattening and apochromatism,and in the meantime meet the requirements of the end values of both long and short focal lengths ranging from 600 to 450 mm.
It has been considered that the image compensation displacement caused by swinging of compensator is equal to the sum of the object swing and image swing around the centre of the pendulum.Based upon this new concept,a mathematical model for the self-levelling compensation function has been presented.As a consequence,the consistency in principle between the"turning" and"parallel displacement" modes,which are admittedly deemed to be traditional in the theory of automatic level,has been obtained.The model has also made it possible to provide a simple and general method for the calculation of compensation function for various types of compensators.
This paper is a further research for automatic generalization of contour lines in sets on the basis of reference No..In the example of relief generalization by using valley line,the following key points are discussed:The algorithm of selecting skeletons by using distances between valley lines,the approach of modification for the heights of interpolates points,the use of supplemental points in tracking and adjustment of skeletons,etc.