Kısa boyların elektro-optik uzaklık ölçerlerle ölçülmesinde presizyon araştırması

Abstract

Bu çalışmada; kısa boyların elektro-optik uzaklık öl çerlerle ölçülmesinde ölçme, hesaplama, kalibrasyon yöntem leri ile ölçmelerin presizyonlarının hesaplanması araştırıl maktadır. Çalışmanın I. bölümünde; elektro-optik uzaklık ölçerle rin çalışma ve ölçme ilkeleri incelenmekte ve bu tip alet lerle ölçülen kısa boyların hesap yüzeyine indirgenmesinin matematik modeli çıkarılmaktadır. II. Bölümde, elektro-optik uzaklık ölçmelerinde oluşan hatalar incelenmiş ve bu hatalara bağlı olarak bir ölçmenin karesel ortalama hata eşitliği verilmiştir. Ayrıca kırılma indisi eşitliği irdelenerek, en uygun atmosferik koşullarda kırılma indisi karesel ortalama hatasının ± 1.10 oranında olabileceği gösterilmiştir. III. Bölümde, elektro-optik uzaklık ölçerlerin kalib rasyon yöntemleri araştırılmaktadır.Şimdiye kadar uygulanan laboratuar ölçemeleriyle kalibrasyon ve arazi ölçmeleriyle II kalibrasyon yöntemlerinin matematik modelleri verilmektedir. IV. Bölümde, DI3 (Wild),AutoRanger (Keuffel and Esser) elektro-optik uzaklık ölçerleriyle: Laboratuarda oluşturulan kısa bazda ve arazide ise Schwendener tipi [ö] kontrol ke narında ve ayrıca B.Witte,H.Fröhlich tipi [lO] kontrol kena rında kalibrasyon ölçmeleri yapılıp değerlendirilmekte ve yön temler karşılaştırılmaktadır. Ölçmelerin okuma ve yöneltme ka- resel ortalama hatalarının hesaplanmasının matematik modeli ve r i lmek t ed ir. V.Bölüm ise,elde edilen sonuçları ve önerileri içermekte dir.

In this research measurement, computation and calibra tion methods of measuring short ranges by electro-optical distance measurement instruments are investigated. Besides the computation precision of measurements are searched throughly. In the first part the functioning and measurement principles of electro-optical distance measurement instru ments are given. Besides these the properties of the carrier waves and modulation waves, their derivation, methods of measuring phase difference of the electro -optical distance measurement istruments are given. Starting from these the mathematical relationship to derive a distance is stipulated, Following these instrumental phenomena for short ranges measured by this brand of instruments the mathematical model of reducing them to the reference surface is derived. In the second part the error that occured during measu rement by electro-optical distance measurement instruments II have been investigated. The mean error of a measurement is given as the sum of two components one of which is inde pendent of the measured range while the other is dependent of the measured ange. Besides these geometrical correction error, centering error, additive constant error, phase me asuring error, pointing error, the error of velocity of lights in vacuo, refractive index error and modulation frequency error were investigated seperately and their formation, characteristics, their effects were discussed. Under various atmospheric conditions for various carrier waves it was shown as a result of the errors of measuring temperature and atmospherical pressure the mean square error of the refrac tive index would be of the order 1.10 under typical conditions. In the third part of this work the methods of calibrati on of these brand of instruments are investigated. Calibra tion methods may be grouped under two headings: 1- Calibration in the laboratory 2- Calibration in the field Modulation frequencies may be found by frequency coun ters in the laboratory end the calibration of the additive constant end phase difference measurement may be done in Ill short bases in the laboratory. The formation of such bases and the mathematical model of evaluation of these measurements are given. In the field calibration may be done by section and intersection methods. For the formation of calibration Lines where the measurement of additive constant and measurement of phase difference may be done jointly for undertaking ca libration measurements, along calibration lines and for eva luation of measurements the most appropriate mathematical model is given. It was shown that this was the best method of determining the mean square error of range measurements. In the fourth part, starting from the measurement done on the short base formed in the Laboratory calibration mea surements were done and evaluated; methods of calibration were compared. In the field the same deeds were carried on calibration lines of the type H.R. Schwendener,B.Witte and H.Fröhlich. Measurements in the laboratory and in the field were carried by DI3 (Wild) and AutoRanger (Kueffel and Esser) electro-optical distance measurement instrument. From the measurement done on the short base formed in the laboratory it was found that the function of phase IV difference measurement is given by the following trigonomet rical functions for the two instruments used throughout this study: For DI3 -2.15[mm].sin(A^+23?13)± 0.22[mm] For AutoRanger 2.13[mm].sin (A^-43?42)±0.35[mm] For the mean square error of a single reading the follo wing values were found for the two instruments: For DI3 ±0.90 [mm] For AutoRanger ±0.53 [mm] From the measurements done on the calibration lines for med in the field it was not possible to determine the func tion of phase difference measurement in a reliable way. I t was found that DI3 did not have an additive constant and for the additive constant of the AutoRanger the following walue was found: K =4. 2 [mm] ±1.3 [mm] It was determined that the additive constants of the two instruments did not depend on the range in a significant way. From field measurements it was found that the reading and pointing mean square error has the following walues for the two instruments: V For DI3 ±1.6 [mm] For AutoRanger ±2.1 [mm] By comparing the results thus obtained it was found that the additive constant and the function of phase diffe rence measurement may be taken following two trigonometri cal functions for the two instruments: For DI3 F [nım]=-2.05.sin(Aı|;+23fl3)±0.4 [nmi] For AutoRanger F [rnm]=4. 2+2.13.sin(Ai];-43?42)±1.3[mm] Z r Z It was demonstrated that to correct the measurements by using the abowe stated trigonometric functions bettered the results. In the fifth part results are given and propositions are explained as for as the subject matter of this thesis is concerned. The random component of the mean square error of a measu rement is composed of reading mean square error, pointing mean square error, centering mean square error, geometrical reduction mean square error and refractive index mean square error. These mean square errors may be controlled by the num ber of measurements. To this end the number of measurements made in one setting of the instrument by independend pointings, and in a range the number of setting the instrument under VI different atmospheric conditions should be determined. The systematic component of the mean square error of a measurement should be determined by calibration. The function of phase difference measurement should be determined at the short bases formed in the laboratory. In calibration lines of the type B.Witte and H.Fröhlich the determination of the additive constant is depended on the closeness of the phase of the function of phase diffe rence measurement to zero. If the function of phase diffe rence measurements has forward and backward phases, then the measurement of calibration lines should be corrected accor ding to this. The reliability and the precision of the additive cons tant computed from the corrected measurements in line with the function of phase difference measurement determined at the calibration line of the type B.Witte, H.Fröhlich type are close to the one computed at the calibration line of the type H.C.Schwendener.