Accession Number : AD0638173

Title :   GROUND REFLECTION PROBLEMS IN TELLUROMETER MEASUREMENTS.

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Tzitchung,Sha ; Sih-an,La

Report Date : 31 MAY 1966

Pagination or Media Count : 41

Abstract : Based on the electronic principle of the tellurometer, a general formula for the phase deviation caused by ground reflection is derived in this paper and the reasons for the measurement errors and figure distortions explained. Combining actual experience and experimental results, the relationship between the distance difference in the surveying line, the reflection coefficient, the reflection area and ground reflection was analyzed. From this analysis, a principle in selecting the surveying line for plateaus and hilly areas was proposed. In studying the methods for minimizing the influence of ground reflection, the techniques of lowering the height of the instrument and the insertion of a metallic net-like shield were thoroughly discussed. Experimental results were cited. Based on theory and actual results, the influence of ground reflection could be greatly reduced by a judicious choice of a surveying line in combination with suitable techniques. Also investigated was the method of correcting the ground reflection curve of flat lands. The method was shown to have a definite practical significance in distance measurements where a higher accuracy is demanded and the distance difference and the reflection coefficient can easily be obtained (e.g., the determination of the zero point). A few actual examples and some tables are given as convenient references for practical work. (Author)

Descriptors :   (*DISTANCE MEASURING EQUIPMENT, ELECTRONIC EQUIPMENT), (*SURVEYING(GEOGRAPHIC), ELECTRONIC EQUIPMENT), ERRORS, RADIO WAVES, ELECTROMAGNETIC WAVE REFLECTIONS, TERRAIN, CHINA

Subject Categories : Geodesy
      Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE