a) Resolving modulation Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. View Answer, 3. Used with survey and 3D point monitoring systems to measure changes in elevation and position of a point. Electronic Distance Measurement (EDM) is a fundamental feature of modern surveying Total Stations. The first commercial unit, serial number 151, was unveiled in 1961. •Modern EDM’s use the precision of a Quartz Crystal Oscillator and the measurement of phase-shift to determine the distance. View Answer. Inscriptions: "TELLUROMETER" Discussion: The first successful microwave EDM was invented by Col. Harry A. Baumann of the South African Trigonometrical Survey, developed by Trevor Lloyd Wadley of the Telecommunications Research Laboratory of the South African Council for Scientific and Industrial Research (CSIR), and … I, The Almanac, Time to First Fix and Satellite Health, Spread Spectrum and Code Modulation of L1 GPS Carrier, Imperfect Oscillators and Clock Corrections, Lesson 6: State Plane Coordinates and Heights, Lesson 7: Static Global Positioning System Surveying, Lesson 8: Real-Time Global Positioning System Surveying, Lesson 10: Global Navigation Satellite Systems and the Future, Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, Department of Energy and Mineral Engineering, Department of Materials Science and Engineering, Department of Meteorology and Atmospheric Science, Earth and Environmental Systems Institute, iMPS in Renewable Energy and Sustainability Policy Program Office, BA in Energy and Sustainability Policy Program Office, 2217 Earth and Engineering Sciences Building, University Park, Pennsylvania 16802. Please send comments or suggestions on accessibility to the site editor. Distance is measured as a function of the speed of light, an electromagnetic signal of stable frequency and elapsed time. View Answer, 4. To understand the full scope of surveying, you … In Figure 6.14, if α is 2 0 30’ and the slope distance is 5,604.32 ft. what is the horizontal distance? Frequency modulation is equipped in all EDM instruments. c) 7.5*106 to 5.9*108 Hz The typical Total Station EDM can measure distances accurate to about 0.1 millimeter or 1/1000 foot, but most land surveying applications only take distance measurements to 1.0 mm or … Cyclic error is usually sinusoidal in nature with a wavelength equal to the unit length of the EDM. If 10mm is the accuracy considered, what will be the maximum value of λ for 1/1000 part? d) Wavelength, frequency The Pennsylvania State University © 2020, GPS and GNSS for Geospatial Professionals. Lower frequency is not suitable in_________ Area Computation & Tacheometric Surveying, Geographic Information System & Topographic Maps, here is complete set of 1000+ Multiple Choice Questions and Answers, Prev - Surveying Questions and Answers – EDM – Electromagnetic Waves, Next - Surveying Questions and Answers – Types of EDM Instruments, Surveying Questions and Answers – EDM – Electromagnetic Waves, Surveying Questions and Answers – Types of EDM Instruments, Analytical Instrumentation Questions and Answers, Electrical Measurements Questions and Answers, Digital Communication Questions and Answers, Linear Integrated Circuits Questions and Answers, Microwave Engineering Questions and Answers, Electromagnetic Theory Questions and Answers, Electronic Devices and Circuits Questions and Answers, Engineering Physics II Questions and Answers, Wireless & Mobile Communications Questions & Answers, Optical Communications Questions and Answers, Analog Communications Questions and Answers, Surveying Questions and Answers – Remote Sensing – Electromagnetic Energy, Wireless & Mobile Communications Questions & Answers – Linear Modulation Techniques. View Answer, 8. For example, if the EDM sends out a wavelength of 100 meters, then by looking at the fractional part of that 100-meter wavelength, it would be possible to determine the tens of meters in the distance. Distance measurement in modern surveying is done electronically. Edm is a surveying instrument used to measure the distance electronically. c) Super wave d) 10000 cm as Amplitude Modulation (AM). EDM (Tellurometer M/RA 1) Catalogue number: 1996.0200.01. c) Determination of wavelength The principle of the measurement device in EDM, which is currently used in a total station and used along with electronic/optic theodolites, is that it calculates the distance by measuring the phase shift during the radiated electromagnetic wave (such as infrared light or laser light or microwave) from the EDM’s main unit, which returns by being reflected through the reflector, which is positioned at a measurement … The instrument sends out a beam of light or high frequency microwaves from one end of line to be measured, and directs it towards the far end of the line. The phase angle ( ) of the modulated wave can be detected by electronics in the EDM. a) Phase comparison With Micro-Dist, however, the two units were interchangeable. The amplitude of the solid Earth tide varies over a fortnightly (2-wk) cycle, as the sun and moon change their relative positions in the sky. Contact Us, Privacy & Legal Statements | Copyright Information Frequencies generated within an electronic distance measuring device (EDM) can be used to determine the elapsed travel time of its signal, because the signal bounces off a reflector (aka corner cube) and returns to where it started. For use, two units were needed, one to send the signal and the other to receive it. All Rights Reserved. View Answer. a) Frequency, time period (NSW Legislation, 2014a) and the Surveying and Spatial Information Regulation 2012 (NSW Legislation, 2014b). a) Direct transmission Join our social networks below and stay updated with latest contests, videos, internships and jobs! b) Resolving amplitude An EDM only needs one oscillator at the point of origin, because its electromagnetic wave travels to a retroprism and is reflected back to its origination. Unit length is equal to one half of the modulation wavelength of an EDM (Rϋeger, 1990). c) Amplitude, wavelength They are reflected at the point up to which distance is to be measured from the instrument … Araen S. Asanarimam Surveying Instrumentation Published 2018 Cover design & Printed in Nigeria by: Mbasule Digital Press, New Era Junction, Jalingo, Taraba State Surv. This cyclic stressing can promote or inhibit fault slip, particularly at the deep roots of faults. A reflector or transmitter receiver at the far end reflects the light or d) Incubation wave a) 10000 m The John A. Dutton e-Education Institute is the learning design unit of the College of Earth and Mineral Sciences at The Pennsylvania State University. Participate in the Sanfoundry Certification contest to get free Certificate of Merit. 1. c) Distance measurement The content of this document is based on existing literature in the field, many years of practical experience of the authors in EDM calibration and on Distance is measured as a function of the speed of light, an electromagnetic signal of stable frequency and elapsed time. c) Resolving frequency It yielded centimeter accuracy over distances from 100 meters to 40 kilometers, and in all weather conditions, day and night. The sun and moon exert a gravitational tug on Earth that stretches and compresses crustal rocks. A total station ( TS) or total station theodolite ( TST) is an electronic/optical instrument used for surveying and building construction. The fundamental elements of the calculation of the distance measured by an EDM, ρ, are the time elapsed between transmission and reception of the signal, Δt, and the speed of light, c. Author and/or Instructor: Jan Van Sickle, Senior Lecturer, John A. Dutton e-Education Institute, College of Earth and Mineral Sciences, The Pennsylvania State University; V3 Consultants, Lakewood, CO. In 1956 – Ordnance Survey – Geodimeter 4 - 299 792.4km/s ±0.5. It is a two-way system, but the EDM is both the transmitter and the receiver of the signal. Modulating wave can also be known as ______ • Measurement of distance is accomplished with a modulated microwave or infrared carrier signal, generated by a small solid-state emitter within the instrument's optical path, and bounced off of the object to be measured. The site editor may also be contacted with questions or comments about this Open Educational Resource.