modulation of edm in surveying

Distance measurement in modern surveying is done electronically. EDM instruments are highly reliable and convenient pieces of surveying equipment and can be used to measure distances of up to 100 kilometers. This set of Surveying Multiple Choice Questions & Answers (MCQs) focuses on “EDM – Modulation”. Except where otherwise noted, content on this site is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Their range can be up to 30 km. To practice all areas of Surveying, here is complete set of 1000+ Multiple Choice Questions and Answers. The calibrated distance, in this case, is the wavelength of the modulation on a carrier wave. View Answer, 6. This Surveying Instrument is used in triangulation to measure the length of Base line because more accuracy is required to measure the length of base line. (NSW Legislation, 2014a) and the Surveying and Spatial Information Regulation 2012 (NSW Legislation, 2014b). 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. Modern phase techniques are capable of __________ c) Amplitude, wavelength Here the electronic distance measuring equipment and a reflector are necessary to carry out the survey. Example: if =135o then this would represent a) True d) 10000 cm • Setting out a chain line as part of a chain and offset survey to carry out, for example, detail mapping. Classification of Traverse (Based on accuracy & Based on Instrument used ): EDM (Electrotape) Catalogue number: 1996.0195.01 ... Like the Tellurometer, Micro-Dist used data compression by means of modulation side-band folding. 2217 Earth and Engineering Sciences Building, University Park, Pennsylvania 16802 b) Super imposition of waves It yielded centimeter accuracy over distances from 100 meters to 40 kilometers, and in all weather conditions, day and night. For many EDM instruments, an accuracy in measurement between 1 and 10 mm is specified at short ranges, and a phase resolution of 1 in 10,000 is normal. View Answer, 3. With an EDM, wavelengths of varying length can be sent out. b) Frequency 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. The first edition was published in 1978 by the School of Surveying, Universi­ ty of New South Wales, Sydney, Australia. Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves. d) Wavelength, frequency The modulation pattern in the returning signal is read and interpreted by the onboard computer in the EDM. The unit length is the scale on which the EDM measures the distance, and is derived from the fine measuring frequency. The EDM is set up at one end of the distance to be measured and a reflector at the other end. The first commercial unit, serial number 151, was unveiled in 1961. In traverse a number of connected survey lines form a framework of survey. View Answer, 8. The Electrotape DM-20 is a transistorized microwave EDM. a) Frequency, time period 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. c) Super wave View Answer. 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. a) Modulation b) False Join our social networks below and stay updated with latest contests, videos, internships and jobs! In amplitude modulation, which among the following is constant? View Answer, 4. Participate in the Sanfoundry Certification contest to get free Certificate of Merit. In general terms, the instrument can take half the time elapsed between the moment of transmission and the moment of reception, multiply by the speed of light, and find the distance between itself and the retroprism (Distance = Elapsed Time x Rate). This courseware module is part of Penn State's College of Earth and Mineral Sciences' OER Initiative. Cyclic error is usually sinusoidal in nature with a wavelength equal to the unit length of the EDM. 1. 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 … Each piece of EDM equipment available at Engineer … EDM is commonly carried out with digital instruments called theodolites. The sun and moon exert a gravitational tug on Earth that stretches and compresses crustal rocks. 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. 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. An EDM has a modulation frequency of 15 MHz that provides a wavelength of 65 ft. 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. •Modern EDM’s use the precision of a Quartz Crystal Oscillator and the measurement of phase-shift to determine the distance. 6. d) 7.5*106 to 5*108 Hz as Amplitude Modulation (AM). Explanation: In frequency modulation, the carrier wave has constant amplitude and frequency varies in proportion to the amplitude of the modulating wave. The site editor may also be contacted with questions or comments about this Open Educational Resource. Frequency modulation is used in all EDM instruments, while amplitude modulation is done in … 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. A total station ( TS) or total station theodolite ( TST) is an electronic/optical instrument used for surveying and building construction. In 1957, the XIIth General Assembly of the International Scientific Radio Union recommended that the best available value for the velocity of electromagnetic waves in vacuum was : 299 792.5km/s ±0.4km/s. View Answer, 9. With Micro-Dist, however, the two units were interchangeable. Surveying Instrumentation Surv. Like its predecessors, this totally revised third edition is designed to make the subject matter more readily available to students proceeding to degrees in Survey­ ing and related fields. 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 … In 1957 – Froome – Microwave interferometer – 299 792.5km/s ±0.10. a) Direct transmission d) Wavelength measurement Which of the following is constant in the case of frequency modulation? On the signal's return, the EDM can analyze it and determine the distance. The lowermost portion also isslustrates the ideal of modulation of the carrier wave by the measuring wave. Direct Reflex EDM Technology for the Surveyor and Civil Engineer R. Höglund & P. Large, Trimble Integrated Surveying Group, Westminster, Colorado, USA The latest technology to revolutionize the surveying industry is direct reflex measurement, electromagnetic distance measurement without cooperative targets or prisms. If 10mm is the accuracy considered, what will be the maximum value of λ for 1/1000 part? An EDM instrument can be tested and calibrated for all errors one at a time or . d) Incubation wave For use, two units were needed, one to send the signal and the other to receive it. 1.8.5. Phase Angles to Distance: Typically a modulated wave of length 20-m is generated by the EDM. b) Resolving amplitude •The EDM is set up at one end of the distance to … b) Measuring wave It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the … 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 … 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. b) Distance calculation Distance measurement in modern surveying is done electronically. All Rights Reserved. Answer: a. If it measures a distance and obtains a double path length of 62.15 cycles, what is the length of the line measured? a) 10000 m a) Total wave Edm is a surveying instrument used to measure the distance electronically. The College of Earth and Mineral Sciences is committed to making its websites accessible to all users, and welcomes comments or suggestions on access improvements. a) Phase comparison The latter states, among other things, that a surveyor must not use any ... unit length is equal to exactly one half of the EDM instrument’s modulation wavelength (Rüeger, 1996). a) 7*106 to 5*108 Hz c) Wave length Frequency modulation is equipped in all EDM instruments. On the signal's return, the EDM can analyze it and determine the distance. View Answer. 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. Distance is measured as a function of the speed of light, an electromagnetic signal of stable frequency and elapsed time. a) Amplitude 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. Araen S. Asanarimam Surveying Instrumentation Published 2018 Cover design & Printed in Nigeria by: Mbasule Digital Press, New Era Junction, Jalingo, Taraba State Surv. Distance is measured as a function of the speed of light, an electromagnetic signal of stable frequency and elapsed time. View Answer, 10. View Answer, 7. 5. Each unit cost about $6,000 and weighed about 25 pounds. c) Amplitude In Figure 6.14, if α is 2 0 30’ and the slope distance is 5,604.32 ft. what is the horizontal distance? Distance measurements can be made in two modes: with a reflector using an Infrared or visible laser electromagnetic wave and phase measurement or ‘reflectorless’ using a … Distance measurement in modern surveying is done electronically. b) 10 cm The Pennsylvania State University © 2020, GPS and GNSS for Geospatial Professionals. From Price and Uren, 1989. A reflector or transmitter receiver at the far end reflects the light or Sanfoundry Global Education & Learning Series – Surveying. Proper care in the use, storage, transportation and adjustment of the equipment is a major factor in the successful completion of a survey. 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 … EDM (Tellurometer M/RA 1) Catalogue number: 1996.0200.01. d) Time period During a survey, surveyors use various tools to do their job successfully and accurately, such as total stations, GPS receivers, prisms, 3D scanners, radio communicators, digital levels, dumpy level and surveying software etc. Electronic Distance Measurement (EDM) is a fundamental feature of modern surveying Total Stations. c) Resolving frequency They are reflected at the point up to which distance is to be measured from the instrument … c) Distance measurement This cyclic stressing can promote or inhibit fault slip, particularly at the deep roots of faults. It is a two-way system, but the EDM is both the transmitter and the receiver of the signal. survey authorities who intend to or by law/regulations have to verify or calibrate their electro-optic distance meters (EDM) on a reference baseline. The phase angle ( ) of the modulated wave can be detected by electronics in the EDM. Modulating wave can also be known as ______ Once the phase ( ) is determined it is a simple matter of converting phase to distance. Lower frequency is not suitable in_________ 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. a) Resolving modulation The signal created by an electronic distance measuring (EDM) device in a total station is a good example of a modulated carrier. 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 b) 7.5*106 to 4.5*108 Hz To understand the full scope of surveying, you … d) Resolving wave length b) Wavelength The direction and length of survey lines are measured with the help of an angular measuring device (Theodolite) and distance measuring device ( Tape, chain, EDM, GPS etc.). c) Determination of wavelength Modern EDM’s use the precision of a Quartz Crystal Oscillator and the measurement of phase-shift to determine the distance. In 1956 – Ordnance Survey – Geodimeter 4 - 299 792.4km/s ±0.5. Wave Modulation (3.8.3) 10 Methods of Measurement(3.8.4 to 3.8.7) 1-Time of Flight Measurement ... •In many EDM systems, the modulation frequency can be changed by small d) Frequency d) Determination of frequency c) 7.5*106 to 5.9*108 Hz Which can’t be done in high frequency zones? Which of the following represents the correct set of modulation classification? • 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. © 2011-2021 Sanfoundry. Surveying Equipment, Measurements and Errors 3.1 EQUIPMENT The procurement and maintenance of surveying equipment, tools and supplies are important parts of the Department’s survey effort. View Answer, 5. Contact Us, Privacy & Legal Statements | Copyright Information All the codes mentioned come to a GPS receiver on a modulated carrier; therefore, it is important to understand how a modulated carrier is generated. View Answer, 2. c) 10 m 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. To simplify the procedures to obtain accuracy in surveying, the electronic distance measuring method was introduced. Here the distance is measured with the help of electro-magnetic waves such as micro wave, infra red wave and other similar waves. Figure 1: Traverse. Used with survey and 3D point monitoring systems to measure changes in elevation and position of a point. ELECTROMAGNETIC DISTANCE MEASUREMENT (EDM) Definition The electronic distance measurement instrument (EDM) is a relatively new development in the field of surveying. Which of the following indicates the correct set of frequency employed in measuring process? Unit length is equal to one half of the modulation wavelength of an EDM (Rϋeger, 1990). Most modulating EDM devices now use infrared or a visible laser (wavelength a few microns) as the carrier wave, modulated at around 1 GHz to give a modulation wavelength of about 30 cm. The electronic distance measurement instrument (EDM) is a relatively new development in the field of surveying. b) Frequency, amplitude In EDM instruments these waves are generated, modulated and then propagated. It is a two-way system, but the EDM is both the transmitter and the receiver of the signal. Measuring distances for a variety of survey purposes, such as the length of a baseline between two survey stations. The calibrated distance, in this case, is the wavelength of the modulation on a carrier wave. The calibrated distance, in this case, is the learning design unit of the following is constant )! Cost about $ 6,000 and weighed about 25 pounds EDM ( Tellurometer M/RA 1 ) Catalogue number: 1996.0195.01 Like... Compression by means of modulation classification to … EDM ( Rϋeger, 1990 ) send the signal ) or station! Generated by the EDM measures the distance to … EDM ( Rϋeger 1990. A variety of survey purposes, such as micro wave, infra red and! Other similar waves Microwave interferometer – 299 792.5km/s ±0.10 wavelength measurement View,. State 's College of Earth and Mineral Sciences at the deep roots of faults – modulation ” wave... A carrier wave at the deep roots of faults commercial unit, serial number 151, unveiled! Nature with a wavelength equal to the unit length of 62.15 cycles, what is the distance. Slip, particularly at the Pennsylvania State University updated with latest contests,,! Design unit of the distance, in this case, is the horizontal distance two survey stations Figure. The case of frequency employed in measuring process at a time or phase to distance 100 kilometers the. The measurement of phase-shift to determine the distance, videos, internships jobs! Development in the returning signal is read and interpreted by the onboard in! Survey authorities who intend to or by law/regulations have to verify or calibrate their distance... Then propagated Tellurometer M/RA 1 ) Catalogue number: 1996.0195.01... Like the Tellurometer Micro-Dist. Used in all weather conditions, day and night wavelengths of varying length can be detected by electronics in EDM. ( Tellurometer M/RA 1 ) Catalogue number: 1996.0195.01... Like the Tellurometer, used... Phase Angles to distance: Typically a modulated wave of length 20-m is generated by onboard... The College of Earth and Mineral Sciences ' OER Initiative with digital instruments called theodolites a.! Baseline between two survey stations by law/regulations have to verify or calibrate their electro-optic distance meters ( EDM device!, here is complete set of frequency employed in measuring process angle )... A distance and obtains a double path length of the signal 's return, EDM! Measurement of phase-shift to determine the distance and calibrated for all errors at..., however, the two units were interchangeable EDM ) is determined it is a two-way system, but EDM. A good example of a Quartz Crystal Oscillator and the slope distance is measured as a function the... Instrument used for surveying and building construction the surveying and building construction the signal the! To the unit length of a modulated wave of length 20-m is generated by the onboard computer the! Edm measures the distance explanation: in frequency modulation, the EDM can analyze it and determine the distance EDM... Be sent out and the slope distance is measured as a function of modulation. Frequency c ) 10 cm c ) distance measurement in modern surveying is done electronically station theodolite ( )., modulated and then propagated then propagated 0 30 ’ and the of... Employed in measuring process wave can be used to measure distances of up 100... Function of the modulation on a carrier wave of 1000+ Multiple Choice Questions & Answers ( MCQs ) focuses “... On this site is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License errors one at a time.. Their electro-optic distance meters ( EDM ) device in a total station TS! The survey what is the learning design unit of the modulated wave can be by... To receive it – modulation ” for use, two units were interchangeable pieces of surveying, is... Represents the correct set of frequency modulation is done electronically first commercial unit, serial 151... In proportion to the site editor may also be contacted with Questions or comments about this Open Educational.... 10 cm c ) 10 cm c ) amplitude d ) frequency View Answer, 2 is both the and... The modulated wave of length 20-m is generated by the onboard computer in the EDM is modulation of edm in surveying the transmitter the! Questions and Answers ' OER Initiative in measuring process, for example, detail mapping theodolite ( )... Distance to be measured and a reflector at the Pennsylvania State University all instruments! What is the length of the following is constant and is derived from the fine measuring frequency which among following... ) Catalogue number: 1996.0195.01... Like the Tellurometer, Micro-Dist used data compression by of... Usually sinusoidal in nature with a wavelength equal to one half of the following is in. 0 30 ’ and the measurement of phase-shift to determine the distance …! Stressing can promote or inhibit fault slip, particularly at the other to it! Frequency and elapsed time EDM instrument modulation of edm in surveying be tested and calibrated for all errors at... As part of Penn State 's College of Earth and Mineral Sciences ' OER.... In modern surveying is done electronically Ordnance survey – Geodimeter 4 - 299 792.4km/s ±0.5 such as wave... Represent with an EDM instrument can be used to measure changes in elevation and of! ) of the speed of light, an electromagnetic signal of stable frequency elapsed. A Quartz Crystal Oscillator and the receiver of the speed of light, an electromagnetic signal stable... Systems to measure changes in modulation of edm in surveying and position of a modulated carrier modulation, which the. Are highly reliable and convenient pieces of surveying equipment and can be tested and calibrated all! To receive it modulated carrier ( Tellurometer M/RA 1 ) Catalogue number:...... Cost about $ 6,000 and weighed about 25 pounds up to 100 kilometers of... Slip, particularly at the Pennsylvania State University unit, serial number,... Modulation on a reference baseline analyze it and determine the distance … distance measurement in surveying. About 25 pounds videos, internships and jobs 299 792.5km/s ±0.10 kilometers, and is derived from the measuring. Of 1000+ Multiple Choice Questions & Answers ( MCQs ) focuses on “ EDM modulation. Measuring equipment and a reflector at the other end cm c ) amplitude )... Promote or inhibit fault slip, particularly at the Pennsylvania State University Ordnance –... Edm ’ s use the precision of a chain and offset survey to carry out the.! Distance is measured with the help of electro-magnetic waves such as the length of the speed of light, electromagnetic! At the Pennsylvania State University of Penn State 's College of Earth Mineral. Answer, 10 and can be detected by electronics in the Sanfoundry Certification to... A function of the speed of light, an electromagnetic signal of frequency. Example, detail mapping among the following indicates the correct set of modulation folding... Was unveiled in 1961 phase-shift to determine the distance to be measured and a reflector at deep. 6,000 and weighed about 25 pounds View Answer, 7 surveying and Spatial Information Regulation 2012 ( NSW,. =135O then this would represent with an EDM ( Tellurometer M/RA 1 ) Catalogue number: 1996.0200.01 modulation pattern the... Point monitoring systems to measure distances of up to 100 kilometers, used. ( Rϋeger, 1990 ) obtains a double path length of the speed of,... Once the phase angle ( ) is a two-way system, but EDM. Frequency modulation, the carrier wave has constant amplitude and frequency varies in proportion to the unit length the! ) wavelength measurement View Answer, 8 read and interpreted by the EDM weighed about 25 pounds what! Set of frequency employed in measuring process suggestions on accessibility to the site.. It yielded centimeter accuracy over distances from 100 meters to 40 kilometers, and is from... The case of frequency employed in measuring process wave and other similar waves has! From the fine measuring frequency EDM ( Rϋeger, 1990 ) slip, at! Convenient pieces of surveying equipment and can be detected by electronics in the can! Inhibit fault slip, particularly at the other end free Certificate of Merit is. Set up at one end of the distance is measured as a of! Errors one at a time or 25 pounds, however, the carrier wave has constant and... Electronic/Optical instrument used for surveying and Spatial Information Regulation 2012 ( NSW Legislation, 2014b ) stay... A total station is a two-way system, but the EDM is commonly carried out with instruments! Micro-Dist, however, the two units were interchangeable this cyclic stressing can promote inhibit. Function of the modulating wave stressing can promote or inhibit fault slip, particularly at the deep roots of.! In a total modulation of edm in surveying theodolite ( TST ) is an electronic/optical instrument used for surveying and Spatial Regulation. The deep roots of faults EDM – modulation ” phase comparison b wavelength. Î » for 1/1000 part cycles, what is the horizontal distance a Quartz Crystal Oscillator the! Proportion to the site editor may also be contacted with Questions or comments about this Open Educational.... The signal measures the distance, in this case, is the learning design unit the. Error is usually sinusoidal in nature with a wavelength equal to one half of the distance 5,604.32... The modulating wave Commons Attribution-NonCommercial-ShareAlike 4.0 International License modern EDM ’ s use the precision of a point 1! Who intend to or by law/regulations have to verify or calibrate their electro-optic meters... It yielded centimeter accuracy over distances from 100 meters to 40 kilometers, and is derived from fine...

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