E.D.M is the electronic distance measuring device, measures the distance from the instrument to its target. The EDM sends out an laser or infrared beam which is reflected back to the unit, and the unit uses velocity measurements to calculate the distance traveled by the beam.
Types of Electronic Distance Measurement Instrument
EDM instruments are classified based on the type of carrier wave as
- Microwave instruments
- Infrared wave instruments
- Light wave instruments
Error in Electronic Distance Measurement Instruments
- Personal Errors
- Instrumental Errors
- Natural Errors