Document Type : Research Paper

Author

• Hasan Shamsi

Abstract

A) In measuring distance by new rangefinders the following methods are used:
1) Phase comparison method
2) Pulse method (measuring travel time of a pulse until it returns)
3) Interferometry method
These methods all depend on the fact that the speed of travel of electromagnetic waves is in the order of the speed of light, and this speed must be precisely known.
In electronic rangefinders, the first two methods are used more frequently. The third method is used to measure very small distances.