# Laser rangefinder - distance realtive to wavelength and number of cycle

## Description

A laser rangefinder is a rangefinder that uses a laser beam to determine the distance to an object. The most common form of laser rangefinder operates on the time of flight principle by sending a laser pulse in a narrow beam towards the object and measuring the time taken by the pulse to be reflected off the target and returned to the sender. Due to the high speed of light, this technique is not appropriate for high precision sub-millimeter measurements, where triangulation and other techniques are often used.

The distance between point A and B is given by the shown formula

Related formulas## Variables

D | distance between two point (m) |

λ | wavelength (m) |

N | the integer number of wave half-cycles of the round-trip (dimensionless) |

ΔN | he remaining fractional part (dimensionless) |