A rangefinder is a tool for measuring length or distance, and can be combined with angle measuring equipment or modules to measure parameters such as angle and area. There are many forms of rangefinders, usually a long cylindrical structure consisting of an objective lens, an eyepiece, a display device (which can be built-in), a battery, and other components.

Laser rangefinders generally use two methods to measure distance: pulse method and phase method. The process of pulse ranging is as follows: the laser emitted by the rangefinder is reflected by the measured object and then received by the rangefinder, which simultaneously records the time of the laser traveling back and forth. Half of the product of the speed of light and round-trip time is the distance between the rangefinder and the object being measured. The accuracy of pulse method for measuring distance is generally around+/-1 meters. In addition, the measurement blind spot of this type of rangefinder is generally around 15 meters.

D=ct/2

D - Test site A B distance between two points;

T-optical round-trip A The time required for one time.