A rangefinder is a radio navigation device that measures the inclined distance between an aircraft and the ground. It consists of an airborne interrogator and a ground transponder. A method of determining the distance between radio waves and a radio station by measuring the time it takes for an aircraft to reach the radio station.
A rangefinder is a tool for measuring length or distance, which can be combined with goniometer devices or modules to measure parameters such as angle and area.
Rangefinders come in many forms, usually a long cylinder consisting of an objective, eyepiece, display, and battery. Laser rangefinders can also emit multiple laser pulses and use the Doppler effect to determine how far objects are from the light source.
Laser rangefinders generally use pulse method and phase method to measure distance. The process of pulse method ranging is as follows: the laser emitted by the rangefinder is reflected by the measured object and then received by the rangefinder, and the rangefinder records the time of the laser. Half the product of the speed of light and the round-trip time is the distance between the
rangefinder and the object being measured. The accuracy of the pulse method is generally about +/- 1 meter. In addition, the measurement blind area of this rangefinder is generally about 15 meters.
