Laser rangefinder is an instrument that uses a parameter modulated by laser to measure the distance to a target. Today, let’s talk about its working principle.
A laser rangefinder is an instrument that accurately measures the distance to a target by adjusting any parameter of the laser. The pulse laser rangefinder emits one or a series of short pulse laser beams towards the target during operation, receives the laser beam reflected onto the target by the photoelectric element, measures the time required for the laser beam to be emitted and received by the timer, and calculates the distance from the rangefinder to the target.
If the power of the emitted laser beam is sufficient, the measurement distance can reach about 40 kilometers, and the laser rangefinder can work day and night. However, if there is a material with high laser absorption rate in space, the distance and accuracy of this distance may decrease.
working principle
1. Use infrared or laser ranging principles
The principle of distance measurement can basically be summarized as measuring the time required for light to travel back and forth to the target, and then calculating the distance D through the speed of light c=299792458m/s and atmospheric refractive index N. Due to the difficulty of directly measuring time, measuring the phase of continuous waves is generally referred to as a caliper. Of course, there is also a pulse rangefinder.
Measuring phase is not about measuring the phase of infrared or laser, but about measuring the phase of modulated signals on infrared or laser. The construction industry has portable laser rangefinders for measuring residential properties, and their working principle is as follows.
2. The plane of the object being measured should be perpendicular to the light
Generally speaking, distance measurement requires a total reflection prism, and a distance measuring instrument for house measurement is directly used to measure the reflection of smooth walls. Mainly because of the close distance, the signal strength reflected by the light is high. At the same time, it can be seen that it should be vertical. Otherwise, the return signal is too weak to obtain the correct distance.
Diffuse reflection can be used to measure the plane of an object.
Generally speaking, it is possible. In practical engineering, using thin plastic sheets as reflective surfaces solves the serious dispersion problem.
4. Pulse laser rangefinder entertainment grade products can achieve a display accuracy of 1 meter and a measurement accuracy of 1 meter. Measurement grade products have a display accuracy of 0.1 meters and a measurement accuracy of 0.15 meters.
The accuracy of phase laser rangefinder can reach 1 millimeter error, which is suitable for various high-precision measurement purposes.
Laser distance measurement uses laser as a light source to measure distance. According to the working mode of lasers, they can be divided into continuous lasers and pulsed lasers. Helium, ion, plutonium and other gas lasers operate in a continuous output state for phase laser ranging. A dual heterojunction gallium arsenide semiconductor laser that can be used for infrared ranging; Solid state lasers such as ruby and glass can be used for pulse laser ranging.
Laser rangefinders have the characteristics of monochromaticity and strong directionality of lasers, and their electronic circuits are integrated into semiconductors. Compared with photoelectric rangefinders, they can not only work day and night, but also improve ranging accuracy, greatly reduce weight and power consumption, and thus measure the distance to distant targets such as artificial satellites and the moon, becoming a reality. If the laser is continuously emitted, the measurement route can reach 40 kilometers and work day and night. If laser is emitted with pulses, the accuracy is generally low, but when used for long-distance measurement, the relative accuracy is very good.
