The Working Principle Of Laser Rangefinder

The laser rangefinder is an instrument that uses a certain parameter of the modulated laser to measure the distance to the target. Let’s talk about how it works today.

The laser rangefinder is an instrument that uses a certain parameter of the modulated laser to accurately measure the distance to the target. The pulsed laser rangefinder emits a beam or a sequence of short pulsed laser beams to the target when it is working. The photoelectric element receives the laser beam reflected by the target. The distance from the instrument to the target.

When the power of the emitted laser beam is sufficient, the measurement range can reach about 40 kilometers or more. The laser rangefinder can operate day and night, but when there are substances with high laser absorption rate in the space, the distance and accuracy of the ranging will be reduced.

working principle

1. Using the principle of infrared ranging or laser ranging

The principle of ranging can basically be attributed to the measurement of the time required for the light to travel back and forth to the target, and then the distance D is calculated by the speed of light c = 299792458m/s and the atmospheric refraction coefficient n. Because it is difficult to measure time directly, it is usually to measure the phase of continuous wave, which is called a phase measuring rangefinder. Of course, there are also pulsed rangefinders.

It should be noted that the phase measurement is not measuring the phase of infrared or laser, but measuring the phase of the signal modulated on infrared or laser. There is a hand-held laser rangefinder in the construction industry for house surveying, and its working principle is the same.

2. The plane of the object to be measured must be perpendicular to the light

Usually precision ranging requires the cooperation of total reflection prisms, and the rangefinder used for house measurement directly uses smooth wall reflection to measure, mainly because the distance is relatively short, and the signal intensity of the light reflected back is large enough. It can be known from this that it must be vertical, otherwise the return signal is too weak and the precise distance cannot be obtained.

3. It can measure the surface of the object as diffuse reflection

Usually, it is also possible. In actual engineering, a thin plastic plate is used as a reflecting surface to solve the serious problem of diffuse reflection.

4. Entertainment grade products of pulse method laser rangefinder can achieve display accuracy of 1 meter, measurement accuracy of ±1 meter, measurement grade products of display accuracy of 0.1 meter, and measurement accuracy of ±0.15 meter.

5. The accuracy of the phase laser rangefinder can reach an error of 1 mm, which is suitable for various high-precision measurement purposes.