The laser rangefinder is an instrument that uses a certain parameter of the modulated laser to measure the distance to the target. The rangefinder emits a beam or a sequence of short pulsed laser beams to the target when it is working, and the photoelectric element receives the laser light reflected by the target. The timer measures the time from emission to reception of the laser beam, and calculates the distance from the instrument to the target.

The rangefinder can be operated day and night, but when there are substances with high laser absorption rate in the space, the distance and accuracy of the distance measurement will be reduced. Let's take a look at the working principles of the instrument!

1. The principle of using infrared ranging or laser ranging:

The principle of ranging can basically be attributed to the measurement of the time required for the light to go 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.

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

Usually precision ranging requires the cooperation of a total reflection prism, and the laser rangefinder directly uses the reflection of a smooth wall to measure, mainly because the distance is relatively short, and the signal intensity of the light reflection 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.

Under normal circumstances, the laser rangefinder can achieve a display accuracy of 1 meter, a measurement accuracy of ±1 meter, a measurement grade product with a display accuracy of 0.1 meter, and a measurement accuracy of ±0.15 meters.