What Is The Working Principle Of A Laser Rangefinder?

1. The principle of using infrared ranging or laser ranging
The principle of ranging can basically be summarized as measuring the time it takes for light to return to the target, and then calculating the distance D through the speed of light c =299792458m/s and the atmospheric refractive index n. Since it is difficult to directly measure time, the phase of a continuous wave is usually measured, which is called a phase-measuring distance meter. Of course, there are also pulse rangefinders.
It should be noted that phase measurement does not measure the phase of infrared or laser, but the phase of the signal modulated on infrared or laser. There is a handheld laser rangefinder used in the construction industry for house surveying that works on the same principle.
2. The plane of the measuring object must be perpendicular to the light
Usually precise distance measurement requires the cooperation of a total reflection prism, but the rangefinder used for house measurement directly uses the reflection of a smooth wall to measure, mainly because the distance is relatively close and the signal strength of the light reflection is strong enough. It can be known from this that it must be vertical, otherwise the return signal will be too weak and the accurate distance cannot be obtained.
3. Can measure the diffuse reflection of the object plane
This is usually possible. In actual projects, thin plastic plates are used as reflective surfaces to solve the problem of serious diffuse reflection.
4. Pulse method laser rangefinder entertainment-grade products can achieve a display accuracy of 1 meter and a measurement accuracy of ±1 meter. Measurement-grade products can achieve a display accuracy of 0.1 meters and a measurement accuracy of ±0.15 meters.
5. The accuracy of the phase laser rangefinder can reach 1 mm error, which is suitable for various high-precision measurement purposes.