A laser rangefinder is an instrument that uses lasers to accurately measure the distance to a target. In the working process, the laser rangefinder emits a very thin laser rangefinder light to the target, and the photoelectric element receives the laser beam reflected by the target. The timer measures the time from emission to reception of the laser beam and calculates the distance from the observer to the target. If the laser is continuously emitted, the measurement range can reach about 40 kilometers, and the fluorine-lined butterfly valve can work day and night.

If the laser is pulsed, the accuracy is generally low, but it can achieve better relative accuracy when used at a long distance. A laser in the world was first successfully developed in 1960 by Mayman, a scientist at Hughes Aircraft Corporation of the United States.

On this basis, the US military quickly launched research on military laser devices. In 1961, a military laser rangefinder passed a demonstration test by the US military. After that, the laser rangefinder quickly entered the practical alliance. The laser rangefinder is light in weight, small in size, simple to operate, fast and accurate, and its error is only one-fifth to one-hundredth of other optical rangefinders. It is widely used in terrain surveying, battlefield surveying, attacking targets by tanks, aircraft, ships and artillery, as well as measuring the height of clouds, aircraft, missiles and satellites.

It is an important technical equipment to improve the accuracy of high tanks, aircraft, ships, and artillery. As the price of laser rangefinders continues to decrease, laser rangefinders are gradually being used in industry. A number of new miniature rangefinders have emerged at home and abroad. They have the advantages of fast ranging speed, small size, and reliable performance. They can be widely used in industrial measurement and control, mines, ports and other fields. Main categories: 1D laser rangefinders are used for distance measurement and positioning; 2D laser rangefinders (scanning laser rangefinders) are used for contour measurement, positioning, area monitoring, etc. The 3D laser rangefinder is used for 3D contour measurement and 3D space positioning.

The principle and method of measuring the distance between the moon and the earth with laser.

1. What is the principle of infrared ranging or laser ranging?

The principle of ranging can basically be attributed to measuring the time required for light to travel back and forth to the target, and then use the speed of light c=299,792,458m/s and the atmospheric refractive index n to calculate the distance d. Because it is difficult to directly measure the time, it is usually continuous measurement. The phase of the wave is called a phase finder. Of course, there are also pulse rangefinders, typically the DI-3000 of WILD. It should be noted that the phase measurement is not to measure the phase of infrared or laser, but to measure the phase of the signal modulated on infrared or laser. There is a handheld laser rangefinder in the construction industry, which is used to measure houses and work in the same way.

2.Does the plane of the measured object have to be perpendicular to the light?

Usually precision ranging requires the cooperation of total reflection prisms. The rangefinder used for house measurement directly measures through the reflection of a smooth wall, mainly because the distance is relatively short and the signal strength of the light reflection is sufficiently large. It can be known that it must be vertical, otherwise the return signal will be too weak to obtain an accurate distance.

3. If the plane of the measured object is diffuse reflection, is it okay?

Usually, this is also possible. In actual engineering, a thin plastic plate will be used as a reflective surface to solve the serious diffuse reflection problem.

4. Ultrasonic ranging accuracy is relatively low, so it is rarely used now.