The measuring principle and method of laser rangefinder: The laser rangefinder is an instrument that uses laser to accurately measure the distance to a target. The laser rangefinder emits a very thin laser rangefinder light to the target when it is working. 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 fired continuously, the measurement range can reach about 40 kilometers, and the fluorine butterfly valve can work day and night. If the laser is pulsed, the accuracy is generally low, but long-distance use can achieve good relative accuracy. In 1960, the American Hughes Aircraft Company scientist Mayman successfully developed a laser in the world for the first time.

The US military quickly conducted research on military laser devices on this basis. In 1961, a military laser rangefinder passed the U.S. military demonstration test, and the laser rangefinder soon entered the practical complex. Laser rangefinders are light in weight, small in size, simple to operate, fast, and accurate. The error is only one-fifth to one-hundredth of other optical rangefinders. Therefore, they are widely used in topographic surveys, battlefield surveys, tanks, etc. Range measurement of aircraft, ships and artillery, measurement of clouds, aircraft, missiles and satellites. It is an important technical equipment to improve the accuracy of tanks, aircraft, ships and artillery. As the price of laser rangefinders continues to drop, laser rangefinders are gradually being used in industry. A number of new miniature rangefinders with the advantages of fast ranging, small size, and reliable performance have emerged at home and abroad, which can be widely used in industrial measurement and control, mines, ports and other fields. The main categories are one-dimensional laser rangefinders for distance measurement and positioning; two-dimensional laser rangefinders for contour measurement, positioning and area monitoring; three-dimensional laser rangefinders.

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 calculate the distance D through the speed of light c=299792458m/s and the atmospheric refraction coefficient n. Because it is difficult to measure time directly, it is usually called a phase measuring instrument to measure the phase of a continuous wave. Of course there is also a pulse rangefinder, the typical one is WILDDI-3000. 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 hand-held laser rangefinder in the construction industry, which is used for house surveying, and the working principle is the same.

Does the plane of the object to be measured have to be perpendicular to the light? Usually precision ranging requires the cooperation of total reflection prisms, and the house measurement rangefinder directly uses the smooth wall reflection to measure, mainly because the distance is relatively close, and the signal strength of the light reflection is sufficient big. Therefore, we can know that it must be vertical, otherwise the return signal is too weak to get an accurate distance. If the plane of the measured object is diffuse reflection, is it okay? It is usually possible. In actual engineering, thin plastic plates are used as a reflective surface to solve the serious problem of diffuse reflection. Ultrasonic ranging accuracy is relatively low, and it is rarely used now.