The Evolution and Functionality of Laser Distance Meters
The laser distance meter is an instrument that uses lasers to accurately measure the distance of the policy. The laser distance meter emits a very thin laser distance meter light to the policy during operation. The photoelectric element receives the laser beam reflected by the policy, and the timer measures the time from emission to reception of the laser beam, and calculates the time from the observer to the policy. the distance. If the laser is fired continuously, the measuring range can reach about 40 kilometers, and the fluorine-lined butterfly valve can operate day and night. If the laser is pulsed, the accuracy must generally be low, but for long-distance measurement, a good relative accuracy can be achieved. The world's first laser was first developed and successfully developed by Mayman, a scientist at Hughes Aircraft Corporation of the United States, in 1960.
The U.S. military quickly opened a study on military laser equipment on this basis. In 1961, the first military laser distance meter passed the U.S. military certification test, and the laser distance meter soon entered a useful consortium. Laser distance meters are light in weight, small in size, easy to operate, fast and accurate, and their faults are only one-fifth to one-hundredths of other optical distance meters, so they are widely used in terrain surveying, battlefield surveying, and tanks. , Aircraft, ships and artillery to measure the range of policies, measure the height of clouds, aircraft, missiles and satellites. It is an important technical equipment for traveling with high accuracy of tanks, aircraft, ships and artillery. Because the price of laser distance meters continues to decrease, the industry is gradually using laser distance meters. A number of new miniature distance meters with the benefits of fast ranging, small size, and reliable functions have emerged at home and abroad, which can be widely used in industrial measurement and control, mines, ports and other fields. The main classification: One-dimensional laser distance meter is used for distance measurement and positioning; two-dimensional laser distance meter (Scanning Laser distance meter) is used for induction measurement, positioning, area monitoring and other fields; three-dimensional laser distance meter (3D Laser distance meter) is used for Three-dimensional induction measurement, three-dimensional space positioning and other fields.
1. What is the principle of using infrared ranging or laser ranging?
The basic principle of ranging can be attributed to the measurement of the time required for the light reciprocating policy, 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 generally used to measure the phase of continuous wave, which is called a phase measuring distance meter. Of course, there are also pulsed distance meters. The typical DI-3000 of WILD requires attention. 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 distance meter for construction work, which is used for house surveys, and its working principle is the same.
2. Is it necessary for the plane of the measured object to be perpendicular to the light?
Generally, precision distance measurement requires the cooperation of total reflection prisms, while the distance meter used for house measurement directly uses smooth wall reflection to measure, mainly because the distance is relatively short, and the signal strength of the light reflected back is large enough. From this we can know that it must be vertical, otherwise the return signal is too small and the accurate distance cannot be obtained.
3. Is it possible if the plane of the measured object is diffuse reflection?
Generally, it is possible. In practical engineering, a thin plastic plate will be used as a reflecting surface to deal with the serious problem of diffuse reflection.