A laser rangefinder is an instrument that uses a laser to accurately measure the distance of a policy
A laser rangefinder is an instrument that uses a laser to accurately measure the distance of a policy. The laser rangefinder emits a very thin beam of laser light to the policy during operation, and the photoelectric element receives the laser beam reflected by the policy. The timer measures the time from the emission to the reception of the laser beam, and calculates the distance from the observer to the policy. It is launched continuously, with a measuring range of about 40 kilometers, and can be operated day and night. If the laser is pulsed, the accuracy is generally low, but for long-distance measurement, it can achieve good relative accuracy. The laser rangefinder is light in weight, small in size, simple in operation, fast and accurate, and its fault is only other optical One-fifth to several percent of the rangefinder is therefore widely used in terrain surveying, battlefield surveying, tank, aircraft, ship and artillery ranging for policy, and measuring the height of clouds, aircraft, missiles and artificial satellites. It is an important technical equipment for the accuracy of traveling high tanks, aircraft, ships and artillery. Because the price of laser rangefinders has been continuously lowered, laser rangefinders have been gradually used in the industry.
A number of new miniature rangefinders have appeared at home and abroad with the advantages of fast ranging, small size, and reliable functions, which can be widely used in industrial measurement and control, mining, ports and other fields. What is the principle of using infrared ranging or laser ranging? The principle of ranging can basically be attributed to the time required to measure the light reciprocation policy, 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 the time directly, it is generally to measure the phase of the continuous wave, which is called a phase-measuring rangefinder. Of course, there are also pulsed rangefinders. 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. In construction, there is a handheld laser rangefinder for house measurement. Its working principle is the same as this. Does the plane of the measured object need to be perpendicular to the light? Generally, precision ranging requires the cooperation of a total reflection prism, and the measurement used for house measurement The distance meter is directly measured by the reflection of the smooth wall, mainly because the distance is relatively close, and the signal strength of the light reflected back is large enough. It can be known from this that it must be vertical, otherwise the return signal is too small, and the accurate distance cannot be obtained. If the plane of the measured object is diffuse reflection, it is generally possible. In practical engineering, a thin plastic plate will be used as the reflective surface to deal with severe diffuse reflection. The problem of ultrasonic ranging is relatively low, and it is rarely used now.
This is to use the characteristics of laser monochromaticity, good coherence, and strong directionality to achieve high-precision measurement and detection, such as measuring length, distance, speed, angle, and so on. Laser ranging can be divided into pulsed laser ranging and continuous wave phase laser ranging in the technical approach. The principle of pulsed laser ranging is similar to radar ranging. The rangefinder emits a laser signal to the policy, and it will be reflected back when it encounters the policy. Because the propagation speed of light is known, it is only necessary to record the reciprocating time of the optical signal. , multiplying the speed of light (300,000 km/s) by one-half of the reciprocating time is the distance to be measured. The handheld and portable rangefinders that are widely used now
