The principle of laser rangefinder is the same as radio radar. After laser alignment is sent out, measure its reciprocating time, and then multiply by the speed of light to get reciprocating interval.Because the laser has the high direction, the high monochromatism and the high power and so on the merit, these about measures the distance interval, the determination policy azimuth, the enhancement accepts the system the signal to noise ratio, guarantees the measurement precision and so on is very key, therefore the laser ranging receives the attention day by day.
The laser radar developed on the basis of the laser rangefinder can not only measure distance, but also can measure the orientation, the speed and acceleration, has been successfully used in the ranging and tracking of artificial satellites, such as the selection of ruby laser laser radar, ranging scale of 500 ~ 2000 km, the error of only a few meters.At present, ruby laser, neodymium glass laser, carbon dioxide laser and gallium arsenide laser are often used as the light source of laser rangefinder.
Ultrasonic sensors are often used to detect distant objects, and because they are not optical devices, they are unaffected by color changes.However, ultrasonic sensors measure the interval according to the speed of sound, so there are some inherent defects that cannot be used in the following situations, while laser sensors do not have the following problems:
(1) when the policy to be tested is not in line with the transducer of the sensor.Because the ultrasonic inspection policy must be in the sensor with a deviation of no more than 10° Angle.
(2) occasions where visible light spots are required for location calibration.
(3) occasions where the required beam diameter is small.Generally, the diameter of ultrasonic beam is 0.76cm when it is 2m away from the sensor.
(4) windy occasions.
(5) vacuum occasions.
(6) large temperature gradient occasion.Because in this case there is a change in the speed of sound.
(7) occasions for rapid response of demand.