A range finder is an instrument that USES a laser to accurately measure the distance of a policy.When the laser rangefinder is working, it shoots a very fine laser rangefinder light to the policy. The laser beam reflected by the photoelectric element is received by the policy. The timer measures the time of the laser beam from emission to reception and calculates the distance from the observer to the policy.If the laser is continuously launched, the range can be up to about 40 km, lined with fluorine butterfly valve and can be operated day and night.If the laser is pulse emission, the general accuracy must be low, but for long distance, can reach a good relative accuracy.The world's first laser was first developed in 1960 by hughes aircraft company scientist maiman.
The U.S. military soon began a study of military laser equipment.In 1961, the first military laser rangefinder was certified by the U.S. military, and soon became a useful combination. Laser rangefinder light weight, small volume, short operation is fast and accurate, its error is only one 5 of the other optical rangefinder to one percent, thus is widely used in topographic survey, field measurement, tanks, planes, ships and artillery range of policy and measure the clouds, the height of the aircraft, missiles and satellites, etc. It is an important technical equipment for the precision of high moving tanks, aircraft, ships and artillery.Because the price of laser rangefinder continues to reduce, the industry is also gradually preliminary use of laser rangefinder.At home and abroad, a number of new micro rangefinder with the advantages of fast ranging, small volume and reliable function, which can be widely used in industrial measurement and control, mines, ports and other fields.The primary classification of one-dimensional laser rangefinder for distance measurement and location;Scanning Laser Rangefinder (2d) is used in Scanning Laser Rangefinder for Scanning, measurement, positioning, regional monitoring and other fields.3D Laser Rangefinder (3D Laser Rangefinder) is used for 3D induction and measurement, 3D spatial positioning and other fields.
The distance measurement principle can be summarized as measuring the time required by the light reciprocation policy, and then calculate the distance D through the light speed c=299792458m/s and atmospheric refraction coefficient n.Because it is difficult to measure time directly, the phase of continuous wave is usually measured, which is called phase measuring rangefinder.Of course, there is also a pulse rangefinder, the typical WILD di-3000 needs to pay attention to, measuring the phase is not to measure the infrared maybe laser phase, but measure the modulation in the infrared maybe laser above the signal phase.Construction work has a hand-held laser rangefinder for measuring houses on the same principle.
General precision ranging needs total reflection prism collaboration, and the house measurement of the rangefinder, directly to the smooth wall reflection measurement, the first is because the distance is relatively close, light reflected back the signal strength is large enough.With this can be known, must be perpendicular, otherwise the return signal is too small to get the exact distance.
It is generally possible to use thin plastic sheets as reflective surfaces in practical projects to deal with the serious problem of diffuse reflection.