Functional characteristics and application of photoelectric distance meter
According to the distance measuring method, the photoelectric range finder is divided into two types: the phase method range finder and the pulse range finder.
The pulse rangefinder uses a beam of light to the target object to measure the time for the target object to reflect the light back, thereby calculating the distance between the instrument and the target object. Because the laser has good directionality and a single wavelength, it is a photoelectric measurement The distance meter generally uses laser as the modulation object, so the pulse type distance meter is also commonly known as the laser distance meter.
The laser range finder using the pulse method can achieve a wide ranging range and can be used for indoor and outdoor measurements. Its typical range is 3.5 meters to 2000 meters, and the high-range laser range finder can reach 5000. meters, the laser range finder for military use can reach a farther range. Due to the ability to measure long-distance measurement targets, in order to intuitively observe the range-finding target by the user, the laser rangefinder generally has a telescopic system, which is also called a laser rangefinder telescope. Figure 1 shows three A typical diagram of a laser rangefinder telescope.
The accuracy of the laser range finder mainly depends on the calculation accuracy of the instrument to calculate the time between laser emission and reception. According to the technology and application used, the laser range finder can be divided into conventional laser range finders with an accuracy of about 1 meter ( Mainly used for outdoor sports, hunting, etc.) and high-precision laser rangefinders for surveying and mapping, land measurement, construction, engineering applications, military and other occasions that require high precision.
The phase method rangefinder is a rangefinder that modulates the phase of the laser light and obtains the distance by measuring the phase difference of the reflected laser light. Due to the need to detect the phase of the reflected laser, the received signal needs to have a strong intensity. Considering the safety of the human eye, the telescopic system like the pulsed laser rangefinder cannot be used, and the range is small. , the typical range of distance measurement is 0.5mm to 150 meters, the general phase method laser range finder uses 635 nanometers (visually red) laser as the debugging object, and is commonly known as infrared range finder, but in fact the definition of laser is not based on It is defined by the color, and if the 635nm laser rangefinder is directly irradiated to the human eye, it will cause irreversible damage. Readers are requested to use and protect it correctly.
