It is the safety sense of green laser

The continuous-wave phase-shift laser ranging target is measured with a continuous modulation of the laser beam irradiation, caused from the measurement beam and from the phase change can be converted to the measured target distance. To ensure measurement accuracy, usually to install laser reflectors on the target under test. It measures the relative error for the millionth. The laser rangefinder with microwave radar combination, you can also play laser wave velocity of the narrow expertise to compensate for the low elevation of the microwave radar work by the lack of ground interference. Laser ranging and optical theodolites, infrared and television tracking system combining to form a photoelectric tracking system can be used as a measurement of the range test equipment is often used as weapons electro-optical fire control system. The customer can switch on or off  green laser pointer .
This laser rangefinder has been widely used ground artillery, tanks, artillery fire control system, greatly improving the hit rate. Laser ranging techniques in accordance with the measurement process can be divided into absolute distance measurements and micro-displacement measurement. Subdivided in accordance with the ranging method. Absolute distance ranging method, pulsed laser ranging and phase laser ranging, micro-displacement measurement trigonometry Laser Ranging and interferometry laser ranging. The principle of the pulsed laser ranging: a very short duration pulse laser (wave), issued by the pulsed laser to reach all parts of the measured object, part of the energy will be reflected back after test distance L, the pulse is reflected back laser known as the echo. Echo return to the rangefinder. Received by the photodetector. After the battery of  green laser pointer is used out.
According to the interval between the main wave signal and the echo signal. Laser pulse from the laser to the round-trip time t between the measured object, you can calculate the distance of the target under test. Where c is the speed of light. The accuracy of the pulse method is generally orders of magnitude in m. The principle of phase laser ranging: the emission of laser light stress on the use of phase change modulation signal when the laser space communication. The phase delay represents the distance calculated according to the wavelength of the modulation wave. Indirect method of phase delay measurements instead of direct measurement of the laser round trip time, distance measurement. The accuracy of this method can reach a millimeter. The laser ranging of the triangulation method is the light emitted by the laser. When the battery is charging, the indication light on the charger used by this kind of  green laser pointer will be on.
Receiving lens to receive the scattered light from the incident point incident on the surface of the object through the converging lens focusing and imaging in the optical position detector sensitive surface. When objects move through the points of light in the displacement of the imaging surface to calculate the relative distance of the object moving. Laser ranging resolution of the triangulation method is high, can reach the micron order of magnitude. Interferometry laser ranging and coherent optical measurements by moving the measured targets, the count of the complete measurement of the distance increment interferometry measurement sensitivity is very high, can reach the nanoscale. The emergence of solid-state lasers and semiconductor laser technology development and high-power, high brightness, high efficiency semiconductor laser diode. The battery of  green laser pointer is full.
Laser ranging device has a compact, light weight, long life, high efficiency, very suitable for the application of the space environment. From the late 1980s. In addition to the United States, Europe and Japan also began to research and development space with a laser distance measuring device. More extensive use of laser ranging devices in space missions. The laser ranging application profiles in space technology. Detection of space debris. Commonly known as space junk, space debris is the space outside the normal work of the aircraft, in addition to all man-made objects, large abandoned satellites, launch vehicles, the final stage. Small aluminum oxide after the burning of solid rocket motors of small particles or paint chips flaking off from the spacecraft. It is the safety sense of  green laser    .