What are the technical principles of laser rangefinder?
Principle of pulse method laser ranging technology:
The phase method is similar to the method used for ultrasonic speed measurement and distance measurement. The maximum measurement distance is usually several hundred meters, which can easily reach the order of millimeters. However, the maximum measurement distance of a rangefinder designed according to this method is limited and cannot be measured. Extension. This method is mainly used abroad. The pulse method laser ranging generally uses infrared laser, including near-infrared laser and mid-infrared laser. Lasers in this band are divided into visible and invisible. And the rangefinder based on this technology has low coherence requirements, fast speed, simple implementation structure, high peak output power, high repetition frequency and wide range, so this project uses the pulse method to design a handheld laser rangefinder.
Principle of phase method laser ranging technology:
The mainstream laser rangefinder on the market is a laser rangefinder based on the phase method. This is because the laser rangefinder based on the phase method can easily overcome a major drawback of ultrasonic ranging: excessive error, making the measurement accuracy reach the millimeter level. The main shortcomings of laser rangefinders based on this method are complex circuits and short operating distances (about one hundred meters. After the efforts of many scientific workers, there are now phase-method laser rangefinders with operating distances of several hundred meters). .
Phase method laser ranging technology uses a laser with a radio band frequency to perform amplitude modulation and measure the phase difference generated by the sinusoidal modulated light traveling back and forth between the rangefinder and the target. According to the wavelength and frequency of the modulated light, the laser is converted flight time, and then calculate the distance to be measured. This method generally requires placing a reflector at the object to be measured to reflect the original path of the laser back to the laser rangefinder, which is then received and processed by the wave detector of the receiving module. In other words, this method is a passive laser ranging technology with cooperative target requirements.
