The principle of laser range finder
1. The principle of using infrared ranging or laser ranging
The principle of ranging can basically be attributed to measuring the time required for light to go back and forth to the target, and then calculate the distance D through the speed of light c = 299792458m/s and the atmospheric refraction coefficient n. Because it is difficult to measure time directly, it is usually to measure the phase of continuous wave, which is called phase measuring range finder. Of course, there are also pulsed rangefinders.
It should be noted that phase measurement does not measure the phase of infrared or laser, but the phase of the signal modulated on infrared or laser. The construction industry has a handheld laser distance meter for house surveying that works on the same principle.
2. The plane of the measured object must be perpendicular to the light
Usually precision distance measurement requires the cooperation of a total reflection prism, while the rangefinder used for house measurement directly measures with smooth wall reflection, mainly because the distance is relatively short and the signal strength of the light reflected back is large enough. It can be known from this that it must be vertical, otherwise the return signal is too weak and the accurate distance cannot be obtained.
3. The object plane can be measured as diffuse reflection
It is usually possible. In actual engineering, a thin plastic plate is used as a reflective surface to solve the problem of serious diffuse reflection.
4. The entertainment-grade products of the pulse method laser rangefinder can achieve a display accuracy of 1 meter, a measurement accuracy of ±1 meter, and a measurement-grade product with a display accuracy of 0.1 meters and a measurement accuracy of ±0.15 meters.
5. The accuracy of the phase laser rangefinder can reach 1 mm error, which is suitable for various high-precision measurement purposes.
3 categories edit
Laser rangefinders are divided into handheld laser rangefinders and telescopic laser rangefinders.
1. Handheld laser rangefinder: the measurement distance is generally within 200 meters, and the accuracy is about 2mm. This is currently the most widely used laser range finder. Functionally, in addition to measuring the distance, it can also generally calculate the volume of the measured object.
2. Cloud service laser rangefinder: transmit the measurement data on the laser rangefinder to mobile terminals such as mobile phones and tablet computers in real time through Bluetooth; through wifi networking, the data can be transmitted to the cloud server, and the measurement can be shared with remote construction partners in real time data.
3. Telescope-type laser rangefinder: the measurement distance is relatively long. The general measurement range is about 3.5 meters to 2000 meters. There are also ranging telescopes with a maximum range of about 10 kilometers. Due to the collimation requirements of the ranging telescope, the range is less than 3.5 meters. It is a blind spot, and laser telescopes larger than 2000 meters generally use
