What are the different classifications of laser ranging sensors?
There are two types of laser ranging sensors: triangulation and time-of-flight.There are three types of time-of-flight laser ranging: pulsed laser ranging, phase-based laser ranging and interferometry laser ranging.
Pulsed laser rangefinder technology takes advantage of the fact that the laser pulse energy is relatively concentrated in time and the instantaneous power is very large (usually up to watts). In the case of cooperative targets, pulsed laser ranging can achieve edge measurements, and universal pulsed laser ranging sensors can measure distances of tens or even tens of thousands of kilometers, achieving accuracy of more than 10 centimeters. When performing a range from a few kilometers to dozens of kilometers, the distance measurement can be performed only by diffusing the signal to the pulse tube using the measured target, even if no cooperative target is used.The disadvantage is that the absolute ranging accuracy is not very high.
The phase laser ranging sensor USES the high frequency sinusoidal signal of fixed frequency to continuously modulate the luminous intensity of the laser source and measure the phase delay generated by the modulating laser back and forth once.The measured distance is calculated by phase delay.
Phase-based ranging measures the time of signal propagation indirectly by measuring the phase delay of the continuous amplitude modulated signal propagating back and forth over the distance to be measured so as to obtain the measured distance.The method has high measurement accuracy, usually at the millimeter scale.
The interferometric ranging method is also a phase ranging method, which is different from the general phase ranging method in that it does not measure the distance by measuring the phase of the laser modulated signal, but by measuring the distance by measuring the change of the interference fringe.