The handheld high-precision telescopic laser rangefinder's operating principle and features
TM1500 High Precision Telescope Handheld Laser Rangefinder Product Principle:
Laser range finders generally use two methods to measure distance: pulse method and phase method. The process of pulse method ranging is as follows: the range finder emits; the laser is reflected by the measured object and then received by the range finder, and the range finder records the time of the laser back and forth at the same time. Half of the product of the speed of light and the round-trip time is the distance between the rangefinder and the measured object. The accuracy of distance measurement by pulse method is generally around +/-1 meter. In addition, the measurement blind zone of this type of rangefinder is generally about 5-15 meters.
TM1500 High Precision Telescope Handheld Laser Rangefinder Features:
The instrument works with semiconductor lasers with wavelengths of 905 nm and 1540 nm. For 905nm and 1540nm laser rangefinders, we call them "safe". YAG laser operating at a wavelength of 1064 nm. The wavelength of 1064 nanometers is harmful to human skin and eyes, especially if the eyes accidentally touch the laser with 1064 nanometers wavelength, the damage to the eyes may be fatal. Therefore, in foreign countries, the 1064 nanometer laser is completely banned in the handheld laser rangefinder. In China, some manufacturers also produce 1064nm laser range finders. As for the 1064nm laser range finder, because it is potentially harmful to the human body, we call it "unsafe".
An overview of phase range finders
Phase ranging is generally used in precision ranging. Due to its high precision, generally at the millimeter level, in order to effectively reflect the signal and limit the measured target to a specific point commensurate with the accuracy of the instrument, this rangefinder is equipped with a reflector called a cooperative target. mirror.
Phase laser ranging is generally used in precision ranging. Due to its high precision, generally at the millimeter level, in order to effectively reflect the signal and limit the measured target to a specific point commensurate with the accuracy of the instrument, this rangefinder is equipped with a reflector called a cooperative target. mirror.
If the angular frequency of the modulated light is ω, and the phase delay caused by one round trip over the distance D to be measured is φ, the corresponding time t can be expressed as:
t=φ/ω
Substituting this relationship into (3-6) the distance D can be expressed as
D=1/2 ct=1/2 c·φ/ω=c/(4πf) (Nπ+Δφ)
=c/4f (N+ΔN)=U(N+)
In the formula: φ——the total phase delay generated by the signal going back and forth to the measuring line once.
ω——The angular frequency of the modulating signal, ω=2πf.
U——unit length, the value is equal to 1/4 modulation wavelength
N——The number of modulated half-wavelengths included in the survey line.
Δφ——The portion of the phase delay less than π generated by the signal going back and forth to the measuring line once.
ΔN——The fractional part of the modulation wave contained in the survey line that is less than half the wavelength.
ΔN=φ/ω
