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Do you know the operation method of laser rangefinder?

2023-11-30

Laser rangefinder is an instrument that uses certain parameters of modulated laser to measure the distance to a target. The measurement range of the laser rangefinder is 3.5 to 5000 meters.


According to the distance measurement method, it is divided into phase method rangefinder and pulse method rangefinder. When a pulse laser rangefinder works, it emits a beam or a series of short pulse laser beams towards the target, and the photoelectric element receives the reflected laser from the target. The timer measures the time from the launch port to receiving the laser beam and calculates the distance from the observer to the target. The phase method laser rangefinder detects distance by detecting the phase difference that occurs when emitted and reflected light propagate in space. The laser rangefinder is lightweight, small in size, easy to operate, fast and accurate, and its error is only one-fifth to one percent of that of other optical rangefinders.


Laser rangefinders generally use two methods to measure distance: pulse method and phase method.


The process of pulse ranging is as follows: the laser emitted by the laser rangefinder is reflected by the measured object and received by the rangefinder. The rangefinder also records the round-trip time of the laser. Half of the product of the speed of light and round-trip time is the distance between the rangefinder and the object being measured.


The pulse method generally has a ranging accuracy of around 1 meter. In addition, the measurement blind spot of this type of rangefinder is generally around 15 meters.


Usage of laser rangefinder:


1. Placing instruments


First, set up the theodolite on the measuring platform, and then install the range finder host on the theodolite bracket after middle note, lock it with the connector fixing screws, insert the battery into the bottom of the host and fix it. Place the reflective prism at the target point, center and level it so that the mirror faces the host.


2: Observing vertical angles, temperature, and air pressure


Aim at the center of the target plate with a theodolite crosshair and measure the vertical angle α。 Meanwhile, observe and record the readings of temperature and barometer. Observing the vertical angle, temperature, and pressure is aimed at correcting the oblique distance measured by the rangefinder, and temperature and pressure corrections are used to obtain the correct horizontal distance.


3. Distance measurement preparation


Press the power button "PWR" to turn on the computer, and the host will self check and display the original set temperature, air pressure, and prism constant values. After passing the self check, it shows "good".


If you want to modify the original setting value, you can press the "TPC" key and then enter the temperature, pressure, or prism constant (usually entered one by one using the "ENT" key and number keys). In general, as long as the same type of mirror is used, the prism constant will not change, but the temperature and pressure observed each time may be different and need to be reset.


4. Distance measurement


Adjust the host's visual axis, adjust the horizontal adjustment handwheel (or theodolite horizontal micro screw) and the main tilt micro screw to accurately align the ranging telescope with the middle of the prism. In a "good" state, it is also possible to determine whether precise aiming is possible based on the sound of the buzzer. The stronger the signal, the louder the sound. Move the rangefinder up, down, left, and right to make the buzzer sound louder, completing the aiming. *.


Application fields of laser rangefinder


Laser rangefinders have been widely used in the following fields: electricity, water conservancy, communication, environment, construction, geology, fire protection, blasting, navigation, railways, agriculture, forestry, real estate, leisure/outdoor sports, etc.