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Method for improving precision of laser distance meter
- Feb 02, 2019 -

Method for improving precision of laser distance meter


At present, in order to improve the accuracy of the laser distance meter, the following solutions are generally adopted. 1. Two APDs and one LD are set in the laser distance meter. Because the impact of the environment on each device is the same. So use one LD to simultaneously emit laser light to two AH) receivers. The internal light path is taken out by the internal emission, and the external light path emitted by the internal light is used to test the distance outside. The distance measured by the external light path minus the distance of the inner light path can be subtracted from the influence of the environment. The disadvantage of this solution is the high cost of APD. Solution 2: Set an LD, an APD, and an optical baffle in the laser distance meter. The LD is first emitted to the outside and reflected from the outside onto the Aro. After the test, use the baffle to block all the light paths to directly receive the Aro from the inside. This external light path of the optical path conversion can reduce the influence of the environment by reducing the internal light path. Specifically, the structure uses a motor to drive a reflector, and the calibration light projected by the laser source E is reflected into the optical path receiving cavity of the rangefinder with one end open, and after the diffuse reflection is formed in the receiving cavity, the photosensitive element in the receiving cavity is received. D receives the optical signal to perform signal comparison. The defect of the structure is that the reflector is an important component participating in the reference positioning during the light receiving process, so the identity of returning to the initial position after rotation is relatively high. In actual use, the reflector often has mechanical deformation structure errors caused by rotation or movement. This error is introduced into the calibration optical system, which will greatly affect the calibration accuracy. At the same time, the two internal and external optical paths are switched during the operation of the reflector. The position must be locked accurately, and the usual reflectors are of light and heavy structure, and need to be locked with other components. In order to reach the correct switching position, the motor drive power consumption is often increased; in addition, the diffused light of the reflector is diffused. The receiving mode has poor stability and is easy to be mixed with external light, which causes instrument recognition errors and reduces the stability of the instrument. Affect the measurement accuracy. Solution 3: Set two LDs and one APD in the laser distance meter. First open the LD of the external light path and test the distance outside. After the test, the inner light path is closed and the inner light path is opened. Let the / [eye number of the internal light path hit the APD. In this way, the external light path can reduce the influence of the APD by reducing the internal light path. The disadvantage of this scheme is that although the influence of APD can be subtracted, the LD itself has a large amount of heat. The heat of the two LDs is hard to be equal. Therefore, the impact of LD is also difficult to reduce.


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