System for reducing background stray light interference of receiving light path and interference reduction method thereof

Abstract

The invention relates to a system for reducing background stray light interference of a receiving light path and an interference reduction method thereof. The system comprises a laser emission collimating head, a narrow-band filter, a first 45-degree reflector, a second 45-degree reflector, an aspherical lens, a diaphragm, a photoelectric detector and a reflector. The laser emission collimating head generates an emission laser beam which sequentially passes through the reflector, the second 45-degree reflector, the first 45-degree reflector and the narrow-band filter and then irradiates a target object, and the emission laser beam is reflected on the target object to generate an echo laser beam. The echo laser beam sequentially passes through the narrow-band filter, the first 45-degree reflector, the second 45-degree reflector, the aspherical lens and the diaphragm and then reaches the photoelectric detector. By increasing the receiving optical path and reducing the receiving field angle, it is ensured that most echo laser beams can be received, meanwhile, less background stray light of solar radiation is sent to the photoelectric detector, and therefore the signal-to-noise ratio is increased, and a miniaturized and lightweight instrument is achieved.

Description

technical field [0001] The invention belongs to the technical field of long-distance laser detection, and in particular relates to a system for reducing the background stray light interference of the receiving light path and a method for reducing the background stray light interference of the receiving light path. Background technique [0002] In the current field of laser ranging, generally a laser ranging instrument is used to emit a laser beam to irradiate the target, and then receive the echo laser reflected by the target to calculate the distance between the ranging instrument and the target. The emitted laser beam has a divergence angle, which is called the emission field of view. In principle, the receiving field of view is greater than or equal to the emission field of view, and most of the echo energy of the emission pulse can be received. In order to increase the detection distance, it is necessary to add Large receiving field of view, but since the sunlight is a c...

AI Technical Summary

Problems solved by technology

The emitted laser beam has a divergence angle, which is called the emission field of view. In principle, the receiving field of view is greater than or equal to the emission field of view, and most of the echo energy of the emission pulse can be received. In order to increase the detection distance, it is necessary to add Large receiving field of view, but since the sunlight is a continuous spectrum, there is the same wavelength band as the emitted laser beam, the increase of the receiving field of view will cause more sun or other background stray light to be received, thus introducing greater noise , leading to the enhancement of the received background stray light energy, which reduces the signal-to-noise ratio and affects the measurement accuracy

However, the small receiving field of view means that the receiving focal length is large, which will increase the volume of the laser ranging instrument, which is not conducive to the miniaturization and lightweight design of the instrument

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