Laser radar system and ranging method

Abstract

The invention discloses a laser radar system and a ranging method. According to the laser radar system, a transmitting unit is used for transmitting a first laser beam that is irradiated on a target object and then is reflected to a conversion unit. The conversion unit is used for converting the first laser beam reflected by the target object into a second laser beam, wherein the frequency of thefirst laser beam is smaller than the frequency of the second laser beam. A receiving unit is configured to receive the second laser beam. A signal processing unit is configured to compare first time with second time to obtain a time difference and thus obtain a distance between the laser radar system and the target object based on the time difference, wherein the first time is time of emitting thefirst laser beam by the transmitting unit and the second time is time of receiving the second laser beam by the receiving unit; or the signal processing unit is configured to acquire the distance between the laser radar system and the target object based on a phase difference between the first laser beam and the second laser beam. Therefore, the cost is lowered and the detection efficiency is improved on the premise that the safety of the human eyes is ensured; and the effect of detecting the distance is improved.

Description

technical field [0001] Embodiments of the present invention relate to the field of optical technologies, and in particular, to a laser radar system and a ranging method. Background technique [0002] Lidar mainly includes three parts: transmission, reception and signal processing. The transmitting part is used to emit pulsed laser light, the laser light is reflected by the target object to the receiving part, and the signal processing part calculates the light flight time by transmitting light and receiving light to determine the distance of the object. [0003] In order to improve the detection distance of lidar, there are currently two main methods, one is to increase the sensitivity of the detector, and the other is to increase the power of the laser. [0004] If the laser radar uses visible light as the light source, it will damage the human retina. In order to achieve human eye safety, the laser radar uses infrared light as the light source. However, in order to improv...

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Problems solved by technology

[0004] If the laser radar uses visible light as the light source, it will damage the human retina. In order to achieve human eye safety, the laser radar uses infrared light as the light source. However, in order to improve the sensitivity of the detector, infrared detectors are generally used. Infrared light detection efficiency is high, but the cost is much higher than conventional detectors, which is not conducive to productization; if the laser emission power is too small, the detection distance will be shorter

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