Coherent laser radar device

摘要

An object of the invention is to obtain a coherent laser radar device that provides one system of a photo detector and eliminates a blind zone, including a pulsed laser that oscillates at a frequency which is identical with or close to an output light of a local light source as a single frequency; a transmission/reception optical system that irradiates a pulsed laser beam from the pulsed laser toward a target as a transmission light and receives a scattered light from the target as a reception light; a light coupling means that couples the output light from the local light source and the reception light; a photo detecting portion that conducts light coherent detection on a coupled light; and a signal processing device that calculates a speed and a distance of a target in accordance with an output of the detection, in which the photo detecting portion comprises: a photo detecting element that conducts the light coherent detection; a microwave switch that changes over a propagation path of an output from the photo detecting element; a microwave amplifier; and a switch control means that changes over the microwave switch so as to transmit a signal before a reference time as a monitor signal and transmit a signal after the reference time as a reception signal with a time at which the pulse light from the pulsed laser has completely passed through the transmission/reception optical system as the reference time.