Laser radar device

A laser radar device comprising:

• a light source array having a single reference light source configured to emit a reference laser beam, an optical splitting element configured to split the reference laser beam into a plurality of laser light beams, and a plurality of light emitting ends, the light source array being configured to simultaneously emit the plurality of laser light beams from the plurality of light emitting ends, respectively;
• an optical splitter configured to separate a plurality of transmission light components from the plurality of laser light beams, respectively, and configured to separate a plurality of local light components from the plurality of laser light beams, respectively;
• an optical modulator configured to modulate one of the transmission light components to generate modulated transmission light;
• a transmission/reception optical system configured to receive, as received light, the modulated transmission light reflected by a target existing in external space, while scanning the external space with the modulated transmission light;
• an optical combiner configured to generate a plurality of interference light components by combining the received light and the plurality of local light components;
• an optical receiver array including a plurality of optical receivers arranged at respective positions that optically correspond to a plurality of different receiving fields of view of the transmission/reception optical system, and configured to generate a plurality of detection signals by detecting the plurality of interference light components;
• a signal processor configured to calculate a plurality of signal spectra of the plurality of detection signals, and calculate a plurality of signal-to-noise power ratios of the plurality of detection signals,
• wherein the signal processor includes:
• a signal divider configured to divide each of the plurality of detection signals into a plurality of time domain signals indicating signal waveforms of a plurality of gate time domains;
• a domain converter configured to, for each of the plurality of detection signals, convert the plurality of time domain signals into a plurality of frequency domain signals, respectively;
• an integrator configured to, for each of the plurality of detection signals, calculate a plurality of spectra of the plurality of time domain signals from the plurality of frequency domain signals, and calculate, as the plurality of signal spectra, a plurality of integration spectra corresponding to the plurality of detection signals by integrating the calculated plurality of spectra;
• an SNR calculator configured to calculate the plurality of signal-to-noise power ratios from the plurality of integration spectra, respectively;
• a selector configured to select at least two integration spectra from among the plurality of integration spectra by using the plurality of signal-to-noise power ratios, and calculate a noise reduction spectrum by adding or averaging the at least two signal spectra;
• and
• an observation quantity calculator configured to calculate observation quantities including a line-of-sight velocity and a velocity vector of the target on a basis of the noise reduction spectrum that is calculated by the selector.