Mitsubishi Electric Corporation

Mitsubushi Electric Corporation

Mitsubishi Electric Tokki Systems Corporation

Nobuki Kotake

Takashi Saito

Masataka Suzuki

Shumpei Kameyama

Masaharu Imaki

Hideaki Ochimizu

Hidenobu Tsuji

Yutaka Kajiyama

Toshiyuki Ando

Yoshihito Hirano

Takayuki Yanagisawa

Akira Shiga

Mamoru Hamada

Yuichi Nishino

Eisuke Haraguchi

Yasuhisa Tamagawa

Mikio Takabayashi

Wataru Yoshiki

Yu Sakai

A laser radar device of the present invention includes: an optical oscillator oscillating laser light; an optical modulator modulating the laser light oscillated by the optical oscillator; an optical antenna radiating the laser light modulated by the optical modulator to an atmosphere, and receiving scattered light from a radiation target as received light; an optical receiver performing heterodyne detection on the received light received by the optical antenna; and a signal processor calculating for a range bin a spectrum of a received signal obtained by the heterodyne detection by the optical receiver, calculating a signal to noise ratio of the range bin, and integrating the spectrum of the range bin and spectra of one or more range bins adjacent to the range bin when the signal to noise ratio is less than or equal to a threshold value.

Laser radar device

An optical transmission unit () transmits an optical signal having a light intensity set as a Low level component of a pulse. An optical partial reflector () is provided on a path through which transmission light is transmitted from a circulator () to the atmosphere, and reflects the optical signal. A detection unit () performs coherent detection on reception light using, as local light, a signal in a Low level section in the optical signal reflected by the optical partial reflector ().

A laser radar device calculates a wind speed for each of a plurality of divided sections obtained by dividing a trajectory drawn by a laser beam in front of a wind turbine.

Laser radar device, wind power generator, and wind measurement method

A data processing device of the present invention includes: a data communication device configured to communicate with a laser radar device to acquire a value of line-of-sight wind-speed, a laser emission angle, attitude information, position information, and a time; a storage device configured to store the value of line-of-sight wind-speed and the time; a central processing unit configured to run a data selector to select a value of line-of-sight wind-speed stored in the storage device and being present within a set time period from a time about the value of line-of-sight wind-speed which is newly acquired by the data communication device, and configured to run a wind vector calculator to calculate a wind vector using the newly acquired value of line-of-sight wind-speed and using the selected value of line-of-sight wind-speed; and a memory configured to preserve the data selector and the wind vector calculator.

Data processing device, laser radar device, and wind measurement system

In conventional laser radar systems, the wind velocity measurement accuracy cannot be improved without changing their time gate widths, which is a problem. A laser radar system according to the present invention includes: an optical oscillator to perform laser light oscillation; an optical modulator to modulate the laser light by oscillation of the optical oscillator; an optical antenna to emit the laser light modulated by the optical modulator into the atmosphere and to receive scattered light from an irradiated target as reception light; an optical receiver to perform heterodyne detection on the reception light received by the optical antenna; and a signal processor to calculate a spectrum of a reception signal obtained by the optical receiver's performing heterodyne detection, to decompose the spectrum using signal-to-noise ratios, and to calculate a velocity of an irradiated target from a decomposed spectrum.

Laser radar system

The problem with a conventional laser radar device is that the SNR of a value of a wind speed degrades due to motion. A laser radar device according to the present disclosure includes: an optical oscillator to emit laser light; an optical modulator to modulate the laser light generated by the optical oscillator; an optical antenna to emit the laser light modulated by the optical modulator into the air, and to receive, as received light, scattered light scattered by an irradiation target; an optical receiver to perform heterodyne detection on the received light received by the optical antenna; a sensor to detect one or more motion amounts of the optical antenna; and a signal processor to calculate spectra of respective received signals obtained by the heterodyne detection performed by the optical receiver, to correct the spectra by using the one or more motion amounts detected by the sensor, to perform an integration of the corrected spectra, and to calculate a speed of the irradiation target from a spectrum resulting from the integration.

A wind velocity searching unitis configured so as to, when a spectrum signal calculated by a spectrum calculating unitis one in a range bin having a signal strength less than a first threshold Th, determine a search center IF of the search scope for a Doppler frequency corresponding to a wind velocity in the range bin by using a wind velocity model selected by a wind velocity model selecting unitand search for the wind velocity in the range bin from the spectrum signal within the search scope whose search center IF is determined thereby. As a result, the probability that the peak of noise is detected erroneously as the peak of the spectrum signal is reduced.

Laser radar apparatus and wind velocity observation method

A system controllerdetermines whether the quality of either a distance image or a light intensity image satisfies reference quality, and, when the quality of either the distance image or the light intensity image dos not satisfy the reference quality, outputs a speed change command to lower a speed, an altitude change command to change a submarine altitude (depth), or the like to a navigation control unit, thereby changing a physical relative relation between a measurement planeand a device in question. As an alternative, the system controller changes a beam scanning rate f, a beam divergence &#x3b8;, or the like within limits at which the amount of variation in a spatial resolution does not exceed a permissible amount.

Laser radar device and radar image generating method

A wind measurement lidar includes: an output unit to output a laser beam; a transmitter-receiver to emit the laser beam produced by the output unit into the air, and to receive a scattered beam of the laser beam; a received signal acquiring unit to obtain a received signal through heterodyne detection of the laser beam and the beam acquired via the transmitter-receiver; a controller to control the transmitter-receiver; a storage to store as a noise signal the received signal obtained when the laser beam is controlled so as to be produced, but not to be emitted into the air; a frequency difference unit to subtract the noise signal from the received signal obtained when the laser beam is controlled so as to be emitted into the air; and a wind speed measurer to measure a wind speed from the subtraction result.

Wind measurement lidar

A laser radar device includes a searchable distance calculation deviceto calculate an amount of attenuation at a time of propagation of a light wave from a temporal change in scattered light intensity measured by a marine snow measurement device, and calculate a searchable distance in a target search devicefrom the amount of attenuation.

A speed calculatorselects a speed calculation method corresponding to a peak value of an SNR which is detected by a peak SNR detectorfrom among a plurality of speed calculation methods of calculating the speed (wind speed) of an aerosol to calculate the speed (wind speed) of the aerosol according to the speed calculation method. As a result, there is provided an advantage of being able to calculate the speed (wind speed) of the aerosol in a short time with a high degree of accuracy.

Laser radar device and method of calculating speed of object to be measured

An optimal position analysis unitspecifies an optimal installation position for a photodetectorby using spectra which by a spectrum and wind speed computing unitcalculated by analyzing output data of a photodetectorinstalled at different installation positions, controls a position adjustment made by an optical unit adjustment driving unit, and optimizes the installation position of the photodetector

Radar device

An S/N calculation circuitto calculate the S/N ratio of a received signal, and an S/N comparison circuitto compare the S/N calculated by the S/N calculation circuitwith a threshold Th are disposed, and a parameter setting circuitcontrols the radiation state of a beam radiated from a transmission optical systemaccording to the result of the comparison performed by the S/N comparison circuit. As a result, even if the state of the propagation environment gets worse, degradation in the communication quality can be prevented and communicative stabilization can be achieved.

Communication device

There is provided a coherence length measurement device () that calculates a coherence length Lbased on a spectrum v calculated by an FFT device () and performs, in case where the coherence length Lis shorter than an FFT gate width G, a setting change to shorten the FFT gate width Gand a pulse width P, and the FFT device () performs frequency analysis on a received signal outputted from an A/D converter () by a unit of an FFT gate following the setting change to calculate the spectrum v of the received signal.

A noise spectral differential unit records a noise spectrum in a state without any received signal, and subtracts the noise spectrum from a received signal spectrum. An offset corrector performs offset correction of the signal spectrum obtained by subtracting the noise spectrum by the noise spectral differential unit with respect to the noise level at a frequency separated from the frequency peak position of the received signal by a prescribed value. A frequency shift analyzer executes signal processing of the signal spectrum resulting after the offset correction and measures a frequency shift. A wind velocity converter makes wind velocity detection from the frequency shift measured by the frequency shift analyzer.

Growing community of inventors

Tokyo, Japan

Nobuki Kotake