Abstract: A diffractive optical element according to the present disclosure includes: a plurality of diffractive optical element segments, each diffractive optical element segment having an asperity shape on the segment's surface to vary phases of light entering the segment according to positions on the segment's surface which the light enters, the each diffractive optical element segment projecting, when the light enters, light having a phase distribution to form a light pattern, wherein the diffractive optical element segments are arranged on a same plane and have, on their surfaces, asperity shapes which are different from each other and correspond to respective light patterns different from each other, the light patterns being formed by light's entering the respective diffractive optical element segments, and wherein the diffractive optical element segments are arranged in respective regions on the diffractive optical element, which are partitioned by lines radially extending from a center of the diffractive optica

Abstract: A laser radar apparatus includes: a scanner capable of beam scanning at a first angular speed; a measurable wind distance calculator monitor to calculate and to monitor a measurable wind distance based on wind measurement data obtained through beam scanning by the scanner; an optical axis angular correction amount deriver to derive an optical axis angular correction amount being able to obtain the largest distance of the measurable wind distance, based on a first angular speed and the wind measurement data obtained through beam scanning at a second angular speed lower than the first angular speed, when decrease of the measurable wind distance is detected by the measurable wind distance calculator monitor; and an optical axis corrector to correct an optical axis angular deviation between transmitted light and reception light, based on the optical axis angular correction amount.

Abstract: A frequency shift correcting unit (25) which corrects a frequency shift of a plurality of first signal spectra within the same time range with respect to a frequency of first laser light beam and corrects a frequency shift of a plurality of second signal spectra within the same time range with respect to a frequency of second laser light beam, and a spectrum integrating unit (26) which integrates a plurality of first signal spectra corrected by the frequency shift correcting unit (25) and integrates a plurality of second signal spectra corrected by the frequency shift correcting unit (25) are provided, and a molecular concentration calculating unit (27) calculates a concentration of molecules in the atmosphere from the first and second signal spectra integrated by the spectrum calculating unit (26).

Abstract: To provide a laser distance measuring apparatus which can increase the measurement frequency per unit time by suppressing the increase in the data amount expressing the measurement time, while ensuring the distance measurement precision and the measurable distance. A laser distance measuring apparatus measures, with a time resolution, a light receiving time which is a time from a time point when the laser beam generating unit emits the laser beam to a time point when the light receiving unit outputs the light receiving signal; calculates an object distance which is a distance to the object, based on the measurement result of the light receiving time by the time measuring device; and changes the time resolution of the time measuring device used for calculation of the object distance, based on detection information.

Abstract: To provide a laser distance measuring apparatus which can realize appropriate measurable distance according to the object distance and the moving speed of the moving body, and quick response of distance detection, without complicating the equipment configuration. A laser distance measuring apparatus is provided with a light receiving unit that receives a reflected light of a laser beam reflected by an object, and outputs a light receiving signal; and a distance calculation unit that calculates an object distance which is a distance to the object, based on the emitted laser beam and the light receiving signal, wherein the distance calculation unit changes a light receiving sensitivity of the light receiving signal, based on a moving speed of the moving body and the object distance.

Abstract: To provide a laser distance measuring apparatus that can set the irradiation range of the laser beam to the front ground surface appropriately regardless of the inclination of the front ground surface. A laser distance measuring apparatus controls the scanning mechanism to performs two-dimensional scan which scan laser beam in an irradiation angle range of the right and left direction to the traveling direction of own vehicle and scans laser beam in an irradiation angle range of the up and down direction with respect to the traveling direction of own vehicle; detects a relative inclination information of the up and down direction of a ground surface in front of own vehicle with respect to a ground surface where own vehicle is located; and moves the irradiation angle range of the up and down direction to up side or down side according to the relative inclination information.

Abstract: A problem with a conventional laser radar device is that a deviation occurs between the receiving field of view and the beam incoming direction because of a change occurring between the angle of a scanner at the time of beam transmission and that at the time of beam reception, and the reception sensitivity degrades.

Abstract: 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.

Abstract: A device includes a light source (1) for generating light with a single wavelength; a modulator (3) for modulating the light generated into transmission light; a beam scanner (7) for carrying out beam scanning by which the transmission light modulated is radiated, and the light reflected is received; a beam scanning controller (8) for controlling the radiation direction; a signal processing unit (12) for performing wind measurement through heterodyne detection using the light generated and the corresponding received light; and an optical axis corrector (9) for correcting the optical axis angular shift between the transmission light and the received light, which accompanies the beam scanning, with respect to the received light used by the signal processing unit (12) or the transmission light used by the beam scanner (7), on the basis of the radiation direction of the beam scanner (7), the angular speed of the beam scanning and the wind measurement distance.

Abstract: A laser radar apparatus in the present disclosure includes: a scanner 60 capable of beam scanning at a first angular speed; a measurable wind distance calculator monitor 30 to calculate and to monitor a measurable wind distance based on wind measurement data obtained through beam scanning by the scanner; an optical axis angular correction amount deriver 40 to derive an optical axis angular correction amount being able to obtain the largest distance of the measurable wind distance, based on a first angular speed and the wind measurement data obtained through beam scanning at a second angular speed lower than the first angular speed, when decrease of the measurable wind distance is detected by the measurable wind distance calculator monitor; and an optical axis corrector 8 to correct an optical axis angular deviation between transmitted light and reception light, based on the optical axis angular correction amount.

Abstract: The problem with a conventional laser radar device is that the SNR of a value of a wind speed degrades due to motion.

Abstract: An optical transmitter 1 includes an optical phase modulator 131 that performs phase modulation on a continuously oscillating light, a light intensity modulator 132 that performs pulse modulation on the light on which the phase modulation is performed, to output the light as a transmission light, a first signal generator 133 that generates a pulse modulation driving signal in which on and off time intervals are repeated periodically, to drive the optical intensity modulator 132, and a second signal generator 134 that generates a saw tooth wave driving signal having an amplitude equal to an integral multiple of a driving voltage needed to acquire a modulation phase of 2? of the optical phase modulator 131, and having a constant period, to drive the optical phase modulator 131.

Abstract: 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.

Abstract: Included are: a fast Fourier analyzer to obtain a received spectrum for each of time gates by performing fast Fourier transform on a received signal for each of the time gates; a signal integration determiner to determine necessity of integration of the received spectrum obtained by the fast Fourier analyzer for each of the time gates; a spectrum integrator to perform integration of the received spectrum obtained by the fast Fourier analyzer depending on a determination result by the signal integration determiner; a frequency shift calculator to calculate an amount of a frequency shift with respect to the laser light emitted by the optical transceiver from the received spectrum integrated by the spectrum integrator; and a wind speed calculator to calculate the wind speed in a direction in which the laser light is emitted by the optical transceiver from the amount of the frequency shift calculated by the frequency shift calculator.

Abstract: A wind velocity searching unit 30 is configured so as to, when a spectrum signal calculated by a spectrum calculating unit 22 is one in a range bin having a signal strength less than a first threshold Th1, 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 unit 29, and 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.

Abstract: The problem with a conventional laser radar device is that the SNR of a value of a wind speed degrades due to motion.

Abstract: A wind velocity searching unit 30 is configured so as to, when a spectrum signal calculated by a spectrum calculating unit 22 is one in a range bin having a signal strength less than a first threshold Th1, 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 unit 29, and 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.

Abstract: A system controller 16 determines 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 2, thereby changing a physical relative relation between a measurement plane 3 and a device in question. As an alternative, the system controller changes a beam scanning rate f, a beam divergence ?, or the like within limits at which the amount of variation in a spatial resolution does not exceed a permissible amount.

Abstract: 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.

Abstract: A laser radar device includes a searchable distance calculation device 2 to 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 1, and calculate a searchable distance in a target search device 4 from the amount of attenuation.