176 results about "Wind lidar" patented technology

The invention discloses an all-fiber direct detection anemometric laser radar system and a closed-loop control method thereof. The system comprises an optical emission part, a frequency locking part, an emission part and a receiving part, wherein the optical emission part is used for emitting a modulated and amplified laser pulse; the frequency locking part is used for detecting the laser frequency variation, feeding back to the laser emission part, adjusting the laser wavelength and further realizing the function of locking the laser wavelength according to the deviation; the emission part is used for enabling the laser beam to point to the detection zone of the atmosphere, coupling the atmospheric back scattered light to a receiver through an optical telescope and modulating the near field signal strength; the receiving part is used for filtering out sun background from a signal and dividing the signal into two paths, one path of signal passes through a Fabry-Perot interferometer, the other path of signal is used as energy reference, the transmittance is obtained through the ratio of the signal intensities of the two paths of signal, and the wind velocity is obtained through inversion according to Doppler frequency shift. The laser radar adopts an all-fiber structure and has the advantages of small size and light weight, the manufacturing cost of the radar is low, the laser radar is controlled through a 3-level closed-loop, and the environmental adaptability and working stability of the laser radar are improved.

The invention discloses a double-frequency coherent wind lidar based on single-frequency continuous light EOM modulation. The double-frequency coherent wind lidar adopts dual-wavelength laser as a light source, and detects difference of dual-wavelength Doppler frequency shifts through coherent beat frequency to invert speed; and meanwhile, Doppler frequency shift information is extracted by adopting a microwave signal, thereby reducing speckle noise due to detection object unevenness and atmosphere turbulence. Besides, two side frequencies are generated through a single-frequency continuous wave EOM modulation method; double-frequency laser is generated through a method of utilizing a filter to filter center light frequency and filter out the two side frequencies; and the double-frequency laser generation method improves stability of a double-frequency gap, and the double-frequency gap can be controlled flexibly by adjusting trigger signals of modulators. According to the scheme, the dual-wavelength laser is obtained through single-frequency continuous wave EOM modulation, the speed is extracted through a microwave mode, and atmosphere wind speed information is inverted; the stability of the double-frequency gap is improved; and the double-frequency coherent wind lidar has the advantages of high detection precision, anti-electromagnetic interference and compact structure and the like.

The invention discloses an ocean buoy platform laser radar three-dimensional wind field cross section detection system which can be used for performing open sea automatic observation and is low in cost, high in measurement accuracy, high in temporal-spatial resolution, continuous in real time and reliable for a long time. The technical scheme is as follows: the detection system is characterized by consisting of a wind measuring laser radar (1), a buoy platform (2), a meteorological data observation module (3), a sea surface data observation module (4), a buoy platform attitude measurement module (5), a laser radar wind field compensation module (6) and an output unit (7), wherein the meteorological data observation module (3), the sea surface data observation module (4), the buoy platform attitude measurement module (5) and the laser radar wind field compensation module (6) are connected with the output unit (7) respectively and transmit signals to a specified client through a communication antenna, and the buoy platform attitude measurement module (5) is also connected with the laser radar wind field compensation module (6). The invention also discloses an ocean buoy platform laser radar three-dimensional wind field cross section detection method.

The invented Rayleigh windfinding laser radar calibration method uses acoustooptic frequency shift and laser spectrum Doppler broadening principle as basis, and utilizes two acoustooptic frequency shifters whose frequency can be regulated, and makes them be series-connected to implement laser frequency zero-crossed wideband continuous regulation, and utilizes Doppler stretcher to stretch spectrum so as to make accurate and quick calibration of Rayleigh windfinding radar.

The invention discloses a laser frequency spectrum retrieval method and a measurement calibration method for a molecular scattering anemometry laser radar and solves the problem that the existing anemometry Rayleigh laser radar is difficult in laser spectrum calibration. The retrieval method includes: allowing the molecular scattering light to perform convolution operation through an etalon transmittance function Ni(v) and an etalon transmittance function Fei(v), allowing the operation result to perform convolution operation with Rayleigh-Brillouin spectrum FR-B(v) to obtain the laser spectrum Fl(v), and fitting with the Gaussian function to obtain the laser spectrum function. The measurement calibration method and system is provided with an etalon controller for changing the cavity length of an etalon, the laser beams entering the etalon scan the cavity length of the etalon to obtain the etalon and molecular scattering light transmittance curve. By the method, accuracy, reliability and precision of wind retrieval are increased.

This application discloses a Doppler wind measurement lidar system. A small part of the laser signal emitted by the transmitting system enters the locked channel of the FP etalon through the locked channel optical path in the receiving optical system and the first analog detection for detecting the laser signal. The laser signal entering the locked channel of the FP etalon is detected by the second analog detector. The laser signals detected by the first analog detector and the second analog detector are collected by the analog acquisition card and sent to the first control system of the control system. The first control system processes the received laser signal collected by the analog acquisition card to obtain the frequency of the outgoing laser and the transmittance of the locked channel. According to the transmittance of the locked channel, the cavity length of the FP etalon is adjusted so that the emitted laser The frequency is locked at the cross point of the transmittance of the two signal channels of the FP etalon, realizing the real-time locking of the outgoing laser frequency and the position of the FP etalon, and improving the measurement accuracy.

The invention discloses a coherent wind measurement laser radar system with adjustable range resolution. In one aspect, the system employs a polarization circular beam splitter 3, locks vertical polarized light in a circular device, and repeatedly passes through AOM to allow emitted laser to generate n upsilon M frequency shift, thereby adjusting laser frequency shift; in another aspect, the system employs EOM 5 to cooperate with the polarization circular beam splitter 3, converts the polarization state of the laser in the circular device reaching preset offset into parallel vibration from vertical polarization, and converts continuous wave laser into pulse width adjustable pulsed light, thereby realizing the adjustment of the range resolution of a coherent wind measurement laser radar. The scheme not only improves the applicability of the coherent wind measurement laser radar on different resolution requirement occasions and under different weather, but also improves the data measurement reliability of the coherent wind measurement laser radar.

The invention discloses a Doppler anemometry laser radar sensitivity calibrating system which comprises a pulse laser, wherein the light-emitting side of the pulse laser is provided with a beam splitter a, one light path of the beam splitter a is sequentially provided with a lens a, an optical fiber, a lens b, a lens c and a rotator, the rotator is provided with a speed sensor, the other side of the lens c is sequentially provided with a reflector b and a lens d; and the other light path of the beam splitter a is sequentially provided with a reflector a, a reflector b and a lens d. The invention also discloses a calibrating method of the calibrating system, which is used for simulating to generate an optical signal comprising Doppler frequency shift information and being capable of not only calibrating a coherent Doppler anemometry laser radar calibrating system, but also calibrating an incoherent Doppler anemometry laser radar calibrating system based on an Fabry-Perot standard or atom filter and subjected to light splitting by adopting an edge detection technology. The system is simple and easy and is suitable for the calibration based on a laboratory environment.

The application discloses an optical receiving system of doppler wind lidar (DWL). According to the invention, two independent optical paths are employed; a fraction of lights, which are ejected by a laser, are collected by a first coupler; and the collected lights pass optical elements including a spectroscope and a reflective mirror and the like and then penetrate into a locking channel of a Fabry-Perot (FP) etalon; atmosphere backward dispersion lights are collected by a second coupler; the collected atmosphere backward dispersion lights pass the optical elements including the spectroscope and the reflective mirror and the like and then penetrate into two signal channels of the FP etalon. Because the optical signals of the locked channel is dispersion lights from a light-emitting window of the laser, so that optical light loss of signal channels is reduced. Moreover, the intensity of the portion of the dispersion lights is larger than the intensity of the atmosphere backward dispersion lights, so that a frequency locking efficiency is improved and a measurement precision of an atmospheric wind field can also be enhanced. Meanwhile, a caliber of the locking channel of the FP etalon can be reduced, so that processing cost of the FP etalon is substantially reduced; besides, the optical path system is simple, which is favor of adjustment of the optical path.

The invention discloses a transflective dual-edge doppler wind lidar based on a single-cavity F-P interferometer and a single detector. The doppler wind lidar comprises a single-cavity F-P interferometer as a frequency detector, wherein the transmission curve and the reflection curve of the single-cavity F-P interferometer form two edges. The intersection point of the transmission curve and the reflection curve of the single-cavity F-P interferometer locks the laser output frequency, so that the dual-edge wind speed detection technique is realized. The transflective dual-edge doppler wind lidar is designed based on the time division multiplexing technique. Since a low-loss fiber delay line is additionally arranged in the reflection light path of the single-cavity F-P interferometer, the transflective signals of the single-cavity F-P interferometer can be acquired at the same time by a single detector. The dual-edge detection technique is realized based on the single-cavity F-P interferometer and the single detector, and the transflective dual-edge doppler wind lidar has the advantages of high utilization rate of laser radar signals, high precision of wind speed detection, low cost, stable system, relative safety for human eyes, all-fiber-optic link, compact structure and the like.

Obtaining global tropospheric vertical wind profiles by directly detecting atmospheric winds using space borne, airborne and/or ground station platforms is accomplished by a DASH interferometer in the back-end of a Doppler wind LIDAR. In the front-end of the Doppler wind LIDAR, a laser illuminates an atmosphere and a telescope collects backscattered laser light return signals from the laser illuminated atmosphere. The DASH interferometer processes return signals from the atmosphere, forming an interferogram and determines from the interferogram a Doppler shift of the return signals, which is equivalent to determining the line of sight wind speed of the Doppler wind LIDAR observation, by measuring the frequency shift caused by winds. From this determination, global and/or non-global atmospheric wind profile data are transmitted over a communications network in either real-time and/or non-real-time, to facilitate weather forecasting, weather modeling, weather avoidance navigation, atmospheric research, hurricane warnings, operations systems selections and deployment of operational assets.

The invention discloses a microwave differential gain-based coherent Doppler wind lidar. According to the technical scheme of the invention, a balanced detector is connected with a bandpass filter, so that invalid signals, away from the Doppler frequency shift, are filtered and eliminated. A pre-amplifier is adopted to amplify an electrical signal outputted by the detector. Meanwhile, a power divider is adopted to divide amplified electrical signal into a monitoring channel and a detection signal. The detection signal is filtered by a pre-emphasis filter. The frequency-domain change of the detection signal is converted to the intensity change of the signal. Through the comparison with the monitoring channel and the transmittance curve of the pre-emphasis filter, the Doppler shift information is obtained. The interference of invalid echo signals is reduced. By adopting the pre-emphasis filter, echo signals are subjected to frequency discrimination, so that the computation amount of signal processing is reduced. The sensitivity and the signal-to-noise ratio of the system are improved. The coherent Doppler wind lidar is higher in resolution distance.

The invention discloses a portable wind gauging laser radar Doppler adjusting method which is characterized in that it arranges a Nd:YAG laser; the impulse light sent by the laser incidents into the rim of the illuminating rotation disk through the collimating mirror and the exiting aperture after weakening and delaying; the rotating of the rotation disk makes the brand light at rotation disk rim to generate Doppler frequency shift; the brand light with Doppler frequency shift signal is transmitted by another optic fiber after the receiving drive plate; the other input end of the melting optical fiber coupler generates crossfire signal as reference light which is coupled with the reflecting light with Doppler frequency shift signal by another optical fiber coupler after adjustable attenuator and achieves to wind gauging laser radar receiver to do signal analyzing and processing.

The invention discloses a data processing method for a wind measurement laser radar, and the method comprises the steps: obtaining the power spectrum of a plurality of signal sequences collected by the wind measurement laser radar in a current period; obtaining a peak point set of each signal sequence; judging whether each peak point set comprises a high signal to noise ratio peak point or not; taking the high signal to noise ratio peak point as an effective peak point if one peak point set comprises the high signal to noise ratio peak point, or else carrying out the tracking correlation of the peak point sets so as to search a real peak point; taking the real peak point as the effective peak point if the real peak point is found, or else determining that the peak point set does not contain the effective peak point; obtaining a radial wind speed matrix; and carrying out the wind field inversion through an observation matrix and the radial wind speed matrix, so as to obtain the wind speed vector of the current period. The invention also discloses a data processing device and system for the wind measurement laser radar, and a readable storage medium. Through the above mode, the system can improve the accuracy of a measurement result.

The invention discloses a Doppler anemometry laser radar radial wind speed real-time correction system. A very small part of laser is split in the system, and is couple to a self-built controllable atmospheric environment through a polarization coaxial optical path. An atmospheric echo signal in the environment is detected. A Doppler anemometry laser radar frequency discrimination system and a data acquisition system are used to inverse a measurement value in the state. At the same time, most of the laser is emitted to natural atmosphere. The echo signal is used to inverse the radial wind speed of natural atmosphere. The difference between the measurement value and the radial wind speed of natural atmosphere is true radial wind speed. According to the invention, the self-built atmospheric environment is controllable; the polarization coaxial optical path eliminates the influence of geometric factors; the system has a real-time calibration function; and the measurement accuracy of a Doppler anemometry laser radar is improved.

The invention discloses a polarization multiplexing-based direct detection wind lidar. based on the principle that laser beams having mutually perpendicular polarization states have different transmittance curves when passing a Fabry-Perot interferometer, a continuous laser beam is divided into two branches having the mutually perpendicular polarization states by the polarization multiplexing technique, one branch is used to detect the atmospheric wind field after subjected to pulse modulation, the other branch is used to lock laser frequency, the two branches share the Fabry-Perot interferometer, and the two branches are combined, separated and detected with a polarization-maintaining combiner and a polarization splitter. The use of one Fabry-Perot interferometer allows frequency shift detection and frequency tracking and locking to be simultaneous; compared with the system comprising a multi-channel Fabry-Perot interferometer or multiple Fabry-Perot interferometers, the lidar has lower cost, compacter structure and higher stability.

The invention provides direct detection anemometry laser radar system and anemometry method based on double working wavelengths. The working wavelengths of the system are in an optical communication band of 1.5 micrometers. A full optical fiber structure is used. Space optical components are not used. The anemometry method uses double working wavelengths. Two working wavelengths respectively occupy odd pulse and even pulse. The frequency positions of two working wavelengths are respectively located at symmetric positions on left and right sides of the transmittance peak of an optical fiber Fabry-Perot discriminator (FFPI). By measuring the transmittance change of an echo signal on two edges of a transmittance curve, Doppler frequency shift is acquired, and radial velocity inversion is carried out. According to the invention, only a single-channel Fabry-Perot interferometer is used; an optical path structure is simplified; the cost is reduced; the number of calibration coefficients which need to be acquired in a calibration process is reduced; unsynchronized changes which are caused due to the fact that a number of channels of the discriminator change with vibration, temperature difference and other environment changes in a double edge technology are avoided; and the system stability is improved.

The invention relates to a lag angle compensation device and a lag angle compensation precision correction method of a satellite-borne wind-detecting laser radar system and belongs to the field of measuring technologies. A lag angle compensation module inside the device is located behind a double-telescope optical scanning system; when a system normally works, echo lasers are transmitted to the lag angle compensation module through the double-telescope optical scanning system and then transmitted to peripheral equipment after compensation of the lag angle compensation module; in the process of lag angle compensation precision correction, a movable insertion type reflection mirror is located on the optical path behind the lag angle compensation module, and a beam expander is placed on one side of the movable insertion type reflection mirror and located at the front end of an area array photoelectric detector; the output end of the area array photoelectric detector is connected with the input end of a control signal processing module; the output end of the control signal processing module is connected with the input end of the lag angle compensation module. The lag angle compensation device and the lag angle compensation precision correction method of the satellite-borne wind-detecting laser radar system have the advantages of being dynamically adjustable in compensation angle and capable of using closed loop detection for precise correction.

The invention discloses an anemometry lidar device and which includes a seed laser device used for producing linear polarization continuous lasers; a beam splitter used for dividing narrow linewidth continuous lasers produced by the seed laser into two parts, wherein a part is output as seed lights from a first output terminal, and the other part is output as local oscillator lights from a secondoutput terminal; an optical transceiver antenna used for transmitting the seed lights from the second terminal to the atmosphere and receive echo signals; an adjustable light delay line used for delaying the local oscillator lights; a signal acquisition and processing module used for estimating wind speed by using the delayed local oscillator lights and the echo signals, thereby obtaining radial wind speed in the current scanning direction. Through the above method, the anemometry lidar device is capable of significantly reducing the requirement for the seed laser, reducing the cost of lidar system, and reducing the purchase difficulty of the seed laser.

The invention discloses a device for locking a laser frequency of seed light based on a seed injection type laser. The device comprises the seed injection type laser, an electrooptic modulator, a tunable F-P etalon, a beam splitting sheet, a photoelectric detector, a data acquisition and analysis unit and an F-P etalon controller, wherein the seed injection laser is used for outputting a continuous seed laser with the wavelength of 1064nm; the data acquisition and analysis unit is used for obtaining a transmissivity measured value of the locking laser on a locking channel of the tunable F-P etalon according to a segmentation proportion of the locking laser and comparing the measured value with a frequency locking reference value and controlling the tunable F-P etalon controller for carrying out regulation if the measured value is different from the frequency locking reference value so that the transmissivity measured value is kept in the frequency locking reference value. According to the device, the signal to noise ratio and the accuracy of luminous intensity measurement in frequency locking can be improved, and the measurement precision of a Rayleigh anemometry laser radar system is improved.

The invention discloses coherent laser radar for simultaneously detecting atmosphere wind speed and the depolarization ratio. The coherent laser radar mainly comprises a light source emitting module (L), polarization frequency mixing modules (S and P) and a signal processing module 15. Echo signals are divided into S polarization light and P polarization light through polarization beam splitters in the polarization frequency mixing modules (S and P), liner polarization local oscillator light is converted into circular polarization light through a quarter-wave plate, the circular polarization light is divided into S polarization light and P polarization light through the polarization beam splitters, and the S polarization light, the P polarization light and signal light in a corresponding polarization state are subjected to frequency beating. According to the scheme, the utilization rate of the echo signals of the coherent wind measuring laser radar can be increased, and the performance of the coherent wind measuring laser radar can be improved; the signals in different polarization states are measured, the depolarization ratio of aerosol is measured, and detection of the coherent wind measuring laser radar on the condition of the aerosol is achieved.

The invention discloses a hybrid wind-measuring laser radar with the integration of the technologies of a coherent laser radar and a direct laser radar. An optical frequency discriminator is used in alaser radar system, echo signal light is divided into two beams of light including Doppler frequency shift information, the beat frequency of the two beams of light and local-oscillator light is carried out, and two balance detectors are used for detection. For intermediate frequency current signals output by the balance detectors, a carrier-to-noise ratio is calculated directly from a time domain, and according to a proportional relationship between the carrier-to-noise ratio and signal intensity, the light intensity information of the signal light can be obtained. Further, a wind speed is calculated according to a method of inverting the wind speed by directly using a wind-measuring laser radar technology. According to the wind-measuring laser radar, the balance detectors are used to detect the light intensity information of the signal light, the optical frequency discriminator is used to identify the Doppler frequency shift information, the technologies of the coherent laser radarand the direct laser radar are combined, the requirement on the computing power is low, and the method has the advantages of compact structure, low cost and high precision.

The invention discloses a direct wind lidar based on the difference stimulated Brillouin gain effect. In the scheme, a continuous laser device is adopted as a light source, after being modulated through a phase or intensity modulator, carrier frequency light of the laser device is used as detection light, and light with frequency at the two sides is used as double-frequency pump light for generating stimulated Brillouin scattering in optical fiber. Atmosphere echo signals and the double-frequency pump light are transmitted oppositely in the optical fiber, the signals carrying Doppler shift generate energy change due to stimulated Brillouin scattering, energy change is detected by a detector, wind speed information of the atmosphere echo signals can be obtained, and a frequency discrimination device is formed by the system. As the frequency discrimination device is used, the laser outgoing frequency is fixed to the middle point of the spacing distance between an absorption peak and a gain peak on a frequency spectrum, and laser frequency does not need to be locked. The lidar system has the advantages of being stable, high in measurement accuracy, low in cost, simple and compact in structure and the like.

The invention discloses a three-body-combined offshore laser radar wind measuring buoyage. The three-body-combined offshore laser radar wind measuring buoyage comprises a buoy, a wind measuring laser radar, a motion sensor module, a fan assembly, storage batteries, meteorological measurement modules, a seawater measurement module and a mooring system for positioning, wherein the wind measuring laser radar, the motion sensor module, the fan assembly, the storage batteries, the meteorological measurement modules and the seawater measurement module are mounted on the buoy. The buoyage can combine the laser radar and the ocean buoy and has advantages in cost and use flexibility in a working process for finishing corresponding offshore wind profile measurement; further, the buoy adopts a three-body-combined structure, the motion response amplitude in waves is smaller, the hydrodynamic performance is excellent, the structural components are convenient and easy to dismount and assemble, the size of the buoyage is relatively small and can meet the requirement for loading into a standard container, package and transport of the whole system by the container can be realized, requirements of land transportation and sea transportation can be met, and the buoyage has the advantages of convenience, rapidness, high flexibility, high price/performance ratio and the like in an optional mode of transportation.

The invention discloses a compound-system Doppler anemometry laser radar. The laser radar is the compound-system Doppler anemometry laser radar in which a coherent detection method and a direct detection method are combined. The laser radar can be used for the fields of laser detection, atmosphere detection and photoelectric detection, and the technology is different from the stripe imaging technology based on a Fiso interferometer and adopted by ALADIN at low altitude and the double-edge technology based on a Fabry-Perot etalon and adopted at high altitude. According to the technical scheme,a coherent detection method is adopted at the low altitude and the direct detection method is adopted at the high altitude for measuring a wind field, wind field detection coverage at the height of 0-30 km, the advantage of high background noise resistance of the coherent detection technology can be fully exerted in low-altitude detection, detection under the shot noise extreme can be achieved, and the advantage of higher detection precision is achieved.