Abstract: Systems and methods for sensing air includes at least one, and in some embodiments three, transceivers for projecting the laser energy as laser radiation to the air. The transceivers are scanned or aligned along several different axes. Each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines air temperatures, wind speeds, and wind directions based on the scattered laser radiation. Applications of the system to wind power site evaluation, wind turbine control, traffic safety, general meteorological monitoring and airport safety are presented.

Abstract: A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Abstract: A laser Doppler velocimeter uses self-mixing amplification of backreflections from scatterers below the surface of a flow. A time domain signal is divided into segments that are roughly equal to a transit time of particles through a focus of a laser beam. The segments are connected to a frequency domain through the use of an FFT algorithm to produce frequency domain data segments. Signal-to-noise ratio is enhanced through signal processing techniques using the segments to produce a final enhanced signal spectrum.

Abstract: An apparatus for the recognition an object in space in accordance with the pulsed time-of-flight principle. The apparatus has a pulsed laser and a photoreceiver arrangement which receives the light pulses reflected back from the object present in the space. The apparatus has a first light deflection apparatus which outputs a first angular position signal representative of its instantaneous angular position to the evaluation circuit, wherein the first light deflection apparatus is arranged rotatably or pivotably about a first axis of rotation and is made for the transmission of light pulses following one another at changing angles in a first plane, wherein a second light deflection apparatus is arranged between the first light deflection apparatus. The apparatus outputs a second angular position signal representative of its instantaneous angular position to the evaluation circuit which has a deflection plate which is arranged rotatably or pivotably about a second axis of rotation.

Abstract: The present invention relates to a frequency shifter in an optical path containing a pulsed laser source, and it is characterized in that it comprises at least one frequency shifter (12, 13) containing an optical propagation medium, the optical path length of which is modified according to the desired frequency shift during at least one pulse among n consecutive pulses from the laser, where n?1.

Abstract: A system according to one embodiment includes a light source for generating light fringes; a sampling mechanism for directing a particle through the light fringes; and at least one light detector for detecting light scattered by the particle as the particle passes through the light fringes. A method according to one embodiment includes generating light fringes using a light source; directing a particle through the light fringes; and detecting light scattered by the particle as the particle passes through the light fringes using at least one light detector.

Abstract: A stage configuration is provided, wherein a ceramic plate is used as the z-stage body to decrease the use of the metal plates in the conventional configuration, so that the compact structure of the z-stage may decrease the vibrational movements of the z-stage. Further, two Laser interferometer are used to detect a movement of different points along a vertical line of the z-stage sidewall to calculate a movement of the specimen surface, so that a horizontal movement of the specimen surface can be detected more accurately.

Abstract: A nanoindenter that includes an interferometer, a rod, a force actuator and a controller is disclosed. The interferometer generates a light beam that is reflected from a moveable reflector, the interferometer determining a distance between a reference location and the moveable reflector. The rod is characterized by a rod axis and includes a tip on a first end thereof, the rod includes the moveable reflector at a location proximate to the tip. The tip is disposed in a manner that allows the tip to be forced against the surface of a sample. The force actuator applies a force to the rod in a direction parallel to the rod axis in response to a force control signal coupled to the actuator. The controller receives the determined distance from the interferometer and generates the force control signal. The invention can also be used as a scanning probe microscope.

Abstract: 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.

Abstract: A gas nozzle measurement apparatus comprises a controllable gas source to provide across a gas plate having gas nozzles, a flow of gas at a constant pressure or constant flow rate, and a sensor plate sized to cover an area comprising at least a portion of the front face of the gas plate. The sensor plate comprises gas flow sensors arranged in locations that correspond to positions of individual gas nozzles of the gas nozzles of the gas plate such that each gas flow sensor can measure a pressure, flow rate, density, or velocity of a gas stream passing through the individual gas nozzle that faces the gas flow sensor, and generate a signal indicative of, or display, the pressure, flow rate, density, or velocity of the gas stream passing through the individual gas nozzle.

Abstract: Methods and systems for collecting high-density wind velocity data for the inflow area of a wind turbine are presented. Wind turbines are provided with one or more wind velocity sensors that provide a plurality of wind velocity measurements to the turbine from various ranges and locations across the inflow. Sensors are proximate to the wind turbine. Sensors mounted on the turbine's nacelle work collaboratively to provide the wind velocity measurements. Sensors mounted on the turbine's hub spin with the turbine blades. Spatial and temporal wind mapping provides improved fidelity of data to the wind turbine control system.

Abstract: A flight control system is configured for controlling the flight of an aircraft through windshear conditions. The system has means for measuring values of selected flight performance states of the aircraft and a control system for operating flight control devices on the aircraft. A windshear detection system located on the aircraft uses at least some of the measured values of the selected flight performance states to calculate a gust average during flight for comparison to pre-determined values in a table for determining whether windshear conditions exist. The control system then operates at least some of the flight control devices in response to an output of the windshear detection system.

Abstract: A method and apparatus for determining gas velocity, which includes generating transmitted radiation having an expected transmission frequency, detecting backscattered radiation, and determining gas velocity in dependence upon any Doppler shift of the frequency of the backscattered radiation, determining a transmission frequency of the transmitted radiation; detecting any difference between the measured transmission frequency and the expected transmission frequency and generating a feedback signal therefrom, and determining gas velocity using said feedback signal.

Abstract: The subject of the present invention is a laser anemometry probe for optical homodyne detection of frequency offset by Doppler effect, comprising two devices (DERF1, DERF2) for transmitting/receiving beams in two different directions, avoiding duplicating a plurality of elements of a mono-axial laser anemometry probe.

Abstract: A light angle detection device according to an embodiment of the present invention includes a first light receiving lens, a first light sensing element, a second light receiving lens, and a second light sensing element. The first and second light receiving lenses and the first and second light sensing elements are disposed such that a first straight line passing through the center of the light receiving surface of the first light sensing element and the vertex of the first light receiving lens, a second straight line passing through the center of the light receiving surface of the second light sensing element and the vertex of the second light receiving lens, and a third straight line passing through the center of the light receiving surface of the first light sensing element and the center of the light receiving surface of the second light sensing element form an isosceles triangle.

Abstract: An optical perturbation sensing system includes a probing beam incident on a medium with perturbations and a sensing beam redirected from the medium and incident on a surface area of a photodetector. A reference beam directed onto the photodetector surface forms, with the sensing beam, an interference pattern on the photodetector surface and a phase patterner with at least two phase regions across its section, generates different phases in different regions of the interference pattern. An array of photodetector elements detects each phase region of the interference pattern and a constructive combiner subtract pairs of the detected signals, squares the subtracted signal squares, and sums the squared signals to form a stronger detected signal with reduced intensity noise, reduced background noise, and reduced sensitivity to phase drifts.

Abstract: A physical quantity sensor has a semiconductor laser, a laser driver for providing, to the semiconductor laser, a driving electric current that is a waveform wherein the maximum portions and minimum portions of a triangle wave have been rounded; detecting means (a photodiode and a current-voltage converting amplifier) for detecting an electric signal that includes an interference waveform that is produced by the self-coupling effect between a laser beam that is emitted from the semiconductor laser and a return beam from a measurement object; and measuring means (a filter circuit, a counting device, and a calculating device) for calculating a physical quantity for the measurement object from interference waveform information.

Abstract: An object of the present invention is to provide a method for preventing turbulence-induced accidents that can expand a detection range to about 20 km without increasing the size of a device or increasing the energy consumption, can perform planar distribution monitoring of turbulence when the turbulence is detected in the flight direction and also can output a signal for autopilot steering input that decreases the fuselage shaking when the turbulence is difficult to avoid, as well as to provide a device having those functions.

Abstract: The invention relates to sensors of the speed of movement of a vehicle over the ground. The sensor comprises illumination means for illuminating the surface and at least one optical sensor able to detect the radiation returned by the surface. The illumination means and the optical sensor have one and the same optical axis, oblique in relation to the surface. This arrangement eliminates the risks of specular reflection dazzling the sensor while avoiding disturbance of the measurement by variations in the height of the sensor relative to the ground.

Abstract: A process for measuring speed or vibration characteristics using a LIDAR device allows the separation of a useful contribution and an interfering contribution in a backscattered signal. To this purpose, a phase characteristic of an optical wave emitted in the direction of a target volume is modulated. The interfering contribution, which originates from a source at a distance from the target volume, appears with variable shifts of said phase characteristic in a heterodyne detection signal. An accumulation then isolates the useful contribution, from which a result is obtained for the speed or vibration measurement. The process can be implemented with a frequency modulation or phase modulation of the optical wave.

Abstract: There is provided a system for forming an optical screen, including a continuous wave or pulsed laser transmitter for transmitting a beam of radiation at a predetermined wavelength and forming a planar or curved surface to be traversed by a moving object, at least one receiver including an array of detectors for receiving reflected or scattered beam radiation from the object and directing it towards the detectors for producing a signal, and a detection logic receiving the signal and determining parameters selected from the group of spatial position, velocity and direction of propulsion of them moving object. A method for detecting a moving object is also provided.

Abstract: A system for monitoring wind characteristics in a volume including a plurality of non-coherent laser anemometers operative to measure wind characteristics in a plurality of corresponding sub-volumes located within the volume and a data processing subsystem operative to receive data from the plurality of non-coherent laser anemometers and to provide output data representing the wind characteristics in the volume.

Abstract: The invention relates to an opto-electronic sensor arrangement (10) with an optical transmitter (20) and an optical receiver (30), such that the optical transmitter (20) and the optical receiver (30) are so positioned that they either form an optical scanner designed as an optical scanner with background gating or form a reflecting light barrier in conjunction with a reflector (60), and such that the optical receiver (30) has a detector (32) in which successive images of the light beam (30a) reflected from the object (50) are detected and are compared in an evaluating unit (36), and the outcome of the comparison provides information on the movement of the object (50) relative to the optical receiver (30), so that the detector exercises a movement function.

Abstract: A method of studying a surface using an interferometer, in which there is relative motion between the surface and the interferometer, the motion having a total velocity Vtot which includes a transversal or traversing component Vt and a longitudinal component Vl.

Abstract: An image pickup device for detecting a moving speed of a shot object and a method thereof are described. First, a coordinate of the image pickup device and a coordinate of the shot object are obtained at a first time point. Next, a coordinate of the image pickup device and a coordinate of the shot object are obtained at a second time point. Then, a moving distance of the shot object is calculated according to the coordinates of the shot object at the first and second time points. A moving speed of the shot object is calculated according to a time difference and the moving distance. Afterward, the obtained moving speed is displayed on the image pickup device, such that the user knows about the moving speed of the shot object.

Abstract: A process for the detection from a vehicle of a visibility interference phenomenon, comprising the following steps: the emission of a beam of light to illuminate the rear of the vehicle, the beam of light being emitted into a field of vision of a camera mounted in the vehicle, and the determination of a presence and the nature of a visibility interference phenomenon on the basis of at least one image captured by the camera.

Abstract: A laser driver (4) causes a semiconductor laser (1) to operate such that a first oscillation period of monotonically increasing the oscillation wavelength and a second oscillation period of monotonically decreasing the oscillation wavelength alternately exist. A photodiode (2) converts laser light emitted from the semiconductor laser (1) and return light from a measurement target (12) into electrical signals. A counting unit (13) counts the number of interference waveform components obtained from an output signal from the photodiode (2) in each of the first oscillation period and the second oscillation period. A computing device (9) calculates the distance to the measurement target (12) and the velocity of the measurement target (12) from a shortest Lasing wavelength and a longest Lasing wavelength in a period during which the counting unit (13) counts the number of interference waveform components and the counting result obtained by the counting unit (13).

Abstract: The non-contact measurement probe is capable of dimensional measurement of a workpiece while it is being machined, and reporting dynamic error for real-time compensation by the machining tool. Measurement includes diameter and roundness of the workpiece. The measurements are automatically fed back to a machine controller for intelligent error compensation. Based on known laser Doppler techniques and real time data acquisition, the probe delivers dimensional accuracy at few microns over a range of 100 mm. The measurement probe employs a differential laser-Doppler arrangement, allowing acquisition of information from the workpiece surface. Moreover, the measurements are traceable to standards of frequency allowing higher precision.

Abstract: An L2F velocimeter comprises a probe for insertion into a fluid, the probe having an open area therein to allow the fluid to pass through. The probe comprises an illumination system to direct a pair of light beams, separated by a distance, through the open area, and a collection system to collect forward scattered light scattered from particles in the fluid. The collection system has an optical axis in common with the illumination system. The velocimeter further comprises an electro optical assembly connected to the probe to provide light to the illumination system, to receive light collected from the collection system, to measure a lapse time in fluctuations of the forward scattered light created by particles passing through the pair of light beams and to calculate the velocity of the fluid based on the lapse time and the separation distance.

Abstract: Method of measuring the velocity of an aircraft at a given instant, by laser Doppler anemometry, by performing the steps of acquiring a backscattered signal on at least three oriented line-of-sight axes, and calculating the spectrum of the backscattered signal on each of the line-of-sight axes. Further, acquiring an additional backscattered signal on at least one additional line-of-sight axis (X4) not coincident with one of the three first line-of-sight axes (X1, X2, X3), and calculating the spectrum of the backscattered signal on the additional line-of-sight axis (X4). Several candidate velocity vectors ({right arrow over (V)}c) and of the projections of the candidate vectors on at least one line-of-sight axis (X1, X2, X3, X4) are calculated. The consistency of the candidate vectors ({right arrow over (V)}c) is calculated as a function of their projections and as a function of each spectrum of the corresponding backscattered signal on the respective calculation axis (X1, X2, X3, X4).

Abstract: A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Abstract: Optical Coherence Tomography (OCT) is a high-resolution, non-invasive technique to image subsurface tissue and tissue functions. A broadband light source illuminates an object and the reflected photons are processed using an interferometer, demodulated into inphase and quadrature components and then digitized. The captured data contains information about the velocity of the moving scatterers but current Doppler estimation algorithms have a limited velocity detection range. Using a two dimensional velocity estimation, Doppler OCT (DOCT) can be used for the detection of in vivo aortic blood flow rates of over 1 m/s peak velocity through an esophageal DOCT probe. Previous methods have used a transverse Kasai (TK) autocorrelation estimation to estimate the velocity which is good for slow velocities, such as in the microvasculature. By calculating the Kasai autocorrelation with a lag in the depth or axial direction, backscattered frequency information is obtained which yields high velocity rate information.

Abstract: A method and optical module for measuring relative movement of an input device and object (15) along at least one measuring axis. A laser device (3) having a laser cavity is provided for generating a measuring beam (13) in respect of each measuring axis. The measuring beam (13) is used to illuminate the object (15) and measuring beam radiation reflected from the object (15) and re-entering the laser cavity generates a self-mixing effect in the laser and causes changes in operation of the laser cavity. A detector (4) is used to generate a measurement signal representative of these changes and an electronic processing circuit (18) selects, in dependence on the speed of relative movement, one of at least two parameters of the measurement signal for use in determining the speed and direction of relative movement.

Abstract: This useful model relates to fiber-optic fluid/gas flow rate measurement transducers and is employed in gas/fluid flow measuring systems, and can be used for water or natural gas consumption monitoring, especially in measuring systems intended for fluid/gas flow monitoring in pipelines and oil/gas wells. The transducer includes optic fiber which comprises at least one Bragg's fiber lattice, wherein the said Bragg's fiber lattice is fitted with at least one concentrator of mechanical stresses which originate in the optic fiber during its interaction with the gas/fluid flow. As a result, the transducer sensitivity increases.

Abstract: A device and method for measuring moving material includes a processor and operating software associated therewith; a light source for emitting at least two polarized light beams in a manner wherein the beams cross thereby creating an interference region and generate a set of fringes; a sensor aligned relative to the interference region wherein the fringes have a predetermined orientation to the directional movement of the material and wherein the sensor is operably equipped to receive scattered light emanating from the interference region and provide a time varying signal to the processor such that the processor can manipulate and convert the signal to speed and distance and a polarizing filter operably associating a polarizing filter with one of the sensor and the emitting means in a manner to substantially preclude reflected polarized light from the interference region back to one of the sensor and the emitting source.

Abstract: A device of detecting light reflecting speed and directions includes a light source, a light-guided pulley, a reflector, photo detectors, barriers, a processor and a display unit. The light source generates incident light, the light-guided pulley is located at one side of the light source, and includes a support moving along the pulley track. The reflector is installed on the support to reflect the incident light. The photo detectors detect the incident light reflected by the reflector. The barriers are located at two sides of the light source and make the incident light to be a light beam and travel in straight line direction. The barriers are respectively installed between said photo detectors to isolate the incident light. The processor receives the light signals transmitted from photo detectors and processes the light reflecting speed and directions according to the light signals. The processed result is displayed on the display unit.

Abstract: A velocimetry apparatus and method for the collection of target-specific images of fluid motions are disclosed. The apparatus includes a camera and a light source. The camera collects and provides images of the fluid showing instantaneous positions of particles in the fluid. The light source provides a light sheet (two-dimensional) or volume (three-dimensional) to illuminate the particles. The camera and the light source are powered by portable energy sources and measure instantaenous velocity of the fluid in a field of view. Shape and distance between first camera, the light source and the portable energy sources are so configured that the apparatus is a self-contained apparatus portable by a diver during operation thereof.

Abstract: A technique is disclosed which offers an improvement in the performance of an atom interferometric (AI) sensor, such as one that is used in an accelerometer or a gyroscope. The improvement is based on the recognition that the AI-based device, which is associated with superior low-frequency performance, can be augmented with a conventional device having a superior high-frequency performance, as well as a wider frequency response, compared with that of the AI-based device. The disclosed technique combines acceleration measurements from the AI-based device, which is characterized by transfer function G(s), with acceleration measurements from the conventional device that have been adjusted by a complementary function, 1??(s), where ?(s) is an approximation of G(s). The conventional device has a considerably wider bandwidth than that of the AI-based device, and the quasi-unity transfer function of the conventional device makes possible the 1??(s) adjustment of the measurements provided by the conventional device.

Abstract: A sensor device for detecting a motion state of a motor vehicle. The sensor device includes at least one laser unit having a light source for emitting coherent light which is transmitted in the direction of a roadway surface, and an interference detector which is designed to detect at least one measurement variable which characterizes interference between the light scattered at the surface and the light of the light source. The measurement variable represents a speed component of the sensor device and/or a distance between the sensor device and the roadway surface. The laser unit is coupled to an evaluation device which is designed to determine, from the measurement variable, at least one variable which characterizes the motion state of the vehicle, in particular a speed component of the center of gravity of the vehicle, a rotational angle or a rotation rate of the vehicle.

Abstract: A system and method for correcting wind speed and direction data collected by a sodar or lidar apparatus for the orientation and/or position of the apparatus. There are sensors mounted to the sodar or lidar apparatus that detect the orientation and position of the apparatus. Software is used to adjust in situ the calculations of wind speeds and directions in three dimensions for deviations from some nominal orientation. Software and data structures can be used to cause the inclusion of the orientation and position of the system with the collected data.

Abstract: A method and apparatus are provided for non-contact optical flow measurement in a pipe, the apparatus having one or more modules configured to sense light that is scattered off several points longitudinally along a wall of a pipe having a medium flowing therein and to provide a signal containing information about a deflection of the wall of the pipe that can be used to determine a parameter related to the medium flowing in the pipe, including a flow rate of the medium. The deflection in the pipe wall is caused by a turbulence induced pressure fluctuation which in turn induces a localized pipe wall deflection.

Abstract: A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Abstract: Sensing results from moving objects, e.g. from photosensing emanating light or from impedance-based sensing, can indicate sensed time-varying waveforms with information about objects. For example, a sensed time-varying waveform can be compared with another waveform, such as a reference waveform produced by objects of a certain type, to obtain comparison results indicating motion-independent information about the object; time-scaling can adjust for displacement rate such as speed. Also, a modulation periodicity value can be obtained from a sensed time-varying waveform and used in obtaining information about an object; for example, a periodic modulation frequency can be used with a given time's chirp frequency to obtain phase information about an object's position. Or, where periodic modulation frequency indicates displacement rate, time scaling during comparison can use a scaling factor based on the frequency.

Abstract: In an electron beam interference system using an electron biprism, which is capable of independently controlling each of the interference fringe spacing s and the interference width W, both of which are important parameters for an interferometer and for an interferogram acquired by the interferometer, an optical system used in a two-stage electron biprism interferometer is adopted. The optical system uses two stages of electron biprisms in an optical axis direction to give the flexibility to the relative magnification relative to a specimen image and that relative to an image of a filament electrode of the electron biprism. In addition, as a two-stage configuration in which two objective lenses (51, 52) are combined, independently controlling the focal length of each objective lens makes it possible to set the relative magnification relative to a specimen image and that relative to an image of the filament electrode of the electron biprism at arbitrary values.

Abstract: Methods and apparatus are provided for integrating various optical components onto a planar substrate using a single semiconductor material system to produce an accelerometer. A light beam is generated on the semiconductor optical accelerometer. The light beam is split to form two light beams using a multimode interference (MMI) coupler. One of the two light beams that is formed is directed towards a reference mirror and the other is directed towards a flexured mirror. The flexured mirror moves as a result of acceleration and thereby reflects the light beam with a different light beam characteristic. The light beams are combined by the MMI coupler to produce an interference light beam. A microprocessor measures acceleration based on the differences in light beam characteristics of the reflected light beams. Along the optical path light beam detectors measure various beam characteristics. The microprocessor accounts for characteristics measured by the detectors when computing acceleration.

Abstract: Indicating relative speed is disclosed. A first grating coupled to a first moving object is illuminated using a coherent light source to generate a first diffracted beam and a diffracted order beam. A second grating coupled to a second moving object is illuminated using the first diffracted beam and the second diffracted beam to generate a third diffracted beam and a fourth diffracted beam. The third diffracted beam and the fourth diffracted beam are measured. A relative speed of the first moving object with respect to the second moving object is indicated based at least in part on the measured third diffracted beam and the measured fourth diffracted beam.

Abstract: A method and apparatus for laser Doppler velocity measurements with a fixed difference, dual beam receiver and using a non-laser, stable frequency reference.

Abstract: A wind anemometer comprises a light source for transmitting pulsed light signals, a receiver for receiving backscattered signals from airborne particles for each pulse of the transmitted pulsed light signals, a detector for detecting the received backscattered signals, and a processor to determine location of the airborne particles with respect to the anemometer based on the detected backscattered signals. The processor estimates wind velocity using changes in location of the airborne particles over at least one time interval.

Abstract: Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Abstract: A coherent Doppler lidar which can oscillate high energy pulses and output laser beams in a longer wavelength range of 1.5 ?m to the atmosphere is provided. The coherent Doppler lidar has a pulse laser an oscillation wavelength of which is controlled by means of injection locking of a seed light output from a master laser, wherein the pulse laser is a type in which a laser medium is disposed in a resonator, a pulse light of a predetermined repetition frequency is input to the laser medium as an excitation light, whereby pulse laser oscillation is generated in the resonator to output pulse laser beams from the resonator, and the laser medium being a type which has at least a region having Tm, Ho:YAG ceramics, and is excited by the excitation light to output pulse laser beams in 2 ?m wavelength band.