A three-axis, non-scanning, self-referenced laser air data sensing system comprises a support having three separate laser diodes providing beams of coherent light, which beams are directed toward separate beam expander mirrors. The expander mirrors reflect an expanding beam back toward a focusing mirror that focuses the beams along three diverging axes at known angles to each other at three separate locations in space. The focused beams form small detection cell regions through which particles in the fluid pass and reflect light. The reflected light is received back along the same paths as the transmission of the source light, and is directed back toward detectors on the base. The reflected light undergoes a Doppler shift, and this reflected light is combined with a reference signal tapped from one of the other of the three coherent light sources for heterodyning the signals for determining the Doppler shift and thus the relative velocity.
A device for measuring air turbulence in the surroundings of an aircraft includes a measurement system having lidars which are mounted on the aircraft and which are intended to carry out, during a flight of the aircraft, twelve measurements of aerodynamic velocity in the environment surrounding the aircraft. The measurement system carries out the twelve measurements at four different measurement points, each time according to three predetermined axes. A central unit which, with the aid of the aerodynamic velocity measurements and of a first order predetermined mathematical model describing an aerodynamic velocity field as a function of twelve variables, determines an aerodynamic velocity field which exists in the environment of the aircraft and which is representative of the air turbulence.
A piezoelectric transformer with multiple outputs comprises a piezoelectric plate, a first input electrode being formed on the top surface of the piezoelectric plate, a second input electrode being formed on the bottom surface of the piezoelectric plate, a plurality of first output electrodes being electrically isolated from each other, being formed on the equally divided remaining portions of the top surface of the plate along a diagonal line, and a second output electrode formed on the remaining portions of the bottom surface of the plate, thereby providing a stabilizer for lighting lamps without a ballast capacitor by supplying a regular voltage to more than two fluorescent lamps.
A method and apparatus for detecting small shifts in optical wavelength is provided. Light having a known wavelength is directed towards a target volume in the atmosphere. Light reflected from the target volume is received and mixed with differentially delayed copies of itself to produce three interference signals. The interference signals are taken at delays spanning one-half the wavelength of the transmitted signal. The intensity of the signal at the three different delays is measured simultaneously, from which the wavelength of the reflected signal can be determined.
A first beam of light from a laser is split by a beam splitter into a reference beam and at least one second beam of light, the latter of which is directed from an optical head into an atmosphere. Light from the at least one second beam of light scattered by molecules or aerosols in the atmosphere is collected by a corresponding at least one telescope of the optical head as at least one light signal. The at least one light signal and the reference beam are simultaneously processed by different portions of a Fabry-Perot interferometer, and resulting fringe patterns are imaged onto a detector and processed by a data processor to determine at least one associated air data product.
At least one second beam of light from a first beam of light generated by a laser is directed into an atmosphere. Light therefrom scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal, which together with a reference beam from the first beam of light are simultaneously processed by an interferometer, and resulting fringe patterns are imaged onto a detector adapted to output a resulting at least one signal responsive thereto. A data processor determines at least one air data product responsive thereto.
