Abstract: A laser Doppler velocimeter is formed using erbium-doped fiber as the lasing medium. The fiber is diode-pumped. By properly modulating the lasing in the fiber, pulses of radiation may be generated. A telescope acts as the transmission device to focus the radiation at a specified point, and may also act as the receiving system for reflected radiation. The portion of the reflected radiation collected by the receiving system is analyzed to determine the Doppler shift caused by aerosols or objects at the focal point of the telescope.

Abstract: A laser Doppler velocimeter is formed using erbium-doped fiber as the lasing medium. Within the velocimeter, all optical signals, transmitted and received, are handled by optical fibers. A telescope with a single optical fiber input/output interface acts as both the transmission device to focus the radiation at a specified point, and as the receiving system for collecting reflected radiation. The portion of the reflected radiation collected by the receiving system is analyzed to determine the Doppler shift caused by targets at the focal point of the telescope.

Abstract: A laser doppler velocimeter system for wind shear detection comprising means for generating a beam of radiant energy, an optical system coupled to the beam for directing a first portion of the beam a predetermined distance to a scatterer of radiant energy, means coupled to the beam for conducting a second portion of the beam through a polarization preserving medium, the length of the medium substantially matching the predetermined distance, means for mixing the second portion of the beam with the radiant energy reflected by the scatterer and means coupled to the means for mixing for measuring a component of the velocity measurements of the scatterer. The velocity includes both horizontal and vertical components. The system may also be adapted for measurement of multiple predetermined distances by using multiple means for conducting a second portion of the beam, each of said multiple means having a length substantially matching one of the multiple predetermined distances.

Abstract: Induced fluorescence of air molecules is used to determine air data parameters such as barometric altitude. The air molecules at a sample location are caused to fluoresce by means of a suitable energy source. A detector having an effective field of view including the sample location measures the fluorescence emitted by the air molecules in the detection sample (the portion of the fluorescing region viewed by the detector). By the use of appropriate filters and/or appropriate selection of the energy source, it is possible to measure fluorescence only from a particular type of air molecule. Since the measured intensity is proportional to the number of excited air molecules, it is possible to compute the density of the air, the static pressure of the air, the partial density and pressure of any individual molecular species, and/or the barometric altitude.

Abstract: A uniquely configured radiation fringe velocimeter is used to measure all three components of velocity remotely from a single point. The device is particularly intended for utilization aboard an aircraft, in which case the velocity being measured may be that of aerosol particles or other scattering centers in the free airstream at a location spaced apart from the surface of the aircraft and thus for the most part, free from any associated turbulence effects, etc.

Abstract: A radiation fringe velocimeter subsystem and a subsystem for determining air density related parameters, are combined into a single optical system (20) which permits various important parameters associated with the operation of an aircraft to be measured at a sample location at a sufficient distance from the aircraft (or any physical attachment thereto) so that the measurements will not be subject to systemic errors such as those caused by air compression effects and airflow disturbances, and which does not require that any Pitot tubes, pressure ports or other similar mechanical devices protrude into the airstream where the measurements are to be made.