초록 ▼

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

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. The device utilizes known optical techniques for splitting and modulating coherent light into three beam pairs focused onto a common detection volume such that three sets of three-dimensional fringe plane patterns are formed at the detection volume, each of the three sets being aligned along a different fringe plane normal vector and moving in the direction of the corresponding fringe plane normal vector at a different predetermined apparent velocity and/or fringe spacing whereby each of the three different sets of fringe patterns will modulate the intensity of the radiation scattered by an aerosol particle at a fixed location within the detection volume with a characteristic modulation frequency. The beams are oriented with respect to one another at the detection volume such that no two of the three normal vectors associated with the three sets of fringe planes are mutually orthogonal and that all three do not all lie on the same plane.

대표청구항 ▼

Apparatus for measuring the three-dimensional velocity of a remotely located object, comprising: first means for producing simultaneously three sets of non-orthogonal, but linearly independent, three-dimensional patterns of radiation, each of said sets having its own distinguishing characteristic an

Apparatus for measuring the three-dimensional velocity of a remotely located object, comprising: first means for producing simultaneously three sets of non-orthogonal, but linearly independent, three-dimensional patterns of radiation, each of said sets having its own distinguishing characteristic and having a normal vector having a significant component in the direction of the main axis of the system as well as a transverse component at right angles thereto; second means associated with said first means for projecting said three sets of patterns onto a detection volume, said detection volume being physically separated in space from said apparatus; third means associated with said second means for focusing radiation backscattered by said object as it passes through said detection volume onto a detection area contained within said apparatus; fourth means disposed in the vicinity of said detection area for measuring the intensity of said backscattered radiation; fifth means responsive to the output of said fourth means and capable of utilizing said distinguishable characteristic for identifying three separate components of said backscattered radiation associated respectively with each of said three sets of radiation patterns; and sixth means responsive to the output of said fifth means for calculating the velocity of said object relative to said apparatus, wherein at least said first, second, third and fourth means are located in physical proximity to one another, whereby they may all be contained within a single, relatively compact, housing aboard an aircraft.