Data processing: measuring – calibrating – or testing – Measurement system – Dimensional determination
Reexamination Certificate
1998-09-18
2001-10-02
Hoff, Marc S. (Department: 2854)
Data processing: measuring, calibrating, or testing
Measurement system
Dimensional determination
C356S003010
Reexamination Certificate
active
06298313
ABSTRACT:
STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
BACKGROUND OF THE INVENTION
1.0 Field of the Invention
The invention relates to detection systems which indicate the presence of an object or target along a path and, more particularly, to a technique preferably utilized in the detection system's passive ranging mode that depends upon the target being enveloped by a sub-refractive atmosphere that provides for the presence of a real image and an inferior mirage image of the targets that are analyzed by ray tracing techniques employed by and of particular importance to the invention to detect for cross-over rays indicative of the height and range of the target being analyzed.
2.0 Description of the Prior Art
Detection systems used in communication and/or counter-measure applications, may employ sensors that operate in response to radiation in the visible band or infrared band of the electromagnetic spectrum. Detection systems further include passive ranging techniques that provide for the detection of a target without betraying the location of the detector. The detection systems extract energy contained in incoming signals as a means for identifying, in terms of height and range, the target that created the incoming signals. The accuracy of this determination is being continuously improved and it is still desired that further improvements be made to these detection systems so as to improve their accuracy.
OBJECTS OF THE INVENTION
It is a primary object of the present invention to provide a method, and a system responsive thereto, for detecting the presence of a target and accurately determining its height and range.
It is a further object of the present invention to provide a method, and a system responsive thereto, for detecting a target enveloped in a sub-refractive atmosphere that provide for a real image and inferior mirage image of the target.
It is a still further object of the present invention to provide a method, and a system responsive thereto, that develops ray tracing of the real image and of the inferior mirage image of the target and utilizes the parameters of the ray tracings of these images to determine the height and range of the target.
Furthermore, it is an object of the present invention to provide a method, and a system responsive thereto, that is particularly suited to perform passive ranging for the detection of low altitude targets.
SUMMARY OF THE INVENTION
The present invention is directed to a method, and a system responsive to, for determining the height and range of a target and that is particularly suited to detect low altitude targets. The technique depends upon the presence of a sub-refractive atmosphere enveloping the target and which is a meteorological condition that makes available inferior mirage images of the target. The method of the invention is preferably practiced in the computer and uses a ray tracing program, that is, a program that embodies two rays being launched into a modeled sub-refractive atmosphere having the initial height and elevation angles of the real image and inferior mirage image and traces the paths thereof. The point of intersection of these ray tracings determines the height and range of the target.
The method comprises providing sensors for receiving electromagnetic radiation created by the target and producing therefrom a real image and an inferior mirage image of the target. The method further consists of determining the elevation of the real and inferior mirage images and also determining the angular separation between the real and inferior mirage images. The method further comprises constructing ray tracing to define each of the real and inferior mirage images and then determining the intersection point of the rays thereof with the intersection point defining the height and the range of the target.
REFERENCES:
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patent: 4591987 (1986-05-01), Brown
patent: 4824245 (1989-04-01), Gardner et al.
patent: 5042922 (1991-08-01), Pepper
patent: 5075856 (1991-12-01), Kneizys et al.
patent: 5255206 (1993-10-01), Pegis
patent: 5282013 (1994-01-01), Gregoris
patent: 5282014 (1994-01-01), Ruhl, Jr. et al.
patent: 5384719 (1995-01-01), Baker et al.
Bechtel, Esq. James B.
Hoff Marc S.
McMahon, Esq. John P.
Pretlow Demetrius R.
The United States of America as represented by the Secretary of
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