Aeronautics and astronautics – Missile stabilization or trajectory control – Automatic guidance
Reexamination Certificate
1999-11-02
2001-10-16
Gregory, Bernarr E. (Department: 3662)
Aeronautics and astronautics
Missile stabilization or trajectory control
Automatic guidance
C244S003150, C244S003170, C342S054000, C342S063000
Reexamination Certificate
active
06302355
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT ON FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the invention relates to devices for creating a three-dimensional image using a coherent, monochromatic electromagnetic radiation (LASER). In particular, the invention relates to a new and improved fiber optic LADAR (LASER detection and ranging) system, coupled with a MULTI SPECTRAL analyzer. It can be used to provide information to guidance systems for vehicles, such as guided missiles, that distinguishes objects based on their chemical composition.
2. Description of the Prior Art
The use of optical target detectors utilizing laser light is disclosed in U.S. Pat. No. 5,014,621, issued May 14, 1991 to Fox, et al. and assigned to Motorola, Inc. This patent utilizes a star coupler to automatically align pencil laser beams upon a target, and to track the target based on reflections of the laser light.
The use of missile referenced beam-rider guidance links is disclosed in U.S. Pat. No. 4,696,441, issued Sep. 29, 1987 to Jones, et al. and assigned to the United States of America. Jones et al. discloses a laser beam in which the strength of the beam is formed into a gaussian cross-section, the beam is directed upon a target at short range, detectors on an in-flight missile detect and measure the strength of the laser beam, and a guidance system guides the missile along the beam by adjusting the guidance controls to maximize the detected strength of the beam.
A detector device for detecting the presence and originating direction of laser radiation is disclosed in U.S. Pat. No. 4,825,063, issued Apr. 25, 1989 to Halldorsson et al. and assigned to Messerschmitt-Bolkow-Blohm GmbH. The Halldorsson device includes a plurality of discrete light collection optics, each discrete optic being capable of gathering laser radiation over a certain solid angle, which overlaps the solid angle of its neighbors.
The above mentioned patents are incorporated by reference as though set forth in full. None of the systems disclosed in these prior art patents provide the features disclosed in the following specification.
BRIEF SUMMARY OF THE INVENTION
An object of the invention is to provide three-dimensional image information to a vehicle guidance system. In one version of the invention, a laser beam illuminates the target. Optical fibers on the vehicle collect optical signals reflected from the target. These reflected optical signals are connected to electrical signals and transmitted to an on-board vehicle guidance and flight control system that directs the vehicle to its target.
In one embodiment, the vehicle includes high power laser transmitter coupled with a fiber optic laser receiver incorporating collection optics. These structures may be packaged in any convenient way as a matter of design choice. For example, if the vehicle is a self-guided missile, then the laser transmitter and fiber optics laser receiver may be packaged in a compatible nose cone. A laser beam is projected from the missile and scanned across the target area in a pre-determined pattern. In particularly advantageous embodiment, the pattern is a spiral scan around the center of the target area, although any pattern could be used as a matter of design choice. Laser light is reflected from the target back to the missile where it is received and analyzed by the misses guidance system.
The guidance system includes a staring array of apertures for receiving laser tank circuit by an elevation optical fiber. The length of the start optical fibers is the same for all apertures in the staring array. The length of the azimuth optical fibers is related to the azimuth angle of the received laser radiation from their respective apertures. Similarly, the length of the elevation optical fibers is related to the elevation angle of the received laser radiation from the respective apertures. The outputs from the tank circuits are then passed to intermediate frequency amplifiers and phase comparators. Signals from the phase comparators are then sent to a processor on the missile which uses these signals to develop a three-dimensional image of the target area.
The guidance systems also includes a non-linear crystal frequency convertor. When the laser beam is projected towards the target, it is first passed through the nonlinear crystal frequency convertor so that a single beam of two frequencies of light is projected. When the returning laser light is received by the missile, it is passed to two separate start tank circuits. The start tank circuits are provided with optical filters so that each start tank circuit is activated by a different frequency of incoming laser light. The outputs of the start tank circuits are used for two purposes in an advantageous embodiment of the invention. First, the outputs are summed together and used in conjunction with the azimuth and elevation tank circuits to allow the missile to construct a three-dimensional image of the target area. Second, the energy level of the outputs of the two start tank circuits is compared to determine a reflectivity ratio. The reflectivity ratio determined from the incoming light may be compared against known reflectivity ratios of objects likely to be found on a battlefield, such as various types of paint, shrubbery, grasses, rocks, asphalt, etc. The missile can use the information, not only to determine the shape and distance of the object, but also to determine what the object is.
By way of illustration, important features of the present invention will be described with respect to its application in self-guided missiles. However, those with skill in the art will appreciate that the invention could easily be applied to other vehicles, such as an underwater torpedoes or manned vehicles, as a matter of design choice.
These and other features of the present invention will be more apparent from the following detailed description.
REFERENCES:
patent: 4195289 (1980-03-01), Cole
patent: 4410237 (1983-10-01), Veldkamp
patent: 4436260 (1984-03-01), Donelan
patent: 4682024 (1987-07-01), Halldorsson et al.
patent: 4787748 (1988-11-01), Rioux
patent: 5198919 (1993-03-01), Reeder
patent: 5283796 (1994-02-01), Fink
patent: 5289493 (1994-02-01), Fink
patent: 5317148 (1994-05-01), Gray et al.
patent: 5345304 (1994-09-01), Allen
patent: 5387996 (1995-02-01), Palombo
patent: 5477383 (1995-12-01), Jain
patent: 5528354 (1996-06-01), Uwira
patent: 5543954 (1996-08-01), Nicholson
patent: 5644386 (1997-07-01), Jenkins et al.
patent: 5710658 (1998-01-01), Jacobson et al.
patent: 5779187 (1998-07-01), Dulat
patent: 5870180 (1999-02-01), Wrangler
patent: 5892575 (1999-04-01), Marino
patent: 6042050 (2000-03-01), Sims et al.
patent: 6163372 (2000-12-01), Sallee et al.
Gleave Joe
Sallee Bradley
BAE Systems Integrated Defense Solutions Inc.
Gregory Bernarr E.
Locke Liddell & Sapp LLP
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