|Publication number||USRE41769 E1|
|Application number||US 11/036,319|
|Publication date||Sep 28, 2010|
|Filing date||Jan 14, 2005|
|Priority date||Apr 16, 2001|
|Also published as||US6507392|
|Publication number||036319, 11036319, US RE41769 E1, US RE41769E1, US-E1-RE41769, USRE41769 E1, USRE41769E1|
|Inventors||Les H. Richards, James E. Nicholson|
|Original Assignee||Bae Systems Information And Electronic Systems Integration Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (44), Referenced by (3), Classifications (18), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention relates generally to optical systems and, more particularly, to optical devices for determining the position of a source of light incident on the device.
Optical systems for determining the geographical position of a source of light are used in a variety of applications. For example, conventional laser-guided missiles make use of reflected light from a laser beam pointed toward a potential target. Once a target is selected, information from the laser beam is used to determine the position of the target relative to the missile.
Such laser-guided missile systems are known in the art. One exemplary system is described in U.S. Pat. 5,784,156, to Nicholson, incorporated herein by reference. The incoming reflected light is detected at apertures located at different points on the exterior of the missile, typically on the nose cone or wing edges. Each aperture is provided with a lens or lens system that focuses the incoming light onto a bundle of fiber optic cables running inside the missile. The fiber bundles then transmit the incoming light onto sensors that convert the incoming light into electrical signals. These electrical signals are then analyzed by computers on board the missile to determine the relative distance, azimuth, and elevation between the missile and the object from which the incoming laser light is reflected.
Each aperture and its corresponding fiber bundle, or bundles, possesses a field-of-view (“FOV”), i.e., an angle from which it can detect light. All of the individual FOV of the apertures together form the overall FOV of the missile. Since the FOV of a given aperture is limited by the optics involved, to increase the FOV of a missile, one must typically increase the number of apertures and lenses employed by the missile. This problem is illustrated in FIG. 1B.
Similarly, another optical laser-guided missile system currently in use employs a plurality of ball lenses at each aperture, with each ball lens associated with a single fiber bundle. This arrangement is shown in
In one embodiment, the laser detection system comprises a ball lens and a plurality of fiber optic bundles placed adjacent the ball lens so that incoming light rays are focused onto the bundles by the ball lens. In one version of the invention, a ball lens is one that can provide, an almost infinite number of “principal” axes for off-axis light. Each fiber optic bundle is aimed in a different direction from each other bundle so that each bundle will have a different FOV even though the same ball lens is used to focus the incoming light rays. Because the fields-of-view of all the bundles together form the overall FOV of the ball lens, the more bundles that are incorporated into the system, the larger the FOV of a given ball lens. In one advantageous embodiment, the bundles may be disposed so that their fields-of-view may overlap partially.
Referring now to
According to a further embodiment to the invention, the advantages obtained by the optical system shown in
Of course, it is not required that all the field-of-views overlap, and in other embodiments in the invention, the field of views can be non-overlapping, as a matter of design choice. In order to receive signals that can be used for guidance, at least adjacent fiber directions should produce an overlapping field-of-view. The fact that all FOVs do not overlap may be advantageous to systems that combine signals to a single detector. The non-overlapping FOVs in this case would produce less background noise due to a reduced field-of-view.
Of course, the above embodiments have been described with respect to two dimensional drawings showing differences in the elevation of the field-of-views for the fiber bundles; however, those who are skilled in the art will recognize that it will be useful to arrange fiber bundles to increase the total FOV of the system in azimuth as well as elevational dimensions.
In another embodiment of the invention, it is useful if the ball lenses are manufactured from different types of materials or glass. This allows one to modify the field-of-view of the lens and to affect the amount of coupling of light to the adjacent fiber bundles. One also has the flexibility to use different sizes of ball lenses. This also affects the overall FOV when used in conjunction with fiber bundles of different diameters and different numerical apertures (“NA”).
In still a further embodiment to the invention, it is possible to substitute a drum lens in place of the ball lens shown in
In still a further embodiment to the invention, it is useful that the effective FOV of the lens/fiber system be varied as follows. All fiber bundles point toward the center of the ball lens. The field-of-view is changed by varying the angle of each fiber bundle relative to the central or principal axis. The amount of overlapping signal depends upon the size of the fiber bundle at a particular angle. By pushing the fiber bundles closer to the ball lens, the amount of overlap between adjacent fiber bundles increases. The FOV can also be changed by varying the NA of each fiber. Therefore, the overall FOV can be controlled by changing the ball lens diameter or material composition, by changing the fiber numerical aperture, by changing the fiber bundle size, and/or by changing the fiber displacement from the ball lens. All of these factors are related to the required guidance precision.
There are many ways information from the reflected light energy may be used to determine the direction to the target. In one embodiment of the invention, each fiber bundle is coupled to a detector that converts the reflected light into electrical signals. The amplitudes of these electrical signals are related to the amount of light energy received from its corresponding fiber bundle. Because each fiber bundle has a unique FOV, those of skill in the art will recognize that the amount of energy received at the various FOVs can be interpolated to calculate the direction to the target.
Although the present invention has been described with respect to its application in guided missile systems, those who are skilled in the art will recognize that the invention also pertains to increased field-of-views in optical systems employing fiber optic cables in connection with optical lenses. For example, the invention is easily adapted to any system that uses reflected laser energy for guidance. For example, any robotic system could use reflected laser light in conjunction with the ball lens for increased precision in navigating toward the target. This could include mobile robots, such as cars, androids, etc. that have a task to move from point A (their present location) to point B where the item of interest is located. Similarly, a robotic arm could be guided to a laser illuminated “part of interest” located on a moving platform, such as a conveyor belt. Still other applications within the scope and spirit of the present invention will occur to those of skill in the art in view of the foregoing disclosure.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4106726||Nov 4, 1969||Aug 15, 1978||Martin Marietta Corporation||Prestored area correlation tracker|
|US4131248||Mar 13, 1968||Dec 26, 1978||E-Systems, Inc.||Optical range resolution system|
|US4395121||Feb 20, 1981||Jul 26, 1983||Societe Anonyme Dite: Compagnie Industrielle Des Lasers||Apparatus for determining the angular position of a target illuminated by light pulses|
|US4598884||Nov 28, 1984||Jul 8, 1986||General Dynamics Pomona Division||Infrared target sensor and system|
|US4634230||Feb 3, 1984||Jan 6, 1987||The United States Of America As Represented By The Secretary Of The Navy||Multi dimensional instantaneous optical signal processor|
|US4675532||Nov 6, 1985||Jun 23, 1987||Irvine Sensors Corporation||Combined staring and scanning photodetector sensing system having both temporal and spatial filtering|
|US4696441||May 6, 1986||Sep 29, 1987||The United States Of America As Represented By The Secretary Of The Army||Missile referenced beamrider|
|US4792675||Feb 6, 1987||Dec 20, 1988||Varo, Inc.||Diffused surface radiant energy receiver|
|US4825063||Mar 8, 1988||Apr 25, 1989||Messerschmitt-BoGmbH||Radiation position detection using time-indicative variable-length fiber array|
|US4835381||Oct 30, 1987||May 30, 1989||Varo, Inc.||Wide field of view radiant energy receiver|
|US4914284 *||Oct 25, 1988||Apr 3, 1990||Messerschmitt-Boelkow-Blohm Gmbh||Optical wide angle sensor head|
|US4923276||Feb 13, 1989||May 8, 1990||Teledyne Industries, Inc.||Tapered optical fiber telescope, tracking system apparatus and method incorporating tapered optical fiber telescopes|
|US4952042||Jun 16, 1989||Aug 28, 1990||The Boeing Company||Missile seeker head|
|US4965453||Sep 17, 1987||Oct 23, 1990||Honeywell, Inc.||Multiple aperture ir sensor|
|US5014621||Apr 30, 1990||May 14, 1991||Motorola, Inc.||Optical target detector|
|US5047776||Jun 27, 1990||Sep 10, 1991||Hughes Aircraft Company||Multibeam optical and electromagnetic hemispherical/spherical sensor|
|US5052635||Nov 30, 1990||Oct 1, 1991||Thomson-Csf||System for the reception of guidance commands for a guided missile in optoelectronic mode|
|US5056914||Jul 12, 1990||Oct 15, 1991||Ball Corporation||Charge integration range detector|
|US5082201||May 11, 1990||Jan 21, 1992||Thomson Csf||Missile homing device|
|US5114227||May 14, 1987||May 19, 1992||Loral Aerospace Corp.||Laser targeting system|
|US5129595||Jul 3, 1991||Jul 14, 1992||Alliant Techsystems Inc.||Focal plane array seeker for projectiles|
|US5181263||Jun 7, 1991||Jan 19, 1993||Motorola, Inc.||Wave-guide I/O for optical or electro-optical components|
|US5191385 *||Oct 7, 1991||Mar 2, 1993||Institut Geographique National||Method for determining the spatial coordinates of points, application of said method to high-precision topography, system and optical device for carrying out said method|
|US5202742||Oct 3, 1990||Apr 13, 1993||Aisin Seiki Kabushiki Kaisha||Laser radar for a vehicle lateral guidance system|
|US5206499 *||Dec 20, 1991||Apr 27, 1993||Northrop Corporation||Strapdown stellar sensor and holographic multiple field of view telescope therefor|
|US5275354||Jul 13, 1992||Jan 4, 1994||Loral Vought Systems Corporation||Guidance and targeting system|
|US5311611||May 4, 1993||May 10, 1994||Ail Systems, Inc.||Imaging ball lens optically immersed with a fiber optic faceplate|
|US5319968||Sep 21, 1992||Jun 14, 1994||Honeywell Inc.||Apparatus for determining 3-axis space craft attitude|
|US5319969||Sep 21, 1992||Jun 14, 1994||Honeywell Inc.||Method for determining 3-axis spacecraft attitude|
|US5323987||Mar 4, 1993||Jun 28, 1994||The Boeing Company||Missile seeker system and method|
|US5345304||Dec 17, 1992||Sep 6, 1994||Texas Instruments Incorporated||Integrated LADAR/FLIR sensor|
|US5357331||Mar 24, 1993||Oct 18, 1994||Flockencier Stuart W||System for processing reflected energy signals|
|US5477383||Feb 5, 1993||Dec 19, 1995||Apa Optics, Inc.||Optical array method and apparatus|
|US5500520||Sep 15, 1994||Mar 19, 1996||Northrop Grumman Corporation||Compact large aperture optical transmitter/receiver for lidars employing a plurality of cassegrain optics and optical fibers|
|US5528358||Jun 29, 1993||Jun 18, 1996||Celsiustech Electronics Ab||Optical angle measuring device|
|US5682225||Jun 7, 1996||Oct 28, 1997||Loral Vought Systems Corp.||Ladar intensity image correction for laser output variations|
|US5760852 *||Nov 3, 1995||Jun 2, 1998||Hughes Electronics Corporation||Laser-hardened eye protection goggles|
|US5771092||May 8, 1997||Jun 23, 1998||Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence||Wavelength agile receiver with noise neutralization and angular localization capabilities (WARNALOC)|
|US5784156||Nov 19, 1996||Jul 21, 1998||Tracor Aerospace, Inc.||Fiber optic guidance system for laser guided missiles|
|US5788180||Nov 26, 1996||Aug 4, 1998||Sallee; Bradley||Control system for gun and artillery projectiles|
|US6014270||Nov 23, 1998||Jan 11, 2000||Lucent Technologies Inc||Cylindrical lenses for alignment of optical sources and destinations|
|US6163372||Feb 9, 1999||Dec 19, 2000||Marconi Aerospace Defense Systems Inc.||Fiber optic laser detection and ranging system|
|US6349160 *||Jul 24, 1998||Feb 19, 2002||Aurora Biosciences Corporation||Detector and screening device for ion channels|
|JP2002090920A *||Title not available|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8757064 *||Aug 6, 2009||Jun 24, 2014||Mbda Uk Limited||Optical proximity fuze|
|US20110185935 *||Aug 6, 2009||Aug 4, 2011||Mbda Uk Limited||Optical proximity fuze|
|US20120002970 *||Jan 5, 2012||Analysis First LLC||Identification and communication systems using optical fibers|
|U.S. Classification||356/141.5, 244/3.16, 250/203.1, 250/208.2, 250/206.2, 250/227.11|
|International Classification||G01S3/783, F41G7/22, G01V1/42, G01C21/02, G01B11/26, F41G7/00|
|Cooperative Classification||G01S3/783, F41G7/2293, F41G7/226|
|European Classification||F41G7/22N, F41G7/22O3, G01S3/783|