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Not Applicable.
The present invention relates to line-of-sight controls for missile systems, particularly for strapdown missile systems.
Missile seekers require a large field of regard (FOR) to acquire and track objects that are not along the missile center-line. In addition, the seekers require Narrow Field of View (NFOV) to get the pixels on target needed for Automatic Target Recognition Automatic Target Correlation (ATC/ATR) functions. The high ratio of FOR to FOV preclude a strap-down solution in most missile seeker applications. However, the present invention provides such ability.
The present invention is of an optical system and method comprising: refracting light with a pair of Risley prisms; and employing a line-of-sight control unit to adjust the pair. In the preferred embodiment, no gimbals are employed for line-of-sight control. The prisms and control unit can be incorporated into a missile seeker/strapdown missile. Preferably units and also included for one or more of non-uniformity compensation, dead pixel replacement, bilinear interpolation, frame summation, and scene correlation.
The present invention is also of a missile seeker and missile seeking method comprising: refracting light with a pair of Risley prisms; and employing a line-of-sight control unit in a missile to adjust the pair. In the preferred embodiment, no gimbals are employed for line-of-sight control. An electronic stabilization unit receives output from the pair. The invention can be operated in a strapdown missile. Preferably units are also included for one or more of non-uniformity compensation, dead pixel replacement, bilinear interpolation, frame summation, and scene correlation.
Objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed nut in the appended claims.
The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating one or more preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings:
The present invention is of a strap-down missile seeker comprising a line-of-sight control comprising a Risley prism pair and not requiring a gimbal. Preferably the missile seeker employs electronic stabilization in conjunction with the line-of-sight control of the invention.
The common method of line-of-sight (LOS) control for missile seekers is to use gimbals. They provide two basic functions: LOS pointing and LOS stabilization. The LOS stabilization aspect can be achieved electronically by using a high frame rate Focal Plane Array (FPA) coupled with image correlation. The present invention solves the LOS pointing aspect using a Risley prism pair to steer the LOS over the FOR. Risley prisms have not heretofore been applied to strapdown missile seeker applications. The combination of electronic stabilization and Risley prisms results in significant cost reduction, fewer moving parts, and fewer failure points in missile seekers.
Gimbals are expensive, require precision alignment, must be well balanced about the gimbal axes, and electrical/gas line interfaces off-gimbal create friction and spring torques resulting in increased LOS jitter. The present invention provides the same functionality at a lower cost and eliminates the gimbal interface issues. This invention is preferably used with fast-framing and electronic stabilization to also provide the gimbal stabilization function.
The strapdown missile seeker 10 of the invention is shown schematically in
Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.
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6853349 | Chishinski | Feb 2005 | B1 |
7058277 | Harkrider et al. | Jun 2006 | B1 |
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20070024978 | Jackson et al. | Feb 2007 | A1 |
Number | Date | Country |
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1357398 | Oct 2003 | EP |
WO-0175388 | Oct 2001 | WO |
WO-0175506 | Oct 2001 | WO |
Entry |
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C. Schwarze, “A New Look at Risley Prisms”; posted on the Internet at photonics.com; originally printed in “Photonics Spectra” magazine; Jun. 2006. |