Aeronautics and astronautics – Missile stabilization or trajectory control – Automatic guidance
Reexamination Certificate
2001-12-07
2003-09-30
Gregory, Bernarr E. (Department: 3662)
Aeronautics and astronautics
Missile stabilization or trajectory control
Automatic guidance
C244S003130, C244S003150, C244S003170, C342S052000, C342S053000, C342S054000, C342S061000, C342S062000, C342S068000, C342S176000, C342S179000, C342S195000, C356S004010, C356S005010, C356S005030, C356S005040
Reexamination Certificate
active
06626396
ABSTRACT:
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a target acquiring mechanism of intercepting missiles in general and to their last stage of homing on target in particular.
It is known that most hit attempts of intercepting missiles did not end in a direct hit on target. This is so for mainly two reasons: Firstly the intercepting missile may be diverted from its flight path to target by decoy countermeasures which are deployed by the target (such as flares for infra-red seeking missiles or chaff for missiles equipped with radar), or as a result of artifacts such as sunlight reflection in case of an infra red seekers and spurious RF echo signals in the case of missiles equipped with radar.
Secondly; even in apparently favorable situations in which the missile is heading toward a valid target, present guiding mechanisms of both infra-red and radar seeker missiles can not handle unexpected fast angular changes between the momentarily missile heading direction and the direction to target which result whenever the latter performs an emergency-breaking maneuver.
For a specific example of missile's equipped with infrared seeking sensors the process of updating the missile's flight path is as follows:
At the time after missile launching the sensor is directed substantially towards the target so that an infrared radiating “hot” spot of the target is located at, or near, the center of its field of view. As the target moves away from the center of the field of view of the missile's sensor so that the missile's flight path correspondingly moves off target, the sensor rotates independently of the missile's body to bring the target's infrared radiating hot spot back into the center of its field of view. A signal representative of the spatial rotation angle through which the sensor rotated during this maneuver is transmitted to a control unit which in turn operates the missile's steering system which, by way of a non-limiting example, activates the missile's control surfaces to change the missiles trajectory according to the guidance law.
This procedure of rotation of the missile's sensor and re-aligning of the missile has to be performed continuously, or quasi-continuously, since a missile cannot make sudden changes in direction, i.e., its flight path is always smooth, even though the missile's sensor is fitted on gimbals that allow for fairly large angles of rotation.
The process involved in updating an air-to-air missile equipped with a radar system is similar, the main difference being that in this case the target is maintained at the center of the field of view of the radar's antenna by maintaining a maximum target echo as received by the radar system.
A third possibility for primary guiding an intercepting missile toward a target is by the use of a data link system that obtains continuously data, which was acquired out side the missile, representative of target flight performance. It is obvious that also data link guidance cannot respond adequately to fast maneuvers of the target from short range.
As a result of the aforementioned reasons, an intercepting missile and an airborne target seldom reach a body-to-body contact. Hence intercepting missiles are equipped with a proximity fuse, which detonates the missile's warhead when the distance between the missile and the target has reached a small predetermined value, and the target is mainly affected by the blast, debris and fragments of the exploding warhead.
A detailed description of the damaging mechanisms of different warheads is given in the book “Conventional Warhead Systems Physics and Engineering Design” by Richard M. Lloyed, Published by the American Institute of Aeronautics and Astronautics, Inc. 1998.
A conclusion of this text is that unless a direct hit on target is achieved, the lethality of a missile can not be guarantied, because only in direct hit, a sufficient enormous amount of kinetic energy and momentum is imparted from the colliding bodies to the target so the target will be “pulverized”. The realization of this “hit to kill” concept is especially important when the target is a ballistic missile carrying an unconventional payload.
This is the reason that “hit to kill” is considered vital to any one of various defense programs such as e.g. the U.S. National Missile Defense (NMD) program.
However the “hit to kill” concept has not yet been implemented to intercepting missiles operating in the lower atmosphere, e.g. such as an air to air missiles launched by an aircraft.
It is therefore desired to have a method and a system which will provide the “hit to kill” feasibility to intercepting missile operating in the low atmosphere.
SUMMARY OF THE INVENTION
The present invention describes an intercepting missile which is equipped with an active imagery laser system which enables the missile to score a direct hit, and method of operation thereof.
Consequently the warhead of the intercepting missile and its activation mechanism may become redundant, a fact which will lead to cheaper and more reliable intercepting missiles.
In accordance with the present invention there is provided a method for guiding an intercepting missile to a body-to-body contact with an airborne target in the atmosphere, the method comprising the steps of: (a) guiding an intercepting missile to within an appropriate distance from the airborne target; (b) illuminating the airborne target, using an illuminator carried by the intercepting missile; (c) acquiring an image of the illuminated airborne target and, (d) steering the missile in accordance with an aimpoint on the image of the airborne target.
In accordance with the present invention there is provided an active imagery guidance system mounted on an intercepting missile for guiding the intercepting missile to a body-to-body contact with an airborne target in the atmosphere, the system comprising: (a) an active imagery system to acquire an image of an airborne target; (b) a mechanism to calculate an aimpoint on the image and, (c) a steering mechanism to steer the intercepting missile in accordance to the aimpoint.
In accordance with the present invention there is provided a hit to kill airborne target intercepting missile operating in the atmosphere comprising of: (a) a primary guidance system to guide the intercepting missile to within an appropriate distance from an airborne target; (b) an active imagery guidance system to guide the intercepting missile to a body-to-body contact with the airborne target.
In accordance with the present invention there is provided a hit to kill airborne target intercepting missile system operating in the atmosphere comprising: (a) a launching sub system to launch the intercepting missile; (b) a primary guidance system to guide the intercepting missile to within an appropriate distance from an airborne target and, (c) an active imagery guidance system to guide the intercepting missile to a body-to-body contact with said airborne target.
Other objects and benefits of the invention will become apparent upon reading the following description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4324491 (1982-04-01), Hueber
patent: 4898341 (1990-02-01), Terzian
patent: 5626311 (1997-05-01), Smith et al.
patent: 5877851 (1999-03-01), Stann et al.
patent: 5940170 (1999-08-01), Berg et al.
patent: 6196497 (2001-03-01), Lankes et al.
Friedman Mark M.
Gregory Bernarr E.
Rafael-Armament Development Authority Ltd.
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