Aeronautics and astronautics – Missile stabilization or trajectory control – Automatic guidance
Reexamination Certificate
1998-08-27
2001-07-03
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Missile stabilization or trajectory control
Automatic guidance
C244S052000, C102S384000
Reexamination Certificate
active
06254031
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to the field of maneuverable vehicles, and more particularly to an improved and low-cost guidance system requiring a minimum number of components, as is desirable in the case of conventional bomb modification, to improve delivery accuracy. This system provides an extremely accurate and low-cost conventional bomb attachment kit that requires no modification to the delivery vehicle.
DISCUSSION OF THE PRIOR ART
A problem continually faced by personnel involved in the design, development, and operation of air-to-ground conventional weapons is how to precisely position those devices to neutralize the target within the constraints of cost, complexity, and aircraft survivability. Conventional weapons, such as unguided bombs, most often require the employment of considerable numbers in order to achieve the desired target results. This, in turn, most often requires large numbers of delivery aircraft using delivery geometry that places them in high risk situations.
Several methods of achieving micro-positioning have been considered. One method is through the use of fixed opposable force-based systems. Such a system will usually be comprised of a large number of thrusters fixed to the body of the maneuverable device. Combinations of these thrusters can then be fired to effect the desired maneuver. Two weapon systems that use this technique are the U.S. Army Hypervelocity missile and the Command Adjusted Trajectory projectile. There are several drawbacks to these fixed opposable force-based thruster-based systems. For most applications, a large number of thrusters are needed. More thrusters relates to a higher cost.
Another technique is the use of Global Positioning System (GPS). Current GPS navigation and guidance systems require three dimensional angular position data in order to navigate an air vehicle from one position to another. Current GPS navigation and guidance systems generally obtain attitude information from an inertial navigation system (INS). Such a system usually consists of three rate gyroscopes, three accelerometers, and associated processing equipment. INS types are very costly. Another experimental system employs GPS carrier phase measurement on multiple antennas (radio interferometry) to determine three-dimensional attitude. As disclosed in U.S. Pat. No. 5,101,356, these systems are also complex and may not have the necessary sensitivity and speed for guidance of smaller vehicles, such as conventional bombs.
SUMMARY OF THE INVENTION
Briefly stated, the present invention contemplates the provision of an improved navigation and maneuver system for conventional bombs, in which the above mentioned disadvantages have been substantially ameliorated.
Rather than the familiar GPS guidance and the on off thruster devices normally associated with thrusters, the present invention employs a unique and innovative “virtual umbilical” method to directly initialize the bomb GPS unit while still in the bomb/cargo bay, an inverse trajectory two point boundary guidance law to continually define best path guidance options using position and velocity states only, an innovative adaptive forward predictor polynomial network for guidance law implantation, and a compact jet reaction control system to effect bomb to target maneuver.
An RF (Radio Frequency) “virtual umbilical” weapon link uses an RF repeater to broadcast the GPS data obtained from the aircraft GPS system into the aircraft weapons bay to provide ephemeris and space vehicle clock data directly to the bomb for initialization. This method eliminates expensive changes to the aircraft by using the already installed GPS receiver system. It also provides for real-time bomb initialization while still in the weapons bay and significantly reduces the time in acquiring of the GPS satellite constellation.
An Adaptive Forward Predictor uses a polynomial network which permits the guidance law to be implemented with a multiplication concept rather than an integration concept. It also allows the trajectory to be wind compensated, permitting the guidance computer to be a low-cost 486-type or pentium processor chip. Moreover, the invention allows the bomb control forces to be obtained during flight using simple multiplication.
A jet Reaction Control Device makes use of a typical gas jet control system to effect bomb maneuver to the target. It permits the maneuver to be accomplished using an extremely low-cost approach. The compact jet reaction control concept permits the entire guidance kit to be packaged in an extremely small volume.
Applications of this new concept are both numerous and varied. it can be used wherever there is a need for very accurate positioning. This includes effecting maneuvers for guided missiles, artillery shells, and space vehicles. Potential applications include, but are not limited to, bombs, stand-off weapons, cruise missiles, unmanned surveillance vehicles, flying decoys to protect ships and aircraft, ground-launched munitions, antisubmarine weapons, atmospheric probes, and precision airdrop systems.
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Barefoot Galen L.
Lockhead Martin Corporation
Temko Charles E.
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