Aeronautics and astronautics – Missile stabilization or trajectory control – Remote control
Reexamination Certificate
1994-11-15
2001-09-25
Tudor, Harold J. (Department: 3641)
Aeronautics and astronautics
Missile stabilization or trajectory control
Remote control
Reexamination Certificate
active
06293488
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates generally to an aircraft-based missile guidance and tracking system, and in particular to a subsystem for digitally computing the roll angle around the line of sight in optics incorporated in such a system, and for adjusting missile guidance signals to compensate for the computed roll angle, about the line of sight.
2. Discussion
A conventional aircraft-based missile guidance and tracking system includes target acquisition optics. An example of such optics is disclosed in U.S. Pat. No. 3,989,947, to Chapman entitled “Telescope Cluster.” As disclosed in Chapman, a system operator locates a missile target and positions an image of the target at the intersection of cross hairs incorporated in the optics. After the operator fires the missile, the optics detect a tracking signal emitted by the missile. This tracking signal is then processed by system computers to produce a guidance signal transmitted to the missile to keep the missile on its intended course. Through use of such a system, a missile fired from an aircraft may be directed to its intended target with a high degree of accuracy.
The high degree of accuracy associated with the abovedescribed typical guidance and tracking system is a result in great part to the system's capability of compensating for aircraft movement subsequent to the firing of the missile. As the system receives the missile tracking signal from the system optics, it processes this signal, along with aircraft position data received from aircraft instrumentation. The processed data is then used in the system missile guidance signals, sent from the system to the missile, to compensate for movement of the aircraft from the original aircraft-to-target coordinates, thus keeping the missile on its intended course.
In particular, one critical component that must be compensated for in the missile guidance signals is the roll of the aircraft around a line of sight of the system optics. For instance, once the missile is fired from the aircraft, it maintains the roll attitude of the aircraft at the time of launch, while the aircraft may roll to the right or left around the original line of sight after the missile is fired. Since the missile tracking system senses the missile positioned in aircraft coordinates, this roll must be corrected in order to stabilize the missile and to prevent the missile from deviating from its intended flight path to the target as the gunner maintains the cross hairs on the target as the aircraft moves.
In the past, roll angle compensation mechanisms incorporated in missile guidance and tracking systems have adjusted guidance commands for roll around the line of sight in system optics through use of electromechanical components, such as resolver/servo systems, to compute the roll angle and to correct the guidance signals output to the missile for the computed roll angle. As a result, however, the roll angle compensation mechanisms were relatively heavy and expensive due to the many mechanical components. In addition, the mechanical components often would go out of alignment due to vibration and wear. As a result, the reliability of such electromechanical error compensation mechanisms was limited.
What is needed then is a roll angle correction system which does not exhibit the limitations of previous electromechanical error mechanisms, and which is less expensive to implement than the previous mechanisms.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a coordinate transformation system is provided for adjusting target tracking and missile position data for changes in aircraft position subsequent to the firing of a missile. The coordinate transformation system finds particular utility in an aircraft-based missile guidance and tracking system having a 2 degree of freedom gimbal-mounted sight unit for aiming at a missile target and for detecting a tracking signal generated by a roll stabilized missile in flight. The mechanism generates guidance signals which are transformed from aircraft coordinates to missile coordinates for guiding the missile to the target.
In the inventive approach, position sensors are provided for generating analog aircraft and missile position signals. Analog to digital converter means are used to convert the analog position signals into digital signals. Microprocessors are connected to the analog to digital converter for computing a roll angle around the line sight of the system sight unit. A microprocessor adjusts the digital signals to compensate for the roll angle. Digital to analog converter means are then used for converting the adjusted digital signals to analog signals, and for outputting the adjusted analog signals to the system for computation of the guidance signals transmitted to the missile.
In addition, sight tracking commands which require compensation in earth coordinates are transformed from aircraft coordinates to earth coordinates, compensated for gravity, then retransformed into aircraft coordinates for use by a digital control mechanism of the stabilized sight.
REFERENCES:
patent: 3829659 (1974-08-01), Margolis
patent: 4219170 (1980-08-01), Esker
patent: 4433818 (1984-02-01), Coffel
patent: 4641801 (1987-02-01), Lynch, Jr. et al.
patent: 4790493 (1988-12-01), Schwarzkopf et al.
patent: 5052637 (1991-10-01), Lipps
patent: 5253823 (1993-10-01), Lawrence
patent: 5263662 (1993-11-01), Fowler et al.
patent: 5429322 (1995-07-01), Waymeyer
Jenkins Thomas E.
Sand Richard J.
Sutton Eric B.
Wells Michael L.
Lenzen, Jr. Glenn H.
Raufer Colin M.
Raytheon Company
Tudor Harold J.
LandOfFree
Coordinate transformation system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coordinate transformation system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coordinate transformation system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2460541