1. Technical Field
The invention relates to a system and method for launching countermeasures such as flares and chaff from one or more dispensers mounted on an aircraft to direct the missile away from the aircraft. More particularly, the invention relates to such a system and method in which the dispense pattern is determined based upon the angle of approach (AOA) of the incoming missile. Even more particularly, the invention relates to such a system and method in which a look-up table of countermeasure responses is incorporated into the dispense mechanism, which is indexed by the azimuth angle of angle of elevation, the estimated distance of the missile to the aircraft, the aircraft speed and altitude, all of which are entered into an onboard computer whereupon the computer through the appropriate software will launch the most efficient number of flares or chaff from the appropriate dispenser or combination of dispensers including the number and types of flares dispensed and the dispense time of the flares.
2. Background Information
It is well understood that most military aircraft today are either shot down or damaged by missile attacks fired from land-based missile launchers or from air-to-air missile attacks. These missiles are usually guided by infrared sensors, radar sensors or both. These missiles are active devices that emit various signals and emissions that are detected by the target (aircraft) which uses the detected signals to evade or launch a countermeasure against the incoming missile. The incoming missile approaches the aircraft at a particular elevation angle and azimuth angle with a particular speed, all of which can be detected by the warning system of the aircraft's counter-measure system which can be an optical, radar or other various detection systems. These measurements are supplied to an onboard computer which then determines the preferred countermeasure to be dispensed against the incoming missile, such as one or more flares and/or chaffs or other types of known countermeasures from one or more dispensers located at various locations on the aircraft.
Radar sensors are highly accurate in identifying and locating their targets. They have the disadvantage that they are active devices that emit radar signals, and their emissions may be detected by the target and used to evade or to launch a counter-attack against the radar source.
Infrared sensors, on the other hand, are passive devices that do not reveal their presence or operation. The great majority of aircraft losses to hostile attacks over the past 20 years have been to infrared-guided missiles. In most cases, the pilots of the aircraft that were shot down were not aware that they were under attack until the infrared-guided missile detonated.
Infrared-guided missiles have the disadvantage that they typically must be initially positioned much more closely to their potential targets in order for the infrared sensor of the missile to be effective, as compared with a radar-guided missile. The fields of view of the infrared sensors are usually quite narrow, on the order of a few degrees. In most cases, the infrared sensor must therefore acquire its potential target prior to launch of the missile and remain “locked onto” the target for the entire time from launch until intercept. If the acquisition is lost during the flight of the missile, it is usually impossible to re-acquire the target without using an active sensor that warns the target of its presence.
There are a number of countermeasures to defeat infrared-guided missiles. Historically, the most common countermeasure has been the use of flares that produce false signals to confuse the infrared sensor. The current generation of infrared-guided missiles utilize counter-countermeasures programmed to ignore flares, based upon distinguishing features of the flares such as their different motion than the previously acquired target and/or their different heat-emitting properties as compared with the previously acquired target. Lamps and directional lasers may be used to blind or confuse the infrared sensor, but these approaches have drawbacks in respect to size, weight, complexity, and power requirements.
In general, current countermeasure systems obtain incoming data and the only discriminator is the hemisphere in which the missile is detected. If possible, the countermeasures are ejected from a dispenser closest to the missile warning which may not always be the best dispense location. Also, the optimum number of flares or chaff dispensed is only estimated resulting in the less than optimum number of flares or chaff and dispensers utilized, not providing the optimum protection to the aircraft under attack. Usually the flares or chaff are dispensed from the same side of the aircraft as the approaching missile which may not provide the best dispense pattern. Therefore, there exists a need for systems and methods to better protect aircraft from attack.
The method and system of the present invention upon detecting the incoming missile selects the appropriate countermeasure which distinguishes by number and type of flares dispensed, the dispense time of flares and the flare dispenser or dispensers used by providing a software program in the computer of the missile warning system, a look-up table of countermeasure responses indexed by the azimuth approach angle of the incoming missile, the elevation angle of the incoming missile and the estimated distance of the missile from the aircraft. Also included in the table or calculation is the speed and altitude of the aircraft which based upon an optimal response will elect and cause to be ejected from the aircraft, the optimum number and type of flares, the dispense time of the flares and the particular flare dispenser or combination of dispensers used for dispensing the flares in order to provide the optimum countermeasure based upon the characteristics of the incoming missile threat.
One or more preferred embodiments that illustrate the best mode(s) are set forth in the drawings and in the following description. The appended claims particularly and distinctly point out and set forth the invention.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example methods, and other example embodiments of various aspects of the invention. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale.
Similar numbers refer to similar parts throughout the drawings.
An aircraft indicated generally at 1, is shown on the left in
The onboard computer contains a program which based upon the various factors supplied thereto as discussed above, determines the type of countermeasures to be dispensed, such as flares 4, chaff or other known missile deterrents. It also determines the number of flares, chaff etc. to be dispensed, the sequence that the flares or chaff (or both) are to be dispensed and from which dispenser or combination of dispensers they are to be dispensed.
The aircraft will normally be equipped with a number of dispensers at various locations in the aircraft frame, such as on both sides of the frame, both in the nose and tail of the frame, as well as on the top and bottom of the frame. The computer of the countermeasure control system will then initiate the number and types of flares or chaff to be dispensed as well as the dispense pattern, such as the dispense timing and the dispenser to be used.
As an example, upon the onboard detection system determining that missile 3 is approaching the aircraft with an angle of elevation of −30° and at an azimuth angle of 240° from the left side of the aircraft it will actuate the left dispenser (CM Choice C) with a sequencing pattern of a type 2 flare and 0.5 seconds later a type 1 flare. This is illustrated in
Returning to
It is readily understood that the number of flares (or chaff), the types of flares and the sequencing thereof, and the particular dispenser or dispensers from which they are being dispensed will vary depending upon the type of aircraft, such as a high speed fighter, a larger slower bomber, a helicopter etc. The particular lookup table and sequencing is merely an example of how the method and systems implementing the present invention can be implemented. The important aspect is that the CM system will be inputted with the various factors discussed above, namely the angle of elevation and azimuth of the incoming missile for use in determining the flare dispensing sequence and the particular dispenser or combination of dispensers from which they are dispensed.
Also, the particular type of flare (or chaff) to be dispensed will be further determined by inputting into an equation the speed of the incoming missile and speed and altitude of the aircraft.
In summary, the present invention is based upon the angle of approach (AOA) of the threat (missile) to the aircraft and then from a computerized lookup table determines the side of dispense, left or right, or nose or tail of the aircraft or combination thereof, based upon the angle of approach of the attacking missile as well as the type of countermeasure to be dispensed.
The table loop logic 504 generates an index to the table of data 506, based at least in part, on the angle elevation and the azimuth. The index can be an address into a memory that stores data associated to the previously discussed table of
The execution logic 508 receives data that was extracted from the table of data 506 by the table loop logic 504. The execution logic 508 will execute the countermeasure (CM) that is represented by the extracted data. The CM may be similar to CMs A, B, C and D discussed above with reference to
Example methods may be better appreciated with reference to flow diagrams. While for purposes of simplicity of explanation, the illustrated methodologies are shown and described as a series of blocks, it is to be appreciated that the methodologies are not limited by the order of the blocks, as some blocks can occur in different orders and/or concurrently with other blocks from that shown and described. Moreover, less than all the illustrated blocks may be required to implement an example methodology. Blocks may be combined or separated into multiple components. Furthermore, additional and/or alternative methodologies can employ additional, not illustrated blocks.
In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. Therefore, the invention is not limited to the specific details, the representative embodiments, and illustrative examples shown and described. Thus, this application is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims.
Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. References to “the preferred embodiment”, “an embodiment”, “one example”, “an example”, and so on, indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in the preferred embodiment” does not necessarily refer to the same embodiment, though it may.
This application claims priority from U.S. Provisional Application Ser. No. 61/306,741, filed Feb. 22, 2010; the disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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61306741 | Feb 2010 | US |