1. Field of the Invention
The present invention pertains to the field of radar detection systems, more particularly to the field of radio wave based proximity fuzes including logic means. 342/68 or 102/215
2. Background of the Invention
A proximity fuze is an explosive ignition device used in bombs, artillery shells, and mines. The fuze senses when a target is close enough to be optimally damaged or destroyed by the weapon's warhead.
An example mission for a helicopter fired missile which includes a proximity fuze is to engage a small team of terrorists who possess a Short Range Air Defense (SHORAD) weapon (e.g. Red Eye, Stinger or SA-7) and intend to shoot down a commercial airliner. The missile is first aimed and then fired from the helicopter. Upon firing, the proximity fuze circuit is powered and enabled (armed). The missile may be guided or unguided during flight. Upon detecting signals indicating a proximal target, the fuze detonates the missile warhead. In such a missile, the proximity fuze may be designed in conjunction with the missile warhead to yield maximum effectiveness over a range of scenarios. In some scenarios the fuze may be required to ignore close encounters with terrain, buildings, or vegetation and yet reliably detonate proximal to the intended target.
Proximity fuzes can and have been based on acoustic, optical and radio frequency techniques. Acoustic is mostly applicable to torpedoes or mines. Optical techniques have issues with rain, smoke, and black targets and the like. Conventional radio frequency techniques include Doppler radar and radar amplitude signals. In addition, proximity fuzes have been based on conventional range gated radar. Conventional radio frequency and radar approaches are limited, however, for close range triggering in clutter environments because of difficulty achieving clutter rejection. Also, narrow band techniques are easily jammed by a small amount of RF power in band. Interference and jamming requirements must be considered in the design to avoid significant performance degradation in the field after substantial investment to deploy the weapon system.
Small missiles present an especially challenging set of systems requirements. Small missiles typically should detonate very close to the target within the lethality range of the small warhead, thus requiring close range precision fuzing. Missile flight may originate close to the ground or just above tree top and travel over or beside buildings or trees or ridges before arriving at the target area. In the target area, nearby structures or ground may need to be ignored while detecting the target and detonating at an appropriate range. Conventional RF techniques lack the resolution to achieve required performance in these complex engagements, especially in a very small package consuming a small amount of power.
Further system requirements include a long shelf life for the system including the power source. Small missiles are manufactured in large quantity and stored for twenty or more years where it is impractical to provide periodic maintenance including battery replacement.
Thus there is a need for an improved small size, long shelf life proximity fuze with short range precision fuzing capable of employing multiple target detection and discrimination methods for maximum effectiveness in complex engagements.