A number of smart submunitions have recently been developed for use from either aircraft or from artillery-launched rounds. Most tend to operate along the same principle, but the latter category (examined further on) requires a complex separation system and must withstand the crushing G forces experienced during firing.
Submunitions are now generally required to incorporate their own autonomous target detection and acquisition device, which is the reason why they are often referred to as "smart weapons". Generally of the size and shape of a large preserves can -- hence the name "Skeet" used by Textron -- they tend to function along the same basic principle, whereby the "can" -- warhead cum sensor -- is tossed into the air in such a way that it wobbles. At a given height (as opposed to altitude) its downwards-looking sensor is thus forced to look at the ground in a closing spiral pattern until it meets a pattern that matches what it was programmed for. The warhead, generally a shaped charge (but an explosively formed penetrator is an alternative) is instantly triggered. This is the case of the air launched Textron Sensor Fuzed Weapon and the Russian SPBE-D on the one hand and the barrel-launched Giat-Bofors Bonus, Giws Smart and Aerojet Sadarm on the other.
The Textron Systems CBU-97A/B Sensor Fuzed Weapon (SFW) is an SUU-66/B Tactical Munitions Dispenser with a warload of ten BLU-108/B submunitions, each with four Skeet warheads. The Skeet is a squat, cylindrical sensor-fuzed warhead with an infrared sensor, a safety and arming device, a thermal battery and a copper liner. The SFW with its load of 40 smart warheads can be released at heights up to 20 000 feet and at speeds up to 1200 kilometres per hour.
After being dropped from the SFW, each BLU-108 is slowed and turned to the vertical by a parachute. An altimeter-activated rocket motor then reverses the descent and spins the submunition, which throws out the four Skeets. Spring-loaded arms impart a wobble to the Skeet, so that it spins about an inclined axis. Its dual-spectrum infrared seeker thus scans a circle that moves outward from the BLU-108, the scan diameter initially increasing as the Skeet climbs, and then decreasing as it falls. On detecting the heat of a tank, the Skeet fires an explosively-formed projectile at the top of the vehicle.
The SFW entered low rate initial production (LRIP) in 1992, and the first full-rate production contract was signed in 1996. The system...