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20-01-2016, 19:36
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חבר מתאריך: 07.04.08
הודעות: 6,949
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מאמר על הספייס 250. המאמר פורסם AVIATION WEEK ולא יכולתי לחתוך אותו.
בתגובה להודעה מספר 1 שנכתבה על ידי AJ-47 שמתחילה ב "תקצירי חדשות צו"ב מהעולם ומאמרים בנושא 2016 מס' 1"
Israel Aims For New Era in Targeting and Precision Israel pushes the state of the art in weapons and sensors
Jan 14, 2016 Bill Sweetman | Aviation Week & Space Technology
Massive Precision
Rafael’s Spice-250 guided bomb, now in its final stages of development, will allow fighters to perform accurate standoff launch-and-leave attacks against an unprecedented number of targets. Coupled with the company’s new Litening 5 targeting pod, it gives the fighter the ability to designate its own targets well beyond effective laser range.
These are two of a number of weapons and systems that constitute new-technology reconnaissance-strike complexes emerging from Israel’s combat experience and intended to attack hard-to-find targets with minimal collateral damage. Spice-250, for instance, has an 80-kg (176-lb.) warhead, while Israel Aerospace Industries’ Harop loitering weapon—in full production for the Israel Defense Forces and for export—carries a 15-kg lethal payload.
In the 250-lb. class, Spice-250 is somewhat similar in mission and size to the Raytheon Small-Diameter Bomb Increment 2 but has a proven guidance technique, already in service on the larger Spice-1000 and -2000 that is different in principle and dispenses with active radar. It is an electro-optical scene-matching system, using a dual-band (daylight and infrared) sensor, and its distinguishing feature is that it does not aim at the pixel containing the target or use geographical coordinates.
Instead, the system is programmed before launch with a set of images of points surrounding the target, derived from satellite or airborne imagery and converted into a map with the aid of a terrain database. The guidance algorithm then locates the target by reference to the relative position of those images. According to Rafael engineers, this approach has several advantages.
The target itself may be camouflaged, but the guidance system can select high-contrast points around it. The system will store more points than it needs for accurate target engagement, so that even if the target or some of the aim points are obscured by cloud or smoke, the target can still be hit. Because the guidance system focuses on specific points in the target scene, it is not confused by extraneous changes in the picture. “We can live with a 50% change in the scene, because we’re not looking at the target,” a Rafael engineer observes.
Rafael claims a 1.5-meter (5-ft.) circular error probability, independent of range—Spice-250 will glide as far as 100 km (62 mi.)—and notes that the image-based guidance system does not require the capability to georeference satellite navigation signals, a capacity not all nations possess. A key requirement for the Spice family was independence from GPS or other satellite navigation systems, because these were considered likely to be jammed or otherwise unavailable in a conflict
The Smart Quad Rack for the Spice-250 glide bomb incorporates front and rear data link antennas. In long-range strike configuration, this F-16 also carries the new Litening 5 targeting pod. Credit: Rafael
Rounding out the Spice-250 guidance system’s modes are semiactive laser homing—if a designation source is available—and a two-way data link that provides damage assessment, a moving-target capability outside laser range, and the ability to abort an attack (for example, to avoid collateral damage if noncombatants enter the target area during an engagement). The weapon is designed for use with a four-round Smart Quad Rack that includes the mission planning processor and data link, with front and rear antennas for 360-deg. coverage. An F-16 can carry 16 weapons, and an F-15I can carry seven racks and 28 rounds, creating what Rafael calls “mass precision” capability.
Litening 5, which started flight tests last year and is expected to enter service by 2018, complements the new weapons. It has new optics with a larger aperture and zoom range, and introduces a third operating band—the shortwave infrared (SWIR) band, about 1.5 microns. SWIR operates well in nighttime conditions, but it’s most important attribute is that it is absorbed less by atmospheric moisture than visible light (0.5-0.7 microns) and provides longer oblique range than either midwave IR or daylight high-definition TV. According to Rafael, Litening 5 will be able to detect and track vehicle targets at ranges of up to 60 km, using an ultra telephoto SWIR sensor with a 0.3-deg. field of view and new automatic moving-target-indication algorithm.
Longer range changes the pod’s role. “This is more than a small step,” says a Rafael executive. “It goes from being a laser targeting pod to a standoff, multi weapon pod.” The 60-km range is beyond the reach of accurate laser designation, because of low-altitude atmospheric absorption and distortion, and geometrical “smearing” of the laser spot along the beam axis. The pod uses Rafael’s MatchGuide software to generate the multipoint template for Spice guidance.
Long-range precision targeting and reconnaissance is also the role of the M-19HD sensor turret, from Israel Aerospace Industries’ Tamam Division and in production for the new Super Heron UAV and other applications.
The 19-in. turret is slightly flattened to ease ground-clearance issues. Behind the large-aperture, wide-zoom-range Newtonian-telescope optical system is a complete array of sensors—high-definition day and night sensors and SWIR—and the system include an eye-safe laser rangefinder and laser designator.
Not surprisingly, a Tamam engineer lists stabilization of the long-focus optics—carried by a diesel-powered UAV—as a big challenge. But he shifts quickly to a different topic, the software challenges of sensor fusion, image processing and exploitation in meeting the specific requirements of intelligence-gathering and targeting: “It’s not National Geographic”; that is, it involves more than just acquiring a picture. “It’s a real art, and there are only four or five players worldwide who can do it,” he says. “It’s a game of understanding the nature of the problem, which is not obvious.” And as a military tool, the system “must be easy to use,” he notes.
The military user needs to know the exact location of objects in the picture. “We know where we are, but we don’t have a digital terrain model for the entire world,” the engineer says.
The basic optics are good enough to see colors clearly at 40-km slant range in daytime mode. However, by using an adaptive color enhancement program, it’s easier to see small details—wires and poles, for instance—in the scene. SWIR can be fused into the image to penetrate haze—providing a “defog” mode—but tends to be noisy, requiring more custom processing.
A turbulence mitigation mode reduces the effect of heat haze, difficult to do but vital at long slant ranges. For the operator, “working for 2 or 3 hr. with a turbulent image is a huge headache,” the engineer says. The U.S. was using neural-net processing in the 1990s to correct for atmospheric distortion in overhead images, but oblique multispectral video is a far bigger challenge. “It’s similar to the software that we use to auto track targets at sea,” the engineer says. “Nothing in the natural sea environment has straight lines.”
Finally—since the M-19HD generates a vast amount of raw data—the system manages the use of the data link, tracking targets automatically and sending imagery as required. All this advanced processing can be ported from the top-of-the-line M-19HD to other Tamam payloads.
RELATED READING
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http://aviationweek.com/defense/isr...a762f45be45c2fd
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