Defense Technology International - December 2007 - (Page 40)

DATA LINKS AIRBORNE MISSING LINK BILL SWEETMAN•MINNEAPOLIS strange thing happened to the ﬁghter aircraft in the past decade: It became an intelligence, surveillance and reconnaissance (ISR) platform. Sensors are at the front of this development. Active electronically scanned array (AESA) radars deliver sub-meter resolution. Much-improved electronic combat subsystems using digital radiofrequency (RF) technology can identify and locate emitters in ways that a few years ago were conﬁned to large, special-purpose, electronic-surveillance measures systems. Targeting pods now have several times the e ective range and resolution of earlier-generation pods, and geo-locate targets with increased accuracy. What has not improved as quickly is the ability to get this information to other users. The baseline ﬁghter data link is the U.S.-developed Link 16 standard, which s h a re s s h o r t text messages and numerical data, but lacks the speed to deliver imagery. Targeting pods such as the Rafael Litening can be equipped with data links capable of passing imagery between the ﬁghter and a close air support controller on the ground. Other systems have been adapted for such short-range, line-ofsight communications. Sweden has long led the world in the use of data links to connect a formation of ﬁghters, and the Saab JAS 39 Gripen comes with a system that lets a formation cooperate. For beyond-line-of-sight (BLOS) communications, Israel’s new F-16I ﬁghters have a two-way satellite link. But huge gaps remain. And the biggest gaps afflict the most advanced ﬁghters—the very-low-observable (VLO) Lockheed Martin F-22 and F-35. The problem with adding VLO systems to a network is that all transmissions can be intercepted. With networked, 40 As ﬁghters become more wired, the F-22 is a disconnected standout A computer-based systems like the Czech Vera-E passive surveillance system (PSS), which uses time-difference-of-arrival models to able once an adversary knows where to look. The designers of the ﬁrst VLO aircraft adopted low probability of intercept (LPI) as the watchword for RF systems. This includes power management, frequency ability and tight beam control with small sidelobes—but it was founded on transmitting as little as possible, which in the pre-network days meant not at all. Both the F-22 and F-35 use RF intra-ﬂight data link systems, which generate steered, stabilized, pencil beams on a handshake arrangement, so that the beams lock on to the receiver aircraft. The Harris Multifunction Advanced Data Link (MADL) on the F-35 uses six phased array antennas to provide spherical coverage around the aircraft. The signals cannot be intercepted unless the listener is on the beam, which is constantly moving. locate the source of any emitter in 3D, a detected signal can cue other sensors to the possible location of a target. And as the 1999 shoot-down of an F-117 Nighthawk by a Serbian missile crew showed, even a VLO aircraft is vulner- These systems have two drawbacks, however. Each pencil beam can talk to only one aircraft at a time and needs a dedicated transmitter to do that, so it is not a network device. And the intra-flight links only talk to other aircraft of the same type. The intra-ﬂight data link on the F-22 is www.aviationweek.com/dti DEFENSE TECHNOLOGY INTERNATIONAL DECEMBER 2007 http://www.aviationweek.com/dti

Table of Contents Feed for the Digital Edition of Defense Technology International - December 2007

Defense Technology International - December 2007 Contents Around the World Science Watch Tech Watch BrahMos: Ramjet Ship Killer r-e-s-p-e-c-t Deja Vu Trump Card Dubai Demos Agile Helos Joint Force Online Charge UGVs Creep, Crawl to Victory Sweet Ride Fast, Lethal Ship Defense Networking Stealth: Why Raptors Can't Talk The Net Cutting Edge First Person In Review Insight

Defense Technology International - December 2007

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