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An active electronically scanned array (AESA), also known as active phased array radar (APAR), is a type of phased array radar whose transmitter and receiver (transceiver) functions are composed of numerous small solid-state transmit/receive modules (TRMs). AESA radars aim their "beam" by emitting separate radio waves from each module that interfere constructively at certain angles in front of the antenna. Advanced AESA radars can improve on the older passive electronically scanned array (PESA) radars by spreading their signal emissions out across a band of frequencies, which makes it very difficult to detect over background noise, allowing ships and aircraft to broadcast powerful radar signals while still remaining stealthy. ==History== Bell Labs proposed replacing the Nike Zeus radars with a phased array system in 1960, and were given the go-ahead for development in June 1961. The result was the Zeus Multi-function Array Radar (ZMAR), an early example of an active electronically steered array radar system. MAR was made of a large number of small antennas, each one connected to a separate computer-controlled transmitter or receiver. Using a variety of beamforming and signal processing steps, a single MAR was able to perform long-distance detection, track generation, discrimination of warheads from decoys, and tracking of the outbound interceptor missiles. MAR allowed the entire battle over a wide space to be controlled from a single site. Each MAR, and its associated battle center, would process tracks for hundreds of targets. The system would then select the most appropriate battery for each one, and hand off particular targets for them to attack. One battery would normally be associated with the MAR, while others would be distributed around it. Remote batteries were equipped with a much simpler radar whose primary purpose was to track the outgoing Sprint missiles before they became visible to the potentially distant MAR. These smaller Missile Site Radars (MSR) were passively scanned, forming only a single beam instead of the MAR's multiple beams. * The first military ground-based AESA was the J/FPS-3 which became fully operational with the 45th Aircraft Control and Warning Group of the Japan Self-Defense Forces in 1995. * The first series production ship-based AESA was the OPS-24 Fire-control radar introduced on the Asagiri-class destroyer DD-155 Hamagiri launched in 1988. * The first airborne series production AESA was the EL/M-2075 Phalcon on a Chilean Air Force Boeing 707 that entered service in 1994. * The first AESA on a combat aircraft was the J/APG-1 introduced on the Mitsubishi F-2 in 1995.〔(【引用サイトリンク】title=Japan Upgrading 60 F-2s With AAM-4, J/APG-2 )〕 * The first AESA on a missile is the seeker head for the AAM-4B air-to-air missile (Mitsubishi F-2, Mitsubishi F-15J).〔 US based manufacturers of the AESA radars used in the F22 and Super Hornet include Northrop Grumman〔(【引用サイトリンク】title=Northrop Grumman Successfully Completes F-22 Radar Flight-Test Certification (NYSE:NOC) )〕 and Raytheon. These companies also design, develop and manufacture the transmit/receive modules which comprise the 'building blocks' of an AESA radar. The requisite electronics technology was developed in-house via Department of Defense research programs such as MMIC Program.〔(A DARPA Perspective on the Future of Electronics )〕〔http://www.ll.mit.edu/news/journal/pdf/vol12_no2/12_2devphasedarray.pdf〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「active electronically scanned array」の詳細全文を読む スポンサード リンク
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