日本利用融合雷达和IRST大幅提高探测范围
日本防卫省报道称，使用针对隐形飞机、弹道导弹和巡航导弹的融合传感器系统使探测范围提高了20%。
The Japanese defense ministry has reported a 20% improvement in detection range with a fused sensor system for use against stealth aircraft and ballistic and cruise missiles.
红外雷达系统显然是为预期的长航时侦察机而设计的，尽管在公布的计划中没有这样的开发计划。这项技术无疑也是日本下一代战斗机的候选技术，尤其是洛克希德·马丁公司的F-35闪电战机，已经具备了这样的复合功能。
The infrared and radar system is evidently intended for a contemplated long-endurance surveillance aircraft, though no such development program is in published planning. The technology is surely also a candidate for Japan’s Next-Generation Fighter, especially since the Lockheed Martin F-35 Lightning already has such composite functionality.
为了测试这项技术，日本在洛克希德马丁公司的UP-3C试验机上安装了一个背向位置的大型红外搜索及跟踪炮塔（IRST）和一个腹装侧视雷达。该部的采购、技术和物流局（ATLA）将在从2012年4月开始的财政年度到2021财政年度执行该计划。它的名字可以翻译为复合无线电和光传感器系统。
To test the technology, Japan has fitted a Lockheed Martin UP-3C trials aircraft with a large infrared-search-and-track turret (IRST) in a dorsal position and a ventrally mounted side-looking radar. The ministry’s Acquisition, Technology and Logistics Agency (ATLA) is running the program from the fiscal year beginning in April 2012 to fiscal 2021. Its name can be translated as Composite Radio and Light Sensor System.
ATLA说，该系统的IRST可以在中波波段搜索弹道导弹，在长波波段跟踪导弹，搜索和跟踪隐形飞机。该雷达采用S波段，使用氮化镓技术，面向UP-3C的左侧。
ATLA said the system’s IRST operates in medium wavelengths to search for ballistic missiles and in long wavelengths to track them and to search for and track stealth aircraft. The radar uses the S band, has gallium-nitride technology and faces to the left of the UP-3C.
在报告截至2019年3月的测试时，该局描述了一个具体目标，即通过使雷达接收到更微弱的信号（这也意味着允许它生成更多的假目标），观察系统是否能够探测更远的目标。IRST用于检查检测结果并拒绝错误的检测结果。这一理念在其他国家也得到了应用。
Reporting on testing up to March 2019, the agency described a specific objective of seeing whether the system could detect targets farther away by making the radar accept fainter signals—which also meant allowing it to generate more false targets. The IRST was used to check detections and reject false ones. This idea has been applied in other countries.
ATLA说，接受的信噪比大概比雷达的正常工作水平降低了3分贝，但并未透露该雷达的名称。
ATLA said the accepted signal-to-noise ratio was reduced by 3 dB—presumably from the normal operating level of the radar, which was not named.
ATLA表示，评估结果证实，可探测目标的范围扩大了20%。信噪比降低3分别，也算差强人意，是雷达方程的理论结果，雷达方程是一个将探测范围与各种因素联系起来的标准公式。
The evaluations confirmed that targets could be detected at 20% greater ranges, ATLA said. For a 3 dB reduction in accepted signal-to-noise ratio, that is about the theoretical result from the radar equation, a standard formula that relates detection range with various factors.
融合这种传感器的另一个优点是雷达在距离上是精确的，但在方向上不是，而IRST具有相反的特性。两者合在一起，可以比单独使用任何一个都更精确地定位目标。但是，IRST需要够好的大气条件，而雷达操作不得使运载飞机暴露在探测和攻击之下。
A further advantage of fusing such sensors is that radars are precise in range but not in direction, whereas IRST’s have the opposite characteristics. Together, they can far more precisely locate a target than either can do separately. But the IRST needs satisfactory atmospheric conditions, while radar operation must not expose the carrying aircraft to detection and attack.
该局没有说明该系统是否也可以在另一个方向运作 - 利用雷达验证从微弱信号实现的IRST探测。这似乎是一个具有可能性的要求，因为隐形飞机的红外辐射很可能在其雷达反射被发现之前就被侦测到了。如果一个传感器在扫描过程中进行了侦测，它可能会提示另一个传感器注视目标的方向，直到获得良好的数据或什么也没有发现。
The agency did not say whether the system also worked in the other direction, with the radar verifying the IRST detections achieved from weak signals. This seems to be a likely requirement, since a stealth aircraft’s infrared emissions may well be detected before its radar reflections can be. If one sensor made a detection in scanning, it could cue the other to stare in the target’s direction until good data were acquired—or nothing found.
这些试验还验证了传感器作为无源雷达工作的理论原理。该术语通常指的是雷达探测到的目标碰巧存在的射频能量反射，例如电视传输。该部概述了2012年的计划，将这一功能描述为利用雷达的辐射，这似乎表明了合作源。
The tests also validated theoretical principles for sensor operation as a passive radar. The term usually refers to a mode in which a radar detects a target’s reflections of radio frequency energy that happens to be present, such as television transmissions. Outlining the program in 2012, the ministry described this function as using emissions from radars, which seems to suggest a cooperating source.
ATLA说，使用多个地面站可以提高被动雷达模式的精度，显然是指发射机。该局强调，这只是一个理论评估。它没有详细说明。
Accuracy in passive-radar mode can be improved by using multiple ground stations, ATLA said, evidently referring to the transmitters. The agency stressed that this was only a theoretical evaluation. It did not elaborate.
ATLA说，IRST对试验中使用的日本火箭表现出非常好的结果。2012年的计划大纲提出，炮塔将来自Airboss，这是富士通的一款红外搜索及跟踪炮塔（IRST），曾在2007年12月被用于探测夏威夷附近的弹道导弹目标。变化之一是增加了长波能力，以便更好地探测弹道导弹弹头；以前，这种传感器只能在中等波长下运作。
The IRST showed very good results against Japanese rockets used in the trials, ATLA said. The 2012 program outline suggested that the turret would be derived from Airboss, a Fujitsu IRST that was used to detect a ballistic missile target off Hawaii in December 2007. One change was the addition of long-wavelength capability for better detection of ballistic missile warheads; formerly the sensor operated in only medium wavelengths.
ATLA说，融合传感器系统采用了先跟踪后检测技术。这是一个过程，在这个过程中，假想的轨迹被投射到目标前面，以确定其表面运动是否合理。
The fused sensor system used the track-before-detect technique, ATLA said. This is a process in which imaginary tracks are projected ahead of a target to work out whether its apparent movement is plausible.
日本有三种机型可以作为这种系统的长航时载体：川崎重工C-2空运机、P-1海上巡逻机以及三菱航空SpaceJet支线喷气机。由于P-1的机身尺寸与用于试飞的UP-3C相似，它很有可能被选为候选机型，尽管它将是日本航空自卫队的一种新型机型，日本航空自卫队可能会对作战系统进行部署。无人驾驶飞机可能会是首选。
Japan has three aircraft types that could serve as long-endurance carriers of such a system: the Kawasaki Heavy Industries C-2 airlifter and P-1 maritime patroller; and the Mitsubishi Aircraft SpaceJet regional jet. Since the P-1 has a fuselage similar in size to that of the UP-3C used for the trials, it should be a likely candidate—though it would be a new type for the Japan Air Self-Defense Force, which would presumably field the operational system. An unmanned aircraft could be preferred.
NGF预计在2030年代中期投入使用。
The NGF is supposed to enter service in the mid-2030s.
这条消息是Bradley Perrett在 Aviation Week & Space Technology 发表的文章。《Aviation Week & Space Technology》由人脉最广、经验最丰富的记者团队提供支持，为新趋势、最佳操作实践和政策、要求和预算的持续更新提供关键情报。 点击此处查看有关 Aviation Week & Space Technology 更多消息。