The untold Pearl Harbor radar story

Ever wonder what happened to the radar set that detected the Japanese aircraft before the raid on Pearl Harbor? This article reveals the fate of that SCR-270 radar set; describes some of the radar development background; and includes typical results of a World War II command, control and communications system that used the SCR-270 as its backbone radar. The SCR-270 was a radio-echo detection and direction finding set for locating aircraft. It operated by transmitting a short-duration pulse of high frequency radio waves, which would be reflected or re-radiated by any metallic or conducting surface within the field of the directive transmitting antenna; therefore, one or more aircraft within the antenna field appeared as a source of reflected radio waves. Rotating the antenna which also served as the receiving antenna, provided a means for determining the azimuth or direction of aircraft. The system measured the time it took a blip or reflected return from the target to appear on a cathode ray tube indicator, to give the distance or range to the detected aircraft. The maximum range of the radar was about 250 miles up to 50,000 feet under all atmospheric conditions including rain, mist, smoke or fog, and during daylight or darkness. The azimuth and range data supplied by the set permitted the plotting of the location of detected aircraft on maps. Major performance characteristics of the radar are provided in the included table     

飞机总体参数与作战效能的关系研究

用计算机辅助飞机设计程序研究了飞机总体参数与作战效能的关系,并在选定的约束条件下对作战效能进行了优化设计和参数敏感性分析。研究表明,如起飞重量一定,则靠飞机性能的改善仅能使作战效能提高２０％～３０％,而装备先进雷达和中程导弹可使作战效能提高１５０％以上。     

Aircraft trajectories considering radar range constraints

The problem of finding an optimal aircraft trajectory subject to constraints defining distance of detection to hostile radar stations is considered. The purpose is to find a trajectory minimizing the flight time between two given positions without hostile radar detection. The flight path is represented using a smooth curve in the form of a spline approximation. The spline representation is used to derive the heading- and bank angles of the aircraft. The position of the aircraft together with the bank- and heading angles are used for calculations of the radar detection range. Furthermore, an example in three dimensions when a Saab 105 approaches a radar station in level flight is investigated.     

基于CAD二次开发的飞行器隐身性能计算方法

在飞行器同雷达对抗时的不同威胁情况下,分析了在雷达仰视照射下飞行器的隐身性能。通过绘制雷达仰角图,得到了目标飞行器在某典型雷达照射下的暴露与隐身区域,从而量化了目标飞行器的隐身性能。通过CATIA二次开发技术实现了CAD模型的便捷修改,为优化外形隐身特性提供支持。最后通过一个具体算例验证种方法的效果,并说明方法具有实用意义。     

Dynamic imaging and RCS measurements of aircraft

Results on radar cross section (RCS) measurements and inverse synthetic aperture radar images of a Mooney 231 aircraft using a ground-to-air measurement system (GTAMS) and a KC-135 airplane using an airborne radar are presented. The Mooney 231 flew in a controlled path in both clockwise and counterclockwise orbits, and successively with the gear down, flaps in the take-off position and with the speed brakes up. The data indicates that RCS pattern measurements from both ground-based and airborne radar of flying aircraft are useful and that the inverse synthetic aperture radar (ISAR) images obtained are valuable for signature diagnostics     

Dominant scatterer identification testing with an integrated X-bandradar system

Radar return data from airborne jet aircraft were collected and analyzed to determine the presence of consistent, dominant radar returns of point scatterers on aircraft simulating landing conditions. These measurements were performed by integrating two separate X-band radars into one system with the ability to simultaneously track and image aircraft. Selected processed data from both radar systems were analyzed and are presented for the airborne jet aircraft     

多雷达航迹的镶拼处理

本文主要讨论如何对航管中心的多雷达航迹相关进行分析处理，其方法将多部不同程式雷达覆盖的管制区域，分成若干小格。     

Correlation filters for aircraft identification from radar rangeprofiles

The potential for identifying aircraft using one or more radar range profiles, in conjunction with a correlator, is investigated. Two types of filter which maximize the expected value of certain correlation peaks are described. The effectiveness of one type of filter was investigated in identification experiments using an extensive data set of real radar range profiles of 24 different aircraft. The results suggest that reliable identification is possible provided aircraft aspect information is used and identifications are based on multiple profiles     

Use of Airborne Monopulse Radar as a Low Approach Aid

The potential of airborne radar to provide pictorial displays as an aid to low approach has stimulated invention of several aircraft approach systems. Early developments are reviewed briefly, and an experiment in producing and flight testing a two-dimensional, range and azimuth, pictorial radar display is described. The monopulse radar equipment and a monopulse display improvement (MDI) technique used in the flight test to enhance the B-scope display are also described in some detail. Representative radar scope photographs are used to illustrate the display available in the aircraft.     

Broadcasting of a Digitally Coded List of Transponder Equipped Aircraft Scanned by FAA Ground Radars as a Means of Collision Avoidance, Navigation, Air Traffic Structuring, and Airfield Approach

An air traffic control system is proposed in which 1) all aircraft are equipped wit transponders, 2) FAA radar sites broadcast a digitally coded list of the identity, altitude, and coordinates of aircraft scanned, 3) each aircraft on receiving this list converts it into a PPI display with the blip of that aircraft branded and blips of off-altitude aircraft blanked, and 4) superimposed on this display are projected maps of airways appropriate to the particular radar and the aircraft altitude. This system could provide a fairly complete capability for air traffic control, structuring, navigation, and collision avoidance at a cost of about 3000 dollars per aircraft. It would replace most navigational and communication equipment now in use and could be operational in several years.     

基于激光雷达的数字化装配检测技术研究

为提高新型飞机装配检测需求,提出了基于激光雷达的装配检测方法,使用激光雷达对装配零部件定位基准进行测量,并对测量数据进行分析,提取出关键尺寸信息,从根本上解决装配问题。结合飞机某部件装配检测实例,对其装配问题进行检测及分析,解决了飞机装配过程中配合尺寸超差问题。结果证明基于激光雷达的装配检测技术可高效准确地检测出飞机装配问题,对实现飞机数字化自动装配具有重要意义。     

The Word Storage Relay (WSR)

One of the more complex systems developed during the cold war was the BOMARC missile system developed by Boeing and the University of Michigan. The BO in the acronym stands for Boeing and the MARC Stands for Michigan Aeronautical Research Center. Boeing built two versions of the BOMARC, the first one designated “IM99A” and the second “IM99B”. The “A” version used a liquid propellant boost system with a range of about 250 miles and the “B” used a solid propellant for boost and had a range of at least 400 miles. The BOMARC was a pilotless aircraft vehicle, developed and deployed to counter the Soviet massed bomber threat     

Pulse Doppler signature of a rotary-wing aircraft

Field measurements of a modified Sikorsky S-55 helicopter target were carried out to investigate rotary-wing aircraft Doppler radar signature phenomenology. The results of the data analysis with regard to classification and identification of the aircraft based on its signature are presented. It was found that using the Doppler radar return and appropriate feature extraction techniques, the helicopter's design features can be estimated. Target backscatter from the main rotor blades, tail rotor blades, or hub can be used for target detection, acquisition, and classification as a rotary-wing aircraft. The extraction of configuration and blade count features can further define the helicopter for identification     

Jerusalem十字架型FSS的仿真设计

在飞行器隐身技术的研究中发现,雷达天线系统通常在飞行器鼻锥方向产生很强的RCS贡献[1]。因此,如何减少雷达天线带外的RCS而又保证自身雷达正常工作已成为目标隐身技术中的一个关键课题。文中介绍了由Jerusalem十字架型振子单元构成的带阻式频率选择表面来有效的控制电磁波的传输和反射,利用单个单元和周期性边界条件的性质,采用理想匹配层(PML)吸收边界、周期边界相结合的方法对无限大频率选择表面进行仿真。借助于有限元软件Ansoft HFSS对Jerusalem十字架型FSS进行了软件建模,并对Jerusalem十字架外形及平面波入射角对频率特性的影响分别进行了仿真,给出了表面波频率选择特性随Jerusalem十字架几何参数和平面波入射角的变化而变化的趋势。     

Probability of Detecting Aircraft Targets

The statistics of aircraft radar cross section (RCS) are estimated by fitting members of the chi-square family of distributions to empirical distributions obtained from blocks of RCS data, each block of data corresponding to a particular aircraft azimuth aspect. The parameters of the fitted distributions vary with azimuth aspect angle, type of aircraft, and radar frequency. Detection probabilities based on the estimated statistics are calculated and compared with detection probabilities based on Rayleigh statistics. This comparison indicates that the average value of radar cross section has much more effect on probability of detection than the normalized variance of RCS, and in the usual situation tends to mask the effect of the normalized variance on probability of detection.     

海面低飞情况下机载航管二次雷达覆盖研究

二次雷达较之一次雷达有许多优点，使其在军用和民用领域得到广泛应用。但当装有航管二次雷达的飞机在海面低飞时，会出现常见的多径效应现象。文章详细分析了飞机机体和海面对航管二次雷达方向图的影响，并利用HFSS软件对飞机在海面低飞时航管二次雷达方向图进行仿真。结果表明，海面影响航管二次雷达的方向图并导致根据其分叉变形，根据平面对天线方向图的影响及其计算公式，对不同飞行高度的方向图进行了计算，得出了在海面低飞时的最佳飞行高度。     

Performance analysis of radar antenna systems

If modern airborne radar systems are to function properly, the radar antenna radiation patterns must meet certain specifications. Until recently, most radar antennas were designed and tested in a clean antenna environment, i.e., there is no near field scattering from host structures or radome effects. However, these higher order effects are the matter of increasing concern with added performance demands in the ever-increasing jammer and clutter interference environments. We investigated the capabilities and limitations of currently available analysis techniques and computer codes for installed performance of airborne radar antenna systems. Then we developed an extended ray-optical technique that could predict total installed performance of airborne radar antenna systems, i.e., the near field scattering from aircraft structures and radome effects. The new analysis technique utilized a ray-tracing method in both airframe and radome simulation. Thus, it can efficiently predict the total installed performance of large radar antenna systems on an aircraft structure     

等离子体隐身结构机翼的RCS分析

等离子体隐身是利用等离子体回避雷达探测系统的一种技术.本文介绍了飞机等离子体隐身的原理,提出了一种在飞机机翼封闭前缘内产生离子体的隐身结构设计方案,进而采用CST NWS高频电磁分析软件,对等离子体隐身结构机翼与金属机翼的RCS进行了分析、对比.研究表明,在前缘设置等离子体隐身结构可以改善机翼的总体雷达散射特性.     

基于低可探测性的参考航迹规划

根据分层规划思想,确定参考航迹是进行航迹规划时首先要解决的问题。在充分考虑雷达探测的各种环境因素及飞行器RCS方位分布特性的基础上,将雷达对目标发现概率作为参考航迹的一个重要评价指标,基于自适应进化算法,采用新的遗传算子,最终生成综合考虑雷达威胁和飞行距离的参考航迹。结果表明,该航迹规划模型能根据对低可探测性和航程的不...     

A statistical hypothesis testing approach to the determination ofsupportable aircraft separation standards

This paper deals with the setting of a statistical hypothesis testing approach to the determination of aircraft separation standards that can be supported within a given Flight Information Region. Given a minimal safety distance to be maintained between two aircraft, we derive a criterion that must be obeyed by their radar plots in order to meet the required separation at a known level of confidence. Conversely, given that a minimal safety distance is maintained between two radar plots, one can find the actual separation that can be guaranteed between both aircraft. The results described here can help to implement automated conflict alert and minimum safe altitude warning facilities