Improving intrusion detection radar

The first monostatic microwave intrusion detection sensor with range cutoff was introduced in 1984. This range cutoff circuit as used in the Model 375 and 385 has proven very effective in preventing nuisance alarms beyond a user-defined range. The Intrepid Digital Transceiver introduced in this paper builds upon this proven technology with the addition of a unique digital signal processing routine that measures range to the intruder. Intrepid Digital Transceiver alternately transmits pulses at two discrete frequencies within K-Band. When an intruder enters the detection zone, the Doppler response at each frequency is digitally recorded. The difference between the two frequencies is controlled so that the phase angle between the two Doppler responses can be used to determine the unambiguous range to the target. As a byproduct of the process targets approaching the transceiver can be distinguished from those moving away from the transceiver. Range information is used to enhance the signal processing. The amount of signal integration is increased with range in proportion to the width of the detection pattern so as to optimize the signal to noise ratio (SNR).     

High Range-Resolution Monopulse Tracking Radar

High range-resolution monopulse (HRRM) tracking radar which maintains wide instantaneous bandwidth through both range and angle error sensing channels provides range, azimuth, elevation, and amplitude for each resolved part of the target. The three-dimensional target detail can be used to improve and extend radar performance in several ways: for improved precision of target location, for target classification and recognition, to counter repeater-type ECM, to improve low-angle multipath tracking, to resolve multiple targets, as a miss-distance measurement capability, and for improved tracking in chaff and clutter. These have been demonstrated qualitatively except for the ECCM to repeater ECM and low-altitude tracking improvement. Initial results from an experimental HRRM radar with 3-ns pulse length show resolution of aircraft into its major parts and precise location of each resolved part accurately in range and angle. Realtime closed-loop tracking is performed on aircraft in flight using high-speed sampled, digitized, and processed HRRM range and angle video data. Clutter rejection capability is also demonstrated.     

Side zone automotive radar

Side Detection System (SDS) based on radar technology for automotive applications is introduced. The functional requirements of such a system are described and the resulting safety enhancement benefits are summarized. Also, the nature of the radar environment for the side zone application is reviewed in qualitative terms. Minimizing cost is a necessary system design driver, and presents a considerable challenge for radar designs in all but the most primitive capability cases. A cost effective design approach and radar system architecture which solves the side zone application problem of separating potentially hazardous target returns from exorbitant amounts of clutter are discussed in some detail. This design has been in road test for several months, and has achieved enthusiastic customer acceptance     

无人机防相撞空中威胁态势的探测与告警研究

空中威胁态势探测与告警是无人机飞行防相撞预警的关键。为此,提出一种基于航迹预测的无人机防相撞空中威胁态势探测与告警方法。在该方法中,先采用滑动窗多项式拟合法对入侵机航迹进行动态预测,然后,在航迹预测基础上,利用无人机与入侵机飞行信息,建立针对入侵机的无人机动态避撞区,最后,结合静态保护区原理,对特定飞行场景下的无人机飞行冲突趋势、空中危险接近趋势和飞行碰撞趋势的探测与告警。仿真实例验证了所提出方法的有效性,也验证了其用于无人机飞行防相撞预警的可行性。     

Smuggling interdiction using an adaptation of the AN/APG-76multimode radar

The AN/APG-76 multimode radar was designed and developed for a multimode attack fighter application requiring rapid search, detection, identification, and precision location of both airborne and surface targets from long standoff ranges under adverse weather conditions. Unique is the radar's ability to generate SAR images of a selected area while simultaneously detecting and tracking all-speed moving objects located within that imaged region. Northrop Grumman Norden Systems has recently upgraded and adapted this radar to smuggling interdiction and related law enforcement missions. These adaptations have added an integrated GPS/INS subsystem for enhanced self-navigation and target location accuracy, a long range wide-band digital data link and ground station for mission control and data dissemination, a 3-D interferometric SAR imaging capability for detailed high resolution topographic mapping, and 1 meter and 0.3 meter resolution SAR modes for positive target identification. Additionally, the radar has been installed into wing-mounted pods and adapted for side-looking and 360 degree coverage applications. Automatic target detection and enhanced-range sea-surveillance and air-targeting modes are also now available through the use of open architecture commercial processors and non-proprietary transportable programming languages     

Use of laser scanning technology for perimeter protection

The Police Scientific Branch (PSDB) is part of the Crime Reduction and Community Safety Group (CRCSG) of the Home Office. Part of PSDB's work includes evaluating and assessing new technologies for perimeter intrusion detection. Laser scanning technology has been used for some time in a range of industrial and commercial applications. These span from detecting hands when they are close to dangerous machinery to preventing collisions at container ports and monitoring manufacturing processes. Laser scanners are non-contact measurement systems and scan their surroundings two-dimensionally. This describes the application of laser scanning to physical security, including modifications to such systems for their use as perimeter intrusion detection systems (PIDS). In these systems, motion detection is provided by a pulsed laser beam by measuring the propagation time for the reflected beam to return to its source. Using this information, a contour plot of the surrounding area is built up. Once this contour information has been obtained, the detector can recognise the addition of an object to its field of view through a change in the programmed surroundings. Consequently, the size, shape, and direction of targets moving in the frame can be assessed and an alarm output given, if required. This explains the main operating principles of the systems, including mechanisms for the detection of a potential intruder and the handling of false alarms. Detection capabilities and the potential for low false alarm rates will be described, along with configurations for operational deployment.     

WARLOC: A High-Power Coherent 94 GHz Radar

This paper describes the development of a high-power, coherent radar system at W-band and discusses potential applications of radars with this new capability. Previous radars in this frequency band were limited by available power-amplifier technology to about 500 W of average power; WARLOC radar represents an increase in power, by 20 times, over previous coherent radars at 94 GHz. This performance improvement is possible due to the development of a gyroklystron amplifier specifically for this and future radars in this frequency band. The gyroklystron amplifier tubes deliver 100 kW peak power and 10 kW of average power at a center frequency of approximately 94 GHz. Other novel features of this radar include the use of highly overmoded waveguides and rotary joints for the transmission of power from the final power amplifier (FPA) to the antenna, and a high-power quasi-optical duplexer. The system uses a relatively large 1.8 m diameter (580-wavelength) Cassegrain antenna, which required the development of an antenna with an rms surface accuracy of 0.0025 in, to obtain long-range detection and identification of small objects. Test data show an antenna gain of 62.5 dB, confirming that the needed surface accuracy was achieved. Two mobile shelters house the radar system, permitting relocation to various test sites. WARLOC is presently operational at the Naval Research Laboratory's Chesapeake Bay Detachment facility, Maryland. It is being employed in radar imaging of airborne and surface objects, and in the scientific study of propagation effects and atmospheric physics phenomena.     

MEMS Electronically Steerable Antennas for Fire Control Radars

Large apertures are of great benefit to applications that are prime powered limited as is found on aerostat and other airborne platforms. Electronically scanned array antennas are often proposed for these applications. However, increasing the aperture area with conventional array technology is met with prohibitive cost, weight, and prime power increases because of the dense spacing of phase shifters and/or active T/R modules. This discusses the recent development of RF MEMS (Microelectromechanical System) switch technology and the use of these switches in a Radanttrade lens configuration for arrays of approximately 10 m² at X-band. A proof-of-concept 0.4 m² MEMS Electronically Steerable Antenna (ESA) containing 25,000 MEMS switches has been successfully designed, fabricated, and tested. The 0.4 m² MEMS ESA was then integrated with an AN/APG-67 radar system to form the MEMS Demonstration Radar System. The MEMS Demonstration Radar System successfully detected both airborne and ground moving targets during a series of extensive radar demonstrations. This is believed to be the first large scale employment of MEMS switches in a scanning antenna and radar system. The low-cost, lightweight, and low power technology demonstrated can enable weight and power constrained platforms with electronic steering.     

Ultra-wideband technology and random signal radar: an ideal combination

Ultra-wideband radar and random signal radar are two types of newly-developed radar systems. This paper introduces the special advantages of the combination of ultra-wideband technology and random signal radar to the international radar community. It shows that these two radar systems have a very close relationship in nature and can gain significant benefits from each other. It can be anticipated that the random signal modulated waveform will open many potential possibilities for the applications of ultra-wideband radar systems to civilian operating environments.     

基于3DT的空时自适应单脉冲参数估计算法

空时自适应处理(STAP)是机载预警雷达抑制杂波和干扰的一项关键技术,而多普勒三通道联合自适应处理(3DT)是适合工程实现的降维(RD)STAP方法。STAP目标检测后还需进一步估计目标的角度参数,因此将自适应单脉冲(AM)技术引入3DT,提出了一种高精度联合估计目标速度与方位空间角的空时自适应单脉冲算法。理论分析与仿真实验结果表明,当目标多普勒频率偏离检测多普勒单元中心频率时,该算法能同时减少目标多普勒跨越损失和空时导引矢量失配损失,进而提高输出信杂噪比(SCNR),改善目标测角精度。     

Low-cost technology for multimode radar

A flexible test bed radar architecture is described which includes an integrated RF electronics package that can support multiple radar applications, including surveillance, fire control, target acquisition, and tracking. This type of architecture can significantly reduce the cost, power, size, and weight of electronics on future weapon delivery platforms. The Army Research Laboratory (ARL) is developing technology to support multimode radar requirements. These requirements include the detection and location of moving or stationary low radar cross section targets in heavy ground clutter and the classification and/or recognition of these targets. We address these requirements with commercial-off-the-shelf (COTS) products and the integration of several enabling technologies. The test bed radar includes a direct digital synthesizer (DDS) for frequency-diverse waveform generation, a flexible wideband transceiver for bandwidth extension and frequency translation, and an open architecture signal processor with embedded wideband analog-to-digital converters for real-time acquisition and processing. Efficient signal processing algorithms have been developed to demonstrate multimode radar capability. This paper discusses the various subassemblies, algorithm efficiency, and field experiment results     

一种机器人砂带磨削的路径规划方法(英文)

机器人砂带磨削系统具有弹性接触和宽行加工两个显著优点,被广泛应用在具有复杂工件的终加工领域,提高表面质量和加工效率。有关在曲率约束下的磨削路径规划研究较为少见。由于工件与接触轮之间存在复杂的弹性接触,因此,机器人磨削路径可以利用接触运动学的一般方法来求解。机器人砂带磨削过程且需要满足一般的砂带磨削工艺要求,其中最重要的是保证接触轮与工件的局部几何特征贴合。在曲率较小的局部,相邻刀位点的弧长加大,以保证加工效率。相反地,在曲率较大的局部,相邻刀位点的弧长较小,以保证加工精度。利用一系列平面与目标曲面相截,得到相应的截平面的轮廓曲线。对于任意一条轮廓线,优化相邻刀位点之间的弧长,在曲率较大的局部增加一个中间刀位点。本文提出了一种包含弧长优化和主曲率匹配的磨削路径生产方法,通过离线仿真验证了有效性,并利用该方法提高了曲面的磨削质量。该路径规划方法为生成光顺且精确的机器人曲面磨削路径提供了理论依据。     

US Air Force EarthRadar for detection and discrimination of buriedunexploded ordnance

The US Air Force EarthRadar system is a multi-purpose sensor designed and constructed using "radar" principles. This technology was originally developed for the US Air Force to detect buried unexploded ordnance (UXO). Bakhtar Associates developed the US Air Force EarthRadar technology under the DoD SBIR program. The system is capable of detecting buried metallic and non-metallic objects, including glass vials. In addition, the manner in which system hardware, signal processing, and the integrated high resolution global positioning system (GPS) are configured makes it ideal for applications such as mapping subsurface geological features, locating cavities and collapse features, and identifying contaminated ground     

吸收变异的粒子群算法及应用

提出了一种改进的粒子群算法,称为ConvergencemutationPSO(CM_PSO)。该算法根据粒子群中各粒子的适应值动态地调整粒子数量,把部分适应度差的粒子适当汇聚到适应度好的区域,在不损失全局搜索能力的同时,增强局部搜索能力。在将该算法应用于雷达组网误差配准问题中,提出了一种基于CM_PSO的误差配准技术。仿真表明,该算法能有效配准,与对比方法相比较,具有更好的收敛精度和更快的进化速度。     

Analysis of queuing behavior of automatic ESM systems

Radar electronic support measures (ESM) systems detect active emitters in a given area and determine their identities and bearings. The high arrival rate of radar pulses in dense emitter environments demands fast automatic processing of arriving pulses so that the ESM system can fulfill its functions properly in real time. Yet, the performance analysis of automatic ESM system in real life Is difficult since both pulse arrivals and widths can be specified only probabilistically. The success of queuing theory in many applications such as computer communication networks and flow-control has encouraged designers to utilize queuing theory in qualifying and judging the performance of automatic ESM systems in dense emitter environments. The queuing behavior of these systems is analytically evaluated under different service disciplines and elaborate computer simulations validate the results. The analysis involves statistical modeling of arrival and departure processes as well as distribution of service times. It permits estimating the blocking probability due to high arrival rates of intercepted radar pulses or due to limited speed of the deinterleaver processor. Queuing analysis is shown to be quite useful to quantitatively assess tradeoffs in ESM systems design     

基于阵列天线的雷达导引头目标角位置模拟器

针对目前雷达导引头目标角位置模拟装备现状和发展趋势,分析利用阵列天线实现目标角度位置的原理,提出了一种基于阵列天线的雷达导引头目标角位置模拟器的设计方案,分析了工程实现所需要的关键技术,并提出了实现方案,包括天线阵设计、目标控制算法和误差特性、矢量调制技术和阵列校准技术。     

改善电子系统故障诊断能力的神经网络虚警过滤器技术

分析了现代电子系统机内测试 (BIT)技术存在的虚警问题 ,提出运用神经网络虚警过滤器(NNFAF)技术来降低虚警、改进BIT能力 ;并介绍了NNFAF的原理和网络开发方法 ;最后分析了NN FAF技术的特点、应用及发展方向。     

基于神经网络的雷达抗干扰效能评估方法

雷达抗干扰效能是衡量雷达设备性能的重要指标,如何准确、客观、快捷地评估雷达抗干扰效能,对雷达、干扰双方均具有重要的现实意义。文章通过对雷达传统的抗干扰效能加权评估方法的分析,提出了基于神经网络的雷达抗干扰效能综合评估方法,并将该评估方法应用于雷达接收机抗干扰的技术等级评判实例中。实例结果表明,该评估方法能客观、定量地评估雷达抗干扰效能,具有一定的实用性。     

Summary of recent Australian radar developments

Over the last 30 years there has been a growing Australian capability in very long-range radar systems, especially over the horizon radar (OTHR) and a related technology, surface wave radar (SWR). Both operate in the high frequency (HF) band between 3 and 30 MegaHertz (MHz), which are wavelengths between 100 and 10 metres, respectively. Based on current evidence, it appears that Australia may have found the tools with which to conduct efficient long-range surface and air surveillance more effectively than by the single use of traditional surveillance forces. Given increasing success and refinement of these technologies, one can see that the SWR systems in particular could, in addition, satisfy a number of potential export requirements and earn useful export credits.