MIMO radar: snake oil or good idea?

MIMO communication is theoretically superior to conventional communication under certain conditions, and MIMO communication also appears to be practical and cost-effective in the real world for some applications. It is natural to suppose that the same is true for MIMO radar, but the situation is not so clear. Researchers claim many advantages of MIMO radar relative to phased array radars (e.g., better detection performance, better angular resolution, better angular measurement accuracy, improved robustness against RFI, ECM, multipath, etc.). We will evaluate such assertions from a system engineering viewpoint. In particular, there are serious trade-offs of MIMO vs. phased array radars relative to cost, system complexity, and risk considering numerous real world effects that are not included in most theoretical analyses. Moreover, in many cases one can achieve essentially the same radar system improvement with phased array radars using simpler, less expensive, and less risky algorithms. We evaluate roughly a dozen asserted advantages of MIMO radar relative to phased arrays.     

The Series 320 Radar: Three-Dimensional Air Surveillance for the 1980s

Air surveillance radars for this decade will be required to provide reliable target location and trajectory information in height as well as the conventional geographical coordinates. These threedimensional radars will perform this task in spite of adverse environmental conditions such as ground, airborne clutter, and electromagnetic interference. The use of powerful false-alarm control processing allows automatic target detection and remoting of target information without overloading central processing capabilities. The technological evolution of the past decade has allowed sophisticated analysis, antenna/receiver/transmitter design, and signal/data processing techniques to be applied to the next generation of practical production radar systems. These radars will meet more severe performance requirements and will be significantly improved in terms of reliability, maintainability, and life cycle cost considerations. A candidate radar to fulfill the air surveillance role of this decade is the Series 320 radar manufactured by ITT Gilfillan.     

Monopulse Radars Excited by Gaussian Signals

This paper presents the theoretical probability densities of the outputs of both an amplitude-comparison monopulse radar and a phase-comparison monopulse radar when the monopulse radars are excited by Gaussian signals plus Gaussian noises. These probability densities are useful for studying the responses of monopulse radars to noise excitations. For example: Noise excitations arise when the monopulse radars are ?viewing? a noise source or a radar target consisting of randomly moving scatterers. The probability densities also serve as useful approximations for characterizing the outputs of monopulse radars when sinusoidal signals plus Gaussian noises excite the monopulse radars. Some special cases of the probability densities are presented in graphs.     

Polish radar technology

Polish radar research and development since 1953 is reviewed, covering the development and production of surveillance radars, height finders, tracking radars, air traffic control (ATC) radars and systems, and marine and Doppler radars. Some current work, including an L-band ATC radar for enroute control, a weather channel for primary surveillance radar, signal detection in non-Gaussian clutter, adaptive MTI filters and postdetection filtering, and a basic approach to radar polarimetry, is examined.<>     

Medium PRF Performance Analysis

A discussion of various types of x-band airborne radars is presented together with their systematic development through the years to the present time. Starting with simple, low pulse-repetition frequency (PRF) radars for measuring radar-target range, airborne radar development proceeded with more sophisticated high PRF Doppler radars where radar-target range and range rate were measured simultaneously. The use of Doppler (frequency) in signal processing allowed the separation of moving from nonmoving targets (ground), enabling the detection of moving targets in the presence of ground clutter. More recent developments in waveform generation and selection has resulted in the development of medium PRF radars, whereby a greater degree of tactical flexibility in target detection is achieved by combining the desirable features of both low and high PRF radars. Part of the available literature gives an overview, together with a specific example of the design and performance of an airborne medium PRF radar. Here, however, the systematic evolution of these radars is emphasized and the necessary theoretical background is developed for their performance calculations. Modern day airborne radars may be equipped with all three modes of operation, low, medium, and high PRF, allowing the operator to utilize the mode best suited for the tactical encounter. Low PRF and high PRF radars have been described elsewhere and are given here primarily for the sake of completeness and for the necessary background for developing medium PRF radar equations. They are also needed for developing the reasons why medium PRF radars came into being.     

Spectrum management: a high stakes game

The optimal use of the frequency spectrum is an incredibly difficult but vital requirement to be achieved. Among the numerous services and applications which are requesting more frequencies, radar and telecommunications are certainly the most demanding. The purpose of this paper is to discuss several technical aspects contributing to the frequency management within the whole spectrum. To this effect it is proposed to analyse the following main aspects: first, a survey of the foreseeable evolution of telecommunications and radars mainly in terms of frequency band needs, radiated power density and waveforms; second, we will provide a comparative analysis of signals used in radars and telecommunications; finally, we propose a few necessary conditions to coordinate the operation of radars and telecommunications within the whole spectrum     

从干扰地对空雷达到干扰空对地雷达效果的等效推算

通过建立干扰条件下地对空雷达上视工作和空对地雷达下视工作的数学模型,结合在发现概率和虚警概率给定情况下检测因子为定值的雷达检测理论,推导出了从干扰机干扰地对空雷达时的干扰效果等效外推到干扰空对地雷达的干扰效果的推理模型。该模型具有外场可操作性。     

Millimeter Radar Instrumentation

Millimeter wavelength radars are used to study plasma effects associated with ionized flow fields of projectiles launched at hypersonic speeds into a free-flight ballistic range. Two CW Doppler radars, at frequencies of 35 and 70 Gc/s, measure the nose-on backscattering radar cross sections during flight. The design and performance of the two radars are described in detail. A signal simulator provides absolute calibration. The purpose is to measure changes that occur in the radar cross sections of hypersonic projectiles caused by highly ionized flow fields. Under certain conditions the nose-on backscattering radar cross section of a blunt-nosed metal projectile decreases drastically when a thin, shock-produced layer of ionized gas covers the projectile. A theoretical analysis of this effect is given. Comparisons between theoretical predictions and experimental data show good correlation.     

Walker Model for Radar Sensing of Rigid Target Fields

The objective of this primarily tutorial item is to describe a general model for the observable data and the appropriate data processing involved in sensing rigid target fields with coherent radars. Any number of radars may be involved, and the scene and each radar may be in any kind of motion-with no restrictions on motion through resolution cells during the coherent processing time of the radars. The motions are assumed to be known. To some extent motion parameters can be estimated from the radar data, e.g., by adaptive parameter adjustments in the data processing; however, this subject is beyond the scope of this discussion. In large measure, the analysis in this item highlights the central conceptual result obtained by J.L. Walker as described in [1] -a major work in radar theory.     

基于傅里叶变换的航迹对准关联算法

研究了在组网雷达存在系统误差情况下的目标航迹关联问题,理论分析了雷达系统误差对目标航迹的影响,并将该影响表示为目标航迹的旋转和平移量。在此基础上,提出了一种基于傅里叶变换的系统误差配准前航迹对准关联算法,该算法将组网雷达的航迹数据看做为一种整体信息,采用傅里叶变换理论来估计和补偿组网雷达目标航迹数据到融合中心航迹数据的相对旋转量和平移量,将雷达网中雷达上报的目标航迹数据对准到融合中心,从而不依赖于估计雷达网系统误差,实现了误差配准前的航迹准确关联,能够为后端的系统误差配准提供可靠的关联目标航迹数据。     

脉冲雷达凝视模式下低轨碎片相对运动特征分析

脉冲雷达凝视模式是一种探测低轨小碎片的重要方式,其中低轨碎片与雷达的径向运动关系是碎片统计分析的基础.为推算碎片相对雷达的运动特征,基于坐标系的相互转换,先利用雷达测站信息,得到可见碎片在地惯坐标系下的轨道信息;再逆向将目标不同时刻的位置转换至测站坐标系下,得到目标的径向运动特征.在不同要素（雷达波束指向、雷达仰角、测站纬度、目标距离）下,仿真及对比分析了各个参数对速度模糊度、雷达可见性等的影响,得出在凝视模式下目标相对雷达近似做径向匀加速运动,这为后续试验工作提供有力的依据.     

Sensitivity of MIMO STAP Radar with Waveform Diversity

Space-time adaptive processing (STAP) is an effective method adopted in airborne radar to suppress ground clutter. Multiple-input multiple-output (MIMO) radar is a new radar concept and has superiority over conventional radars. Recent proposals have been applying STAP in MIMO configuration to the improvement of the performance of conventional radars. As waveforms transmitted by MIMO radar can be correlated or uncorrelated with each other, this article develops a unified signal model incorporating waveforms for STAP in MIMO radar with waveform diversity. Through this framework, STAP performances are expressed as functions of the waveform covariance matrix (WCM). Then, effects of waveforms can be investigated. The sensitivity, i.e., the maximum range detectable, is shown to be proportional to the maximum eigenvalue of WCM. Both theoretical studies and numerical simulation examples illustrate the waveform effects on the sensitivity of MIMO STAP radar, based on which we can make better trade-off between waveforms to achieve optimal system performance.     

Probability of Pulse Coincidence in a Multiple Radar Environment

Elementary probability theory is used to develop three formulas for the probability of two or more pulses being coincident at an observer's aircraft position in a multiple radar environment. The first formula is for nonscanning tracking type radars with different pulsewidths (PWs) and pulse repetition frequencies (PRFs), the second is for generically identical nonscanning radars with similar PWs and PRFs, and the third is for scanning type radars such as air search radars with similar PWs and PRFs. The probability of coincidence is related to the mean-time-between-coincidences (MTBC) and to the average coincidence rate. Two sample problems are given.     

Design and applications of airborne radars in the VHF/UHF band

The simultaneous need for ground penetration and high resolution dictates the use of frequencies less than 500 MHz for imaging ground penetrating radar (GPR) designs. It is possible to build such systems with good performance and yet not interfere with ground installations operating in the same bands. The total number of airborne GPR systems needed to saturate the market is small, (possibly less than ten), and so the buildup of noise in this spectral region occupied by these radars will be negligible. This is fortunate, since there is a clear need for such radars in such areas as humanitarian demining and unexploded ordnance (UXO) mapping. Some formal set of guidelines is needed beyond that given in Part 15 of the FCC regulations, which both recognizes the need for airborne UWB radar operations, and still protects licensed users in the band     

Comparison of Two Major Classes of Coherent Pulsed Radar Systems

Two classes of coherent radar types are analyzed to ascertain whether any significant advantages exist for a given system. The classes compared are those coherent radars which transmit a phasecoherent pulse-to-pulse RF carrier as opposed to those which transmit randomly phased RF carriers but store the coherent information at the radar for Doppler extraction. Rigorous new analytical development is avoided in favor of examination of the considerable existing literature, examination of practical limitations, and synthesis of generic solutions from key concepts. Examination is made of coherent radar classes from the viewpoints of reconnaissance ance and intelligence measurement, new radar design and devlopment, and electronic countermeasures vulnerability. The conclusion that the classes of coherent radars examined have a priori and a posteriori equivalent performance has significant implications not published in any reference source.     

Radar Handbook, 3rd Edition (M.I. Skolnik, Ed; 2008) [Book Review]

Thirty eight radar experts contribute to this edition, which includes six completely new chapters on the following topics: ground penetrating radar; remote sensing with radar on satellites; multifunctional radar systems for fighter aircraft (MFAR); digital signal processing for radar; civil marine radar; and propagation. Each chapter contains references, ranging from 10 to 197, with a median of 71. The index runs 18 pages printed in double columns, but is not necessarily complete. Some topics, such as MIMO radar and long range radars to track satellites and ballistic missiles, will have to wait for a 4th edition. This text is the most authoritative, broadest, and deepest single volume on radar. The emphasis is on real world performance and real hardware that has been tested and works successfully in the real world, and the physics relevant to radar systems, as well as radar system engineering cost tradeoffs.     

The SCR-270 in Japan

The deficient state of the radar in use when the war in Korea erupted in 1950 is described. The installation of the SCR-270 radar system is discussed, and its siting is considered. Test and performance results are examined     

对测量雷达的一些新需求与精细测量技术

新一代测量雷达在发展各种先进武器平台与航空航天及空间技术方面有广泛的应用前景。本文讨论对测量雷达的一些新的需求及相关技术,对雷达精细测量的需求与有关技术是本文讨论重点。     

Ukraine institute of radio astronomy high-resolution radars

A review is given of recent activities undertaken in the Institute of Radio Astronomy of the National Academy of Sciences of Ukraine for the development of high-resolution radars. The radars developed include 95- and 36-GHz cloud radars and an airborne, Ku-band SAR radar system. They are capable to perform real-time, high-resolution measurements. The set-up of these instruments, the novel technical solutions, and the signal processing technique introduced are discussed. The results obtained with such instruments during measurement campaigns are presented as well.