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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1976年第5期24卷 585-598页

作者： APPLEBAUM, SP SYRACUSE UNIV RES CORP SYRACUSENY

A method for adaptively optimizing the signal-to-noise ratio of an array antenna is presented. Optimum element weights are derived for a prescribed environment and a given signal direction. The derivation is extended to the optimization of a "generalized" signal-to-noise ratio which permits specification of preferred weights for the normal quiescent environment. The relation of the adaptive array to sidelobe cancellation is shown, and a real-time adaptive implementation is discussed. For illustration, the performance of an adaptive linear array is presented for various jammer configurations.

关键词： adaptive arrays Signal to noise ratio Linear antenna arrays Phased arrays Antenna arrays Jamming Receiving antennas Working environment noise Interference Antennas and propagation

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adaptive arrays FOR COMMUNICATION-SYSTEMS - OVERVIEW OF RESEARCH AT OHIO-STATE-UNIVERSITY

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1976年第5期24卷 599-607页

作者： COMPTON, RT HUFF, RJ SWARNER, WG KSIENSKI, AA OHIO STATE UNIV DEPT ELECT ENGNELECTR SCI LABCOLUMBUSOH 43212

adaptive array research at The Ohio State University is presented in a summary form. The main objective of the research was to assess the capabilities of adaptive arrays for communication systems in real environments. Consequently the theoretical work was often corroborated by experimental implementation and testing of proposed techniques. Specifically, three systems in which adaptive arrays were successfully incorporated are described, a single channel spread spectrum communication system, a TDMA satellite communication system, and a remote sensor communication system. Numerous other adaptive array studies are briefly summarized.

关键词： adaptive arrays Communication systems Interference adaptive systems Sensor arrays System testing Least squares approximation Senior members Spread spectrum communication Time division multiple access

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adaptive arrays for narrowband CDMA base stations

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ELECTRONICS & COMMUNICATION ENGINEERING JOURNAL 1998年第4期10卷 156-166页

作者： Grant, PM Thompson, JS Mulgrew, B Univ Edinburgh Dept Elect & Elect Engn Edinburgh EH9 3JL Midlothian Scotland

Base station antenna arrays are a promising method for providing significant capacity increases in cellular mobile radio systems. This paper examines receiver structures and algorithms to assess the potential capacity gains from the employment of multiple receiver antenna elements, of different sizes, for code division multiple access (CDMA) systems.

关键词： DS-CDMA radio receivers performance Multiple access communication antenna array receivers Mobile radio systems reverse link capacity gains spread spectrum communications array signal processing cellular radio channel capacity receiving antennas cellular mobile radio systems narrowband CDMA base stations land mobile radio receiver array processing algorithms direction-of-arrival estimation receiver structures Antenna arrays pseudonoise codes radio links adaptive antenna arrays base station antenna arrays spread spectrum communication multiple receiver antenna elements mobile to-base station IS-95 standard adaptive arrays channel modelling Signal processing and detection code division multiple access receiver design

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adaptive arrays - INTRODUCTION

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PROCEEDINGS OF THE IEEE 1976年第2期64卷 239-272页

作者： GABRIEL, WF USN ELECTR TECHNOL DIV RES LAB ANTENNA SYST STAFF WASHINGTON DC 20375 USA

adaptive array antenna systems are currently the subject of intense interest and investigation/development for radar and communications applications. The principal reason for the interest is their ability to automatically steer nulls onto undesired sources of interference, thereby reducing output noise and enhancing the detection of desired signals. These systems usually consist of an array of antenna elements and a real-time adaptive receiver-processor which has feedback control over the element weights. This paper provides a tutorial introduction to adaptive arrays from the viewpoint of antenna beam-forming and null steering. The particular vehicle chosen for discussion is the Howells-Applebaum analog servo-control-loop processor. This processor derives feedback control error signals from the correlations between element signals, i.e., on the basis of the covariance matrix of the set of system inputs. A simple two-element array with a single adaptive control loop is addressed first, in order to set the stage for analysis of a basic K-element linear array with K adaptive control loops. The set of linear differential equations associated with the controlloop network can be solved by a Q-matrix transformation into orthonormal eigenvector space. The purely mathematical Q-matrix is interpreted in terms of orthogonal beam-forming networks, similar in principle to a Butler matrix beam-forming network. The Q-matrix network produces a set of K orthogonal normalized eigenvector beams whose output powers are proportional to the eigenvalues of the covariance matrix. These beams are utilized in a convenient expression for calculating the time-dependent output pattern function for the array. Performance characteristics have been calculated for different distributions of interference sources to demonstrate the effects of power level, source location with respect to the quiescent beam pattern, source spacing in terms of array resolution, source bandwidth, continuous source distri

关键词： adaptive arrays Antenna arrays adaptive control Radar antennas Interference Feedback control Signal processing Covariance matrix adaptive systems Radar applications

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adaptive arrays CAN BE USED TO SEPARATE COMMUNICATION SIGNALS

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 1981年第2期17卷 234-247页

作者： HACKETT, CM Rockwell International Corporation Newport Beach CA USA

Using eigentheory, it is shown how up to n unknown independent narrowband signals arriving from different directions at an array of n antenna elements can be separated into n channels where each channel contains primarily one signal. An expression for the signal-to-interference ratio (SIR) on eachoutput channel is determined analytically and evaluated for many illustrative cases. The results show that in most cases the SIR is + 10 dB or greater; only when two signals arrive within a few degrees of each other does the SIR fall substantially below 0 dB.

关键词： adaptive arrays Antenna arrays Signal analysis Interference Narrowband Radar antennas Bandwidth Receiving antennas Frequency Directive antennas

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adaptive arrays FOR MULTIPLE SIMULTANEOUS DESIRED SIGNALS

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 1983年第5期19卷 761-767页

作者： GUPTA, IJ Electro Science Laboratory Department of Electrical Engineering Ohio State Uinversity Columbus OH USA

Steered beam adaptive arrays for multiple simultaneous desired signals are discussed. It is shown that the performance of a steered beam adaptive array depends upon the range of input signal strengths and the choice of the steering vector. Optimum steering vectors for various input signal strengths are given. All choices of steering vectors are equally effective in the rejection of jammers.

关键词： adaptive arrays Jamming Signal to noise ratio Laboratories Artificial satellites Protection Least squares approximation Feedback loop Signal generators Interference

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adaptive arrays - A NEW APPROACH TO THE STEADY-STATE ANALYSIS

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1982年第1期30卷 128-138页

作者： ZOHAR, S Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA

Our main goal is a closed-form expression for the steady-state output signal-to-noise ratio (SNR) of an n -element adaptive array excited by one desired narrow-band signal and K - 1 narrowband jammers. This is facilitated by representing each excitation by a complex n -dimensional vector-the excitation vector. We show that the important system parameters are functions of scalar products of pairs of these exctiation vectors. In particular, the normalized output SNR of the array is shown to be the ratio of determinants whose elements involve these scaler products. Such determinants are also shown to be involved in the expressions for the optimal array weights.

关键词： adaptive arrays Steady-state Jamming Closed-form solution Narrowband Signal to noise ratio Antenna arrays Propulsion Space technology Transient analysis

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adaptive arrays WITH MAIN BEAM CONSTRAINTS

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1976年第5期24卷 650-662页

作者： APPLEBAUM, SP CHAPMAN, DJ SYRACUSE UNIV RES CORP SYRACUSENY 13210

Initial applications of adaptive array theory to the radar sidelobe jamming problem ignored the problem of incidental cancellation of the desired signal returns. In more recent applications, longer transmitted waveforms have combined with returns from extended clutter and/or strong targets to create a more serious signal cancellation problem. There are several ways in which the adaptive processor can be constrained from responding to desired main lobe target returns while maintaining good cancellation of interference in the sidelobes. This paper examines the major techniques for constraining the response of the adaptive processor, including methods of controlling the response of the array in the absence of external interference. Time domain and frequency domain techniques are discussed. The majority of the discussion is devoted to angle domain techniques such as pilot signals, preadaption spacial filtering, and control loop spatial filtering. Analysis is presented showing the relationship between these techniques. Finally, examples are given showing the effects of these constraints as well as control of the quiescent array pattern.

关键词： adaptive arrays Interference constraints Filtering Radar applications Radar theory Jamming Clutter Interference cancellation Programmable control adaptive control

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adaptive arrays IN AIRBORNE MTI RADAR

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1976年第5期24卷 607-615页

作者： BRENNAN, LE MALLETT, JD REED, IS TECHNOL SERV CORP SANTA MONICACA 90403

The ability of an AMTI (airborn moving target indication) radar to reject clutter is often seriously degraded by the motion of the radar. An adaptive receiving array can compensate for platform motion and provide excellent AMTI performance. Scattering from aircraft structure can also distort antenna patterns and reduce AMTI capability. The technique described here can adapt the element weights to compensate for near-field scatterers and element excitation errors. Another important advantage is the ability to null out discrete active interference sources without significantly degrading AMTI performance.

关键词： adaptive arrays Airborne radar Radar antennas Radar scattering Antenna arrays Linear antenna arrays Programmable control adaptive control Radar clutter Doppler radar

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EXPERIMENTAL AND THEORETICAL COMPARISON OF SOME ALGORITHMS FOR BEAMFORMING IN SINGLE RECEIVER adaptive arrays

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1991年第1期39卷 21-28页

作者： WAHLBERG, BG MAREELS, IMY WEBSTER, I UNIV NEWCASTLE DEPT ELECT ENGN & COMP SCINEWCASTLENSW 2308AUSTRALIA

This paper is concerned with adaptive null steering in single receiver adaptive arrays. The single receiver structure allows only output power for a given set of weights to be measured. The problem, then, is to adaptively adjust the weights of the antenna array, based on output power measurements only, so as to reject interference signals while maintaining a fixed response in a given look direction. Current least mean square (LMS)-based iterative techniques use perturbations of the beamformer weights to obtain an estimate of the gradient of a given cost (power) function in order to update an initial guess. The key idea of this paper is to determine the optimal beamformer weights in a single step, by estimating the covariance matrix of the array sensor outputs using a weight perturbation technique. Based on this covariance matrix estimate three different approaches for finding the beamformer weights are studied. The first one corresponds to a sample matrix inversion (SMI) scheme, with the sample covariance matrix replaced by the one obtained from the perturbation estimation method, while in the second approach the weights are determined using an eigenvalue decomposition of the covariance matrix estimate. In the third approach the direction-of-arrivals (DOA's) of the incoming wavefronts are first estimated, and then, in a second step, the beamformer weights are calculated from the DOA estimates. The advantage of the third approach is that this method is not affected by correlation between the different sources. In comparison with iterative techniques, the new approach offers much faster beamforming, albeit at the expense of increased susceptibility to unmodeled characteristics. Subsequent modifications of the algorithm in light of experimental studies have enhanced robustness by providing scope for accommodating model errors.

关键词： Covariance matrix adaptive arrays Sensor arrays Power generation Antenna measurements Power measurement Direction of arrival estimation Weight measurement Directive antennas Antenna arrays

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