Electromagnetic Scattering Concepts Applied to the Detection of Targets Near the Ground
Electromagnetic Scattering Concepts Applied to the Detection of Targets Near the Ground

Author: David Allen Hill

Publisher:

Published: 1970

Total Pages: 150

ISBN-13:

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Problems related to the detection of targets in the presence of clutter and ground are investigated. The two basic problems are the change in the target response due to the presence of the ground and the recognition of the target response when contaminated with clutter return. The transient fields of short dipoles in the presence of a dielectric half-space are examined and exact closed-form solutions are obtained for some particular source and observation points. The solution for the case of the source and observation points coincident is used to determine the interaction between a dipole source and the interface and the resultant dipole impedance change. The same solutions are used to compute the change in the dipole modes of scatterers due to the presence of a half-space, particularly the shift in the s-plane poles of the target. Results are presented for both dielectric and perfectly conducting half-spaces. (Author).

Complex Natural Resonances of Radar Targets Via Prony's Method
Complex Natural Resonances of Radar Targets Via Prony's Method

Author: C. W. Chuang

Publisher:

Published: 1975

Total Pages: 38

ISBN-13:

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It has been shown that extraction of complex natural resonances and residues from exact transient responses via Prony's method is both efficient and accurate. However, in the art of radar interrogation the exact transient response is difficult to obtain and the authors must be content with an approximate one. Knowing the complex natural resonances of objects is essential to one type of radar target discrimination. In this paper the authors consider the use of Prony's method in extracting complex natural resonances from approximate backscattered ramp responses of radar targets. A ramp waveform is used in radar target discrimination because a good approximation to the time domain response can be obtained with only a few harmonically related frequency domain responses via Fourier synthesis. By applying Prony's method to this approximate ramp response, a few dominant resonances which are close to the origin of the complex frequency plane can be extracted. This is quite encouraging because for the purpose of radar target discrimination only a few dominant modes are needed. Objects considered are prolate spheroids, simple wire aircraft models and some realistic aircraft models. The accuracy of this method is found to be good when compared to the results obtained by other techniques.

Complex Natural Resonances of an Object in Detection and Discrimination
Complex Natural Resonances of an Object in Detection and Discrimination

Author: Richard K. Mains

Publisher:

Published: 1974

Total Pages: 60

ISBN-13:

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The report extends and formalizes the concept of using the complex natural resonances of objects as a tool in radar target discrimination. The complex natural resonances which characterize an object are found to be excitation invariant; i.e., the positions of the resonances in the complex frequency plane do not shift as the object is viewed along different incident directions or with different polarizations, which permit a minimum amount of data to be used in object discrimination. Once the dominant (low frequency or long time) natural resonances have been obtained for those objects of interest, a predictor-correlator type of processing can be applied to multi-frequency radar scattering data from an unknown target. It can be established from which of the known objects the scattering most likely originated. This done on the basis of correlations among the scattering and the various sets of natural resonances; the set of natural resonances showing the highest correlation identifies the most probable target.

Continuation of the Investigation of Multi-frequency Radar Reflectivity and Radar Target Identification
Continuation of the Investigation of Multi-frequency Radar Reflectivity and Radar Target Identification

Author: D. L. Moffatt

Publisher:

Published: 1975

Total Pages: 38

ISBN-13:

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This report summarizes research during the period July 1, 1974 to June 30, 1975 under the contract on two technical objectives of the Air Force: improved detection and discrimination of radar targets and reduction of nonspecular scattering by wing geometries. The report is contained in two main sections. The first section outlines methods for deducing the complex natural resonances of arbitrary radar targets and the use of these resonances via predictor-correlator processing for detection and discrimination. Illustrative examples of both natural resonance extraction and discrimination are given for aircraft targets. The second section of the report summarizes the analysis of a loaded two-dimensional wind model for horizontal polarization. Hybrid techniques combining moment methods and the geometrical theory of diffraction are used and the loading consists of surface impedance patches. Examples of reduction of the nonspecular cross section are given. A 'folded dipole' like antenna is used as an alternate mechanism for controlling edge diffracted fields.

Detection And Identification Of Visually Obscured Targets
Detection And Identification Of Visually Obscured Targets

Author: Carl E. Baum

Publisher: Routledge

Published: 2019-09-26

Total Pages: 451

ISBN-13: 1351455664

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Beginning with a review of the current need for identification of buried and surface unexplored ordnance such as mines, shells, bombs, this book then explains existing techniques for electromagnetic detection of such targets. A detailed treatment of target signatures (natural frequencies and related parameters) for identification and discrimination of false alarms is also given.

Micro-Doppler Characteristics of Radar Targets
Micro-Doppler Characteristics of Radar Targets

Author: Qun Zhang

Publisher: Elsevier

Published: 2016-10-31

Total Pages: 226

ISBN-13: 012809883X

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Micro-Doppler Characteristics of Radar Targets is a monograph on radar target's micro-Doppler effect theory and micro-Doppler feature extraction techniques. The micro-Doppler effect is presented from two aspects, including micro-Doppler effect analysis and micro-Doppler feature extraction, with micro-Doppler effects induced by different micro-motional targets in different radar systems analyzed and several methods of micro-Doppler feature extraction and three-dimensional micro-motion feature reconstruction presented. The main contents of this book include micro-Doppler effect in narrowband radar, micro-Doppler effect in wideband radar, micro-Doppler effect in bistatic radar, micro-Doppler feature analysis and extraction, and three-dimensional micro-motion feature reconstruction, etc. This book can be used as a reference for scientific and technical personnel engaged in radar signal processing and automatic target recognition, etc. It is especially suitable for beginners who are interested in research on micro-Doppler effect in radar. - Presents new views on micro-Doppler effects, analyzing and discussing micro-Doppler effect in wideband radar rather than focusing on narrowband - Provides several new methods for micro-Doppler feature extraction which are very helpful and practical for readers - Includes practical cases that align with main MATLAB codes in each chapter, with detailed program annotations