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【期刊论文】Complex ISAR Imaging of Maneuvering Targetsvia the Capon Estimator
吴仁彪, Zheng-She Liu, Member, IEEE, Renbiao Wu, and Jian Li, Senior Member
IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 47, NO.5, MAY 1999,-0001,():
-1年11月30日
An inverse synthetic aperture radar (ISAR) can be used to produce high-resolution images of moving targets of interest by utilizing the relative motion between the target and the radar and by transmitting signals with large bandwidth. Most ISAR imaging algorithms are based on the range-Doppler processing, which implies that the Doppler shifts remain constant during the coherent integration time. For maneuvering targets, the Doppler shifts are time varying. In this case, the algorithms will produce blurred images. We present herein an adaptive Capon spectral estimation algorithm for the complex ISAR image formation of maneuvering targets. It is an efficient recursive implementation of the well-known Capon complex spectral estimation algorithm by using FFT and simple matrix operations.
ISAR imaging,, recursive FIR filtering based method,, recursive spectral estimation.,
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【期刊论文】ATR scheme based on 1-D HRR profiles
吴仁彪, R.Wu, Q.Gao, J.Liu and H.Gu
ELECTRONICS LETTERS 21st November 2002 Vol. 38 No.24,-0001,():
-1年11月30日
A new automatic target recognition (ATR) scheme based on oncdimensioaal high range resolution profiles is presented, which features joint range alignment and classification This meThod CKI also be used to form mean-or eigen-templates to fianher improve the ATR performance Experimental results are provided to demonstcate the performance of the new algorithm.
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【期刊论文】Arrav pattern SVntnesis and robust beamforming for a complex sonar system
吴仁彪, R.Wu, Y.Ma, R.D. James
IEEE Proc-Rodar, Sonar Naving, Vol. 144, No.6, December 1997,-0001,():
-1年11月30日
In modern radar, sonar and wireless communication systems digital beamforming technology based on sensor arrays is widely used to suppress unwanted interfering signals and detect interested target signals.Beam pattern synthesis for arbitrary arrays and robust beamforming for imperfect arrays are two crucial technical issues associated with digital beamforming.In a complex volumetric underwater acoustic transducer array, due tostructural shadowing and scattering. the practical beam pattern significantly deviates from its designed pattern, which would greatly degrade the detection and direction. finding performance of the sonar system. An efficient method is proposed to design beam patterns for arbitrary arrays and is applied to robust beamforming for this sonar system. Sea experimental results show that the proposed robust beamforming method achieves a much lower sidelobe level and a much higher direction. finding accuracy than the conventional beamforming technique.
Beamforming,, Sonar arrays,, Pattern synthesis method
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【期刊论文】Array Pattern Distortion and Remedies in Space-Time Adaptive Processing for Airborne Radar
吴仁彪, Renbiao Wu, Member, IEEE, and Zheng Bao, Senior Member
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 46, NO.7, JULY 1998,-0001,():
-1年11月30日
Space-time adaptive processing (STAP) for airborne early warning radar has been a very active area of research since the late 1980's. An airborne rectangular planar array antenna is usually configured into subarrays and then partial adaptive processing is applied to the outputs of these subarrays. In practice, three kinds of errors are often encountered, i.e., the array gain and phase errors existing in each element, the channel gain and hase errors, and the clutter covariance matrix estimation errors due to insufficient secondary data samples. These errors not only degrade the clutter suppression performance, but also cause the adapted array patterns to suffer much distortion (high sidelobes and distorted mainbeams), which may result in the rise of falsealarm probability and make the adaptive monopulse tracking and sidelobe blankering more difficult. In this paper, the causes of the above three kinds of errors to array pattern distortion are discussed and a novel quadratic soft constraint factored approach is proposed to precisely control the peak sidelobe level of adapted patterns. The soft constraint factor can be determined explicitly according to the peak sidelobe level desired and the known or desired tolerant error standard deviations. Numerical results obtained by using high-fidelity simulated airborne radar clutter data are provided to illustrate the performance of the proposed approach. Although the method is presented for STAP, it can be directly applied to the conventional adaptive beamforming for rectangular planar arrays used to suppress jammers.
Adaptive arrays,, airborne radar
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【期刊论文】An Acoustic Proximity Ranging System for Monitoring the Cavity Thickness
吴仁彪, Xi Li†, Renbiao Wu†, Srihari Rasmi‡, Jian Li†, Louis N. Cattafesta III‡, Mark Sheplak‡
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, Vol. 50, No. 7, July 2003,-0001,():
-1年11月30日
To control high speed underwater vehicles, a proximity ranging system is needed to monitor the cavity thickness. In this paper, we study a time-of-ight (TOF) principle based acoustic proximity ranging system. By taking into account the acoustically hard boundary at the air-water interface, werst present a two-stage computationally e�cient time delay estimation algorithm, referred to as the PEARS (Parameter Estimation for Acoustic Ranging Systems) algorithm, which is applicable to arbitrary transmitted waveforms. Numerical results based on a simulated waveform demonstrate that the PEARS estimates can approach the Cramer-Rao bound as the signal-to-noise ratio increases. We then present experiments performed by using commercially available acoustic transducers to further verify our method. To update TOF estimates quickly, a specially designed continuous wave (CW) is applied to the transducer. Experimental results show that PEARS can achieve high measurement accuracy for ranging distances less than 100mm with an achievable parameter update rate of approximately 1.5kHz.
Cavity thickness,, proximity ranging,, time delay estimation,, acoustic transducer
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