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| Parameter and 2-D AOA Estimation of LFM Sources with Spatio-Temporal Undersampling |
| Tian Da;Chen Tian-qi |
| College of E.E.; UEST of China; Chengdu 610054; China |
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Abstract Time-Frequency parameter estimation and direction finding for nonstationary signals impinging on an antenna array over a wide frequency band (2~18GHz) is under in-vestigation, and a new method for parameter and 2-D Angle-Of-Arrival (AOA) estimation of spatio-temporal undersampled LFM sources is proposed in this paper. The proposed method uses time domain dechirp algorithm for chirp rates estimation. By filtering in the fractional Fourier domain, signals are extracted from the mixture of sources and noise. Un-ambiguous initial frequency estimates are obtained from the output of the reference element and its time delayed version, while 2-D AOA estimation is based on the array model in FRFT beamspace. Numerical simulations show that this method can deal with multiple LFM sources. Parameter and AOA estimation with high accuracy is available at low SNR.
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Received: 15 January 2003
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2004, Vol. 26 
