Yi JiangDept. Of Electrical and Computer Engineering .ppt

Yi Jiang Dept. Of Electrical and Computer Engineering University of Florida, Gainesville, FL 32611, USA Outline Motivation – QR technology for landmine detection Temporally uncorrelated interference model Maximum likelihood estimate Capon estimate Statistical performance analysis Numerical examples Temporally correlated interference and noise Alternative Least Squares method Numerical examples Motivation Motivation Motivation Related Work Problem Formulation Simple Data model Conditions Array steering vector known with no error Signal waveform known with no error Noise vectors i.i.d. Task To estimate signal complex-valued amplitude Properties of ML (3) Numerical Example Numerical Example Properties of Capon (1) Properties of Capon (2) Properties of Capon (3) Numerical Example Numerical Example Numerical Example Numerical Example Unbiased Capon Numerical Example Numerical Example New Data Model New Feature Alternative LS Alternative LS Step (4) of ALS Two cases: Damped/undamped sinusoid Let Step (4) of ALS Step (4) of ALS Discussion Numerical Example Numerical Example Numerical Example Numerical Example Numerical Example Arbitrary signal Let Lemma. For large data sample, minimizing is asymptotically equivalent to minimizing Base on the Lemma. ALS always yields more likely estimate than SML Order of AR can be estimated via general Akaike information criterion (GAIC) MS Thesis Yi Jiang Array Signal Processing in the Know Waveform and Steering Vector Case Characteristic response of N-14 in the TNT is a known-waveform signal up to an unknown scalar. Quadrupole Resonance -- a promising technology for explosive detection. Challenge -- strong radio frequency interference (RFI) Main antenna receives QR signal plus RFI Reference antennas receive RFI only Signal steering vector known Both spatial and temporal information available for interference suppression Signal estimation mandatory for detection DOA estimation for known-waveform sign