摘要:

The paper is a study of a time-domain adaptive array processor operating in a broadband environment. The processor is a variant of that due to Widrow; in particular processing is carried out in octave bands and sensor data are not time shifted. The constraint system consists of four to seven linear point and gradient constraints, together with a soft norm constraint. Computations assume full adaptation, stationary data and sensor amplitude and phase errors. Calculations are made of array gain, array response and of the detectability of wanted-signal spectral lines in the output beam. Comparison is made between the performance of this processor and that of a conventional beamformer and of a frequency-domain adaptive processor. A wide variety of noise environments are selected, some fairly complex. Frequency bands are taken to cover a range of six octaves. The general conclusion is that the time-domain processor is both economical on processing time and has a reasonable level of robustness against sensor errors and time-varying environments. The performance loss due to suboptimal processing is normally not great, but for certain types of noise environments it can be significant.

DOI:10.1049/ip-f-1.1983.0022

出版商:IEE    

年代:1983

数据来源: IET

摘要:

Using sonar data characterised by the presence of a strong interference, adaptive beamforming is performed by the stochastic gradient descent algorithm in the frequency domain. The weights are constrained to have a unity response in the look direction. Convergence rates are estimated from averaged adaption curves, and, in most cases, these are found to be in reasonable agreement with theoretical values. It is conjectured that a marked discrepancy in one case is due to phase errors in the data covariance matrix.

DOI:10.1049/ip-f-1.1983.0023

出版商:IEE    

年代:1983

数据来源: IET