Normalized leakage LMS self-adaptive mobile target detector based on FRFT

Abstract

The invention discloses a normalized leakage LMS self-adaptive mobile target detector based on FRFT, belonging to the technical field of radar signal processing and detecting. The existing statistics method and FRFT method are respectively applied to mobile target detection in sea clutter in the presence of the defects such as undesirable sea clutter inhibition, complex parameter evaluation and poor real-time. The invention combines the time domain LMS algorithm with the FRFT domain mobile target detection method, the kurtosis iterative computation is adopted for rapidly determining a best transform angle; an FRFT domain self-adaptive spectral line enhancer is constructed for improving the signal-to-noise ratio for inhibiting the sea clutter, the leakage factor is introduced into a weighting vector iterative formula for reducing the influence of memory effect to the spectral line enhancer, the step length is normalized in power for improving the convergence rate, and the amplitude value of output signal is regarded as the detection statistic. The detector can self-adaptively inhibit the sea clutter, and the target motion parameter evaluation is high in precision; and the detector is suitable for applying to the detection and filtration of LFM signal, and has popularization and application values.

Description

1. Technical field [0001] The invention belongs to the technical field of radar signal processing and detection, in particular to the moving target detection technology of sea detection radar. 2. Background technology [0002] Fast and robust weak moving target detection in the background of sea clutter is always a difficult problem in the field of radar signal processing, which is of great significance in both military and civilian applications. The radar cross section (Radar Cross Section, RCS) of a moving small ship is very small, and its echoes are often submerged in sea clutter and noise. The traditional method for detecting weak moving targets in sea clutter is to use sea clutter Sea clutter is regarded as a random process based on statistical theory, but its versatility is poor and the detection process is complicated. In the case of high sea conditions, the non-Gaussian characteristics of sea clutter make it difficult to accurately model sea clutter. difficulty. Th...

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Problems solved by technology

Only when the FRFT whose transformation order matches the signal parameters is used, the mean square error of the corresponding adaptive process can converge to its minimum value, while in other FRFT domains, the algorithm cannot effectively converge, while the traditional FRFT domain The method of performing two-dimensional peak search to determine the optimal transformation order is not only computationally intensive, but also the parameter estimation accuracy is not high

At the same time, the adaptive filter has a memory effect on the changing frequency, which leads to a significant increase in the lag error of the filter output and reduces the performance of the filter

The above problems limit the practical application of the FRFT domain moving target detection method

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