Detection in reverberation using space time adaptive prewhiteners

Abstract

A major problem in moving platform active sonar systems is the detection of targets in spatially distributed and Doppler-spread reverberation. This paper presents a novel space time adaptive prewhitener for reverberation based on a two-dimensional autoregressive model. The space time adaptive prewhitener jointly processes received data in angle and Doppler to improve the separation of a target from reverberation. The detector using the space time adaptive prewhitener is shown to yield better detection performance than previously known schemes when operating in a reverberation background containing target echoes.

Signal Subspace Extraction algorithm for detection in the presence of reverberation

“…detection method. By comparison with the prewhiten method [4], the PCI method is effective whatever the respective Doppler [1]. However even when reverberation power is high, there are still some reverberation echoes with lower power.…”

Reverberation suppression using non-negative matrix factorization to detect low-Doppler target with continuous wave active sonar

“…However, in addition to reflection from the target, the received signal contains reverberations caused by reflection from scatterers. Conventional target detection algorithms, including the matched filter, are sensitive to reverberations, and extensive research has been conducted to improve detection in this condition [1][2][3][4][5][6][7][8][9][10][11].…”

“…Moreover, CW pulses and some variants [2] are still widely used in active sonar systems. Consequently, signal processing for suppressing reverberation at the receiver is needed, and some algorithms have been proposed in this vein [6][7][8][9][10][11].…”

“…However, the effectiveness of this approach deteriorates when the Doppler shifts of the reverberation and the target echo are similar. To overcome this limitation, algorithms based on principal component inversion (PCI) have been developed [8][9][10]. The signal subspace extraction (SSE) algorithm has recently been proposed as an improvement to the PCI-based algorithm by expressing the reverberation model as a sum of higher and lower reverberation echoes [11].…”

Improved space time prewhitener for linear frequency modulation reverberation using fractional Fourier transform

“…The inter-sensor time delay would be compensated by beamforming, and the Doppler frequency is dependent on the direction of arrival (DOA). 4 The received signal x(t) is divided into K blocks by sliding windows in time domain, the observed data in the Kth block of lth beam is denoted by x K,l (t), t ¼ 1, 2 … T, where T is the length of window. To whiten the reverberation using AR model, the data block adjacent to the current block temporally or spatially is chosen as the reference signal, given by x Kþ1,l (t) or x K,lþ1 (t), respectively.…”