Blind deconvolution for robust signal estimation and approximate source localization

Abstract

Synthetic time reversal (STR) is a technique for blind deconvolution in an unknown multipath environment that relies on generic features (rays or modes) of multipath sound propagation. This paper describes how ray-based STR signal estimates may be improved and how ray-based STR sound-channel impulse-response estimates may be exploited for approximate source localization in underwater environments. Findings are based on simulations and underwater experiments involving source-array ranges from 100 m to 1 km in 60 -m-deep water and chirp signals with a bandwidth of 1.5-4.0 kHz. Signal estimation performance is quantified by the correlation coefficient between the source-broadcast and the STR-estimated signals for a variable number N of array elements, 2 ≤ N ≤ 32, and a range of signal-to-noise ratio (SNR), -5 dB ≤ SNR ≤ 30 dB. At high SNR, STR-estimated signals are found to have cross-correlation coefficients of ∼90% with as few as four array elements, and similar performance may be achieved at a SNR of nearly 0 dB with 32 array elements. When the broadband STR-estimated impulse response is used for source localization via a simple ray-based backpropagation scheme, the results are less ambiguous than those obtained from conventional broadband matched field processing.

Research on space target detection ability calculation method and spectral filtering technology in sky‐screen's photoelectric system

“…The development process of high performance weapons needs to grasp the dynamic parameters of the arms and ammunition, such as flying target's initial velocity and terminal velocity, target flight attitude, target spreading, and so on. These parameters are the core technical index to measure the weapon's performance . At present, the dynamic parameter test of the flying target mainly consists of the intersection multi‐sky‐screen testing system, the intersection optical screen testing system, and linear array CCD across testing system, etc.…”

Broadband sparse-array blind deconvolution using frequency-difference beamforming

“…shimah@umich.edu measurements from a known source (Siderius et al, 1997), higher order statistics (Broadhead and Pflug, 2000a,b), information criteria (Xinhua et al, 2001), adaptive algorithms (Weber and Bohme, 2002;Sibul et al, 2002), time frequency analysis (Martins et al, 2002), multiple convolutions (Smith, 2003), an assumption about the probability density function of the signal (Roan et al, 2003), and a least-squares criterion (Zeng et al, 2009). The blind deconvolution technique used in this study, synthetic time reversal or STR (Abadi et al, 2012), develops the requisite additional information from the assumption that sound is conveyed from the unknown source to the receiving array by modes or rays. STR [also known as artificial time reversal (ATR) (Sabra and Dowling, 2004;Sabra et al, 2010)] is a fully passive technique for blind deconvolution that does not involve iterative procedures, parameter searches, or optimizations.…”

Performance Measurement of Photoelectric Detection and Target Tracking Algorithm

“…,the first item has nothing to do with 1 y , so as to make d (y) is minimal, it should made the second item of formula (17) as the largest. This term represents using the 2 (x) K calculation of the kernel density estimation in current position of the 1 y frame, i  is a weighted value.…”

“…In (18), 1  and 2  are the spectrum wavelength range of the optical system imaging CCD, according to the effective aperture of optical lens, CCD optical detector total luminous flux of photoelectric tracking system is , it can be calculated by (19). …”

“…With the development of photoelectric technology, microelectronic technique, optical imaging technology and high speed processing equipment, the performance of a variety of offensive weapons increases continuously [1]. As the main firepower, high-tech weapons such as precision-guided munitions have been used widely, which has become a salient feature of modern warfare.…”