Results 161 to 170 of about 3,240 (206)

Non-recurrent wideband continuous active sonar

2012 Oceans, 2012
This paper presents a continuous active sonar (CAS) waveform which enables high revisit rates and wideband processing gains to be achieved with suppression of range-ambiguous returns. Non-recurrent wideband linear FM signals with circular Costas frequency-staggering across chirp repetition intervals is shown to provide ambiguity functions with good ...
G. Hickman, J. L. Krolik
openaire   +1 more source

Antisubmarine Warfare: Passive vs. Active Sonar

The Two-Year College Mathematics Journal, 1983
(1983). Antisubmarine Warfare: Passive vs. Active Sonar. The Two-Year College Mathematics Journal: Vol. 14, No. 5, pp. 434-435.
L. Whitt, K. Wilk
openaire   +1 more source

A Theory of Active Sonar Detection

Proceedings of the IRE, 1959
The results of a theory of echo detection developed for radar are extended to sonar for the case of narrow-banid transmitted signals. The exposition specifically omits discussion of the decision problem and the statistical nature of the whole process of detection.
J. Stewart, E. Westerfield
openaire   +1 more source

Coherence degradation in active sonar systems

The Journal of the Acoustical Society of America, 1978
This paper quantifies the degradation in performance of a quadrature receiver when the phase of the input target signal is time-varying and the background noise is additive Gaussian. The quadrature receiver, a conventional signal processor, consists of a replica-correlator followed by a quadratic detector.
R. C. Higgins, J. T. Francis, J. G. Kelly   +2 more
openaire   +1 more source

Active listening in passive-sonar soundscapes

The Journal of the Acoustical Society of America, 2006
Listening tasks differ across a variety of dimensions. Tasks that are characteristic of competing channels are those in which command and control signals are delivered simultaneously. Such signals are typically highly uncertain, statistically independent, and nonredundant. Tasks that are characteristic of cooperative channels are those in which sources
Gregory Wakefield, Thomas Santoro
openaire   +1 more source

Adaptive waveform selection for active sonar

Proceedings of ICASSP '94. IEEE International Conference on Acoustics, Speech and Signal Processing, 2002
Investigates an adaptive waveform selection scheme where selection is based on overall tracking performance of the active sonar system. The assumption of an optimal receiver allows the inclusion of transmitted waveform specification parameters in the tracking sub-system equations, leading to a waveform selection scheme where the next transmitted ...
D.J. Kershaw, R.J. Evans
openaire   +1 more source

Characterization of active sonar targets

2018
<p>The problem of characterization of active sonar target response has important applications in many fields, including the currently cost-prohibitive recovery of unexploded ordinance on the ocean floor. We present a method for recognizing these objects using a multidisciplinary approach that fuses machine learning, signal processing, and feature
Daniel Schupp-Omid, Ananya Sen Gupta, Mark Andersland, Anton Kruger   +3 more
openaire   +1 more source

Application of DORT to active sonar

Oceans '04 MTS/IEEE Techno-Ocean '04 (IEEE Cat. No.04CH37600), 2005
Active sonar in shallow water is often reverberation-limited and the detectability is often limited by the presence of too many false alarms. The problem of improving detection, and classification, in shallow water is being worked on in several different ways. The time reversal operator decomposition (DORT) is a technique that has recently been applied
C.F. Gaumond, D.M. Fromm, J. Lingevitch, R. Menis, G. Edelmann, D. Calvo, E. Kim   +6 more
openaire   +1 more source

Interference Mitigation for Multistatic Active Sonar

IEEE Journal of Oceanic Engineering, 2015
Two methods for detecting and classifying mutual interference between sources in multistatic active sonar systems are developed and compared for frequency-modulated transmissions. Both methods compare the output of matched-filtered time-series data using two different waveform replicas: the intended transmit replica and a hypothesized interferer ...
Jason M. Aughenbaugh, Brian R. La Cour, James M. Gelb   +2 more
openaire   +1 more source

Fundamentals of Bistatic Active SONAR

1989
The purpose of this paper is to provide an introduction to bistatic active sonar. We consider only the simplest case of a single source and a single spatially-separated receiver. The extension to multiple sources and receivers is straightforward and involves the same concepts and principles.
openaire   +1 more source