Browsing Reprints by Subject "Low Frequency Active Sonar (LFAS)"
Now showing items 1-19 of 19
-
About the effective Doppler sensitivity of certain nonlinear chirp signals (NLFM)
(NATO. SACLANTCEN, 1993/08) -
Acoustic characterization of a shallow water site
(NATO. SACLANTCEN, 1993/08)Results are presented from an exercise aimed at providing a low frequency active sonar environmental characterization of a specific shallow water site in the Gulf of Mexico. Downward refracting acoustic transmission and ... -
Array performance and variability at short range near Vestfjorden
(NATO. SACLANTCEN, 1993/08)An experiment was conducted in October 1989 in shallow water near Vestfjorden in support of low frequency active sonar system research at SACLANTCEN. This report addresses some acoustic measurement results from that test ... -
Benchmark evaluation of multistatic trackers
(NURC, 2006/08)This paper provides an overview of the Special Session on Multistatic Sonar and Radar Tracking at FUSION 2006. This includes background on the Multistatic Tracking Working Group, a brief description of the datasets and ... -
Considerations related to warfare system design and operation of tactical platforms in a low- frequency active sonar environment
(NATO. SACLANTCEN, 1993/08)Low-Frequency Active Sonar System (LFASS) can provide significant improvements in the detection, localization and classification of very quiet submarine contacts. Achievement of the predicted performance improvements will ... -
Correlation of backscatter with bottom topography
(NATO. SACLANTCEN, 1993/08)Practical data from low frequency sonar operations in shallow water has been analysed to demonstrate that a high degree of correlation exists between the received signal due to bottom hackscattering and the hottom gradient ... -
Effect of different bandwidths for the detection of extended targets in reverberation
(NATO. SACLANTCEN, 1993/08)In this paper, firstly the theoretical background of bandwidth effects on detection in noise and reverberation is presented in some detail, and secondly the relevant results of sea. trials with a low frequency active sonar ... -
Environmental impact on mobile sonar shallow water operations
(NATO. SACLANTCEN, 1993/08)Shallow Water operations provide unique challenges for mobile sonars. In many cases propagation conditions can be optimized - our studies have shown that sound channeling can occur in approximately 75% of the strategic ... -
Low frequency active sonar (LFA) bottom loss requirements
(NATO. SACLANTCEN, 1993/08)A bottom interaction simulator was developed to investigate LFA bottom bounce losses, i.e., the mismatch losses, which occur in matched filter processing of bottom and target reflected signals due to the time spreading ... -
Low frequency active sonar noise rejection in a multistatic sonar system
(NATO. SACLANTCEN, 1993/08)The use of low frequency active sonar for ASW has repercussions on automated detection performance. Input data contain not only target returns, but also noise formed by returns from the environment The detector may report ... -
Low frequency resonance backscatter from near-surface bubble clouds
(NATO. SACLANTCEN, 1993/08)When active sonar systems are used to insonate the sea surface, anomalous scattering is observed in the form of enhanced backscatter, and more importantly, in the form of discrete, bright echoes. The most plausible explanation ... -
On the integration of through-the-sensor geoacoustic inversion techniques for environmental adaptation schemes in low frequency active sonars
(NURC, 2007/12)The environmental conditions in shallow water areas are known to strongly affect the performances of low frequency active sonars (LFAS). In particular, interactions of the acoustical field with the seabed interface have ... -
On the physics and design of electrical discharge sources for active undersea surveillance
(NATO. SACLANTCEN, 1993/08)Underwater electrical arcs have long been used as an impulsive sound source, although efforts to improve efficiency and control acoustic output have been limited by inadequate understanding of the arc initiation process. ... -
Performance assessment of broadband impulsive noise jammers
(NATO. SACLANTCEN, 1993/08)A noise jammer raises the noise level observed by a threat sonar to degrade the sonar's detection performance. In this paper we assess the potential for a specific noise jammer waveform used to countermeasure low frequency ... -
Signal processing for an active sonar system suitable for advanced sensor technology applications and environmental adaptation schemes
(NURC, 2006/08)An overview of the basic elements of an active sonar system in conjunction with a description of the signal processing chain utilized at the NATO Undersea Research Centre for detection and localization of undersea targets ... -
Source localization for a low frequency active multistatic sonar system
(NATO. SACLANTCEN, 1993/08)In a low frequency active bistatic or multistatic sonar system, it is essential tohave accurate knowledge of the location of the transmitting source ship. Inaccuracies inthis information translate directly to errors in the ... -
Spatial and temporal coherence in a long range, upslope environment
(NATO. SACLANTCEN, 1993/08)In an active acoustic test conducted off the USA Pacific Coast in November-December 1991, a low-frequency source, kept stationary over the deep basin, insonified from long range the coastal slope and shelf. An autonomous, ... -
Statistical characterization of shallow-water bistatic sonar reverberation and noise
(NATO. SACLANTCEN, 1993/08)Shallow-water, low-frequency bistatic sonar measurements often exhibit high noise caused by bathymetric reverberation and other sources. Understanding the noise statistics is an essential first step in developing filters ... -
Through-the-sensor geoacoustic inversion along a towed horizontal line array: results from real data set in the Mediterranean sea
(NURC, 2007/12)The assessment of active sonar performances in shallow water strongly depends on the environmental conditions. Of most importance, bottom properties are known to strongly affect the forward acoustic propagation and ...