Browsing Reprints by Subject "Signal processing"

Now showing items 1-20 of 78

    • A data-driven control strategy in synergy with continuous active sonar for littoral underwater surveillance 

      Ferri, Gabriele; Munafó, Andrea; Alves, João; LePage, Kevin D. (CMRE, 2017/11)
      In this work, we describe a data-driven Mission Management Layer (MML) running on-board AUVs which manages the phases of a littoral surveillance mission and exploits the characteristics of Continuous Active Sonar (CAS) ...

    • A fast display processor for sonar echoes 

      Bodholt, Helge (NATO. SACLANTCEN, 1979/12)
      This paper presents a display processor for a CRT, which shows a horizontal projection of underwater targets. Sonar echoes are drawn as short lines across a 50 beam, in random scan and with 50 Hz refresh. The high speed ...

    • A micro-programmable correlator for real-time radar processing 

      Alker, Hans Jorgen (NATO. SACLANTCEN, 1979/12)
      This paper presents a novel design of a multibit, digital correlator for incoherent scatter radar observations. By utilizing bit-slice microprocessor elements and internal control by microcode instructions, a high-speed ...

    • A modular approach to signal processing 

      Curtis, T. E. (NATO. SACLANTCEN, 1979/12)
      This paper outlines work in progress on modular systems for beamforming and signal processing. The modules described were developed using commercially available digital L.S.I circuits and the emphasis during development ...

    • A modular signal processing software development system 

      Rigsbee, Peter A. (NATO. SACLANTCEN, 1979/12)
      A software development system is being built by the U.S. Naval Research Laboratory (NRL) to aid production of modular signal processing software for U. S. Navy airborne ASW platforms using the Navy's Advanced Signal Processor ...

    • A novel method to enlarge the scanning region of a focused beamformer 

      Trucco, Andrea (NATO. SACLANTCEN, 1997)
      Often focused beamforming systems use the Fresnel approximation to compute the required delays. Unfortunately, such an approximation has a validity region that is very narrow around the broadside direction. To investrgate ...

    • A shallow water system for maximizing echo to reverberation ratio 

      Williams, Robert Bruce (NATO. SACLANTCEN, 1993/08)
      A method for increasing incident energy on mid-depth targets while at the same range reducing boundary reverberation for shallow water ducts has been devised. The basis of the approach is couched in range dependant normal ...

    • A versatile signal-processing system for producing the angular and frequency distribution of acoustic energy in real time 

      Griffin, James M. (NATO. SACLANTCEN, 1979/12)
      For a number of years the US Naval Research Laboratory (NRL) has been conducting a research program in underwater sound propagation using large aperture hydrophone arrays. This research requires the spectral and angular ...

    • About the effective Doppler sensitivity of certain nonlinear chirp signals (NLFM) 

      Rosenbach, Karlhans; Ziegenbein, Jochen (NATO. SACLANTCEN, 1993/08)

    • Achievable signal gains for line arrays in shallow water 

      Hanrahan, J. J. (NATO. SACLANTCEN, 1993/08)
      The well-documented conformance of signal gain to a 20 log n relationship for deep water, refracted paths, does not apply to shallow water where angular spreading effects from boundary roughness limit the signal gains that ...

    • Active detection enhancement in coastal areas 

      Haralabus, Georgios; Baldacci, Alberto; Laterveer, Rene (NURC, 2006/08)
      The processing chain used for active detection analysis in association with measures of performance that allow real time performance monitoring is presented. Real life examples demonstrating environmental volatility ...

    • Adaptive filter of seabed clutter onboard the AUVs of an active multistatic sonar network 

      Micheli, Michele; Tesei, Alessandra; Ferri, Gabriele; Stinco, Pietro (CMRE, 2019/05)
      This work aims at reducing the false alarm rate of a multistatic active sonar working in coastal, shallow waters. The sonar system is implemented through a heterogeneous manned-unmanned network including autonomous underwater ...

    • Adaptive normalization of active sonar data 

      Baldacci, Alberto; Haralabus, Georgios (NURC, 2006/08)
      In active sonar detection the background interference is reduced through normalization prior to applying a detection threshold. From the two mainstream normalization algorithms, i.e. the sliding window and the split window, ...

    • Adaptive sub-band processing in active detection and tracking 

      Baldacci, Alberto; Haralabus, Georgios; Coraluppi, Stefano; Prior, Mark K. (NURC, 2007/11)
      Broadband active systems have the potential to increase detection performance in reverberation-limited areas through increased signal bandwidth, i.e. small resolution cell. However, large bandwidth could over-resolve the ...

    • Advanced digital processor research at DREA 

      Crowe, D. Vance (NATO. SACLANTCEN, 1979/12)
      This informal presentation deals with an array processor built by ESE Ltd of Toronto under contract to the Defense Research Establishment Atlantic, Dartmouth, Nova Scotia, Canada. The processor and software was delivered ...

    • Ambiguity reduction of underwater targets in framework of topic modeling 

      Sildam, Jüri; LePage, Kevin D. (CMRE, 2019/06)
      An unsupervised track classification approach based on appropriate discriminative and aggregative features derived from beamformed and normalized matched-filtered data is applied to sonar multistatic tracking and extended ...

    • Arrays and array processors: future real time applications in oceanography and sonar 

      Baggeroer, Arthur B. (NATO. SACLANTCEN, 1979/12)
      In the last several years oceanographic applications of arrays have increased substantially. The spatial resolution and redundancy provided by arrays have been necessary in the interpretation of signal propagation in complex ...

    • Bayesian multi-class covariance matrix filtering for adaptive environment learning 

      Braca, Paolo; Aubry, Augusto; Millefiori, Leonardo; De Maio, Antonio; Marano, Stefano (CMRE, 2019/05)
      Covariance matrix estimation is a crucial task in adaptive signal processing applied to several surveillance systems, including radar and sonar. In this paper we propose a dynamic environment learning strategy to track ...

    • Belief propagation based AIS/radar data fusion for multi-target tracking 

      Gaglione, Domenico; Braca, Paolo; Soldi, Giovanni (CMRE, 2019/05)
      A data fusion technique aiming at combining observations from two classes of sensors is proposed. The first class consists of sensors that produce periodic noisy observations of the targets; moreover, they may also miss ...

    • Channel-adapted source for shallow water 

      Gingras, Donald F. (NATO. SACLANTCEN, 1993/08)
      In shallow water areas the utilization of active sonar is complicated by the fact that in these environments the performance of active systems is degraded by source signal interaction with channel boundaries. These boundary ...