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Triple mode filters with coaxial excitation

Gerini, G. (author), Bustamante, F.D. (author), Guglielmi, M. (author), TNO Fysisch en Elektronisch Laboratorium (author)

In this paper we describe triple mode filters in a square waveguide with integrated coaxial input/output excitation. An important feature of the structure proposed is that it is easily amenable to an accurate full wave analysis. In addition to theory, a practical six pole filter with two transmission zeros is also demonstrated

conference paper 2004

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Experimental comparison of bearing estimation techniques for short passive towed sonar arrays

Colin, M.E.G.D. (author), Groen, J. (author), Quesson, B.A.J. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Although Low Frequency Active Sonar (LFAS) is considered one of the best means of detection and localization of a submarine in shallow water, the use of an active system is not always possible for tactical reasons. It is therefore interesting to include a passive mode in these systems by using the receiving array as a passive array. However,...

conference paper 2004

document

A Novel Technique for the Design of Frequency Selective Structures Integrated with a Waveguide Array

Monni, S. (author), Gerini, G. (author), TNO Fysisch en Elektronisch Laboratorium (author)

A single mode model and a full multimode equivalent network (MEN) approach have been adopted for the design of an FSS integrated phased array. The single mode equivalent transmission line model allows a systematic design of the FSS, starting from the requirements, and the results of this simple design procedure are similar to well known...

conference paper 2004

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On the availability of a k-out-of-N system given limited spares and repair capacity under a condition based maintenance strategy

de Smidt-Destombes, K.S. (author), van der Heijden, M.C. (author), van Harten, A. (author), TNO Fysisch en Elektronisch Laboratorium (author)

This paper considers a k-out-of-N system with identical, repairable components. Maintenance is initiated when the number of failed components exceeds some critical level. After a possible set-up time, all failed components are replaced by spares. A multi-server repair shop repairs the failed components. The system availability depends on the...

article 2004

document

Simultaneous localisation of multiple emitters

Naus, H.W.L. (author), van Wijk, C.V. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Exploiting several arrays of sensors enables simultaneous detection of a number of emitters. Fusion of the respective array data yields lines containing possible positions as a function of the frequency. Identifying multiple intersections eventually leads to unambiguous localisation of the sources. The usual unwanted ghost detections do not...

conference paper 2004

document

River dike deformation measurement with airborne SAR

Groot, J. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Due to extremely high water levels or extremely dry periods, river dikes can deform and eventually burst. The deformation can be measured with repeat-pass synthetic aperture radar (SAR) interferometry. Two flights (5.5-day interval) with an airborne C-band SAR were carried out to verify a particular case. During the second flight, the dike was...

article 2004

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A high frequency transient detector suitable for monitoring marine mammal activity

Laterveer, R. (author), Beerens, S.P. (author), van IJsselmuide, S.P. (author), Snyder, M. (author), Newcomb, J. (author), TNO Fysisch en Elektronisch Laboratorium (author)

As part of a program to study the effect of man-made noise on marine mammals an EARS Acoustic Recording System) buoy was deployed in the Ligurian sea. The EARS buoy was deployed at a position with a high probability of marine mammal activity at a depth of around 950 m. It was operating for almost 19 days and collected acoustic data sampled at...

conference paper 2004

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Shape and Doppler corrected beamforming for low frequency active sonars

Groen, J. (author), Beerens, S.P. (author), Doisy, Y. (author), TNO Fysisch en Elektronisch Laboratorium (author)

ASW operations have shifted toward shallow water environments, where water space is limited and manoeuvring an essential part of operations. The problem that is tackled in this article is the performance loss due to the shape and motion of a manoeuvring sonar. Standard beamforming in towed sonar arrays is based on the assumption that all...

conference paper 2004

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Target Acquisition Performance as a Function of Resolution using Radar Change Detection

van den Broek, A.C. (author), Smith, A.J.E. (author), van Dekker, R.J. (author), Steeghs, T.P.H. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Results from a study for ground surveillance with synthetic aperture radar (SAR) are presented. In particular change detection performance as a function of resolution and target size is investigated using simulated and measured SAR data. For the simulation five homogeneous target sets with sizes varying from one to eight meter have been used and...

conference paper 2004

document

Protecting a nation's critical infrastructure: The first steps

Klaver, M.H.A. (author), Luiijf, H.A.M. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Modern societies are increasingly dependent on a set of critical products and services which comprise the Critical Infrastructure (CI). Relatively well-known threats as well as the new terrorist threat increase the need for Critical Infrastructure Protection (CIP). Using a methodological approach, The Netherlands determined its CI that consists...

conference paper 2004

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Object-based detection of hazards to the European gas pipeline network using SAR images

van Dekker, R.J. (author), Lingenfelder, I. (author), Brozek, B. (author), Benz, U. (author), van den Broek, A.C. (author), TNO Fysisch en Elektronisch Laboratorium (author)

In this paper the results of a study for a hazard detection system for Europe’s extensive high pressure gas mains transmission systems are presented. The system is designed to trace uncontrolled digging, ploughing, excavating activities using draglines or other machinery, construction works and planting of trees near pipelines using remote...

conference paper 2004

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Speed and security; logistics and security can go hand in hand

van Dijk, C.N. (author), Uiterweerd, F. (author), TNO Fysisch en Elektronisch Laboratorium (author)

conference paper 2004

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SAKAMATA: A tool to avoid whale strandings

Benders, F.P.A. (author), Beerens, S.P. (author), Verboom, W.C. (author), TNO Fysisch en Elektronisch Laboratorium (author)

World-wide a concern exists about the influence of man-made noise on marine life, and particularly of high power sonar. Most concern lies with marine mammals that use acoustics for hunting, communication and/or navigation. This concern is fed by recent strandings of whales that could be related to military sonar transmissions and seismic...

conference paper 2004

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Fundamentals of microwave power amplifier design

de Hek, A.P. (author), van den Bogaart, F.L.M. (author), TNO Fysisch en Elektronisch Laboratorium (author)

public lecture 2004

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JIT Just-in-Time kennismanagement

Wagenaar, W.J.G.P. (author), de Jong, K.Y. (author), TNO Fysisch en Elektronisch Laboratorium (author)

conference paper 2004

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IMI - An information system for effective Multidisciplinary Incident Management

van der Lee, M.D.E. (author), van der Vugt, M. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The field of crisis response and disaster management can be characterized, upon many other factors, by distributed operations, not daily routine work and multidisciplinary aspects. In designing and developing information systems for crisis response these factors need special attention. On behalf of regional emergency services, TNO Physics and...

conference paper 2004

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The sonar equation and the definitions of propagation loss

Ainslie, M.A. (author), TNO Fysisch en Elektronisch Laboratorium (author)

A rigorous application of the traditional definition of sonar equation terms leads to the appearance of an unexpected factor, not routinely included, equal to the ratio of the characteristic impedance at the receiver to that at the source. An omission of this factor can lead to non-negligible errors for realistic conditions. It is further argued...

article 2004

document

Internal tides in the Bay of Biscay: Conversion rates and seasonal effects

Gerkema, T. (author), Lam, F.P.A. (author), Maas, L.R.M. (author), TNO Fysisch en Elektronisch Laboratorium (author)

Internal tides in the Bay ofBiscay are studied using a numerical linear hydrostatic internal-tide generation model, in which along-slope uniformity is assumed. The focus is on the seasonal changes in the generation and dynamics. The results are compared with observations made near the shelf-break in early summer. They were obtained using a towed...

article 2004

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Problem-Matched Basis Functions for Microstrip Coupled Slot Antennas based on Transmission Line Greens Functions

Bruni, S. (author), Llombart Juan, N. (author), Neto, A. (author), Gerini, G. (author), Maci, S. (author), TNO Fysisch en Elektronisch Laboratorium (author)

A general algorithm for the analysis of microstrip coupled leaky wave slot antennas was discussed. The method was based on the construction of physically appealing entire domain Methods of Moments (MoM) basis function that allowed a consistent reduction of the number of unknowns and of total computation time. The basis function obtained were...

conference paper 2004

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Benchmarking operational SAR ship detection

Greidanus, H. (author), Clayton, P. (author), Indregard, M. (author), Staples, G. (author), Suzuki, N. (author), Vachon, P. (author), Wackerman, C. (author), Tennvassas, T. (author), Mallorqui, J. (author), Kourti, N. (author), Ringrose, R. (author), Melief, H. (author), TNO Fysisch en Elektronisch Laboratorium (author)

The performances of eight satellite SAR ship detection systems (most of them operational) are compared, by running a benchmark test on RADARSAT images of various modes. No single system is best under all circumstances.

conference paper 2004