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Principles of integrated maritime surveillance systems

Preface. Acknowledgements. 1. Introduction. 2. Maritime Surveillance Applications. 3. Maritime Environment. 4. Sensors. 5. Sensor Platforms. 6. Principles of Automatic Target Recognition in a Maritime Environment. 7. Multisensor Data Fusion. 8. Communications Systems and Data Links. 9. Simulation of Maritime Surveillance Systems. 10. New Technologies, New Functions and Solutions. 11. Cost Analysis and Implementation Planning. Index.

High-Resolution Direction-of-Arrival Estimation via Concentric Circular Arrays

Estimating the direction of arrival (DOA) of source signals is an important research interest in application areas including radar, sonar, and wireless communications. In this paper, the problem of DOA estimation is addressed on concentric circular antenna arrays (CCA) in detail as an alternative to the well-known geometries of the uniform linear array (ULA) and uniform circular array (UCA). We define the steering matrix of the CCA geometry and investigate the performance analysis of the array in the DOA-estimation problem by simulations that are realized through varying the parameters of signal-to-noise ratio, number of sensors, and resolution angle of sensor arrays by using the MUSIC (Multiple Signal Classification) algorithm. The results present that CCA geometries provide higher angle resolutions compared to UCA geometries and require less physical area for the same number of sensor elements. However, as a cost-increasing effect, higher computational power is needed to estimate the DOA of source signals in CCAs compared to ULAs.

A circularly polarized antenna with electromagnetic bandgap structures

In this paper, we propose a novel method to increase the axial ratio bandwidth of a circularly polarized microstrip patch antenna. Demonstrated method consists of polarization dependent rectangular-shaped mushroom-like electromagnetic bandgap structures positioned around circularly polarized radiator patch. Since the structure itself has a polarization-dependent behavior, it was seen that a secondary minimum point can be introduced in the frequency dependency of axial ratio in main lobe direction. Additionally, increment in maximum gain is achieved as a result of natural characteristics of electromagnetic bandgap structures. Simulations made by HFSS show that axial ratio bandwidth can be increased using polarization-dependent electromagnetic bandgap structures. In this configuration, 3-dB axial ratio bandwidth can be broadened significantly.

Direction-of-arrival estimation via concentric circular antenna arrays

The estimation of direction-of-arrival (DOA) of source signals has been well-studied research area in both military and civil applications. The MUSIC (Multiple SIgnal Classification) algorithm based on the signal subspace separation idea has already been investigated and employed for uniform linear arrays (ULA) and uniform circular arrays (UCA) in DOA estimation extensively. However, an important disadvantage of the ULA geometry in DOA estimation is that it can only estimate the azimuth angle. To estimate the elevation angle, UCA geometries are employed in many applications. As the concentric circular arrays (CCA) that are discussed in this paper have better angle resolutions compared to ULAs, and as they require smaller physical area compared to UCAs with the same number of array elements, CCAs are proposed to be used in mobile applications as a preferable alternative. The DOA estimation problem for CCAs is defined and the steering matrix is expressed in this paper, moreover the performance analysis is investigated by simulations.

Simulation of Maritime Surveillance Systems

This chapter is about techniques for using computers to imitate, or simulate, the operations of various kinds of real world maritime surveillance facilities and processes. The contents of the chapter is organized as follows:

Multisensor Data Fusion

The main objective of multisensor data fusion is to combine elements of raw data from multiple sensors to extract the greatest amount of information possible about the sensed environment which is greater than the sum of its contributing parts. In the literal sense, data refers to the actual measurements taken or information obtained by the sensors and fusion is the process of combining the data or information in such a way that the results provide more information than the sum of the individual parts [7.1, 7.4].

Cost Analysis and Implementation Planning

The acceptability or feasibility of any system design would depend, to a large extent, on its cost and affordability and this requires an estimation to be made of the cost of all the subsystem/components of the total system. Cost estimation is often done in two steps which we may call type-A and type-B. The type-B cost estimate of the final system design to be implemented would be required to be as accurate as possible, say ± 10%, for budgeting purposes. When different system options are being evaluated for cost-effectiveness, more easily available and perhaps less accurate price information (type-A estimates), say ± 25%, would be adequate.

Principles of Automatic Target Recognition in a Maritime Environment

In this chapter the problems related to the “recognition” of vessels in a maritime surveillance area will be discussed. In the context of this chapter “recognition” will be used as a generic term which includes both “classification” and “identification” activities. The main problematic area is the recognition by machines of noncooperative vessels using microwave radars; this is the main topic of this chapter.

Maritime Surveillance Applications

For our purpose in this book we shall class the maritime surveillance systems into two categories; civilian surveillance systems and military systems. We shall call the former Vessel Traffic System (VTS) or more fully Vessel Traffic Management and Information Systems (VTMIS) [2.7]. The International Association of Lighthouse Authorities (IALA) promulgate guidance and assistance to Administrations and Authorities considering the implementation of a new VTS, or the upgrading of an existing one.

New Technologies, New Functions and Solutions

As maritime transport and traffic increases so does the requirement for implementing more and more VTMIS’s which aim at providing safety, efficiency and protection of the environment in case of accidents/incidents. As a consequence we see increasing research and development being applied to enhancing the VTS system performance and capabilities.