Fuzzy Functional Dependencies as a Method of Choice for Fusion of AIS and OTHR Data.

Medhat Abdel Rahman Mohamed Mostafa,Nikola Lekić,Nikola Stojkovic,Miljan Vucetic,Aleksej Makarov

doi:10.3390/s19235166

Medhat Abdel Rahman Mohamed Mostafa, Nikola Lekić + Show 3 more

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https://doi.org/10.3390/s19235166

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Abstract

Maritime situational awareness at over-the-horizon (OTH) distances in exclusive economic zones can be achieved by deploying networks of high-frequency OTH radars (HF-OTHR) in coastal countries along with exploiting automatic identification system (AIS) data. In some regions the reception of AIS messages can be unreliable and with high latency. This leads to difficulties in properly associating AIS data to OTHR tracks. Long history records about the previous whereabouts of vessels based on both OTHR tracks and AIS data can be maintained in order to increase the chances of fusion. If the quantity of data increases significantly, data cleaning can be done in order to minimize system requirements. This process is performed prior to fusing AIS data and observed OTHR tracks. In this paper, we use fuzzy functional dependencies (FFDs) in the context of data fusion from AIS and OTHR sources. The fuzzy logic approach has been shown to be a promising tool for handling data uncertainty from different sensors. The proposed method is experimentally evaluated for fusing AIS data and the target tracks provided by the OTHR installed in the Gulf of Guinea.

Highlights

An exclusive economic zone (EEZ) is a 200 nmi-wide area which spreads from territorial waters towards the open sea in which a coastal state has exclusive rights to exploit biological and mineral sea resources
We explore the connection between fuzzy functional dependencies (FFDs) and the problem of over-the-horizon radar (OTHR) tracks and automatic identification system (AIS) data fusion
Due to the inaccuracy and the inconsistency of data provided by OTHR and AIS platforms, we evaluate the closeness of records in order to detect FFDs which are possible candidates for associating related targets

Summary

Introduction

An exclusive economic zone (EEZ) is a 200 nmi (approximately 370 km)-wide area which spreads from territorial waters towards the open sea in which a coastal state has exclusive rights to exploit biological and mineral sea resources. We considered functional dependencies (FDs), which are a basic concept for data fusion and data cleaning, between AIS records and OTHR tracks. OTHR by its nature involves some level of inaccuracy In our case, it measures the range, azimuth and radial speed of targets with accuracy expressed in terms of the corresponding resolution cells. One of the challenging problems in our work is measuring similarities among AIS records and OTHR tracks considering their respective attributes. The main idea is to find the intensity of similarity in order to detect the same targets and possible threats This assumption leads us to extending FDs to fuzzy functional dependencies. FDs defined in various ways [17] are not used only for database design purposes, and in other challenging applications such as data cleaning [18], record matching [19], query relaxation [20], and knowledge discovery [21]

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