Detection of oceanic electric fields based on the generalised likelihood ratio test (GLRT)

Galvanic corrosion phenomena between the hull and the propeller of a ship induce static electric fields in sea water. These signatures can be observed on a vectorial electrical sensor and the authors investigate the design of a detection/localisation method based on the generalised maximum likelihood ratio test (GLRT). Incorporating a spatio-temporal analysis of the signals in the physical model, it is possible to partially estimate the trajectory of the target and to perform a detection decision. The resulting system consists in the calculation of the projection of the observation on a set of parameterised signatures and in selecting the projection that has the largest energy. An original method is proposed in order to determine the convenient partitioning of the set of projection bases. Due to the characteristics of the signals, classical results concerning performance analysis are not convenient and a specific framework is developed in order to analytically determine the behaviour of the system. A comparison with Monte Carlo simulations tends to prove the validity of the theory and the efficiency of the processing.