Performance evaluation of underwater target tracking using data fusion on acoustic and electromagnetic data

Underwater passive acoustic target tracking is challenging in littoral environments. One way to mitigate the difficulties is to add non-acoustic sensors and use data fusion. The topic of this paper is how to evaluate, in an objective way, the performance of data fusion in this application. Different performance measures are discussed. The performance measures are applied on data from a trial where one acoustic and one electric source were towed by a ship, simulating an underwater target. The trial was performed in a very shallow water littoral environment. Data were recorded using a passive acoustic horizontal line-array and an array of underwater electric sensors. The results show that there is a risk of degraded performance after fusion, if the data from the sensors have very different quality. In order to reduce this risk, it is crucial to reliably evaluate the quality of each estimate at all times.