Driven by the underlying need for a yet to be developed framework for fusing heterogeneous data and information at different semantic levels coming from both sensory and human sources, we present some results of the research being conducted within the NATO Research Task Group IST-106 / RTG-051 on “Information Filtering and Multi Source Information Fusion”. As part of this on-going effort, we discuss here a first outcome of our investigation on multi-level fusion. It deals with removing the first hurdle between data/information sources and processes being at different levels: representation. Our contention here is that a common representation and description framework is the premise for enabling processing overarching different semantic levels. To this end we discuss here the use of the Battle Management Language (BML) as a way (“lingua franca”) to encode sensory data, a priori and contextual knowledge, both as hard and soft data.