The analysis of some context-aware services, in which the central element comes to be the user and its mobile device plunged in a rich and heterogeneous sensing environment, has driven us to face the design of context-aware systems as a multisensor data fusion process. In this paper we propose a fusion framework that describes the information flows and identifies the necessary functional blocks to build context-aware systems whose aim is to accomplish a collaborative dasiamissionpsila. Our three-staged model is inspired in the JDL fusion model, reformulated to fulfil context-aware systems functional modelling needs. It is focused on supporting the process of building and analyzing the systempsilas dasiainformational picturepsila, to later reason about it and make decisions on services, infrastructure and user interaction. In contrast to traditional fusion models, our proposal underlines the non-linearity of context-aware problems solving.