Toolkits such as PlaceLab  have been successful in making location information freely available for use in experimental ubiquitous computing applications. As users’ expectations of ubiquitous computing applications grow, we envisage a need for tools that can deliver a much richer set of contextual information. The high-level situation of the current environment is a key contextual element, and this position paper focuses on a method to provide this information for an ad-hoc group of people and devices. The contributions of this paper are i) a demonstration of how information retrieval (IR) techniques can be applied to situation determination in context-aware systems, ii) a proposal of a novel approach to situation determination that combines these adapted IR techniques with a process of cooperative interaction, and iii) a report of preliminary results. The approach offers a high level of utility and accuracy, with a greater level of automation than other contemporary approaches.