Knowing the position of a device at a given time is fundamental to provide services tailored to the current user location. However, not all devices are able to perform positioning by their own, even when positioning systems are available in the environment where the user is located. This article presents a context-aware positioning model that allows devices participating in mobile ad-hoc networks, to sense their context and exchange positioning information with their peers. Thus, nodes knowing their own position could share it with their neighbors, allowing the latter to perform positioning. We discuss the performance of the model in a simulated mobile outdoor environment, populated with different types of devices. Our experiment shows that nodes without positioning capabilities are able estimate their position, although with reduced accuracy compared to those using a direct positioning strategy, such as GPS.