  We propose efficient distributed algorithms to aid navigation of a user
through a geographic area covered by sensors. The sensors sense the level of
danger at their locations and we use this information to find a safe path for
the user through the sensor field. Traditional distributed navigation
algorithms rely upon flooding the whole network with packets to find an optimal
safe path. To reduce the communication expense, we introduce the concept of a
skeleton graph which is a sparse subset of the true sensor network
communication graph. Using skeleton graphs we show that it is possible to find
approximate safe paths with much lower communication cost. We give tight
theoretical guarantees on the quality of our approximation and by simulation,
show the effectiveness of our algorithms in realistic sensor network
situations.
