Date Added: Jul 2010
Cooperative positioning algorithms have been recently introduced to overcome the limitations of traditional methods, relying on GNSS or other terrestrial infrastructure. In particular, SPAWN (Sum-Product Algorithm over a Wireless Network) was shown to provide accurate position estimate even in challenged indoor environments, thanks to exchange of local information among peers. In this paper, the authors extend the SPAWN framework by considering a hybrid scenario, where agents combine satellite and peer-to-peer terrestrial measurements. The novel Hybrid SPAWN (H-SPAWN) approach allows increased availability and robustness compared to GNSS-only positioning in light and deep indoor scenarios, while keeping the advantages of a distributed implementation of the original SPAWN.