  The problem of mobile position estimation in multipath scenarios is
addressed. A low-complexity, fully-adaptive algorithm is proposed, based on the
pseudo maximum likelihood approach. The processing is done exclusively on-board
at the mobile node by exploiting narrowband downlink radio signals. The
proposed algorithm is able to estimate via adaptive beamforming (with spatial
smoothing) the optimal projection matrices that maximize the likelihood; in
addition, it can associate the line-of-sight over the trajectory, hence
achieving an integration gain. The performance assessment shows that the
proposed algorithm is very effective in (even severe) multipath conditions,
outperforming natural competitors also when the number of antennas and
snapshots is kept at the theoretical minimum.
