Systems and methods using iterative particle reduction for localization and pattern recognition are disclosed. In one embodiment, a method for localization of a plurality of sensor nodes includes establishing a set of particles representing candidate positions for the plurality of sensor nodes; iteratively reducing the set of particles using a plurality of particle reduction iterations, wherein each particle reduction iteration eliminates at least some particles based on at least one constraint and a set of remaining particles from a prior iteration; and after performing the plurality of particle reduction iterations, determining a set of probable locations of the plurality of sensor nodes based on a final set of particles.