Abstract: Provided is a method for determining positions of one or more target receivers, wherein the one or more target receivers and one or more reference receivers receive a plurality of signals transmitted at unknown times from a plurality of sources that are located at unknown positions and not synchronized with each other. The method includes: obtaining times of arrival of the plurality of signals at the one or more target receivers; obtaining a plurality of times of arrival of the plurality of signals at the one or more reference receivers; and computing, based on the plurality of times of arrival of the plurality of signals at the one or more reference receivers, a plurality of reference positions of the one or more reference receivers, and the times of arrival of the plurality of signals at the one or more target receivers. The method may include determining directions of the plurality of sources.