Localizations of Targets inside Enclosed Structures with a Single Sensor

In urban sensing and through-the wall radar, the existence of targets in proximity to walls introduces multipath returns. Coherent and noncoherent target localization are typically achieved by using multiple sensors at the expense of system cost, covertness, inflexibility in sensor positioning, and complexity in hardware and processing requirements. In this paper, target localization with a single sensor is achieved by exploiting the target multipath from the walls. A data association algorithm is derived that correctly associates the time-of-arrival (ToA) of the multipath returns to the walls they originate from. This is followed by nonlinear least squares technique to achieve noncoherent target localization. The proposed technique can be used for multiple targets provided that the ToAs of the direct path and multipath returns are all resolvable. Simulations and experimental data are used to validate the proposed algorithms.