Multiple Sources Localization With WSN, Eliminating the Direction-of-Arrival Ambiguity Symmetric With Respect to the Planar Array

By equipping planar arrays on the sensor nodes in the wireless sensor network, multiple sources can be simultaneously located with the direction-of-arrival (DOA) estimates obtained at each array. However, the ambiguous DOA estimates which are symmetric with respect to the planar array cannot be avoided. This intrinsic ambiguity due to the array's spatial-frequency response would significantly degrade the localization performance. Generally, the conventional methods either assume no ambiguity in direction finding, or the ambiguity can be eliminated with additional prior knowledge or some special design on the hardware. This paper proposed a method capable of algorithmically eliminating the aforementioned DOA ambiguity, requiring neither additional prior knowledge nor special design. Numerical simulations illustrate the efficacy of the proposed method in eliminating the ambiguity and locating the sources. A Cramér-Rao-based lower bound on the localization error is also derived as a benchmark.