Full-Wave Method for RF Sources Location

A full-wave method for the location of EM transmitters is presented. The goal is the detection of RF sources that can be used as beacons in indoor scenarios, especially in large industrial warehouses, through a simple method (based on the amplitude of the measured field in a set of receivers) able to determine the position with an error of at most 2.5 % the size of the place. This percentage of error results from a compromise between the accuracy and the necessity of a simple method with low requirements both from a technical and economical point of view. The theoretical bases of the method are the integral equations relating the electric fields with their sources. From theses equations, a cost function relating the measured field in a set of receivers and the position of the transmitter is calculated. The minimization of the cost function with respect to the position variables allows the determination of the source coordinates. As the cost function has local minima, global optimization strategies are used (i.e., establishment of an equivalent convex problem with one minimum, or the usage of evolutionary algorithms for finding the global minima). The method has been designed to work with several carriers in the VHF band, minimizing the effects of propagation blocking due to obstacles and multipath that typically occur at higher frequencies.