Estimation of emitter power, location, and path loss exponent

Received Signal Strength (RSS) localization has the advantage of simplicity over common schemes that use angle-of-arrival, time-of-arrival, and time-difference-of-arrival information. Signal power is relatively easy to measure with low cost and light weight equipment. The RSS at a receiver is a function of distance between an emitter and receiver, the reference power η0, and the path loss exponent α. In many applications, limited a priori knowledge of α and η0 is available. Since using inaccurate values of α and η0 in the localization equations can introduce bias errors in the position estimate, it is preferable to estimate α, η0 and emitter position together. This paper develops a new formulation that leads to a least squares solution for the joint estimation of α, η0 and emitter position. In the simulation example, the estimation errors are close to the theoretical lower bound.