Statistically Efficient Passive Ranging Using Signal Intensity Observations From a Single Fixed Sensor

In this paper, a passive ranging problem with elevation angle, azimuth angle, and signal intensity measurements is presented. The signal intensity is inversely proportional to the squared distance between target and sensor. All measurements are obtained from a single fixed sensor and the emitted signal intensity is unknown. The observability is investigated through the Fisher information matrix (FIM) and Cramer–Rao lower bound. The maximum-likelihood (ML) estimator is used for the estimation of the trajectory of the target and the FIM is calculated numerically. The simulation results prove the feasibility of passive ranging using signal intensity measurements from a single stationary passive sensor. The estimates are shown to be statistically efficient.