Emitter location via joint 3-D parametric estimation

Separating and locating each digital communication signal in a dense signal environment is often impossible using traditional two-parameter FDOA/TDOA joint estimation tools. The conventional 2-D tools produce biased estimates when multiple emitters are located spatially close to each other and share the same regions of the spectrum at the same time. By adding a third parameter for the joint estimation, we show how to achieve separation and localization not possible with conventional 2-D tools. In this paper, a new 3-D joint estimation tool called the alpha cross ambiguity function (¿-CAF) is introduced that exploits signal modulations with cyclostationary properties for jointly estimating time difference of arrival (TDOA), frequency difference of arrival (FDOA), and cyclic frequency (¿) for spectrally, temporally, and spatially interfering signals arriving at two spatially separated receivers. The ¿-CAF parameter estimation algorithm is introduced along with an analysis of its performance compared to conventional 1-D and 2-D estimators.