Passive localization of an emitting source by parametric means

Following a parametric formulation of the nonlinear problem of localizing an emitting source on a constant-course and constant-speed three-dimensional trajectory from Doppler measurements, an exact solution in the absence of noise is constructed. This solution also shows the minimum data requirements. For the case where noise is present, two methods are proposed and compared: an extension of the noise-free method and the maximum-likelihood estimator. It is concluded that, while the extension of the noise-free method requires less computational, it requires a much lower noise level for acceptable performance. It is found that the maximum-likelihood estimator compares favorably with the Cramer-Rao bound at higher noise levels