Limitations of joint space and time processing for moving source localization with a few sensors

The problem of instantaneous source location estimation with passive differential delay measurements is considered. A maneuvering source is assumed to move close to a few sensors and radiates both broadband and narrowband noise. Differential Doppler compensation is required to estimate differential delays between sensors. As near field source motion induces high dynamics in range and signal level, threshold variation linked with inherent signal ambiguity is the prevailing effect in delay estimation. These effects are studied through the calculation of multiple passband modified Ziv-Zakai lower bound. Taking these effects into account, an instantaneous estimator of location, speed and course is presented. The new and conventional estimators performance are then compared on simulation and with an at sea experiment.