Ambiguities in 3D target motion estimation for general radar measurements

摘要

A recent analysis reveals that any attempt to estimate the underlying two-dimensional (2D) motion of a surface target via general bistatic synthetic aperture radar yields ambiguities, so that alternate target trajectories can give the same measurement data. These ambiguities are of a continuous nature and are fundamentally distinct from the discrete ambiguities that arise in pulse-Doppler moving target indication radar. The current investigation relaxes the constraint that the mobile target lies on the surface of a ground plane, so that air targets with general 3D motion are considered. Specifically, the current paper develops methods for constructing alternate fictitious 3D target trajectory and speed profiles in time which yield identical radar measurements as that obtained from the true 3D target motion. These ambiguities are shown to remain even with the inclusion of bistatic range rate or Doppler measurements. Thus, the energy patterns of the radar transmission and reception beams determine the ability to localise and estimate the 3D target trajectory and speed profiles for general bistatic radar collections.