Random Phase Center Motion Technique for Enhanced Angle-Doppler Discrimination Using MIMO Radars

A random Phase Center Motion (PCM) technique
is presented in this paper, based on Frequency Modulated
Continuous Wave (FMCW) radar, in order to suppress the angle-
Doppler coupling in Time Division Multiplex (TDM) Multiple-
Input-Multiple-Output (MIMO) radar when employing sparse
array structures. The presented approach exploits an apparently
moving transmit platform or PCM due to spatio-temporal
transmit array modulation. In particular, the work considers
a framework utilizing a random PCM trajectory. The statistical
characterization of the random PCM trajectory is devised, such
that the PCM and the target motion coupling is minimal, while
the angular resolution is increased by enabling the virtual MIMO
concept. In more details, this paper discusses sidelobe suppression
approaches within the angle-Doppler Ambiguity Function (AF)
by introducing a phase center probability density function within
the array. This allows for enhanced discrimination of multiple
targets. Simulation results demonstrate the suppression angle-
Doppler coupling by more than 30 dB, even though spatiotemporal
transmit array modulation is done across chirps which
leads usually to strong angle-Doppler coupling.