MIMO-OFDM radar array configuration for resolving DOA ambiguity

In direction-of-arrival (DOA) estimation using millimeter waves or ultrasonic, the physical size of the sensors can require inter-element spacing of greater than half wavelength. The accompanied benefits of such spacing are larger array aperture and reduced mutual coupling, but the serious problem of DOA ambiguity arises. This paper proposes a method to suppress grating lobes by employing a MIMO radar array configuration. The resultant virtual array has sufficient half wavelength spacings to significantly suppress grating lobes while the transmit and receive array elements have greater than half wavelength spacing. The grating lobe suppression performance is evaluated by simulation of MIMO-OFDM radar system that also has frequency diversity properties against DOA ambiguity. The simulation results show that the grating lobe suppression performance increases with signal-to-noise ratio (SNR). The effectiveness of the proposed array configuration and frequency diversity for resolving DOA estimation is also demonstrated.

[1]  Marcelo Sampaio de Alencar,et al.  Mutual Coupling Effects in a Linear Adaptive Antenna Array with Random Spacing , 2007, 2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications.

[2]  Shannon D. Blunt,et al.  The impact of mutual coupling on MIMO radar emissions , 2011, 2011 International Conference on Electromagnetics in Advanced Applications.

[3]  D. Ramakrishnan,et al.  MIMO Radar Space-Time Adaptive Processing for Multipath Clutter Mitigation , 2006, Fourth IEEE Workshop on Sensor Array and Multichannel Processing, 2006..

[4]  Ahmed A. Kishk,et al.  MIMO-OFDM radar for direction estimation , 2010 .

[5]  Athanassios Manikas,et al.  Study of ambiguities of linear arrays , 1994, Proceedings of ICASSP '94. IEEE International Conference on Acoustics, Speech and Signal Processing.

[6]  Jian Li,et al.  On Parameter Identifiability of MIMO Radar , 2007, IEEE Signal Processing Letters.

[7]  M. Viberg,et al.  Two decades of array signal processing research: the parametric approach , 1996, IEEE Signal Process. Mag..

[8]  D. Fuhrmann,et al.  Transmit beamforming for MIMO radar systems using partial signal correlation , 2004, Conference Record of the Thirty-Eighth Asilomar Conference on Signals, Systems and Computers, 2004..

[9]  Chris J. Bleakley,et al.  DOA estimation of multiple sparse sources using three widely-spaced sensors , 2009, 2009 17th European Signal Processing Conference.

[10]  C.J. Bleakley,et al.  Phase-Difference Ambiguity Resolution for a Single-Frequency Signal , 2010, IEEE Signal Processing Letters.

[11]  A. Shapoury.  A subspace approach for DOA estimation of uniform linear arrays with increased element spacing applicable to wideband transmission , 2005, 2nd International Conference on Broadband Networks, 2005..