Synthetic sparse planar array design for two-dimensional DOA estimation.

• The expression of the Synthetic Augmented Cross Array (SACA) is derived, which utilizes the concept of 2D array motions. • The proposed SACA structure can achieve dramatically high uniform DOFs with only a few physical sensors. • The generalization of SACA named as Improved Synthetic Augmented Cross Array (ISACA) is proposed. • The ISACA can achieve larger DOFs than SACA and further reduce the mutual coupling effect. • The properties of both SACA and ISACA are analyzed and simulations verify the superiority. Array motion can efficiently enhance the achievable number of degrees-of-freedom (DOFs) by the virtue of filling the holes in the difference co-array. In this paper, the concept of synthetic array based on array motion is extended to two dimensional cases. A new structured sparse planar array on a moving platform named as Synthetic Augmented Cross Array (SACA) is proposed. The proposed array yields a co-array with much larger virtual uniform rectangular array in it. Closed-form expressions of DOFs with different moving trails are also delineated. Then by further improving the DOFs of SACA, a series of generalized configurations named as Improved Synthetic Augmented Cross Array (ISACA) are proposed. With the same number of sensors, it can achieve larger DOFs than SACA. Numerical results are provided for performance comparison and validations of analysis. [ABSTRACT FROM AUTHOR]