Synthetic Augmented L-shaped Array design and 2D Cramér-Rao bound analysis based on Vertical-Horizontal Moving Scheme

This paper introduces an innovative approach to enhance the effectiveness of the L-shaped array using synthetic aperture processing. Through the implementation of the Vertical-Horizontal Moving Scheme (VHMS), a novel 2D array structure called the Synthetic Augmented L-shaped Array (SALA) is developed, featuring varied element spacing along the x and y axes of a 1D linear array. Comparative analyses demonstrate that the SALA achieves a larger difference coarray and higher degrees of freedom compared to arrays with an equivalent number of physical elements. The paper also provides a comprehensive derivation of the Cramér-Rao Bound (CRB) for 2D moving arrays, with detailed analyses of its conditions and properties. Simulation results highlight the SALA's superior capabilities in detecting multiple sources and providing precise 2D direction of arrival estimation, along with a lower CRB, indicating its potential for practical implementation in diverse scenarios.