DOA Estimation Exploiting Moving Platform of Unfolded Coprime Array
International journal of intelligent engineering and systems · 2022
Coprime array configurations have occupied a significant concentration due to its properties like simplicity and ability to detect a higher number of targets with respect to the number of elements in an antenna array.Nevertheless, the constructed array still has some empty positions (holes) that need to be filled to enhance the degrees of freedom (DOFs).Motion array can successfully address this issue, fill some holes and expand the number of the lags by shifting the distance of the elements in the coprime array half the wavelength, thus it can detect a great amount of sources compared to a fixed array.In this paper, a new synthetic array aperture named "Enhanced Unfolded Coprime Array" (EUFCA) formed on the moving platform concept is proposed to address the problem of the empty positions and provide a central consecutive lag by generating a hole-free virtual array.The proposed array configuration enhances unfolded coprime array (UFCA) by changing the position of some physical elements.Formal expression of the uniform degrees of freedom (uDOF) and the unique lags of the synthetic array are derived.Simulation results present the achievable large number of uDOF that enhance the DOA estimation process by detects more source signals compared with other array structure designs.For 18 elements in EUCFA, with different (M,N) pair such as (5,9) and (6,7), the number of achievable uDOFs for moved array is 215 and 213 respectively comparing to fixed array that generate 58 and 54 uDoFs respectively.The ratio between the contiguous lags before and after movement is 3.71 and 3.94 for the aforementioned pairs respectively which indicate the ration of maximum number of extra contiguous lags obtained for EUFCA.