Research Of Compact Array Super-Resoltution Algorithm

More attentions are paid to the research and development of High Frequency Surface-Wave Radar (HFSWR) due to its'potentiality in military and civil application recently. As the working frequency is relatively low (3~30MHz), the wavelength is long. In order to maintain the performance of radar system, such as signal-to-noise ratio and angular resolution, the size of receiving antenna array is always very large and exceeds ten thousand square meters. The large size would bring lots of problems and trouble in Engineering Practice. Therefore, research on the compact receiving array of HFSWR is becoming urgently. As the beam width of compact receiving array is relatively wide, the angular resolution attained by digital beam forming (DBF) can't satisfy the system requirement. It's a necessary to use the super-resolution algorithm getting the direction of arrival signal.Firstly, the basic principle of array signal processing and array antenna is introduced. Then do some analyze of the circular array pattern. The mathematical principle of classic super-resolution algorithms: MUSIC algorithm and ESPRIT algorithm is introduced, too.The super-directivity array antenna plays an important role in designing the compact array. In combination of the application precondition of super-directivity in HF band and the good quality of circular array, this dissertation adopt a super-directivity synthesis method designing super-directivity circular array. In this method the dominance of external noise is ensured by constraining the array REIN(the Ratio of External to Internal Noise (REIN), and the desired side lobe level is achieved by implementing linear constraints through iteration, we can get the highest possible directivity. Making use of the good quality of odd element circular array, we can decide to adopt the 5-element super-directive circular array with 3 meter radius as the sub-array of radar receiving array antenna by analysis.In order to satisfy the system's angular discrimination resolution requirement, we make use of super-directivity circular arrays arranged in equal space linear way. We analyze the feasibility via MUSIC and ESPRIT algorithm estimating the direction of arrival in the mentioned array. Then MUSIC and ESPRIT algorithm are analyzed choosing different number of array elements of sub circular array to get the same resolution of traditional array. We can infer that the designed largely-reduced size array can estimate the direction of arrival via super-resolution algorithm.