Doa Estimation Based On The Conformal Antenna Array And Dbf A Number Of Algorithms Research

The conformal array is usually mounted on the surface of aircrafts and some other mobile platforms. Its major advantage is the aerodynamics of aircraft can almost not be affected. Conformal array also has the advantage of good conceal characteristic, suiting for wide angle scan, and facilitating to install. However, in contrast to ordinary arrays, the antenna elements of a conformal array have many unique electromagnetic characteristics. Conformal array has the"shadow effect"because of the metallic cylinder, so not all of elements can receive the signal from special direction; the element pattern has direction; the mutual couple between elements becomes more complicated and electromagnetic diffraction effect can not be neglected. Unlike normal arrays, adaptive signal processing on conformal arrays is more complex. In this thesis, based on cylindrical conformal array, MUSIC(multiple signal classification) algorithm for DOA(direction-of-arrival) estimation and robust DBF(digital beamforming) algorithm in DOA error situation are studied; array modeling errors and corresponding calibration methods are studied also. The main contents are as follows:Firstly, theories of conformal array are introduced, and a uniform conformal array patterns formula is given. As a base of conformal array, circular array's characteristic is studied deeply.Secondly, MUSIC algorithm for DOA estimation on conformal arrays is discussed. A fast and efficiently algorithm for circular arrays—UCA-RB-MUSIC(uniform circular array real beamspace MUSIC) algorithm is studied in detail. For the arrays mounted on curved surface of a cylinder, a new algorithm—subarray dividing MUSIC algorithm is proposed. This method can avoid the"shadow effect"result from metallic cylinder, which will deteriorate MUSIC algorithm's performance.Thirdly, DBF algorithms on conformal array are studied, and the effects from DOA estimation errors are discussed deeply. A robust DBF algorithm—RCB(robust capon beaming) algorithm is applied on conformal arrays for DBF, both 1D and 2D situations are studied.Finally, DOA estimation and DBF performance deterioration result from array errors are analyzed, and corresponding calibration methods are proposed.