Estimation of the Cramer-Rao Bound for Radio Direction-Finding on the Azimuth of Planar Antenna Arrays of the Non-Symmetric Form

The paper deals with planar antenna arrays, such as circular, octagonal, hexagonal and rectangular, for the task of direction-finding on azimuth and elevation angles. The boundaries of the Cramer-Rao are calculated for different situations, including the location of signals in azimuth and elevation planes, and signal-to-noise ratios. Each antenna array consists of the same number of omni-directional antenna elements equal to 24, the distance between which is half the wavelength. In addition, the expressions for the steering vectors of two types of asymmetric antenna arrays, i.e. arcuate and L-shaped are given. Their influence on the direction-of-arrival estimation accuracy is considered, and the exact expressions of the Cramer-Rao boundary are given. It is established that the best geometry is arc-shaped.