Performance Analysis of Optimum Tilt Angle and Beam Configuration to Derive Horizontal Wind Velocities by Postset Beam Steering Technique

Software beam synthesis by postset beam steering (PBS) technique is used to derive the horizontal wind velocities from multireceiver phased-array radar data. In order to improve the efficiency of beam synthesis, the Capon beamforming method is used to synthesize time series signals in the desired line-of-sight angle within the radar transmit beam volume (3.6^° beamwidth). This paper describes beam synthesizing in optimum directions to reduce the error in the measurement of horizontal wind velocities using the PBS technique. For this purpose, beams are synthesized at various tilt angles with multibeam configuration. From the synthesized beam, power spectral distribution is obtained by one of the subspace methods, i.e., eigenvector (EV). The mean Doppler frequency and radial wind velocity at the desired line-of-sight angle are derived by an adaptive-moment estimation method from an EV-produced power spectrum. Using the moments obtained in various radial directions, horizontal wind components are derived by the conventional method for wind profiler radars. Also, an analysis is done for the required number of beams to improve PBS-based wind estimation. The statistical comparisons of performances of various tilt angles and beam configurations are being studied using the data collected from a multireceiver phased-array radar system (middle and upper atmosphere radar, Shigaraki, Japan). The analyzed results show that beam synthesis at the tilt angle from 1.5 ^° to 2.0^° using a 16-beam configuration minimize the error in horizontal wind estimation by PBS technique.