Methods for Anomalous Azimuth Estimate Censoring in Small Element Antenna Arrays

Abstract

There are abnormal azimuth estimates caused by multipath propagation and adjacent signal spectra overlapping in azimuth estimates of radio source created by radio monitoring complexes in broad band. In case of multipath propagation, the radio signal phase formed by addition of multipath components in antenna depends on their amplitudes and phases. If amplitudes of multipath components are approximately identical, and the initial phase difference is from160 to 200° then the radio signal phase in each antenna may have abnormal value which does not correspond to the direction of multipath component arrival and results in abnormal azimuth estimates. When adjacent signal spectra are overlapping there appear the abnormal estimates depending on the amplitude and azimuth of spectral component signals from different radio sources. Determination and censoring methods are offered for the both types of abnormal estimates. Censoring of the abnormal estimates caused by a multipath propagation involves determination of estimation histogram areas where estimates are grouped or deleted in case they do not belong to this area. Censoring of abnormal estimates caused by adjacent signals spectra overlapping is based on correlative approach, and consists in determination of the range formed by adjacent frequency samples, for which azimuth estimates are strongly correlated between themselves. Application of proposed methods is shown by statistical simulation modeling results and radio monitoring complex data processing results.

Keywords

• anomalous azimuth estimation
• censoring
• radio monitoring
• histogram
• multipath
• radio source corner coordinates