Analysis of the Calibration Data Measured with a High-Frequency Antenna Array.

Abstract : This report contains an analysis of the antenna calibration data taken with a high frequency (HF) antenna array and a pilot source towed behind a small aircraft. The analysis used an array calibration method developed by E.K.Th. Hung. The objective was to determine whether this method was adequate for calibrating the HF antenna arrays in the Canadian Forces Supplementary Radio (CFSRS) modernization project. The study showed that the calibration method significantly improved the performance of the array in detecting low-elevation (11 deg. or less) targets and estimating their directions. The degree of improvement decreased as the target elevation increased. At an elevation of 49 deg., it was marginal at best. This study also uncovered the presence of systematic errors in the calibration data. These errors increased rapidly with the pilot source elevation. It is not possible to decide whether or not the calibration method is adequate for the CFSRS antenna arrays. In this study, the calibration method could be inadequate for high elevation targets, or the method was adequate but the systematic errors negated the improvements gained in the calibration.