Performance Comparison AN/FRD-10 vs. Pusher

Abstract

The possibility of replacing some of the AN/FRD-10 Circular Disposed Antenna Array (CDAA) facilities with lower cost PUSHER type of CDAA is an option available to planners. It is generally assumed that the ability of the PUSHER to receive signals of interest (SOI) is only slightly less than that of the larger AN/FRD-10 and AN/FLR-9 types of CDAA. However, no specific analysis of the actual difference in performance is known to exist. This report provides a preliminary performance analysis of the two types of facilities. Detailed performance-related measurements have been made at a number of AN/FRD-10 CDAA sites. These measurements were made as a part of the U.S. Navy's Signal-to-Noise-Enhancement Program (SNEP). The objective of the SNEP is to identify and mitigate all factors that degrade the ability of receiving sites to recieve SOI and process data from them. Similar measurements have also been made at PUSHER sites, although complete data is available from only a single PUSHER site. This report uses data accumulated from the AN/FRD-10 sites and from one measured PUSHER site to examine the differences in their ability to receive SOI. The performance Evaluation Technique (PET) developed by the Naval Postgraduate School was used to evaluate the performance of each kind of CDAA. To simplify this initial analysis, the assumption was made that an AN/FRD-10 site containing an RFSS type of RF switch would be replaced with a PUSHER. Only the technical properties of the two types of CDAA were considered. The additional adverse impact of internal and external sources of man-made noise on performance was not included. It was assumed that the impact of EMI would be the same for both types of systems. In addition, the effect of nighttime overloading and saturation of the R F-distribution systems (RFD) from the relatively high levels of total signal power collected by the antenna elements were not considered in this preliminary analysis.