GNSS Antennas and Front Ends

Abstract

Although the focus of this text is on the algorithms for software signal processing of the Global Navigation Satellite System (GNSS) signals, it is important to consider the source of that data stream to be processed. Since “software” signal processing is stated, it implies an input digital data stream. Thus, the purpose of this chapter is to provide some insight into how the satellite signals propagating through space result in this digital data stream. This is done, of course, via a GNSS antenna/front end. There are numerous books completely devoted to the topics of antenna and others to front-end design; see Balanis (1996) and Tsui (2000). The purpose of this chapter is to illustrate functional designs for GNSS, discuss the tradeoffs associated with different designs, and provide a basic understanding of the source of the digital data to be processed. The focus is on the narrowband GNSS L1 signals, primarily the Global Positioning System (GPS) Coarse/Acquisition (C/A) code, but references are made to the Galileo BOC(1,1) code where appropriate. At the end of the chapter, multiple-band GNSS front ends are introduced.