GPS Overview and User Equipment Antijam Design

Abstract

The Global Positioning System (GPS) features an all-weather global coverage navigation sensor with 0.01-nmi positioning accuracy. In the following paper, GPS is described with emphasis on antijam considerations developed in the USAF AFAL Generalized Development Model, GDM. Section 1 provides an overview of the GPS ground, space, and user segments. Section 2 describes antijam issues and techniques applicable to GPS. Section 3 describes the GDM design with emphasis on antijam. features. The objectives of the paper are thereby threefold. The first is to give an overview of GPS, how it works, its participants, and its status. The second is to provide a tutorial discussion of spread spectrum receiver design related to GPS (some knowledge of signal processing principles is therein assumed). The third is to provide an example of GPS receiver design which incorporates antijam features.