TABLE OF CONTENTS This chapter discusses the details of the Global Positioning System (GPS) signal structure, its specifications, and general properties. The chapter begins with a review of the general performance objectives and quantitative requirements of the signal. Because the GPS signal falls into a broad category of signals known as spread spectrum signaling, the fundamentals of spread spectrum signaling are introduced. The chapter continues with a detailed description of the GPS signal structure for both the precision (P code) and civil coarse/acquisition (C/A code) signals. The various minor distortions and imperfections permitted by the GPS satellite user interface specification are also discussed. Although the general format of the navigation data is summarized, details of the navigation message are given in the next chapter. The radio frequency signal levels and relevant signal-to-noise ratios are discussed next. The chapter concludes with a discussion of the signal performance characteristics including: 1) C/A- and P-code cross-correlation properties for multiple access, and 2) performance bounds on the C/A- and P-code pseudorange tracking accuracy for the optimal delay-lock loop tracking receivers.
A brief summary of Galois fields that are the mathematical basis for maximal length and Gold sequences is given in the Appendix.
Based on the navigation accuracy and system requirements and the relevant physics/communication theory discussed in the previous chapter, the system level accuracy requirements can now be stated and translated into signal measurement accuracy...
