| Popis: |
This chapter describes the structure of Global Positioning System signals. On each of two frequencies, there is a carrier signal, and this is modulated by ranging code(s), as well as data. The two ranging codes are coarse/acquisition (C/A) and P(Y) codes. These are PRN bit sequences. Each satellite uses a different C/A code and a different P(Y) code so that a receiver can identify which satellite a signal is being transmitted from. The coarse/acquisition code is used for the Standard Positioning Service whereas the P(Y) code is used for the Precise Positioning Service. The data is used for navigation. It is referred to as the navigation message. It is made of several items of data, including satellite ephemeris. |
