GPS Software Receivers - Fundamentals of Global Positioning System Receivers: A Software Approach - page 198

FIGURE 9.6 ( continued )
(20 ms resolution). The corresponding beginning of the C/A code is at 196 (10 ms
resolution). Thus, the navigation data point at 196 is lined up with the beginning
of subframe 1. This relation can be obtained from the beginnings of the C/A
code labeled (1), (2), (3), ... and the beginnings of navigation data labeled 1,
2, 3, ... at the bottom of the figure. The corresponding data point can be found
from beginning of the C/A code as 9802893. This number 9802893 is obtained
from the tracking program. This is the beginning of the C/A code with index of
196 and obtained from the tracking program.
In Figure 9.6b the first navigation data point occurs at 7 ms and the data are
padded with 14 points at the beginning. The beginning of the subframe 1 is at
the 100th navigation data point. The beginning of the C/A code in front of the