GPS Navigation data structure

 

▷Navigation Data Structure

 - Navigation data is modulo 2 added to P and C/A codes at 50 bps.

 - Each data frame requires 30 sec for transmission and consists of five 300 bit subframes.

 - Subframe 1 contains clock correction parameters and special data.

 - Subframe 2 and 3 contain precise SV ephemeris data.

 - Subframe 4 contains special message data.

 - Subframe 5 contains constellation almanac data.

 - Subframe 4 and 5 consist of 25 pages of data.

12.5 minutes are required for complete reception of subframes 4 and 5.