1) Week Number (1-10 bits): 10 bits symbolize the no. of present GPS week at the beginning of information transmission. Here, complete zeros signify week ”0”. This week number adds up and augments at the start of next week epoch.
2) User Range Accuracy (13-16 bits): These bits provide User Range Accuracy (URA) of the module.
3) Satellite Health (17-22 bits): The next 6 bits signify the health condition of the operating satellite module. The MSB bit out of these six-bits indicate integrity of the navigation data; i.e ’0’ = all navigation information is OK; whereas ’1’ = some or all navigation information is bad. The next 5 LSBs indicate the signal power in accordance with the codes.
4) Issue of Data & Clock (23-24 bits): The 2 MSBs are 10-bit Issue of Data & Clock (IODC) term. The IODC designates an issue no.