Satellite Signal Acquisition, Tracking, and Data Demodulation - Understanding GPS: Principles and Applications - page 213

X1A = Remainder[X1 / 4092]
Zslip=Z*37
X2 = X1 Zslip
If X2 < 0 Then X2 = X2 + 15,345,037

−

End of week

Yes Z = 403,199 AND

X1 > 15,339,838

Yes

No

X1 > 15,340,907

End of X1 cycle

Yes

X1 > 15,340,563

X1B=X1A+1
X2A = X1A
X2B = X1B

No

No

X1 > 15,340,907

No

End

Set D1B Flag

Yes

Yes

X1 > 15,340,563

Set D1B Flag

No

X1B = Remainder[X1 / 4093]

X1B=X1A+1

Yes

X1 > 15,339,941

Yes

Set D2B EOW

X2 > 15,344,655

X2=X2
X2A = Remainder[X2 / 4092]
X2B=X2A+1

No

Set D2A EOW

End

Yes

X2 > 15,340,907

No

X1B = Remainder[X1 / 4093] Set D2A Flag

Yes

X2 > 15,340,563

Set D2B Flag

No

X2A = Remainder[X2 / 4092]
X2B = Remainder[X2 / 4093]

End

Figure 5.32 Flowchart of P code setter algorithm.

navigation solution has converged. Under certain jamming conditions, it may be
impossible to acquire the C/A code but possible to acquire P(Y) code. Then, direct
P(Y) code acquisition is essential. This is possible only if the navigation state has
sufficient position, velocity, and time precision, plus the ephemeris data for all SVs
to be acquired, or this information is transferred to the receiver by an operating host