GPS Satellite Signal Characteristics - Understanding GPS: Principles and Applications - page 125

2 A

C/A code phase

1,575.42 MHz = carrier frequency
1.023 Mbps = clock rate
50 bps = data rate

90°

P code phase

A

1,575.42 = carrier frequency
10.23 Mbps = clock rate
50 bps = data rate

P(Y) code signal = long secure code with 50-bps data
C/A code signal = 1023 chip Gold code with 50-bps data

Lt APt Dt ( )=[ () ()]cos( t )+ 2 [ AG t D t ( ) ( )]sin( t ) ω ⊕ ω ⊕ ω 1

i 1 i i 1 i i

Figure 4.6 GPS signal structure for L1.

0 0 00 00 0 0 0

1 1 1 1

P(Y) code

50-Hz data

0

1

P(Y) code data ⊕

1 0 1 0 1 1 0 1 1 0 1 1 1

C/A code

1 0 1

50-Hz data

0 1

1 0

C/A code data

⊕

Figure 4.7 GPS code mixing with data.