GALILEO - Understanding GPS: Principles and Applications - page 573

1191.795-MHz carrier frequency

Reference 10.23 MHz

× 116.5

50-Hz symbol clock

÷ 204600

E5a
data
message

50 sps

Interleaving
and
UW Insertion

Add
CRC

Add tail
bits

FEC
Encoding

d E5a (t)

1 kHz Clock

÷ 10230

20-bits
secondary
code

R c,E5a-d Mcps

E5a-d
Code generator

c E5a-d (t)

E5a
Data channel

100-bits
secondary
code

COS

c E5a-p (t)

R c,E5a-p Mcps

E5a-p
code generator

cos(k. /4)

π

E5a
Pilot channel

X

+

Look-up
table

+

250 Hz Sym bol Clock

−

SIN

E5 signal

E5b
data
message

Interleaving k {1,...8}

250 sps

∈

Add Tail
bits

FEC
Encoding

Add
CRC

and sin(k. /4)

π

UW Insertion

X

1 kHz Clock

d E5b (t)

10230 ÷

4-bits
secondary
code

R c,E5b-d Mcps

d E5b-d (t)

E5b-d
code generator

E5b
Data channel

100-bits
secondary
code

d E5b-p (t)

R c,E5b-p Mcps

E5b-p
code generator

E5b
Pilot channel

Counter
1..8

AltBOC(15,10) Subcarrier frequency

÷ (2/3)

Reset

Figure 10.4 Possible AltBOC modulation implementation scheme.