Global Positioning System Reference
In-Depth Information
Table 10.3
Distribution
of L1 Useful Power Among
Channels
Relative Signal
Power
Channel
L1P
50%
L1F-d
25%
L1F-p
25%
10.3.2.2 E6 Signal
The transmitted GALILEO E6 signal
St
E
t
x
6
()consists of three components:
•
The E6C data channel (E6C-d):
The modulating signal is the modulo-two
addition of the E6C navigation data stream
d
E
6
C
(
t
) with the E6C-d channel
PRN code sequence
c
E
6
C
-
d
(
t
). The resulting signal is binary phase shift keyed
onto the E6 carrier at 5.115
10
6
chip/s - BPSK-R(5).
•
The E6C pilot channel (E6C-p):
The modulating signal is the E6C-p channel
PRN code sequence
c
E
6
C
-
p
(
t
). This is binary phase shift keyed onto the E6 car-
rier at 5.115
×
10
6
chip/s - BPSK-R(5).
•
The E6P channel:
The modulating signal is the modulo-two addition of the
E6P navigation data stream
d
E
6
P
(
t
), the E6P channel PRN code sequence
c
E
6
P
(
t
),
and the binary E6P subcarrier
sc
E
6
P
(
t
). This is binary phase shift keyed onto the
E6 carrier with a code chipping rate of 5.115
×
10
6
chips/s and a subcarrier of
×
10.23 MHz - BOC
c
(10,5).
E6 signal components are multiplexed onto the E6 carrier signal by means of a
modified hexaphase modulation [6]. E6C signal channels are modulated onto the
in-phase component and the E6P channels are modulated on to the quadrature com-
ponent of the E6 carrier signal.
[
]
()
()
(
)
2
P
t
α
⋅
s
t
t
−
α
⋅
s
t
t
×
cos
2
π
f
t
−
x
x
x
()
E
6
E
6
ECd
6
-
E
6
ECp
6
-
E
6
t
St
=
x
[
]
E
6
()
()
(
)
t
t
t
2
P
β
⋅
s
t
+
γ
⋅
s
t
×
sin
2
π
f
t
x
x
x
E
6
E
6
E
6
E
6
EP
6
E
6
,int
where:
t
s
()
t
=
d
()
t
⋅
c
()
t
= the E6C-d signal component
x
ECd
6
-
EC
6
ECd
6
-
t
s
()
t
=
c
()
t
= the E6C-p signal component
x
ECp
6
-
ECp
6
-
t
s
()
t
=
dt
()
⋅
ct
()
⋅
sct
()
= the E6P signal component
x
EP
6
EP
6
EP
6
EP
6
()
()
()
()
t
t
t
s
6 6
= the intermodulation product that
ensures the constant envelope property of the transmitted signal
t
=
s
t
⋅
s
t
⋅
s
t
x
x
x
E
6,int
E C d
6
-
ECp
-
EP
γ
E
6
, adjust the relative power of the four compo-
nents. The values determine the distribution of the total useful power among the sig-
The coefficients,
α
E
6
,
β
E
6
, and
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