Global Positioning System Reference
In-Depth Information
with
1
22
[
]
(
)
(
)
()
()
()
()
t
t
t
s t
=
⋅
s
t
+
js
⋅
t
⋅
sc
t
−
jsc
⋅
tT
−
4
x
x
x
E
5
Ead
5
-
Eap
5
-
Ed
5
-
Ed
5
-
sc
⋅
E
5
1
22
(
)
[
]
(
)
()
()
()
t
t
+
⋅
s
t
+
js
⋅
t
⋅
sc
t
−
jsc
⋅
tT
−
4
x
x
sc
Ebd
5
-
Ebp
5
-
Ed
5
-
E
5
-
d
⋅
E
5
1
22
(
)
[
]
(
)
()
()
()
t
t
+
⋅
s
t
+
js
⋅
t
⋅
sc
t
−
jsc
⋅
tT
−
4
x
x
Ep
5
-
Ep
5
-
sc
Ead
5
-
Eap
5
-
⋅
E
5
1
22
[
]
(
)
(
)
()
()
()
t
t
+
⋅
s
t
+
j
⋅
s
t
⋅
sc
t
−
j
⋅
sc
t
−
T
4
x
x
Ep
5
-
Ep
5
-
sc
E
Ebd
5
-
Ebp
5
-
⋅
5
where the useful signal components are:
t
=
the E5a-d signal component
s
()
t
=
dt
()
⋅
c
()
t
x
5
Ead
-
Ea
5
Ead
5
-
t
s
()
t
=
c
()
t
=
the E5a-p signal component
x
5
Eap
-
Eap
5
-
t
s
()
t
=
d
()
t
⋅
c
()
t
=
the E5b-d signal component
x
5
Ebd
-
Eb
5
Ebd
5
-
t
s
()
t
=
c
()
t
=
the E5b-p signal component
x
5
Ebp
-
Ebp
5
-
t
x
t
x
t
x
The respective dashed signal components
s
5-
(),
s
t
5-
(),
s
t
5-
(), and
t
Ead
Eap
Ebd
t
x
s
5-
(), are product signals according to the following equations:
t
Ebp
()
()
()
()
t
t
t
t
s
t
=
s
t
⋅
s
t
⋅
s
t
x
x
x
x
Ead
5
-
Eap
5
-
Ebd
5
-
Ebp
5
-
()
()
()
()
t
t
t
t
s
t
=
s
t
⋅
s
t
⋅
s
t
x
x
x
x
Eap
5
-
Ead
5
-
Ebp
5
-
Ebd
5
-
()
()
()
()
t
t
t
t
s
t
=
s
t
⋅
s
t
⋅
s
t
x
x
x
x
Ebd
5
-
Ebp
5
-
Ead
5
-
Eap
5
-
()
()
()
()
t
t
t
t
s
t
=
s
t
⋅
s
t
⋅
s
t
x
x
x
x
Ebp
5
-
Ebd
5
-
Ead
5
-
Eap
5
-
5-
()are the four-level subcarrier functions used
for the AltBOC modulation and represented in Figure 10.3:
The parameters
sc
t
Ed
5-
()and
sc
t
Ep
8
(
)
()
∑
sc
t
=
a
⋅
rect
t
−
k T
⋅
8
Ed
5
-
k
T
sc
sc
E
E
5
5
k
1
8
(
)
()
∑
sc
t
=
b
⋅
rect
t
−
k T
⋅
8
Ep
5
-
k
T
sc
sc
E
E
5
5
k
1
with
T
sc
E
5
being the E5 subcarrier period and coefficients
a
k
and
b
k
according to
Table 10.5.
The relative sharing of the total useful power in E5 among the four signal chan-
nels is as shown in Table 10.6.
At reception, the multiplexing adopted for the transmission of the E5a and E5b
signals allows three alternative receiver implementations and processing:
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