US 8,019,540 B2Granted

Method and apparatus for processing navigational signals in a satellite navigation system

AssigneeEuropean Space Agency

InventorMatthias Soellner

Life of this patent

Estimating the term…

Abstract

In a method and apparatus for processing a received navigation signal x′(t) of a satellite navigation system, the received navigation signal x′(t) contains at least four navigation codes. The navigation codes are modulated by a complex BOC signal and a defined subcarrier frequency such that the resulting signal has a constant amplitude. The resulting signal is then also modulated by means of a carrier signal. The navigation signal x′(t) is demodulated and then processed by a complex correlation with at least one reference signal.

Claims6

Dependent claims

A method of determining information for determining position of a terminal based on a received modulated navigation signal of a satellite navigation system, said received modulated navigation signal containing at least four navigation codes, the received navigation signal being generated by

encoding the navigation codes in a complex binary offset carrier (BOC) signal with a defined subcarrier frequency such that a resulting encoded navigation signal has a constant amplitude, and modulating the encoded navigation signal onto a carrier signal in a second modulation to generate said modulated navigation signal to be transmitted;
said method comprising:
a satellite of said satellite navigation system transmitting said modulated navigation signal to said terminal;
said terminal receiving said transmitted modulated navigation signal and demodulating the received modulated navigation signal in order to obtain the encoded navigation signal;
generating at least one reference signal (r1, r2, r3, r4) by multiplication of one of the at least four navigation codes by a subcarrier signal, said at least one reference signal (r1, r2, r3, r4) being represented by
r
1
=
e
1
·
C
·
[
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
-
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
⁢
]
⁢
⁢
or
r
2
=
e
2
·
C
·
[
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
-
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
-
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
]
⁢
⁢
or
⁢
r
3
=
e
3
·
C
·
[
·
j
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
-
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
-
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
]
⁢
⁢
or
r
4
=
e
4
·
C
·
[
·
j
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
-
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
]
wherein e1, e2, e3, e4 correspond to one of the at least four navigation codes, fs corresponds to a subcarrier frequency of the BOC signal and C is a constant;
performing a complex correlation of the encoded navigation signal and said at least one reference signal;
determining a time offset between the navigation code in the encoded navigation signal and said at least one reference signal as a result of said complex correlation;
and
using the thus determined time offset as a basis for position determination of said terminal.

458 more elements

A method of determining information for determining position of a terminal based on a received modulated navigation signal of a satellite navigation system, the method comprising:

receiving, by the terminal from a satellite of the satellite navigation system, a modulated navigation signal, wherein the modulated navigation signal includes at least four navigation codes, and wherein the modulated navigation signal is generated by
encoding the navigation codes in a complex binary offset carrier (BOC) signal with a defined subcarrier frequency such that a resulting encoded navigation signal has a constant amplitude, and
modulating the encoded navigation signal onto a carrier signal in a second modulation;
demodulating the received modulated navigation signal in order to obtain the encoded navigation signal;
generating at least one reference signal by multiplication of one of the at least four navigation codes by a subcarrier signal;
performing a complex correlation of the demodulated encoded navigation signal and said at least one reference signal;
determining a time offset between the navigation code in the demodulated encoded navigation signal and said at least one reference signal as a result of said complex correlation;
and
using the determined time offset as a basis for position determination of said terminal.

6 more elements

Dependencies are inferred from the claim text.

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Abstract

encoding the navigation codes in a complex binary offset carrier (BOC) signal with a defined subcarrier frequency such that a resulting encoded navigation signal has a constant amplitude, and modulating the encoded navigation signal onto a carrier signal in a second modulation to generate said modulated navigation signal to be transmitted;
said method comprising:
a satellite of said satellite navigation system transmitting said modulated navigation signal to said terminal;
said terminal receiving said transmitted modulated navigation signal and demodulating the received modulated navigation signal in order to obtain the encoded navigation signal;
generating at least one reference signal (r1, r2, r3, r4) by multiplication of one of the at least four navigation codes by a subcarrier signal, said at least one reference signal (r1, r2, r3, r4) being represented by
r
1
=
e
1
·
C
·
[
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
-
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
⁢
]
⁢
⁢
or
r
2
=
e
2
·
C
·
[
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
-
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
-
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
]
⁢
⁢
or
⁢
r
3
=
e
3
·
C
·
[
·
j
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
-
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
-
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
]
⁢
⁢
or
r
4
=
e
4
·
C
·
[
·
j
·
sign
⁡
(
cos
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
-
jsign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
)
)
+
(
1
+
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
+
π
/
4
)
)
+
(
1
-
j
)
·
2
2
·
sign
⁡
(
sin
⁡
(
2
⁢
π
⁢
⁢
f
s
⁢
t
-
π
/
4
)
)
]
wherein e1, e2, e3, e4 correspond to one of the at least four navigation codes, fs corresponds to a subcarrier frequency of the BOC signal and C is a constant;
performing a complex correlation of the encoded navigation signal and said at least one reference signal;
determining a time offset between the navigation code in the encoded navigation signal and said at least one reference signal as a result of said complex correlation;
and
using the thus determined time offset as a basis for position determination of said terminal.

458 more elements