US2012057658A1PendingUtilityA1
Authenticating a Signal Based on an Unknown Component Thereof
Est. expiryFeb 2, 2028(~1.6 yrs left)· nominal 20-yr term from priority
H04B 2201/70715H04B 1/707
45
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Cited by
0
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Claims
Abstract
Authentication of a signal, signal A , that is provided as having been received from a source at a first global location by comparing it to a signal that is received from the source at a second global location, signal B , where signal B contains an unknown signal that is unique to the source, and determining that signal A contains the same unknown signal that is contained in signal B .
Claims
exact text as granted — not AI-modified1 . A method executed in a first receiver comprising the steps of:
receiving a signal S received A that is substantially equal to
∑
i
=
1
j
{
α
i
A
cos
(
2
π
(
f
L
1
+
f
i
,
D
A
)
t
+
ϕ
i
A
)
+
β
i
A
sin
(
2
π
(
f
L
1
+
f
i
,
D
A
)
t
+
ϕ
i
A
)
}
where
α i A is equal to A i A D i (t−τ i A )x i,C (t−τ i A ),
β i A is equal to B i A D i (t−τ i A )x i,Y (t−τ i A ),
cos(2π(ƒ L1 +ƒ i,D A )t+φ i A ) and Sin(2π(ƒ L1 +ƒ i,D A )t+φ i A ) are carrier signals from satellite i at a frequency that is substantially equal to ƒ i,L1 , which experience a Doppler frequency shift of ƒ i,D during transit from satellite i to said first receiver, and arrive at the first receiver with a phase shift of φ i ,
A i A and B i A are amplitude constants pertaining to signals A, and B, that are outputted by satellite i,
D i (t) is data signal that is outputted by satellite i,
r i A is transit delay from satellite i to said first receiver,
x i,C (t) is a publicly known first code signal from satellite i, and
x i,Y (t) is a second code from satellite i that is publically not known,
developing, from signal S received A , signal
S
ds
A
=
∑
i
=
1
j
{
α
i
A
cos
(
2
π
(
f
i
,
x
A
)
t
+
γ
i
A
)
+
β
i
A
sin
(
2
π
(
f
i
,
x
A
)
t
+
γ
i
A
)
}
for one or more preselected time intervals, where
ƒ i,x A =ƒ IF +ƒ i,D A or ƒ i,x A =ƒ i,D A −{circumflex over (ƒ)} i,D A ,
ƒ IF is a preselected intermediate frequency, {circumflex over (ƒ)} D A is an approximation of ƒ D A , and
γ i A is a phase shift; and
communicating to a computing module the processed signal for said one or more preselected time intervals.
2 . The method of claim 1 where said step of communicating to a computing module includes communicating information about said one or more preselected time intervals.
3 . The method of claim 1 where said computing element is remote to said first receiver.
4 . The method of claim 1 , further comprising the steps of:
a second receiver, receiving a signal S received B that is substantially equal to
S
received
B
=
∑
i
=
1
j
{
α
i
B
cos
(
2
π
(
f
L
1
+
f
i
,
D
B
)
t
+
ϕ
i
B
)
+
β
i
B
sin
(
2
π
(
f
L
1
+
f
i
,
D
B
)
t
+
ϕ
i
B
)
}
where
α i B is equal to A i B D i (t−τ i B )x i,C (t−τ i B ),
β i A is equal to B i B D i (t−τ i B )x i,Y (t−τ i B ),
A i B and B i B are amplitude constants pertaining to said signals A i and B i that are outputted by satellite i, and
τ i B is transit delay from satellite i to said second receiver;
responsive to said information about said one or more preselected time intervals,
said second receiver developing, from signal S received B , signal
S
ds
B
=
∑
i
=
1
j
{
α
i
B
cos
(
2
π
(
f
i
,
x
B
)
t
+
γ
i
B
)
+
β
i
B
sin
(
2
π
(
f
i
,
x
B
)
t
+
γ
i
B
)
}
or a set of signals
S i,ds B =α i B cos(2π(ƒ i,x B ) t+γ i B sin(2π(ƒ i,x B ) t+γ i B ),
for at least i=1, 2 and 3, for said one or more preselected time intervals, where
ƒ i,x B =ƒ IF +ƒ i,D B or ƒ i,x B =ƒ i,D B −{circumflex over (ƒ)} i,D B , independent of ƒ i,x A
ƒ IF is a preselected intermediate frequency, {circumflex over (ƒ)} D A is an approximation of ƒ D A , and
γ i A is a phase shift; and
said computing element processing signal S ds A with signal S ds B for said one or more preselected time intervals, said processing including cross-correlation, to determine location of said first receiver relative to location of said second receiver.
5 . The method of claim 4 where said computing element is co-located with said second receiver.
6 . The method of claim 4 where said computing element is remote from said second receiver.
7 . The method of claim 4 where ƒ i,x A =ƒ IF −ƒ i,D A , ƒ i,x B =ƒ i,D B −{circumflex over (ƒ)} i,D B , and
where said processing signal S ds A with signal S ds B involves converting S ds A to
S
dw
A
=
∑
i
=
1
j
{
α
i
A
cos
(
2
π
(
f
i
,
z
A
)
t
+
γ
i
A
)
+
β
i
A
sin
(
2
π
(
f
i
,
z
A
)
t
+
γ
i
A
)
}
,
where
ƒ i,x A =ƒ i,D A −{circumflex over (ƒ)} i,D A.
8 . The method of claim 1 where said step of said first receiver sending to said computing element the processed signal for said one or more preselected time intervals, together with information about said one or more preselected time intervals, includes sending to said computing element an assertion pertaining to location or locations of said first receiver at said one or more preselected time intervals.
9 . An arrangement comprising
an antenna for receiving satellite signals; a processing unit that is coupled to said antenna, and means for communicating with a remote apparatus;
where
via said antenna said processing unit receives a signal S received A that is substantially equal to
∑
i
=
1
j
{
α
i
A
cos
(
2
π
(
f
L
1
+
f
i
,
D
A
)
t
+
ϕ
i
A
)
+
β
i
A
sin
(
2
π
(
f
L
1
+
f
i
,
D
A
)
t
+
ϕ
i
A
)
}
where
α i A is equal to A i A D i (t−τ i A )x i,C (t−τ i A ),
β i A is equal to B i A D i (t−τ i A )x i,Y (t−τ i A ),
cos(2π(ƒ L1 +ƒ i,D A )t+φ i A ) and Sin(2π(ƒ L1 +ƒ i,D A )t+φ i A ) are carrier signals from satellite i at a frequency that is substantially equal ƒ i,L1 , which experience a Doppler frequency shift of ƒ i,D during transit from satellite i to said first receiver, and arrive at the first receiver with a phase shift of φ i ,
A i A and B 1 A are amplitude constants pertaining to signals A i and B i that are outputted by satellite i,
D i (t) is data signal that is outputted by satellite i,
τ i A is transit delay from satellite i to said first receiver,
x i,C (t) is a publicly known first code signal from satellite i, and
x i,Y (t) is a second code from satellite i that is publicly not known,
said processing unit develops, from signal S received A , signal
S
ds
A
=
∑
i
=
1
j
{
α
i
A
cos
(
2
π
(
f
i
,
x
A
)
t
+
γ
i
A
)
+
β
i
A
sin
(
2
π
(
f
i
,
x
A
)
t
+
γ
i
A
)
}
for one or more preselected time intervals, where
ƒ i,x A =ƒ IF +ƒ i,D A or ƒ i,x A =ƒ i,D A −{circumflex over (ƒ)} i,D A ,
ƒ IF is a preselected intermediate frequency, {circumflex over (ƒ)} D A is an approximation of ƒ D A , and
γ i A is a phase shift; and
said processing unit communicates to a computing module the processed signal for said one or more preselected time intervals.
10 . The arrangement of claim 9 where said step of communicating to d computing module includes communicating information about said one or more preselected time intervals.
11 . The arrangement of claim 9 where said computing module is remote to said apparatus.
12 . The arrangement of claim 11 , further comprising:
a second receiver receiving a signal S received B that is substantially equal to
S
received
B
=
∑
i
=
1
j
{
α
i
B
cos
(
2
π
(
f
L
1
+
f
i
,
D
B
)
t
+
ϕ
i
B
)
+
β
i
B
sin
(
2
π
(
f
L
1
+
f
i
,
D
B
)
t
+
ϕ
i
B
)
}
where
α i B is equal to A i B D i (t−τ i B )x i,C (t−τ i B ),
β i A is equal to B i B D i (t−τ i B )x i,Y (t−τ i B ),
A i B and B i B are amplitude constants pertaining to said signals A i and B i that are outputted by satellite i, and
τ i B is transit delay from satellite i to said second receiver;
responsive to said information about said one or more preselected time intervals, said second receiver developing, from signal S received B , signal
S
ds
B
=
∑
i
=
1
j
{
α
i
B
cos
(
2
π
(
f
i
,
x
B
)
t
+
γ
i
B
)
+
β
i
B
sin
(
2
π
(
f
i
,
x
B
)
t
+
γ
i
B
)
}
or a set of signals
S i,ds B =α i B cos(2π(ƒ i,x B ) t+γ i B )+β i B sin(2π(ƒ i,x B ) t+γ i B ),
for at least i=1, 2 and 3, for said one or more preselected time intervals, where
ƒ i,x B =ƒ IF +ƒ i,D B or ƒ i,x B =ƒ i,D B −{circumflex over (ƒ)} i,D B , independent of ƒ i,x A
ƒ IF is a preselected intermediate frequency, {circumflex over (ƒ)} D A is an approximation of ƒ D A , and
γ i A is a phase shift; and
said computing element processing signal S ds A with signal S ds B for said one or more preselected time intervals, said processing including cross-correlation, to determine location of said first receiver relative to location of said second receiver.
13 . The arrangement of claim 9 where said computing element is co-located with said second receiver.
14 . The arrangement of claim 9 where said computing element is remote from said second receiver.
15 . The method of claim 12 where ƒ i,x A =ƒ IF −ƒ i,D A , ƒ i,x B =ƒ i,D B −{circumflex over (ƒ)} i,D B , and
where said processing signal S ds A with signal S ds B involves converting S ds A to
S
dw
A
=
∑
i
=
1
j
{
α
i
A
cos
(
2
π
(
f
i
,
z
A
)
t
+
γ
i
A
)
+
β
i
A
sin
(
2
π
(
f
i
,
z
A
)
t
+
γ
i
A
)
}
where
ƒ i,x A =ƒ i,D A −{circumflex over (ƒ)} i,D A.
16 . The arrangement of claim 9 where said step of said first receiver sending to said computing element the processed signal for said one or more preselected time intervals, together with information about said one or more preselected time intervals, includes sending to said computing element an assertion pertaining to location or locations of said first receiver at said one or more preselected time intervals.Cited by (0)
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