US 2012/0057658 A1Published application

Authenticating a Signal Based on an Unknown Component Thereof

OwnerPeter Levin, David S. De Lorenzo +2inventors

InventorsPeter Levin, David S. De Lorenzo, Per K. Enge, Sherman C. Lo

Life of this patent

Estimating the term…

Abstract

Authentication of a signal, signalA, 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, signalB, where signalB contains an unknown signal that is unique to the source, and determining that signalA contains the same unknown signal that is contained in signalB.

Claims16

Dependent claims

A method executed in a first receiver comprising the steps of:

receiving a signal SreceivedA 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
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(
f
L
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+
f
i
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}
where
αiA is equal to AiADi(t−τiA)xi,C(t−τiA),
βiA is equal to BiADi(t−τiA)xi,Y(t−τiA),
cos(2π(ƒL1+ƒi,DA)t+φiA) and Sin(2π(ƒL1+ƒi,DA)t+φiA) are carrier signals from satellite i at a frequency that is substantially equal to ƒi,L1, which experience a Doppler frequency shift of ƒi,D during transit from satellite i to said first receiver, and arrive at the first receiver with a phase shift of φi,
AiA and BiA are amplitude constants pertaining to signals A, and B, that are outputted by satellite i,
Di(t) is data signal that is outputted by satellite i,
riA is transit delay from satellite i to said first receiver,
xi,C(t) is a publicly known first code signal from satellite i, and
xi,Y(t) is a second code from satellite i that is publically not known,
developing, from signal SreceivedA, 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
ƒi,xA=ƒIF+ƒi,DA or ƒi,xA=ƒi,DA−{circumflex over (ƒ)}i,DA,
ƒIF is a preselected intermediate frequency, {circumflex over (ƒ)}DA is an approximation of ƒDA, and
γiA is a phase shift;
and
communicating to a computing module the processed signal for said one or more preselected time intervals.

148 more elements

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 SreceivedA 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
αiA is equal to AiADi(t−τiA)xi,C(t−τiA),
βiA is equal to BiADi(t−τiA)xi,Y(t−τiA),
cos(2π(ƒL1+ƒi,DA)t+φiA) and Sin(2π(ƒL1+ƒi,DA)t+φiA) are carrier signals from satellite i at a frequency that is substantially equal ƒi,L1, which experience a Doppler frequency shift of ƒi,D during transit from satellite i to said first receiver, and arrive at the first receiver with a phase shift of φi,
AiA and B1A are amplitude constants pertaining to signals Ai and Bi that are outputted by satellite i,
Di(t) is data signal that is outputted by satellite i,
τiA is transit delay from satellite i to said first receiver,
xi,C(t) is a publicly known first code signal from satellite i, and
xi,Y(t) is a second code from satellite i that is publicly not known,
said processing unit develops, from signal SreceivedA, 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
ƒi,xA=ƒIF+ƒi,DA or ƒi,xA=ƒi,DA−{circumflex over (ƒ)}i,DA,
ƒIF is a preselected intermediate frequency, {circumflex over (ƒ)}DA is an approximation of ƒDA, and
γiA is a phase shift;
and
said processing unit communicates to a computing module the processed signal for said one or more preselected time intervals.

152 more elements

Dependencies are inferred from the claim text.

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Abstract