Controlled access satellite navigation receiver
First Claim
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1. A controlled access satellite navigation receiver comprising:
- a secret code segment memory that stores segments of a secret code to be transmitted by a satellite in the future;
a correlator that correlates signals received from the satellite with secret code segments retrieved from the memory; and
,a position filter that estimates position intermittently based on pseudoranges computed from secret code segment correlations.
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Abstract
A controlled access satellite navigation receiver has only incomplete knowledge of secret codes transmitted by satellites. This incomplete knowledge allows only intermittent position determination. Incomplete secret codes and the intermittent positions they provide are useful for authenticating navigation signals or controlling access to secret satellite services.
17 Citations
19 Claims
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1. A controlled access satellite navigation receiver comprising:
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a secret code segment memory that stores segments of a secret code to be transmitted by a satellite in the future; a correlator that correlates signals received from the satellite with secret code segments retrieved from the memory; and
,a position filter that estimates position intermittently based on pseudoranges computed from secret code segment correlations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a controlled access satellite navigation receiver comprising:
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receiving a signal from a satellite; demodulating and sampling the signal to convert it to digital form; correlating the signal against a secret code segment; and
,computing secret pseudoranges from the secret code segment correlation. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification