Patent ID: 8068534
Filing Date: 2011-11-29
Classification: H04B

Abstract:
1. A method comprising the steps of: receiving via a first receiver a first signal that is composed of a plurality of signals where A i and B i are amplitude constants pertaining to signal from satellite i, D i (t) is data signal from satellite i, superscript A designating signals of said first receiver, τ i is transit delay from satellite i to said first receiver, x i,C (t) is a first code signal from satellite i, x i,Y (t) is a second code from satellite i, which is at least nearly orthogonal to the first code, cos(2π(f i,L1 +f i,D )t+φ i ) is a carrier signal from satellite i of frequency f i,L1 that experiences a Doppler shift of f i,D during transit from the satellite to the first receiver, and arrives at the first receiver with a phase shift of φ i , and sin(2π(f i,L1 +f i,D )t+φ i ) is a signal that is orthogonal to the cos(2π(f i,L1 +f i,D )t+φ i ) carrier signal; where x i,C (t) is publicly known, and x i,Y (t) is adapted to be publicly unknown; receiving via a second receiver a second signal that is composed of a plurality of signals signal that contains a second unknown signal which communicates information that is different from, but related to, the information communicated by the first unknown signal, superscript B designating signals of said second receiver; and processing the first signal and the second signal to authenticate an assertion that at least a subset of said plurality of signals of which signal S