Patent ID: 7969354

Claim:
An arrangement in an environment that includes a plurality of sources, where source C i of said sources outputs a carrier modulated signal c i that includes a signal component that is modulated by a first code pertaining to source C i and a signal component that is modulated by a second code pertaining to source C i , where the first code is a known code, i=1, 2, . . . n, the arrangement comprising: a processor; a first apparatus that is configured to receive a signal S A that contains a plurality of comingled signals, where signal S i A of said plurality of comingled signals is a replica of signal c i that is altered by a Doppler frequency shift f i,D A and a time delay τ i A that are related to attributes of source C i and to global location of said first apparatus, the second code being secret to said first apparatus, index i in said first apparatus running 1, 2, . . . , n1, where n1<n, develop signal S A by processing said signal S A to at least convert said carrier signals to intermediate frequencies, where bandwidth of signal S A is not markedly lower than bandwidth of signal S A , and apply signal S A to said processor, which is geographically removed from said first apparatus; a second apparatus that includes a module that is configured to receive a signal S B comprising a second comingled plurality of signals, where signal S i B of said second plurality of comingled signals is a replica of signal c i that is altered by a Doppler frequency shift f i,D B and a time delay τ i B that are related to attributes of source C i and to global location of said second apparatus, index i in said second apparatus running 1, 2, . . . , n2, where n2<n develop signal S B by processing said signal s B to at least convert said carrier signals to intermediate frequencies, where bandwidth of said signal S B is not markedly lower than bandwidth of signal s B , and apply signal S B to said processor; where (a) said processor computes cross-correlation of signals S A ({circumflex over (f)} i,D A ) with signals S B ({circumflex over (f)} i,D B ), to obtain a set of delays δ i , i=1, 2, . . . n, and employs said set of delays to authenticate a statement relative to said first apparatus, where index i in said processor running 1, 2, . . . , n3, where n3≦n1 and n3≦n2, S A ({circumflex over (f)} i,D A ) is said signal S A that is processed to compensate for Doppler frequency shift f i,D A by an estimate of the Doppler frequency shift {circumflex over (f)} i,D A , and S B ({circumflex over (f)} i,D S ) is said signal S B that is processed to compensate for Doppler frequency shift f i,D B an estimate of the Doppler frequency shift {circumflex over (f)} i,D B , (b) from a set that consists of said first code and said second code, the arrangement generates only the first code.