Patent ID: 8050309

Claim:
A multipath discriminator module for a communications and/or navigation system that implements spread spectrum modulation, wherein the module has an input suitable for receiving navigation signals, a sampler for supplying sampled signals at a frequency twice the apparent frequency (fc) of a code of said navigation signals, and a submodule for calculating an error signal (e k ) from said sampled signals (r k+1/2 ), and a locally generated spreading code (C |K|L ) wherein: e k = K β ⁢ ℛ ⁡ ( Z κ -- Z κ - + S ⁢ ⁢ β ) ⁢ with ⁢ ⁢ { Z κ - = [ r k · t ⁢ ⁢ 2 · C  K  ⁢ L ] ⊗ h k b Z κ -- = [ r k · t ⁢ ⁢ 1 · C  K  ⁢ L ] ⊗ h k b ⁢ ⁢ ⁢ or ⁢ ⁢ { Z κ - = [ r k · C  K - t ⁢ ⁢ 2  ⁢ L ] ⊗ h k b Z κ -- = [ r k · C  K - t ⁢ ⁢ 1  ⁢ L ] ⊗ h k b “K β ”=constant “h k b ” designating the impulse response of a lowpass filter “Z K ” designating a signal sample “ (x)” designates a real portion of an operand x and ⁢ ⁢ S β = - g ⁡ ( - t ⁢ ⁢ 1 ⁢ Tc ) g ⁡ ( - t ⁢ ⁢ 2 ⁢ Tc ) ⁢ ⁢ ⁢ with ⁢ ⁢ g ⁡ ( aTc ) = Sin ⁢ ⁢ Π ⁢ ⁢ a ⁢ ⁢ Cos ⁢ ⁢ Πβ ⁢ ⁢ a π ⁢ ⁢ a ⁡ [ 1 - ( 2 ⁢ βa ) ] “β” designating the attenuation factor of the SRC signal “Sβ” is an offset “Tc” designating a duration of one bit of a pseudo-noise sequence “t1” is a first sampling instant and “t2” is a second sampling instant.