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Pseudorandom noise ranging receiver which compensates for multipath distortion by making use of multiple correlator time delay spacing

  • US 5,414,729 A
  • Filed: 11/29/1993
  • Issued: 05/09/1995
  • Est. Priority Date: 01/24/1992
  • Status: Expired due to Term
First Claim
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1. A receiver for demodulating and decoding a composite radio frequency (RF) signal consisting of a plurality of transmitted pseudorandom noise (PRN) encoded signals comprising:

  • an RF downconverter, connected to receive the composite RF signal and to provide a composite intermediate frequency (IF) signal;

    means for generating a local sample clock signal;

    a sampling circuit, connected to receive the composite IF signal and the local sample clock signal, and to provide digital in-phase (I) samples and quadrature (Q) samples of the composite IF signal;

    a plurality of channel circuits, each channel circuit for demodulating and decoding one of the transmitted PRN encoded signals, and connected in parallel with the other channel circuits such that the each channel circuit receives the I samples and Q samples at the same time as the other channel circuits, wherein each channel circuit further comprises;

    a PRN code signal generator, connected to receive a synchronizing adjustment signal and to provide a local reference PRN code signal;

    means for decoding the I and Q sample signals, connected to receive the I samples, the Q samples, and the local reference PRN code signal, the decoding means for multiplying the I and Q samples by the local reference PRN code signal, and providing decoded I and Q samples;

    autocorrelation means, connected to receive the decoded I and Q samples, for determining the autocorrelation power level at multiple code phase delays; and

    parameter estimator means, connected to receive the autocorrelation power level at multiple code phase delays, for determining paramenters of a direct path signal to the receiver.

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