In comparison with prior encryption-mode receivers, a receiver according to this invention offers greater signal-to-noise ratios for the L1 and L2 P signals, and greater precision in the phases and delays of these signals. Unlike the prior receivers, this receiver offers the capability for separate and independent tracking of the L1 and L2 P signals to eliminate fading crossover, separate and independent measurement of the L1 and L2 P amplitudes, the option of dual-band measurements without a separate L1 P channel, removal of a half-cycle ambiguity in the L2 P phase, and the option of operation in either the code mode or the encryption mode with maximum commonality of hardware and software between modes. Finally, this processing method would still work even if the L1 and L2 P codes were to be encrypted with different A codes.

This work was done by Lawrence Young, Thomas Meehan, and Jess B. Thomas of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at under the Information Sciences category.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to

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Refer to NPO-30367, volume and number of this NASA Tech Briefs issue, and the page number.