Accession Number : ADA258974


Title :   Acquisition of Direct Sequence Spread Spectrum Signals using Digital Signal Processing Techniques


Descriptive Note : Master's thesis


Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING


Personal Author(s) : Schmitz, Ronald E


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258974.pdf


Report Date : Dec 1992


Pagination or Media Count : 141


Abstract : This thesis investigates the use of digital signal processing (DSP) techniques to achieve initial synchronization with Global Positioning System (GPS) Pseudo-Noise (PN) signals. Synchronization with the transmitted PN signal is essential to the despreading of the transmitted Direct Sequence Spread Spectrum (DS/SS) signals and decoding of the transmitted satellite data. The use of DSP methods to decrease the time required to achieve initial synchronization is investigated. This thesis proposes an initial acquisition section of the GPS receiver and derives the equations to show the method is mathematically feasible. Computer simulations of the proposed receiver using received signals corrupted by Doppler shifts and noise and having various code offsets, show that coarse acquisition of GPS signals can be achieved using DSP methods. However, the correlation of the sequences is distorted by zero padding to allow the use of radix-2 FFTs. This distortion can be accounted for and proper coarse acquisition is still achieved.


Descriptors :   *SIGNAL PROCESSING , *DATA ACQUISITION , *SYNCHRONIZATION(ELECTRONICS) , *SPREAD SPECTRUM , *FAST FOURIER TRANSFORMS , INPUT , SIMULATION , GLOBAL , ACQUISITION , COMPUTERS , PROCESSING , THESES , DECODING , DISTORTION , EQUATIONS , NOISE , SEQUENCES , TIME , CORRELATION , SIGNALS , GLOBAL POSITIONING SYSTEM , RECEIVERS , ARTIFICIAL SATELLITES


Subject Categories : Electrical and Electronic Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE