Global Positioning System

In this thesis, we study the effect of Rice fading on the performance of Global Positioning System (GPS) receivers. The field-theoretic foundation of pseudo-random-noise (PRN) codes, their implementation, and their use in generating unique navigation messages in the GPS receiver is reviewed. The processing of the spread-spectrum signals within the digital delay locked loop (DDLL) in the receiver is also considered. In particular, we derive numerical expressions that can be easily evaluated for the probability error and the mean-time to lose-lock, for a DDL operating in an additive white gaussian noise (AWGN) channel in the presence of Rice fading. The results obtained generalize results in the literature for the Rayleigh fading environment.

The purpose of this thesis was to study the reliability and the accuracy of GPS positioning in Palm Beach and Broward counties. By studying the predictions of DOP values using Pathfinder Office and performing some statistical analysis on theoretical GPS data using the software SAS 8.0, the conclusion was made that PDOP values not only depend on the number of available satellites, but also on their relative positions. By field testing, and comparing the recorded data with the theoretical GPS data, it was seen that non-DGPS could be rather accurate. Furthermore, it can be justified for a GPS unit to eliminate the Z coordinate measurement since vertical position errors are larger than horizontal errors, which may lead to improved accuracy. On the other hand, some 'visibility problems' were encountered while testing the GPS units under driving conditions. Different ways to compensate for this disadvantage were studied. In the end, the different features of the GPS unit were discussed and a way to improve the system was also proposed.

The purpose of this study was to explore outcomes of a GIS/GPS integration process: to (a) examine student responses to GIS and GPS inclusion in their curriculum, (b) determine whether a relationship exists between inclusion of GIS into existing K-12 curriculum and student achievement, (c) examine the effectiveness of GIS professional development for teachers, and (d) evaluate teacher perceptions of the value of integrating GIS into their existing curricula. This study was quantitative and quasi-experimental in design. The samples consisted of 1,425 students from one middle school and 62 teachers from Palm Beach County School District. Two instruments were used in this study: student surveys and teacher feedback forms. Data from the student surveys indicated that students perceive their learning is enhanced by inclusion of GIS and GPS. Data from the teacher feedback forms revealed positive perceptions of the GIS/GPS program as an integrative tool for their existing curricula and a positive assessment of the GIS professional development training. The relationship between GIS instruction and student academic achievement was evaluated, measured by FCAT reading scores and final grades in science and social studies. The findings support the constructivist theory that students learn best when actively engaged in the process. In this study standardized FCAT reading test results and science and social studies grades corroborate the students' perceptions that GIS and GPS integration enhances their learning. Study results show FCAT reading scores were higher for GIS students than for non-GIS students. The research further indicated a significant increase in FCAT reading scores for non-native English speaking GIS students and a significantly higher average science grade for non-White GIS students.