Title: Integration of Code-Based Precise Point Positioning and Reduced Inertial Sensor System
Author(s): Ibrahim E. Hassan, Tashfeen B. Karamat, Ahmed El-Rabbany, Aboelmagd Noureldin
Published in: Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016)
September 12 - 16, 2016
Oregon Convention Center
Portland, Oregon
Pages: 1214 - 1221
Cite this article: Hassan, Ibrahim E., Karamat, Tashfeen B., El-Rabbany, Ahmed, Noureldin, Aboelmagd, "Integration of Code-Based Precise Point Positioning and Reduced Inertial Sensor System," Proceedings of the 29th International Technical Meeting of The Satellite Division of the Institute of Navigation (ION GNSS+ 2016), Portland, Oregon, September 2016, pp. 1214-1221.
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Abstract: In Global Positioning System (GPS), Precise Point Positioning (PPP) achieves the highest accuracy in point positioning. It approaches centimeter-level accuracy in static mode and sub-decimeter accuracy in kinematic mode. PPP is an alternative approach to carrier-phase-based Differential GPS (DGPS) and offers advantages over DGPS. PPP uses GPS observations from a single receiver for position estimation, which is simpler than using multiple GPS receivers. However, PPP needs rigorous modelling for all errors and biases, which are otherwise cancelled out or mitigated when using DGPS. PPP’s popularity is on the rise, as it is ideal for land-vehicle positioning and navigation. However, in challenging environments, PPP suffers from a signal loss that prevents continuous navigation and reduction in the number of visible satellites that causes accuracy degradation. This research integrates PPP with a Reduced Inertial Sensors System (RISS) — a low-cost system that uses data from reduced MEMS-based inertial sensors and vehicle odometry to provide continuous and inexpensive land-vehicle navigation systems. The system is integrated in a tightly coupled mode through the use of an Extended Kalman Filter (EKF), which employs an improved error model for the RISS data. The system was tested using data from real driving routes with single-frequency code-based PPP/RISS (SF-code-PPP/RISS), dual-frequency code-based PPP (DF-code-PPP/RISS), and smoothed dual-frequency code-based PPP (SDF-code-PPP/RISS). The performance of the developed PPP/RISS was evaluated using position RMS and maximum errors during continuous GPS availability as well as during signal outages. The developed integrated algorithms were assessed using real road test that capture different navigational conditions. The results show that when five or more satellites are available, SDF-code-PPP/RISS solution is superior to that of SF- and DF-code-PP/RISS. For latitude, SDF-code-PPP/RISS solution was 20% and 13% more precise than the SF- and DF-code-PP/RISS counterparts, respectively. For longitude, SDF-code-PPP/RISS solution was 34% and 16% more precise than the SF- and DF-Code-PP/RISS counterparts, respectively. Similarly, the altitude solution was improved by 49% and 15%, respectively. During GPS signal outages of 60 seconds, SDF-code-PPP/RISS’s algorithms outperformed that of SF- and DF-code-PPP/RISS by about 20% when the satellite availability level was set to three satellites.