Performance Analysis on Carrier Phase-Based Tightly-Coupled GPS/BDS/INS Integration in GNSS Degraded and Denied Environments
Open Access
- 14 April 2015
- Vol. 15 (4), 8685-8711
- https://doi.org/10.3390/s150408685
Abstract
The integration of Global Navigation Satellite Systems (GNSS) carrier phases with Inertial Navigation System (INS) measurements is essential to provide accurate and continuous position, velocity and attitude information, however it is necessary to fix ambiguities rapidly and reliably to obtain high accuracy navigation solutions. In this paper, we present the notion of combining the Global Positioning System (GPS), the BeiDou Navigation Satellite System (BDS) and low-cost micro-electro-mechanical sensors (MEMS) inertial systems for reliable navigation. An adaptive multipath factor-based tightly-coupled (TC) GPS/BDS/INS integration algorithm is presented and the overall performance of the integrated system is illustrated. A twenty seven states TC GPS/BDS/INS model is adopted with an extended Kalman filter (EKF), which is carried out by directly fusing ambiguity fixed double-difference (DD) carrier phase measurements with the INS predicted pseudoranges to estimate the error states. The INS-aided integer ambiguity resolution (AR) strategy is developed by using a dynamic model, a two-step estimation procedure is applied with adaptively estimated covariance matrix to further improve the AR performance. A field vehicular test was carried out to demonstrate the positioning performance of the combined system. The results show the TC GPS/BDS/INS system significantly improves the single-epoch AR reliability as compared to that of GPS/BDS-only or single satellite navigation system integrated strategy, especially for high cut-off elevations. The AR performance is also significantly improved for the combined system with adaptive covariance matrix in the presence of low elevation multipath related to the GNSS-only case. A total of fifteen simulated outage tests also show that the time to relock of the GPS/BDS signals is shortened, which improves the system availability. The results also indicate that TC integration system achieves a few centimeters accuracy in positioning based on the comparison analysis and covariance analysis, even in harsh environments (e.g., in urban canyons), thus we can see the advantage of positioning at high cut-off elevations that the combined GPS/BDS brings.Keywords
This publication has 26 references indexed in Scilit:
- Integer estimation methods for GPS ambiguity resolution: an applications oriented review and improvementSurvey Review, 2012
- Contribution of the Compass satellite navigation system to global PNT usersChinese Science Bulletin, 2011
- An Integration of GPS with INS Sensors for Precise Long-Baseline Kinematic PositioningSensors, 2010
- Analysis of long-range network RTK during a severe ionospheric stormJournal of Geodesy, 2005
- An integer ambiguity resolution procedure for GPS/pseudolite/INS integrationJournal of Geodesy, 2005
- On Improving Navigation Accuracy of GPS/INS SystemsPhotogrammetric Engineering & Remote Sensing, 2005
- Influence of Dynamics and Trajectory on Integrated GPS/INS Navigation PerformanceThe Journal of Global Positioning Systems, 2003
- Real-time differential carrier phase GPS-aided INSIEEE Transactions on Control Systems Technology, 2000
- Stochastic Modeling for Real-Time Kinematic GPS/GLONASS PositioningNAVIGATION: Journal of the Institute of Navigation, 1999
- GPS error modeling and OTF ambiguity resolution for high-accuracy GPS/INS integrated systemJournal of Geodesy, 1998