IEEE Access (Jan 2024)
GNSS Urban Positioning With Multipath Mitigation Using Duration Time of Time-Differenced Code-Minus-Carrier
Abstract
The demand for various emerging navigation-based technologies, particularly for autonomous and unmanned systems, has increased recently, requiring accurate and robust positioning performance to support these systems. While the global navigation satellite system is a key technology that can meet these demands, it faces significant challenges in urban areas due to multipath errors caused by tall buildings and signal obstructions. This study proposes a method for achieving precise absolute navigation in urban areas, even for users of low-cost, single-frequency receivers. To overcome these challenges, the proposed method utilizes the characteristics of multipath errors to ensure accurate navigation. As users move through urban areas, multipath errors tend to fluctuate and may cause frequent signal loss. The introduction of the “duration time” concept enables users to quickly select measurements with relatively small multipath errors based on the characteristics of multipath errors. Users can mitigate multipath errors by utilizing selected measurements and achieve more stable position estimation. By introducing duration time into time-differenced code-minus-carrier measurements and successfully selecting measurements using duration time, we confirmed that the navigation accuracy in urban areas can be improved. Field tests were conducted in an urban environment to verify the enhanced navigation performance of the proposed system. Hence, standalone navigation achieved meter-level performance, and integrated navigation combined with Doppler measurements achieved decimeter-level performance. This demonstrates that the proposed methods can mitigate position jumps caused by multipath errors in urban areas, ensuring stable position estimation performance.
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