Precise Attitude Determination Based on High-Rate GNSS-TDCP/INS Integration

Shuai Guo, Hongzhou Yang, and Yang Gao

Peer Reviewed

Abstract:	Accurate attitude determination is critical for a wide range of applications in autonomous navigation, aerospace, unmanned aerial vehicles (UAVs), and geodetic surveying. The traditional approaches, which rely on inertial measurement units (IMUs) or multiantenna Global Navigation Satellite System (GNSS) solutions, face challenges such as sensor drift, high costs, and limited update rates. To overcome these limitations, this study presents a high-precision attitude estimation method leveraging high-rate GNSS Time-Differenced Carrier Phase (TDCP) measurements, combined with Real-Time Kinematic (RTK) and INS tight integration for enhanced robustness. TDCP can eliminate most systematic errors, including ionospheric and tropospheric delays, satellite clock errors, and receiver clock drifts, by differencing consecutive carrier phase measurements. Unlike expensive IMU-based solutions, TDCP provides a lightweight, GNSS-only alternative for real-time attitude estimation without accumulating inertial drift. The high-rate TDCP can capture rapid angle changes, including pitch and heading in vehicle dynamics, which are often missed by conventional low-rate systems. The high sampling rate enables finer granularity in detecting angular changes, significantly improving the accuracy of heading and pitch estimation during maneuvers such as sharp turns or sudden accelerations. While TDCP excels in dynamic scenarios, it faces limitations in static or slow-moving conditions because attitude is derived from the receiver’s displacement increments between epochs. The RTK/INS tight integration algorithm is adopted to help the system maintain continuous attitude estimation even during low dynamics. The proposed algorithm offers a cost-effective, high-accuracy alternative for platforms requiring real-time attitude control without the need to apply expensive inertial systems. Field tests were conducted using a ground vehicle performing sharp turns and slow-speed maneuvers. The experimental results show that the high-rate TDCP effectively captures rapid heading and pitch changes, reducing errors during aggressive maneuvers. RTK/INS tight integration ensures uninterrupted attitude solution output, overcoming TDCP’s limitations. The root mean square (RMS) errors reach 0.226° for pitch and 0.950° for heading.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	2110 - 2120
Cite this article:	Guo, Shuai, Yang, Hongzhou, Gao, Yang, "Precise Attitude Determination Based on High-Rate GNSS-TDCP/INS Integration," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 2110-2120. https://doi.org/10.33012/2025.20253
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