GNSS Multifrequency Joint Code Tracking Loop With Dynamic Inter-Frequency Bias Estimation and Compensation

The joint reception of global navigation satellite system (GNSS) multi-frequency signals can enhance loop tracking accuracy and robustness, particularly in challenging environments. However, dynamic inter-frequency bias (IFB) exists between the code delays of different frequency bands, disrupting coherence and degrading tracking performance. Existing methods typically treat IFB as prior information for compensation, restricting the adaptability and practical deployment of multi-frequency reception technologies. This paper proposes a multi-frequency joint code tracking loop architecture that tracks and compensates for dynamic IFB, without relying on ionospheric delay models or other prior information. The proposed method is fully compatible with standard tracking architectures, enabling seamless integration into existing GNSS receivers. To validate its effectiveness, theoretical analyses are conducted, including thermal noise jitter calculation formula and dynamic stress response characteristics. Monte Carlo simulations are performed using Global Positioning System (GPS) L1 C/A and L5 signals to validate the theoretical model. Real-world data experiments confirm that the proposed loop significantly enhances L1 positioning accuracy in urban environments, achieving up to 78.4% improvement over the standard tracking loop (STL).