The use of low tracking loop bandwidths improves sensitivity and mitigates multipath. When applied to carrier-phase tracking, this method is analogous to using long coherent integration times. Based on this concept, we developed a receiver architecture capable of supporting phase-locked loop (PLL) bandwidth values as low as 0.1 Hz. This low bandwidth is achieved by leveraging external Doppler aiding from an inertial measurement unit (IMU) and incorporating a dedicated clock-locked loop. The IMU only needs to be stable over short time intervals. This method was analyzed via the z-transform and implemented for Global Positioning System C/A+L5Q and Galileo E1C+E5aQ signals. This approach was first tested with simulated signals and later with real-world data from the TEX-CUP measurement campaign. The results show a significant reduction in code/carrier-phase residuals and a roughly 50% improvement in positioning accuracy plus integrity compared with conventional delay-locked loop/PLL tracking when applied to a float real-time kinematic solution. Additionally, the ultra-low-bandwidth PLL observations enable the resolution of carrier-phase ambiguities for nearly 100% of epochs within the first 400 s of the TEX-CUP data sets, including those from urban areas. This paper also discusses various implementation considerations for operational deployment of this method. Keywords     «

The use of low tracking loop bandwidths improves sensitivity and mitigates multipath. When applied to carrier-phase tracking, this method is analogous to using long coherent integration times. Based on this concept, we developed a receiver architecture capable of supporting phase-locked loop (PLL) bandwidth values as low as 0.1 Hz. This low bandwidth is achieved by leveraging external Doppler aiding from an inertial measurement unit (IMU) and incorporating a dedicated clock-locked loop. The IMU...     »