Comparative Analysis of Commercial PPP-RTK and Network RTK Services for Urban and Suburban Vehicle-Borne Kinematic Positioning in Central Italy

This paper presents a comparative analysis of commercial Precise Point Positioning-Real Time Kinematic (PPP-RTK) and Network RTK (NRTK) services for vehicle-borne kinematic positioning in urban and suburban environments in Central Italy. The study aimed to investigate the performance of low-cost GNSS devices by employing the PPP-RTK technique, which integrates undifferenced atmospheric corrections and satellite clock corrections as well as evaluating the contribution of the IMU. The motivation is driven by the growing demand for high-precision positioning in mass-market applications such as cooperative intelligent transport systems (C-ITS) and location-based services, where low-cost GNSS equipment often fails to meet accuracy requirements. The experimental setup involved a real-world kinematic test using three navigation devices based on low-cost u-blox receivers, augmented by either a commercial PPP-RTK service or the Umbria region’s NRTK. The test track, designed to be heterogeneous in terms of satellite visibility and multipath sources, included varied environmental conditions such as tunnels, overpasses, and tree-lined avenues. Results showed that the three low-cost receivers could reach a decimetre level of accuracy in degraded environment. Moreover, PPP-RTK/IMU and NRTK provided almost identical performance while PPP-RTK was slightly worse. The contribution of the IMU has been significant, particularly in mitigating potential biases in the vertical component, thereby enhancing reliability. Additionally, the IMU has provided continuous solutions in GNSS-denied environments.