Performance Evaluation of Kinematic PPP Using Qinertia Cloud: GPS vs. GPS+GLONASS

This study evaluates the performance of kinematic Precise Point Positioning (PPP) using the Qinertia Cloud free online service under two processing strategies: GPS-alone and combined GPS+GLONASS, in open-sky environments with negligible multipath effects. Dual-frequency GNSS observations were collected from ten well-distributed fixed stations across Libya, each observed continuously for 24 hours. Both static and kinematic processing modes were applied, with the 24-hour static PPP solution adopted as the reference for accuracy assessment The results demonstrate that both strategies provide continuous positioning solutions at the level of a few centimeters. However, the integration of GLONASS enhances positioning performance. The Root Mean Square Errors (RMSEs) in the East, North, and Height components are reduced from approximately 2.5 cm, 4 cm, and 6.5 cm for GPS-only solutions to about 2 cm, 1.5 cm, and 2 cm, respectively, when GPS and GLONASS are combined. Furthermore, the multi-constellation approach substantially decreases the proportion of gross errors - defined as errors exceeding 5 cm in the horizontal components and 10 cm in the vertical component - from 8%, 5%, and 5% to 2%, 1%, and 1% in the East, North, and Height components, respectively. Additional improvements are observed in the maximum absolute errors, which decrease from 13 cm, 22 cm, and 30 cm to 5 cm, 13 cm, and 17 cm in the respective components. Overall, the findings confirm that the Qinertia Cloud free online service can deliver reliable kinematic PPP solutions under open-sky conditions using GPS-only observations, while the inclusion of GLONASS improves accuracy and reliability, making it more suitable for high-precision kinematic applications.