As the 25th solar cycle is approaching its peak, the Real-time Kinematic (RTK) positioning performance is significantly affected by solar activity and the ionosphere. This study focuses on a triangulation network in the Hong Kong region with baseline lengths ranging from 10 to 20 km. The rover station is located at a distance of 16 km from the nearest reference station. A complete dataset spanning the entire solar activity cycle from 2013 to 2023 was collected for analysis. Virtual observations of the rover station’s position were generated using Network RTK (NRTK) processing mode. The results show that during years of low solar activity, the overall fixing rate exceeds 80%. However, in years of high solar activity, the fixing rate exhibits a noticeable correlation with local time, reaching its lowest point at around 16:00 local time, dropping to approximately 66%. In years of low solar activity, the horizontal and vertical accuracy, with a 95% confidence level, remain below 5 cm and 10 cm, respectively. In contrast, during years of high solar activity, the accuracy deteriorates to 7.5 cm and 13 cm in the horizontal and vertical direction. In addition, as the Vertical Total Electron Content (VTEC) increases, the RTK positioning performance gradually declines. On the other hand, with the increase of Rate of TEC Index (ROTI), the RTK positioning performance deteriorates rapidly.