Abstract Low-cost real-time kinematic (RTK) receivers exhibit weaker resistance to multipath effects, leading to a significant decline in single point positioning (SPP) performance in remote ocean environment. We comprehensively analyze the impact of carrier phase smoothing multipath reduction algorithm on the performance of low-cost RTK receivers in remote ocean environment. The results show that the multipath effects on RTK receivers in remote ocean environment are 2~3 times greater than that in land environment, with the strongest resistance observed at E5 frequency. The effectiveness of smoothing multipath reduction is related to pseudorange multipath effects. After using smoothing multipath reduction algorithm, the SPP accuracy of RTK receivers improves by 62% in remote ocean environment and 24% in land environment. The SPP accuracy of GPS/Galileo/BDS-3 multi-systems is superior to 1 meter, meeting the precision requirements for fine ocean operations.