D-RTK: Real-Time Kinematic Positioning Augmented by Dual Reference Stations in Challenging Environments

Considering the vulnerability of Single-reference Real-Time Kinematic (S-RTK) in challenging environment, this study proposes a Dual-reference RTK (D-RTK) positioning strategy. D-RTK utilizes two reference stations to estimate the coordinates of one rover station, enhancing the availability and reliability over S-RTK. The mathematical model of D-RTK is derived from the established S-RTK model, with a focus on reference calibration between two baselines and baseline integration considering condition-based weight factor. The proposed strategy includes an improved integer least-squares framework suitable for dual reference stations positioning to handle the challenges of high-dimensional ambiguity resolution. The performance of D-RTK is validated through experiments in representative challenging environments: medium-long baseline and severe obstructions in deep canyons. Results demonstrate that D-RTK significantly outperforms S-RTK and conventional method with dual baselines in terms of positioning accuracy and ambiguity resolution success rate. The study concludes that D-RTK is a viable solution for low-cost users to enhance GNSS positioning performance in some environments where traditional S-RTK struggles.