Exploiting Melbourne-Wübbena-derived wide-lane priors for BDS-2/BDS-3 multi-frequency single-epoch positioning

Reliable ambiguity resolution is critical for rapid BDS short baseline positioning and deformation monitoring. This study proposes a BDS-2/BDS-3 multi-frequency single-epoch ambiguity resolution method using wide-lane float auxiliary observations derived from Melbourne-Wübbena combinations. A linear mapping relates these observations to the multi-frequency ambiguity parameters, while a statistically consistent update refines the float ambiguity estimates and covariance matrix before the final LAMBDA search. Separate triple-frequency models are developed for BDS-2 B1I/B2I/B3I and BDS-3 B1C/B1I/B3I observations within a unified extra-wide-lane (EWL), wide-lane (WL), and narrow-lane (NL) sequential resolution framework. The method was evaluated against conventional double-differenced (DD) RTK and multi-frequency sequential resolution without MW assistance using a controlled moving platform experiment and two 24 h mining area short baseline datasets. The proposed method achieved fix rates of 99.84%, 99.89%, and 99.48% in the three moving platform periods, and 99.67% and 99.51% for the two mining area baselines. The fixed solution errors in the east (E), north (N), and up (U) directions were 0.58, 0.49, and 0.84 cm for Mine 1, and 0.74, 0.64, and 0.96 cm for Mine 2. These results indicate that the proposed approach improves the float ambiguity model and fixed solution stability under the tested conditions.