Letter: Improvement of seafloor positioning through correction of sound speed profile temporal variation

Dear Editor, This letter proposes a high-precision seafloor transponder positioning method based on the correction of sound speed profile (SSP) temporal variation. In the proposed method, the ocean sound speed error is modeled as the temporal variation of a background SSP, and the linearized expression of the acoustic travel time with respect to the sound speed coefficient is derived based on the ray acoustic model. Moreover, the proposed method introduces the constraint of acoustic ranging observations between seafloor transponders and determines the weights of travel time and ranging observations using Akaike's Bayesian information criterion (ABIC) to reduce the positioning error caused by the correlation between sound speed and position parameters. The experimental results in the South China Sea show that the proposed method performs better than the global navigation satellite system-acoustic ranging combined positioning solver (GARPOS) [1], in terms of rigid distance errors and long baseline positioning accuracy.