A novel inverted ultra-short baseline based on acoustic frequency combs for AUV self-positioning

Abstract Motivated by the comprehensive achievements of autonomous underwater vehicle (AUV) in cooperative networking for ocean detection and observation, underwater positioning technology, which is one of the key technologies for AUV spatio-temporal measurements, has been put forward with higher requirements on multi-user, autonomous perception, and low-cost. In this paper, an inverted ultra-short baseline (iUSBL) scheme is proposed, and acoustic frequency combs (AFCs) are applied to underwater positioning for the first time. Four-way orthogonal AFCs with distinctive time–frequency features, high peak power, and high detectability are designed as broadband response signals, which are emitted separately from the four transducers of the iUSBL deployed on the seabed. Under the premise of time synchronization between the AUV and the underwater station, the one-way travel time (OWTT) and phase information of each received AFC responses signal are extracted through matched filtering and Fourier transform at the AUV node equipped with a single hydrophone. Finally, the iUSBL positioning method aided by the high-precision AFC distance measurement is adopted to achieve self-positioning. The results of the experiment in the practical environment proved that this low-cost system can realize self-positioning for AUVs with less than 1% slant range error.