Underwater Real-Time Heading Determination Method by Using a Dual-Beacon Design of Ultrashort Baseline (USBL) Acoustic Positioning

Heading information has been an essential part of navigation for underwater vehicles. This article proposes a method for determining underwater real-time heading by using a dual-beacon design of ultrashort baseline (USBL) acoustic positioning. The dual-beacon design with a fixed baseline is installed on the underwater vehicle, and the heading can be determined by the geometric relationship of the dual-beacon design in the Earth-north-up (ENU) coordinate. Simulation experiments show that the heading accuracy is affected by various factors, such as beam incident angle, ranging accuracy, azimuth measurement accuracy, calibration accuracy of installation errors, and baseline length. Among them, the heading determination performance is more sensitive to the azimuth measurement accuracy. When the azimuth measurement accuracy increases from 0.02° to 0.2°, the heading accuracy decreases more than six times. Then, the performance of the proposed method is evaluated through real underwater experiments. The results show that when the baseline length is 10 m and the maximum slant range is 200 m, the heading accuracy reaches 4.73°. Therefore, the proposed method can achieve high-precision and long-duration underwater heading determination capabilities.