A Simulation method for USBL Localization Performance Analysis using a Stereo Array

To measure the trajectory of underwater vertical motion vehicle and estimate its localization performance, a stereo array ultra-short baseline(USBL) positioning model was presented, and the corresponding simulation algorithm was established for accuracy analysis. The time delay and time delay difference were used as measurement elements to solve the target location based on a time synchronization system. In the simulation test, the localization performance using the planar array and the stereo array was compared, the results showed that both arrays had high-precision performance in horizontal, while in vertical the stereo array was proved to be superior than the planar array by forming a equivalent baseline parallel to Y axis. The root mean square error (RMSE) of the planar array and the stereo array was changing with range and depth. When the baseline length was 0. 25m in horizontal and 0. 15m in vertical and the time delay difference error was 0.5 $\mu$s, the RMSE based on a stereo array was 0. 16m at the range of 50m which was the half of that based on a planar array, and it increased to 0. 30m at the range of 100m which was a quarter of that based on a planar array. So this method provides a technical way to estimate the measurement system performance in underwater vertical motion vehicle design and test.