複雑地形照合航法によるAUVの自己位置推定

抄録

AUVs (Autonomous Underwater Vehicles) are attracting attention as a new bottom survey platform for diverse purposes. Due to the fact that AUVs operate underwater, localization is one of the most fundamental issues to be addressed. Although TAN (Terrain-aided Navigation) has been gaining attention as a self-contained localization method, most of the current TAN approaches require high-end navigational devices and observational payloads. This makes it difficult for TAN to be employed in a wide variety of AUVs, especially in compact-class AUVs. In this research, we propose a new TAN approach that can be implemented with the most basic navigational devices. Moreover, our approach presents a method that can resolve TAN's vulnerability to terrain monotonicity. In this method, the initial vehicle position at which localization is conducted is determined based on the results of a preliminary survey on known terrain information. Around this initial position, the vehicle continues steady turning maneuvers while our localization is ongoing. To verify the effectiveness of our approach, we conducted simulations by using actual sea bottom bathymetry information and AUV navigation data. The simulation results showed that our approach can provide localization accuracy equivalent to that of conventional USBL (Ultra-short Baseline)-based acoustic position fixing, and that in our approach, the pre-survey phase gives a significant impact on localization accuracy.