Feedback error-state Kalman filter with time-delay compensation for hydroacoustic-aided inertial navigation of underwater vehicles

This article is intended as a tutorial to assist engineers who want to develop and implement low-cost underwater vehicle inertial navigation systems (INS) aided by time-delayed hydroacoustic position measure-ments. A discrete-time unit quaternion error-state Kalman filter (ESKF) is used for sensor fusion. The ESKF is implemented as a feedback algorithm with reset functionality. This is motivated by the need for long -endurance autonomous underwater vehicles (AUVs). Proprietary navigation systems do not allow users to add more measurement equations to the code if additional sensors are available. However, the open-source filter architecture presented in the article provides for this. The article also aims to make in-house development of strapdown INS accessible and affordable for vendors of low-cost AUV systems. Finally, a case study of an AUV with a standard sensor suite is included to demonstrate the performance of the ESKF aided by time-delayed position measurements.