Underwater multi-sensor multi-target bearing-only tracking based on delayed measurements

Abstract

The multi-sensor bearing-only tracking system plays an important role in underwater target localization. However, due to propagation delays, observations from multiple sensors at the same time are asynchronous, as the signals are emitted from the target at different moments, creating a time offset issue. Additionally, as the relative distance between the target and sensors changes, the time intervals between two consecutive observations by the sensors also vary. Furthermore, missed detections, false alarms, and target birth and death phenomena negatively impact state estimation. To address these issues, this paper proposes a multi-sensor bearing-only tracking algorithm that considers propagation delay. Using the Gauss–Helmert model to achieve accurate state transitions, the algorithm establishes kinematic and temporal constraints between multi-sensors. Simultaneously, it employs a loopy belief propagation method to calculate the posterior probabilities of each target and perform fusion updates. To improve tracking accuracy in complex environments, a time decay factor is proposed to reduce the covariance of sensors with higher delays, and a trajectory birth-and-death management strategy combined with delayed decisions is proposed. Simulation results show that this algorithm outperforms traditional algorithms that ignore propagation delays in state estimation accuracy and perform better than existing bias compensation algorithms in environments with false alarms and missed detections.