# Robust Smoothing Cardinalized Probability Hypothesis Density Filter-Based Underwater Multi-Target Direction-of-Arrival Tracking with Uncertain Measurement Noise

## TL;DR

This paper introduces a new method for tracking multiple underwater targets with uncertain noise by combining noise estimation and smoothing techniques.

## Contribution

The novel contribution is integrating Saga–Husa noise estimation and backward smoothing into the CPHD filter for robust underwater multi-target tracking.

## Key findings

- The proposed method improves robustness and accuracy in uncertain underwater noise environments.
- Backward smoothing enhances tracking precision when combined with dynamic noise estimation.
- Simulations confirm superior performance over existing DOA tracking techniques.

## Abstract

In view of the typical multi-target scenarios of underwater direction-of-arrival (DOA) tracking complicated by uncertain measurement noise in unknown underwater environments, a robust underwater multi-target DOA tracking method is proposed by incorporating Saga–Husa (SH) noise estimation and a backward smoothing technique within the framework of the cardinalized probability hypothesis density (CPHD) filter. First, the kinematic model of underwater targets and the measurement model based on the received signals of a hydrophone array are established, from which the CPHD-based multi-target DOA tracking algorithm is derived. To mitigate the adverse impact of uncertain measurement noise, the Saga–Husa approach is deployed for dynamic noise estimation, thereby reducing noise-induced performance degradation. Subsequently, a backward smoothing technique is applied to the forward filtering results to further enhance tracking robustness and precision. Finally, extensive simulations and experimental evaluations demonstrate that the proposed method outperforms existing DOA estimation and tracking techniques in terms of robustness and accuracy under uncertain measurement noise conditions.