Bearings-only tracking with fusion from heterogenous passive sensors: ESM/EO and acoustic

The performance of the conventional bearings-only tracking (BOT) from a single passive sensor largely depends on the sensor platform maneuvers. This paper presents a new BOT approach based on fusion from two heterogenous bearings-only sensors residing on the same moving or stationary platform. The two sensors are an ESM/EO with negligible propagation delay and an acoustic sensor with significant propagation delay. Since target range information is contained in the acoustic propagation delay, the problem is therefore observable even when the platform is stationary. An out-of-sequence measurement fusion from the acoustic and ESM/EO sensors (OOSM-AE) is developed to estimate the target trajectory. It consists of an unscented Kalman filter (UKF) to handle in-sequence ESM/EO measurements and an OOSM unscented Gauss-Helmert filter (OOSM-UGHF) to handle out-of-sequence acoustic measurements. Simulation tests are conducted to demonstrate the performance of this new BOT approach.