Airborne emitter tracking by fusing heterogeneous bearing data

In this work, we focus on the task of localizing and tracking multiple non-cooperative objects by a passive antenna array and an optical sensor. Both sensor systems are mounted on an unmanned aerial vehicle and collect bearing measurements from objects, whereby the number of the latter is unknown. For localization and tracking, the imprecise but unique bearing data collected from the antenna array has to be correlated with the precise but ambiguous bearing data collected from the optical system. To achieve the optimal solution a batch algorithm is proposed which fuses both data sources. The proposed work flow is as follows: Firstly, the antenna array determines the direction of arrival of an emitted signal, and then the optical sensor is used to detect possibly emitting targets in the corresponding area. Secondly, the bearing data of both sensors are fused in a single localization and tracking framework. Experiments on real world data show that the proposed method is capable to localize and track multiple emitters using bearing data from heterogeneous sensors. The fusion of both sensor data types achieves a much higher accuracy in comparison to a system using only an antenna array. In addition an operator has a direct optical feedback of the observed emitters.