In this study, a software system is proposed for estimating the status of resources and the progress of tasks in Human-Robot Collaborative(HRC) assembly cells. The proposed system is responsible for collecting the stream of sensor data and the output from multiple runtime modules, such as systems that provide the position of the worker, robot execution engine. The systems ensure that the data is managed dynamically and uniformly so as to be applied to both robots and human operators. The system functions as a collection point of data, where they get fused, providing a more accurate representation of the state of the cell. The output of the HRC data fusion system constitutes a trustful information source that can be utilized for feeding information to trigger other processes at the coordination or the business layer. In this work, the necessary mechanisms that constitute the HRC monitoring system are presented and validated through a case study from the automotive industry, where human and robots are collaborating for the assembly of a vehicle’s subassembly.