In the literature there exist many proposed architectures for sensor fusion applications. This paper briefly reviews some of the most common approaches, i.e the JDL fusion architecture, the Waterfall model, the Intelligence cycle, the Boyd loop, the LAAS architecture, the Omnibus model, Mr. Fusion, the DFuse framework, and the Time-Triggered Sensor Fusion Model, and categorizes them into abstract models, generic and rigid architectures. While an abstract model does not guide the designer in the concrete implementation, the generic architectures provide a generic design but leave open several design decisions regarding operating system, hardware, communication system, or database system. Rigid architectures specify at least some of these aspects and therefore provide existing hardware designs, tools, and source code at the cost of flexibility.