The design of cyber-physical systems remains challenging because of their highly heterogeneous nature that makes modeling, design and analysis hard. Despite extensive work in model-based approaches, few unified simulation tools are available today for such systems. This paper proposes a simulation strategy that benefits from the characteristics of recent FPGA platforms and advances in the high-level synthesis tools. Our proposal consists in using these tools to build a cyber-physical system simulator running at high-speed on a FPGA; in this view, high-level synthesis is used not only in the traditional prototyping phase of the embedded systems, but also to synthesize its physical environment, which is jointly simulated on the FPGA. Our paper proposes a case study illustrating this approach: the simulation of the automatic identification system required in maritime communications. The simulation executed on the latest FPGA generation is accelerated by a factor x654 compared to software alternatives demonstrating that FPGAs exhibit appealing characteristics for such simulations.