|
Abstract:
|
Attitude Determination and Control Systems (ADCS) for CubeSats must be verified under realistic, closed-loop conditions before flight integration; however, test campaigns that preserve flight electrical interfaces while providing representative sensor and actuator behavior are expensive and often limited to partial coverage. This paper presents a proposal to repurpose SimuCam, an FPGA-based hardware-in-the-loop (HIL) platform already employed in the ESA PLATO and ESA EnVision missions, into a reusable HIL testbed for CubeSat ADCS. The contribution is architectural rather than experimental. The expected end-to-end system is outlined, and the hardware and software modifications required for feasibility are assessed, without reporting performance results. A central design principle is indistinguishable Input/Output (I/O). From the ADCS hardware perspective, emulated peripherals should match their flight counterparts in signaling, startup and reset behavior, configuration states, sampling latency, timing jitter bounds, and error reporting. The proposed design is structured as a layered, modular framework comprising (i) a real-time dynamics core that maintains the virtual spacecraft state, (ii) a sensor-emulation layer that transforms that state into synthetic measurements, (iii) an actuator-emulation layer that interprets ADCS commands and closes the loop by updating the state, (iv) a physical-interface layer that reproduces electrical signaling, protocol framing, device timing, and fault behaviors, and (v) a test-orchestration layer for scenario control, logging, and fault injection. To make the proposal concrete, a micro case study describes how the commercial STIM210 gyroscope could be emulated. A real-time dynamics model is intended to drive the gyroscope emulator so that it can publish angular-rate and related outputs at device-compatible rates using the same protocol, enabling the ADCS to operate as if connected to flight hardware. The paper focuses on the internal architecture and interface fidelity required to support closed-loop ADCS testing, independently of the specific spacecraft or environmental dynamics models adopted in a given test scenario, establishing a practical starting point for a reusable CubeSat ADCS HIL infrastructure based on SimuCam. |
