GlobVision developed a generic and configurable processor-in-the-loop (PIL) simulation environment for high-fidelity and reliable verification and validation of NEOSSat’s embedded flight software (FSW) and electronics. In the PIL simulation environment, NEOSSat FlatSat emulator (i.e. an engineering embedded system model of NEOSSat) runs the on-orbit version of FSW and embedded electronics while interfacing with NEOSSat’s high-fidelity simulator that GlobVision developed as part of the RSS-GeMS project. The NEOSSat simulator provides FlatSat emulator with near realistic spacecraft attitude, orbital and space environment parameters as well as simulated values of some other signals within the spacecraft bus (including sensor and actuator signals) that are not emulated on FlatSat. The PIL simulation environment can be commanded through NEOSSat’s integrated test and operations system (ITOS). Two main modules were developed for the PIL simulator: PIL Hardware Module (PIL-HM) and PIL Software Module (PIL-SM). The PIL-HM facilitates communications between the digital inputs/outputs of the NEOSSat simulator and the mixed signal (i.e., digital and analog) inputs/outputs of the emulated FlatSat. The PIL-HM uses two cards: a D/A card and a serial communications card. The PIL-SM enables the communication between the NEOSSat simulator and the PIL-HM.
The NEOSSat PIL simulator succeeded in complementing the capabilities of the FlatSat and the NEOSSatSim, resulting in an enhanced simulation environment which can be used for supporting end-to-end spacecraft FSW V&V and operations.