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STK/ODySSy

Advanced Solutions Inc. (ASI) and Analytical Graphics, Inc (AGI) have developed a modular flight software architecture that provides a means for rapid spacecraft development, assembly, test, and integration as well as providing highly autonomous on-board operations. This on-board system is an enhancement to ASI's revolutionary On-board Dynamic Simulation System (ODySSy™) through the addition of selected elements from AGI's Satellite Toolkit (STK™). STK/ODySSy™ provides spacecraft flight software with unique capabilities by greatly accelerating the entire spacecraft lifecycle. This makes STK/ODySSy™ unique in that it allows testing of actual mission sequences on the flight vehicle while the spacecraft is in various stages of development, assembly, test and launch operations; all without any external support equipment or simulators. During flight, STK/ODySSy™ optimizes spacecraft operations by providing on-board autonomous mission planning and execution including real-time maneuver validation and constraint checking. These unique capabilities, traditionally found only in ground-based analysis tools and simulation environments, are now be available directly on-board the spacecraft enabled by the emergence of faster processors and advanced avionics architectures.

ASI has developed spacecraft flight software with Built-In Simulation/Test which can be targeted and adapted to a wide variety of Command and Data Handling (C&DH) hardware architectures and mission requirements. This modular software streamlines the entire spacecraft development lifecycle and not only provides highly autonomous core flight software that is adaptable to any mission, but also replaces traditional development, integration and test elements. ASI's software greatly simplifies and accelerates spacecraft integration and test activities. This is accomplished with the revolutionary STK/ODySSy™ which allows the C&DH system to support all phases of the spacecraft lifecycle and contains an On-Board version of AGI's Satellite Toolkit (STK™) for autonomous mission planning and operations.

 

During ground-based operations (i.e., Assembly, Integration and Test), STK/ODySSy™ intercepts and modifies sensor inputs using mathematical models of each sensor, and intercepts and responds to actuator commands. STK/ODySSy™ facilitates accelerated integration and testing, since these functions without STK/ODySSy™ require complex interfaces to electrical ground support equipment (EGSE), and are limited in the analysis of flight-like timelines and flight software logic flow. Flight sequences and commands can be completely tested when STK/ODySSy's simulation and test functions are enabled. STK/ODySSy™ includes detailed actuator, sensor, dynamics, and environment models including reaction wheels, magnetic torque rods, inertial measurement units, star sensors, sun sensors, magnetic field, orbit, environmental disturbances, and translational and rotational dynamics. STK/ODySSy™ enhances integration and test by facilitating high-fidelity "test like you fly" capabilities. A spacecraft dynamics loop is closed within the flight software allowing mission products to fully operate by providing realistic inputs to and outputs from flight software, allowing flight software mode transitions and fault protection, and by testing proper sequencing of mission products.

ASI's original ODySSy™ capabilities have been extended such that it can be used on-orbit in an autonomous planning/prediction mode. In this case, STK/ODySSy™ will be initialized with a state based on the current estimated/sensed state of the spacecraft, but will be run out to some future time using the high fidelity propagation capabilities inherent in STK™. This will allow STK/ODySSy™ to assess predicted spacecraft performance for an upcoming potential mission event. The autonomous planning software will perform constraint checking on the predicted STK/ODySSy™ state data and generate mode and configuration commands based on the STK/ODySSy™ prediction. For example, ODySSy™ will be able to assess if a ground target of interest is upcoming and if the spacecraft can image or communicate with that target in a way that is safe across all spacecraft subsystems. Furthermore, the capabilities of STK™ are combined with the functionality within ODySSy™ to perform optimized on-board maneuver planning. STK/ODySSy™ will provide much of the core functionality required for the autonomy function of the Modular C&DH Software architecture. The same capabilities also provide enhanced on-orbit checkout and fault protection functions.