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SOLIS 11.4 delivers a substantial upgrade

By: Kyle Andringa

ASI is confident in saying that SOLIS 11.4 is, by far, the most capable and versatile COTS Spacecraft Simulation and Analysis System ever developed. Driving SOLIS’s capability is our embedded, flight-proven, MAX (Modular Autonomous Extendable) Flight Software with ODySSy (Onboard Dynamic Simulation System); developed, tested, scrutinized, and refined to change the way our customers think about designing and operating spacecraft.

We believe Flight Software to be the nucleus of spacecraft development, capable of accelerating (or decelerating) everything our industry is trying to do. From the proposal phase, to design, testing, integration and operations, SOLIS is changing the game.

Capability enhancements

  • Dynamic Mode Controller allows users to configure any number of attitude control modes. Mode types include: Hold, Idle, Rate Damp, Sun Acquisition, Tracking, EigenSlew, & Rendezslew
  • New/Improved Mode Types:
    • Sun Acquisition: Sun Acquisition modes are utilized to converge a desired target axis toward the sun without the need for full attitude knowledge. They are generally used during initial acquisition, safe mode, and reboot operations.
    • Tracking: Any number of tracking modes can be created to align/clock to any ephemeris object in the system.‑ Supported ephemeris objects include:‑ Nadir-Centric, Nadir-Detic, Velocity, Magnetic-Field, Sun, Inertial Vectors/Quaternions, Orbiting-Objects, Surface-Objects, and Scans.
    • RendezSlew: This slew mode type replaces the previous "DirectTo" phase plane controller to provide seamless transition from/to any attitude/rate condition.‑ There are several advantages to this mode:
      • Unlike DirectTo, RendezSlew is a guidance mode not a controller. This allows for the Target Planner to be run in "Perfect Control" mode, where it is not required to define actuators.
      • RendezSlew follows a predefined trajectory to achieve the slew resulting in a precisely known slew duration and the ability to seamlessly transition to target tracking and scans with minimal settling time.
      • RendezSlew solves the Two-Point-Boundary Value (TPBV) problem in real-time to optimize transitions between modes.
    • Full 6-DOF: Users can choose to utilize STK orbit propagators or ODySSy.‑ When using ODySSy, thrust maneuvers (and Environment Disturbances) will produce delta-V into the orbit and any torque disturbance on the spacecraft.‑ All rotational and translational impacts are modeled simultaneously to produce high-fidelity simulation of burn events.
    • Multiple Attitude Controllers and Momentum Controllers can now be defined and easily transitioned via a single command.
    • Attitude Control Frame can now be rotated relative to the Body Frame. Actuators are now assigned on a per-axis basis to support hybrid actuator control.
    • Momentum Control can now be defined in the Body, Inertial, or Orbit Frame.
    • Actuator Sets can be configured to support nearly any type of control allocation; including delta-V, reaction control, and hybrid thruster configurations. Actuator sets can be easily used to analyze and resolve reaction wheel failure situations.
    • Reaction Wheel Null-Space Control is now included to allow systems with > 3 wheels to control wheels to a commanded momentum state. This logic is typically utilized to keep wheel speeds away from zero using null-space vectors resulting in no net-torque on the system.
    • Reaction Wheel Commanding now supports speed-control
    • Thrusters now support manual commanding (typically for Delta-V)
    • Sun Avoidance logic is now included to keep sensitive payloads from pointing toward the sun.
    • Coarse Sun Sensors (angle sensors) are now supported with algorithms to blend angle sensors into vector measurements.
    • Extended Kalman Filter has been expanded to support boresight and cross-boresight measurement covariances.
    • Improved support for thruster-based attitude and momentum control including non-linear limit cycle controllers
    • More flexibility and control of simulation initial conditions
    • New concept of Mission Modes, such as "Safe Mode", "Nominal Operations", etc.
    • Multiple Central Bodies are now managed to support pointing to one Central Body while orbiting another. For example, a spacecraft could be orbiting Mars while tracking an axis to JPL and clocking to the Sun.‑ The possibilities are limitless.
    • Surfaces can now be configured to provide Aerodynamic and Solar Pressure rotational and translational disturbances.
    • Slew Rate and Acceleration Limits have been expanded to include spherical, rectangular, and actuator-based limits. Actuator-based limits compute the complex agility shapes of any reaction wheel or thruster set based on true orientations and inertias.‑ Utilizing these shape limits allows the spacecraft to take full advantage of its agility capabilities.
    • The Development Tool (DevTool) has been refined, tested, and improved to provide users the ability to easily and rapidly introduce custom logic into the system.
      • The DevTool has been used by ASI to write nearly all the underlying flight software. Its use has massively improved the speed, robustness, reliability, and consistency that logic and algorithms can be developed.
      • The DevTool and Configuration Manager are being used by our customers to perform Hardware-In-The-Loop (HWIL) simulation with SOLIS.
    • The Automation Interface has been completely overhauled to provide a highly-capable interface to perform Large-Scale Monte-Carlo. MATLAB scripts are provided to allow users to easily setup multi-run simulations with the ability to modify any parameters that exist in the flight software or simulation.
    • The Target Planner has been expanded and improved:
      • The Target Planner can now schedule any type of mode based on STK Access constraints. This was formerly limited to just "Spotlight" modes.
      • The Target Planner can now schedule scans from one point to another, including options for scan direction and clocking direction.
      • The Target Planner can now perform STK Access constraints from an STK Sensor to a target in addition to constraints from the Satellite to Target.
      • The target planner can now be used in conjunction with "Perfect Attitude Control"
      • The Target Planner can now be used via Automation
    • SOLIS can now produce a Parameter Database from the Configuration Manager page documenting all parameters that exist in the system.

    General enhancements

    • All telemetry has been reviewed, expanded, and consistently-named to provide the best information from the system.
    • User-interfaces have been improved across the whole system
    • Underlying flight software (MAX) has been restructured to provide the most capable and intuitive system to interact with. All data is being exchanged via well-defined interfaces.‑ Users can easily access any of this information via the DevTool.
    • Telemetry monitor interface has been improved to recognize enumerations
    • FlightJAS sequencing capabilities have been expanded. User interface now supports sequences with input arguments.
Posted: 5/2/2018 3:34:18 PM