Simulating A Satellite

1. Simulating A Satellite CSGC Mission Operations Team Cameron Hatcher James Burkert Brandon Bobian Aleks Jarosz

2. Computer Simulators • Two Simulators – Flight Computer and Hardware • Run on Linux Computers • The two computers send data back and forth • Send commands through Telnet and SCL interface

3. Flight Computer Simulator • Simulates the actual flight computer • Allows VXWorks • Real Time Operation System developed by WindRiver Systems • Software is run in same environment as the satellite • Can make commands to the hardware • Receives replies from the hardware

4. Hardware Simulator • Accepts requests from Flight Computer Simulator • Sends realistic replies • Has different equations to calculate values for sensors • Simulates every hardware sensor onboard the satellite • Ex. Temperature sensors and voltage sensors • Certain sensors are set to change dependent upon tasks • Ex. Calculated remaining battery charge

5. Satellite Tool Kit (STK v5.0) • Modeling and visualization software suite • Versatile piece of software • 2-D and 3-D modeling • Visualization windows • Modeling abilities • Mission design • Sun vs. shade time • Access times • Scheduling • Mission simulation • Scenarios • Practice time for Mission Operators

6. Mission TrainingHow STK will be used for mission simulation training • Simulating real time Data • Display health and status of CX based off simulators • Recognizing raw telemetry data • Failure Management and Error Analysis (FMEA) • Telemetry data analysis • Create problem scenarios • Test how satellite will react to different situations • Diagnostics • Use simulated telemetry to diagnose problems • Troubleshoot problems and create contingency plans

7. STK – Orbital Mechanics • Position • Telemetry Display • Position Covariance • Perturbations • Collisions • Attitude • Telemetry Display • Tip-off Predictions • Communication • Power

8. STK - Communications • Modeling • Ground Yagis • Satellite Transmit • Satellite Receive • Computations • Signal • Access Times • Gains • Interference • RF Environment • Refraction • Rain • System Temperature

9. STK - Power • Modeling • Size • Efficiency • Orientation (Pointing) • Computations • Solar Power • Effective Area • Solar Intensity • Angle of Incident Radiation

10. Spacecraft Command Language(SCL) • SCL is a high level scripting language that allows for ease of use in scheduling events and keeping track of the systems sensors using a SCL user defined database

11. Scripts • Each script in SCL runs commands • The scripts are able to check key variables in the SCL database. • All of the scripts have the capability to be put into a schedule.

12. SCL Database • The SCL database is a user defined database that contains any and all variables that the user wishes to monitor. • The database is updated at regular intervals with certain scripts that will update parts of the database specific to a certain subsystem. • Contains all satellite sensor values • Calculated values

13. Rules and Constraints • A constraint limits the values that a variable can be • A rule is used to alerts the operator if a variable goes beyond a certain range • If a variable goes into a critical range, a rule will take corrective measures • Ex. Shutting off non-critical systems, such as cameras

14. ASPEN • Automated Scheduling and Planning ENvironment • Used to create schedules for SCL • Mission Operator originally creates schedule by hand • Using ASPEN schedule can be adjusted for any conflicts that occur • Ex. Two commands trying to use the same relay • Schedules are compiled to an SCL executable format

15. Running a Simulation • Schedule is uploaded to the Flight Computer Simulator and executed • Commands are sent between the two simulators • STK sends information to the hardware simulator • Mission Operators monitors SCL environment and Telemetry GUI during pass times • Telemetry GUI monitors the SCL database • Any problematic values will be shown in red or yellow