Command & Data Handling Conceptual Design Review

1. Command & Data Handling Conceptual Design Review Tyler Tracey

2. Presentation Outline • Subsystem Requirements • Concept Design • Data Budget • Processing Analysis (Kalman filter) • DHU Example • Conclusions • Schedule Tyler Tracey

3. Subsystem Requirements • The C&DH subsystem shall: • function during an acceleration of 4000g • function between -20 and 50 °C [TBC] • function during exposure to 5 Gy [TBC] • consume no more than 2.5 W [TBC] • have a mass of no more than 1.7 kg [TBC] • be capable of performing 106 flops/s [TBC] • be capable of issuing 103 commands/s [TBC] • be capable of handling 1.5x105 bits/s [TBC] • be capable of storing 30 Mbytes [TBC] Tyler Tracey

4. Concept Design Tyler Tracey

5. Data Budget • Essential tool for determining requirements for: • data handling • data storage • data bus bandwidth • transmitter data rate • Data budget will evolve as project progresses • Must be defined for each mission phase Tyler Tracey

6. Tyler Tracey

7. Processing Analysis • Maximum processing requirements will be driven by the ADCS Kalman filter Tyler Tracey

8. Processing Analysis • For n=m=l=12, one iteration = 30434 flops • If ADCS control loop must iterate 10 times per second  304340 flops/s required • This figure does not account for: • variable matrices in Kalman filter equations • control loop flops • sensor integration flops • inherent housekeeping functions Tyler Tracey

9. Example: SSTL OBC386 • Selected for the 2007 NORSAT microsatellite Tyler Tracey

10. Conclusions A bus architecture has been selected for the C&DH subsystem, either federated or distributed C&DH requirements highly sensitive to camera mission profile and performance meeting 4000 g requirement is feasible more work needed to determine processing requirements; feasibility expected 2008-11-21 Tyler Tracey 10

11. Schedule Tyler Tracey

12. Questions?