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Control & Data Handling, Operator Control, Aircraft Interface to C&DH

College of Engineering Space Physics Research Laboratory Department of Atmospheric, Oceanic & Space Sciences. Control & Data Handling, Operator Control, Aircraft Interface to C&DH. LRR-X Internal Concept Review NASA Goddard Space Flight Center 23 April 2002. Steve Musko

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Control & Data Handling, Operator Control, Aircraft Interface to C&DH

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  1. College of Engineering Space Physics Research Laboratory Department of Atmospheric, Oceanic & Space Sciences Control & Data Handling,Operator Control, Aircraft Interface to C&DH LRR-X Internal Concept Review NASA Goddard Space Flight Center 23 April 2002 Steve Musko Space Physics Research Laboratory University of Michigan Ann Arbor, MI USA

  2. Outline • C&DH Block Diagram & Aircraft Interface • Requirements • Operating System • Flight Software Architecture • Telemetry • Commands • Operator Laptop Software C&DH, LRR-X Concept Review

  3. C&DH Block Diagram &Aircraft Interface C&DH, LRR-X Concept Review

  4. PC-104 Stack (front) C&DH, LRR-X Concept Review

  5. PC-104 Stack (back) C&DH, LRR-X Concept Review

  6. Flight SoftwareRequirements • Collect • Science data from the correlator board • Analog housekeeping values from the analog I/O board • Time and position from the GPS receiver • Aircraft status from RS-232 port • Combine science data, analog housekeeping, GPS time and position and aircraft status into real-time telemetry (TM) packets and one-minute TM files • Store TM files in flash memory • Communicate with operator laptops via Ethernet • Receive and execute commands • Transmit real-time TM packets to laptops • Support bulk FTP data uploads from flash memory • Control temps using PID algorithm C&DH, LRR-X Concept Review

  7. Flight SoftwareOperating System • QNX operating system • Real time, preemptive, multiprocess, multithread, multiprocessor • PC compatible (and other processors) • Complete set of utilities (FTP, Telnet, drivers etc.) • 20 year company track record • Scalable: OS features can be added as needed • Reliable: • Microkernel architecture • Processes execute in separate memory spaces C&DH, LRR-X Concept Review

  8. Flight SoftwareQNX Architecture C&DH, LRR-X Concept Review

  9. Flight Software Architecture C&DH, LRR-X Concept Review

  10. Flight SoftwareLRR-X App Architecture • The LRR-X application is a collection of threads that communicate with each other via QNX message passing • Read_Hskp_Thread • Read_Sci_Data_Thread • Form_TM_Pkts_Thread • Store_TM_Files_Thread • Send_Real_Time_TM_Thread • Process_GSE_Cmds_Thread • Read_GPS_Data_Thread • Sync_With_GPS_Time_Thread • Cntl_Temps_Thread • Check_Limits_Thread C&DH, LRR-X Concept Review

  11. Flight SoftwareTelemetry • TM packets are combined into one minute TM files and stored on flash disk. Filenames are derived from TM packet time tags. • All TM packets are transmitted in real time to the operator laptop computers • TM files on flash disk can be uploaded to the the operator laptop computers using FTP any time the instrument is powered up (even while the LRR-X application is running). • There is a single TM packet type that contains science data, housekeeping, GPS time and position and aircraft status C&DH, LRR-X Concept Review

  12. TM Packet Contents C&DH, LRR-X Concept Review

  13. Flight SoftwareTM Rate & Storage Capacity • Total TM packet size is 5226 bytes • TM production rate is 3.03 Hz x 5226 bytes = 15,835 bytes/sec (54.4 Mbytes/hour) • 940 Mbytes of Flash memory provides 17.3 hours of TM file storage C&DH, LRR-X Concept Review

  14. Instrument Commanding • The instrument executes command scripts • Command scripts are: • Text files that are edited on the operator laptop • Downloaded to flight computer flash memory • At initialization, the flight software loads and runs a default command script if it exists on flash disk • All commands can be sent individually directly from the operator laptop C&DH, LRR-X Concept Review

  15. Sample Command Script C&DH, LRR-X Concept Review

  16. Instrument Commands • Set PID temp loop control values • Set truncation map values • Set Test Control Register value • Execute command script (for nested scripts) • Start data collection • Stop data collection C&DH, LRR-X Concept Review

  17. Operator LaptopSoftware Requirements • Store real time TM packets on laptop hard disk • Display real time or stored science TM in several forms • Polar Visibility Plot • Raw correlator and totalizer values • Brightness Temperature Image • Display real time or stored housekeeping TM in tabular and strip chart form • Alert the operator if any critical housekeeping limit is exceeded • Support command script editing and execution • Support individual command execution • Support FTP file transfer with the instrument flash disks and the aircraft FTP file server C&DH, LRR-X Concept Review

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