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

Musko, 23 Apr 02C&DH, LRR-X Concept Review2 of 17 Outline C&DH Block Diagram & Aircraft Interface Requirements Operating System Flight Software Architecture Telemetry Commands Operator Laptop Software

Musko, 23 Apr 02C&DH, LRR-X Concept Review3 of 17 C&DH Block Diagram & Aircraft Interface

Musko, 23 Apr 02C&DH, LRR-X Concept Review4 of 17 PC-104 Stack (front)

Musko, 23 Apr 02C&DH, LRR-X Concept Review5 of 17 PC-104 Stack (back)

Musko, 23 Apr 02C&DH, LRR-X Concept Review6 of 17 Flight Software Requirements 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

Musko, 23 Apr 02C&DH, LRR-X Concept Review7 of 17 Flight Software Operating 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

Musko, 23 Apr 02C&DH, LRR-X Concept Review8 of 17 Flight Software QNX Architecture

Musko, 23 Apr 02C&DH, LRR-X Concept Review9 of 17 Flight Software Architecture

Musko, 23 Apr 02C&DH, LRR-X Concept Review10 of 17 Flight Software LRR-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

Musko, 23 Apr 02C&DH, LRR-X Concept Review11 of 17 Flight Software Telemetry 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

Musko, 23 Apr 02C&DH, LRR-X Concept Review12 of 17 TM Packet Contents

Musko, 23 Apr 02C&DH, LRR-X Concept Review13 of 17 Flight Software TM 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

Musko, 23 Apr 02C&DH, LRR-X Concept Review14 of 17 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

Musko, 23 Apr 02C&DH, LRR-X Concept Review15 of 17 Sample Command Script

Musko, 23 Apr 02C&DH, LRR-X Concept Review16 of 17 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

Musko, 23 Apr 02C&DH, LRR-X Concept Review17 of 17 Operator Laptop Software 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