1. 2006/4/17Extended SOT17@NAOJ1 Solar-B mission onboard control and data handling (data recorder, downlinks, observation tables…) Toshifumi Shimizu ISAS/JAXA shimizu@solar.isas.jaxa.jp

2. 2006/4/17Extended SOT17@NAOJ2 Presentation Outline Base knowledge for planning observations. 3 telescopes on Solar-B: field of view Onboard observation control: Observation tables Onboard data flow Solar-B data recorder and downlinks Consider the amount of data for planning observations

3. 2006/4/17Extended SOT17@NAOJ3 Solar-B Flight model Solar-B under system-level test Shake test (2005 Oct)TV test (2006 Mar) Beautiful photo (2006 Mar)

4. 2006/4/17Extended SOT17@NAOJ4 3 high-performance telescopes EUV Imaging Spectrometer (EIS) –Diagnostics of the coronal thermal properties and dynamics Solar Optical Telescope (SOT) –High resolutional observations of magnetic and velocity fields at the photosphere X-Ray Telescope (XRT) –High resolution imaging of the corona Coordinated observations among three telescopes

5. 2006/4/17Extended SOT17@NAOJ5 Solar-B Field of Views 320arcsec 160arcsec SOT XRT 360arcsec 512arcsec EIS 800arcsec 2000arcsec Maximum size of FOV is shown here.

6. 2006/4/17Extended SOT17@NAOJ6 Sequence control of observations is managed by observing tables in Mission Data Processor (MDP). –One table for filter observation, the other for SP observation –The table is the list of macro-commands for taking observables with time interval. –FPP takes observables according to the arrival of macro-commands Onboard Observation Sequence Control DHU MDPCTM FPP SOT Table (1)Commands to CTM-E (2)Commands to FPP-E (3)MDP commands for table control(4) Macrocommands (issued from table) (5) Servo ON/OFF Angle set/reset Onboard observation controls

7. 2006/4/17Extended SOT17@NAOJ7 Observation table –Consists of “PROGRAM” (main routine and sub routines) and “SEQUENCE”s. –The sequences are the list of macro-commands for taking observables with time interval. Onboard Observation Sequence Control SEQUENCE tables (#100) for the time sequence of macro-commands Observation PROGRAMs (#20) to form nest structures

8. 2006/4/17Extended SOT17@NAOJ8 FPP science images are processed to reduce the data volume in telemetry and then to generate telemetry packets. Onboard Science Data Processing Onboard Science Data Processings Data recorder

9. 2006/4/17Extended SOT17@NAOJ9 Solar-B Data Recorder and Data Downlinks –Capacity: 7Gbits for science data (total volume is 8Gbits) –The volume is shared among SOT/XRT/EIS Nominal allocation SOT: XRT: EIS = 70% (4.9Gbits) : 15% (1.05Gbits) : 15% (1.05Gbits) Allocation ratio can be adjusted according to observational coordination in operation meetings –4Mbps high telemetry (X-band) downloads ~1.7 Gbits FPP data in one station (10min duration). Solar-B data recorder and downlinks

10. 2006/4/17Extended SOT17@NAOJ10 Solar-B data recorder and downlinks How much data can be obtained per day? –Depends on how many downlink stations available –Solar-B orbit: Sun synchronous polar orbit, ~95min period –Downlink stations planned Uchinoura Space Center (USC, Japan) two contacts (max) in the morning, two contacts (max) in the evening Svalbard stations (Norway, under support of ESA) every revolution, 15 contacts per day –Estimated downlinked data volume Svalbard –1 contact duration 3~11min (El. 6 ~ 90 deg) –Total contact duration ~138 min in one day USC –1 contact duration 5~11min –Total contact duration 32min in one day Downlink rate ~4Mbps Total downlinked data 40.8Gbits 、 science data 35.7Gbits (4.4Gbytes)

11. 2006/4/17Extended SOT17@NAOJ11 Science data per day 35.7Gbits (4.4Gbytes) –Nominal allocation SOT:XRT:EIS= 70%:15%:15%= 25.0Gbits: 5.4Gb:5.4Gb Allocated telemetry rate for FPP (compressed) data –Rate averaged per day ~300 Kbps, or 25.0Gbits for one day –Burst (high data rate) observations can also be performed with the allocated capacity of data recorder Burst observation for a certain period, then minimized observation in the rest Possible maximum rate for FPP ~1.3 Mbps (in nominal) ~1.8 Mbps (in SOT dominant)  ~50 min to occupy 4.9Gbits in data recorder The rest of the time is in idle. Data volume predictions for planning

12. 2006/4/17Extended SOT17@NAOJ12 Predicting volume of data products is key in planning observation sequences –Due to telemetry bandwidth –Although high rate observations possible for FPP Science data can be compressed in MDP –MDP has an ASIC chip for 12bit JPEG/DPCM Pixel data is bit-compressed from 16 bit-pixel to 12 bit; 8 look-up tables 12bit JPEG (DCT): lossy –~3 bits/pixel for SOT/FG data –~1.5 bits/pixel for SOT/SP data, when compression noise is comparable to photon noise level 12bit DPCM: lossless, 6-8 bits/pixel Compression ratio depends on images and required quality Data volume predictions for planning

13. 2006/4/17Extended SOT17@NAOJ13 Data volume predictions for planning FPP FG Camera simulated image, made from La Palma data

14. 2006/4/17Extended SOT17@NAOJ14 SOT Observational Capabilities - Focal Plane Instruments Package (FPP)- Spectral (SP) Observation Broadband Filter Imager (BFI) Narrowband Filter Imager (NFI) A 4Kx2K CCD camera shared Typical Observables Spectro-Polarimeter (SP) Filter (FG) Observation Filtergram Dopplergram Long. Magnetogram Stokes IQUV Shutterd exposure Shutterless exposure

15. 2006/4/17Extended SOT17@NAOJ15 continuum (G-band) Multi-wavelength filter observations with SOT Magnetic fields Obtained with SVST @ La Palma CaII H H alpha

16. 2006/4/17Extended SOT17@NAOJ16 Example ： 2005/7 Observation at La Palma Run 5 CCDs simultaneously CaII H G-band Blue continuum H alpha Red continuum G-band DOT Data volume after Speckle processing 1.3K x 1K 90”x70” 5 images every 30sec  220Kpixel/sec In case of Solar-B data  3bit/pixel compression 650Kbps Need to restrict FOV, or reduce time resolution, or have burst observation in a certain period

17. 2006/4/17Extended SOT17@NAOJ17 Observation Example To study magnetic/dynamical nature of microflare- associated small emerging fields in AR. Need telemetry ~300 Kbps continuously for a long period SP observation –Fast mapping, 80” wide scanning, NS size=80”, 0.32” resolution –One map completed every 15 min –Data size: 229Kpixel every 3.6 sec. –Telemetry: 96 Kbps with 1.5bits/pixel compression. FG observation –G-band, 3 wavelengths in Halpha, Longitudinal magnetogram, Dopplergram, repeated every ~45 sec. –80”x80” FOV, 0.08” resolution for G-band and magnetogram, 0.16” for Halpha and Dopplergram –Data size: 3.25M pixel every 45sec –Telemetry: 222 Kbps with 3 bits/pixel compression

18. 2006/4/17Extended SOT17@NAOJ18 Observation Example (2) To study short-term magnetic evolutions of entire AR. SP observation –Normal mapping, 180” wide scanning, NS size=180”, 0.16” resolution –One map completed every 90 min –Data size: 191Kpixel/sec. –Telemetry: 290 Kbps with 1.5bits/pixel compression. FG observation –G-band, 3 wavelengths in Halpha, Longitudinal magnetogram, Dopplergram, repeated every ~ 1 min. –160”x160” FOV, 0.16” resolution (2x2 summing) –Data size: 8.4M pixel every 60 sec –Telemetry: 420 Kbps with 3 bits/pixel compression Total 710Kbps Twice of 300Kbps  Observation in ½ period and no observation in the rest time

19. 2006/4/17Extended SOT17@NAOJ19 Observation controlled by observation tables: Typical Time Cadences typical data rate for XRT (1) ~ 600 k pixel / min –example 1: Continuous Observation (576 k pixel / min) 384”×384”, 1”-resolution, 30sec-interval of a filter pair. –example 2: High-Speed Observation (576 k pixel / min) 384”×384”, 1”-resolution, 5sec-interval of a filter pair, 10min-continuous observation and 50min intermission. –example 3: Combination of FFI and PFI (586 k pixel / min) 384”×384”, 1”-resolution, 40sec-interval of a filter pair. 2048”×2048”, 4”-resolution, 200sec-interval of a filter pair. (1) The total rate of 400kbps (about 15 downlink/day) is assumed. SOT, XRT and EIS usually share this data rate in the ratio of 70%, 15% and 15 %. XRT image data is 12bit/pixel and may be compressed to about 6bit/pixel by DPCM. XRT case

20. 2006/4/17Extended SOT17@NAOJ20 2Mbps max  1.3 Mbps EIS Data Flow CCD Readout Electronics EIS ICU Large hardware CCD window S/C MDP Small spectral window (25 max) Data compression DPCM(loss less) or 12bit-JPEG  250 kbps max for short duration,  40 kbps average Telemetry data format Average rate depends on number of downlink station. 1  slit obs. 40  slot obs. 250  slot obs. Spec.width 16 40 250 Spatial width 256  512  256 No. of lines 8 4 4 Compression 20% 20 % 20% Cadence 2 sec 5 sec 15 sec Rate 38.4 kbps 38.4 kbps 40 kbps 10 min cadence for 4  4 rastering Observation table control