2006/4/17Extended SOT17@NAOJ1 Solar-B mission onboard control and data handling (data recorder,...

2006/4/17 Extended SOT17@NAOJ 1

Solar-B mission onboard control and data handling

(data recorder, downlinks, observation tables…)

Toshifumi ShimizuISAS/JAXA

[email protected]


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


Solar-BSolar-BFlight model Solar-B under system-level test

Shake test (2005 Oct) TV test (2006 Mar) Beautiful photo (2006 Mar)


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


Solar-B Field of Views

320arcsec

160arcsec

SOT

XRT

360arcsec

512arcsec

EIS

800arcsec

2000arcsec

Maximum size of FOV is shown here.


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

MDP CTM

FPPSOTTable

(1)Commands to CTM-E

(2)Commands to FPP-E

(3)MDP commands for table control (4) Macrocommands(issued from table)

(5)Servo ON/OFFAngle set/reset

Onboard observation controls


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

OBS Program Version No

Main-Routine Loop Count

Call Sub-Routine # Sub-Routine Repeat Count Interval Time



End of Main-Routine －－

Call FG Sequence Table # FG Sequence Table Repeat Count Interval Time



End of Sub-Routine －－

Main Routine

4 Sub-Routines

Sequence Table Version No

Command Parameter Command ID =Macro-Command DMF COMP Code 1 COMP Code 2 PAR No ROI No Reserved

Interval Time

Command Parameter Command ID =Macro-Command DMF COMP Code 1 COMP Code 2 PAR No ROI No Reserved

Interval Time

Command Parameter Command ID =Inst. Command Inst Command Parameter Set Reserved

Interval Time

End of Sequence --- ---

SEQUENCE tables (#100)for the time sequence of macro-commands

Observation PROGRAMs (#20)to form nest structures


FPP science images are processed to reduce the data volume in telemetry and then to generate telemetry packets.

Onboard Science Data Processing

CCD seq

process

Science process

Bit comp

process

Image comp

process

Telemetry packet

generation

FPP MDP

To ground via DHU

Interface

ENA

CLK

DAT0-15

BUSY

1MHz

(section 3.6) (section 3.7)

(section 3.8)

(section 3.9) (section 3.9) (section 3.10)

Onboard Science Data Processings

Data recorder


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


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)


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


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




FPP FG Camera simulated image, made from La Palma data


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

Stokes IQUV

Shutterd exposure

Shutterless exposure

2006/4/17 Extended SOT17@NAOJ 15continuum (G-band)

Multi-wavelength filter observations with SOT

Magnetic fields

Obtained with SVST @ La Palma

CaII H

H alpha


Example： 2005/7 Observation at La Palma

Run 5 CCDs simultaneously CaII H G-band Blue continuum H alpha Red continuum

G-bandDOT

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


Observation Example To study magnetic/dynamical nature of microflare-associat

ed 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, Dopplergr

am, 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


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, Dopplergr

am, 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


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


2Mbps max1.3 Mbps

EIS Data Flow

CCD Readout Electronics EIS ICU

Large hardware CCD window

S/C MDP

Small spectral window (25 max)

Data compressionDPCM(loss less) or 12bit-JPEG

250 kbps max for short duration, 40 kbps average

Telemetrydata format

Average rate depends on number of downlink station.

1 slit obs. 40 slot obs. 250 slot obs.Spec.width 16 40 250Spatial width 256 512 256No. of lines 8 4 4Compression 20% 20 % 20%Cadence 2 sec 5 sec 15 secRate 38.4 kbps 38.4 kbps 40 kbps

10 min cadence for 44 rastering

Observation tablecontrol

2006/4/17Extended SOT17@NAOJ1 Solar-B mission onboard control and data handling (data recorder,...

Documents

Transcript of 2006/4/17Extended SOT17@NAOJ1 Solar-B mission onboard control and data handling (data recorder,...