first year on-orbit activities of sgli on gcom-c...first year on-orbit cal activities of sgli, sep...

1First year on-orbit cal activities of SGLI, Sep 26, 2018 SPIE Hawaii 2018

First year on-orbit

calibration

activities of SGLI

on GCOM-C

satellite

Kazuhiro TANAKA

GCOM project team

JAXA

SGLI-VNR image 2018-01-01 20:44 UTC

Topics GCOM and SGLI

SGLI specification and performance

Initial on-orbit check out results

Thermal band (TIR) performance

Lunar calibration

Next step

2

GCOM-C LaunchH-IIA rocket F-37

01:26:22 UTCOn Dec. 23, 2017

Japanese name“SHIKISAI”

First year on-orbit cal activities of SGLI, Sep 26, 2018 SPIE Hawaii 2018

3

Global Change Observation Missionfor Climate（GCOM-C）

Global Change Observation Mission for Climate (GCOM-C) carries the opticalradiometer, Second-generation Global Imager (SGLI). SGLI has been designedto provide continuous global observation of the Earth’s surface, ocean, andatmosphere and to understand the global mechanism of carbon cycle andradiation budget. SGLI on GCOM-C consists of two sensor units, VNR (Visibleand Near Infrared Radiometer) and IRS (Infrared Scanning Radiometer).

+X satellitevelocity

+Z Earth

+Y

Second generation

Global Imager

（SGLI）

Visible and Near

infrared Radiometer

（SGLI-VNR)

Infrared Scanning

Radiometer

(SGLI-IRS)

Star

Tracker

Sensor Second generation Global Imager

Orbit

Sun synchronous quasi recurrent

orbit

Altitude : 798km

Inclination : 98.6deg

Local time： 10:30±15min

descending

Size 4.7m(X) × 16.5m(Y) × 2.6m(Z)

Weight 2000kg

Power > 4000W（EOL）

Launch December 23, 2018

Deigned

Life> 5 years


4

March 17, 2016 at TSKUBACompatibility test with satellite system

SGLI

VNR

SGLI

IRS

Flight

direction

4.6m (X)

2.2m (Z)

16m (Y)

Satellite 2 ton

SGLI 520kg


Second Generation GlobalImager (SGLI)

5

PL telescopes(55deg FOVx 2)

NP telescopes(24deg FOV x 3)

SolarDiffuser

1.5m1.4m

Infrared Scanning Radiometer(IRS)

SunCalWindow

Earth Obs.Window

DeepSpaceWindow

1.5m

0.7m

センサ概要

SGLI VNR Non-Polarized Obs. (NP) x 11ch, IFOV = 250m, Obs. Swath = 1150km

Polarized Obs. (PL) x 2ch, IFOV 1km, Obs. Swath = 1150km

SGLI IRS Short wave infrared (SWI) x 4ch, IFOV = 250m/1km, Obs. Swath = 1400km

Thermal infrared （TIR) x 2ch, IFOV = 250m, Obs. Swath = 1400km

Visible and Near Infrared Radiometer(VNR)


6

Observation wavelength

•19 channels observation

29 standard products

Concentrates on cloud, aerosol and vegetation parameter retrievals


7

250m resolution Chl-a Kuroshio currentFeb. 27, 2018


8

250m resolution SST Kuroshio currentFeb. 27, 2018


9

VNR Performancepre-launch test results


See details at SGLI Sensor Characterization homepage, http://suzaku.eorc.jaxa.jp/GCOM_C/data/prelaunch/index.html

Pre-Launch Test Performance of VNR (Non Polarized bands, NP)

Saturation Det. Depend.

Radiance Corrected Radiance Corrected (4095DN) Worst Lstd x 0.3 Error (max) Dark Lstd

[micron] [nm] [m] [W*] [DN] [W*] [DN] [DN] [W*] [W*/DN] [%] [DN] [%] [DN] (min)

VN01 380.0 10.7 250m 210 3194 60 913 304 249 0.0657 0.92% 8.4 0.31% 1.37 659 250

VN02 412.5 10.4 250m 250 2910 75 873 263 329 0.0859 1.57% 13.7 0.46% 1.08 786 400

VN03 443.2 10.2 250m 400 3196 64 511 228 484 0.1252 0.75% 3.8 0.43% 1.01 487 300

VN04 489.9 10.4 250m 120 2934 53 1296 307 155 0.0409 0.59% 7.6 0.26% 1.50 858 400

VN05 529.6 19.7 250m 350 3553 41 416 244 379 0.0985 1.19% 5.0 0.65% 0.90 457 250

VN06 566.2 20.0 250m 90 3332 33 1222 330 102 0.0270 1.28% 15.6 0.56% 1.18 1017 400

VN07 672.0 22.3 250m 62 3226 23 1197 270 74 0.0192 1.43% 17.1 0.37% 1.18 988 400

VN08 672.1 22.1 250m 210 3645 25 434 268 220 0.0576 1.88% 8.2 0.50% 0.79 537 250

VN09 763.1 11.4 (250m) 350 3633 40 415 253 370 0.0963 1.87% 7.8 0.51% 0.26 1592

VN10 866.8 21.1 250m 30 2852 8 760 364 39 0.0105 0.30% 2.3 0.36% 1.59 470 400

VN11 867.1 21.3 250m 300 3620 30 362 233 320 0.0829 1.79% 6.5 0.61% 0.74 478 200

Note: SNR of VN09 is specified for 1km Mode. [W*] = [W/m2/str/µm]

Pre-Launch Test Performance of VNR (Polarized bands, PL)

Saturation Det. Depend.

Radiance Corrected Radiance Corrected (4095DN) Worst Lstd x 0.3 Error (max) Dark Lstd

[micron] [nm] [m] [W*] [DN] [W*] [DN] [DN] [W*] [W*/DN] [%] [DN] [%] [DN] (min)

PL01 671.9 20.9 1km 250 2940 25 294 310 322 0.0850 1.51% 4.4 0.83% 0.49 614 250

PL02 866.2 20.3 1km 300 2701 30 270 247 427 0.1111 0.90% 2.4 0.93% 0.42 646 250

[W*] = [W/m2/str/µm]

Sigma (max) SNR

Spec.

Chλc Band Width

Signal Level (min) Noise

Lmax Lstd Dark

(max)

Gain

(min)

IFOV

Gain

Chλc Band Width

Signal Level (min)

Linearity Error (max)

IFOV

Noise

Lmax Lstd Dark

(max)

Gain

(min)

Linearity Error (max) Sigma (max) SNR

Spec.

Gain

(1200)

10

IRS Performancepre-launch test results

Pre-Launch Test Performance of IRS (SWIR bands)

Saturation

Radiance Corrected Radiance Corrected (4095DN) Lstd Worst Lmax Lstd Dark Lstd

[micron] [nm] [m] [W*] [DN] [W*] [DN] [DN] [W*] [W*/DN] [%] [DN] [DN] [DN] [DN] (min)

1.05 21.8 1km 253.3 3529.0 58.2 811.5 102.1 282.3 0.0707 0.2% 5.1 1.5 0.9 0.8 942 500

1.38 20.7 1km 102.4 3385.4 8.3 270.3 99.8 118.6 0.0297 -0.9% -8.6 4.1 0.8 0.8 329 150

SWI-3 1.63 191.3 250m 49.8 3723.6 3.0 220.0 93.2 50.5 0.0127 -1.1% -7.7 3.8 2.2 2.0 100 57

SWI-4 2.21 51.9 1km 20.0 3668.5 1.9 342.8 97.0 21.4 0.0054 -0.1% 3.3 2.2 0.9 0.9 368 211

[W*] = [W/m2/str/µm]

Pre-Launch Test Performance of IRS (TIR bands)

Saturation

Radiance Corrected Radiance Corrected (4095DN) (max) Tstd Worst Tmax Tstd Space Tstd

[m] [K] [DN] [K] [DN] [340K] [DN] [DN/K] [%] [%] [DN] [DN] [DN] (max)

2150.0 1263.4 158% 534.9 18.94 0.35% 1.89% 1.3 1.2 1.1 0.06 0.2

2146.0 1257.7 138% 986.8 18.90 0.35% -0.88% 1.4 1.3 1.3 0.07 0.2

2071.9 1261.0 159% 676.3 17.27 -0.44% -1.99% 1.6 1.5 1.5 0.09 0.2

2056.1 1260.5 133% 1225.1 17.27 -0.80% -1.97% 1.8 1.8 1.7 0.10 0.2

250m resolution, TDI = YES, Upper = BOL(COLD) / Lower = EOL(HOT)

IFOV

250m

250m

340

340

300

300

Noise

Sigma (max) NEdT [K]

Spec.

(500m)

Ch

SWI-1

Gain

Sigma (max)IFOVBand

Width

Spec.

Lmax Lstd Linearity Error (max)Gain

(min)Dark

Signal Level (min)

SNR

Noise

Chλc

Band

Width

Gain

[micron]

Signal Level (min) Back

GroundTmax Tstd Gain

300K

Error (worst)

SWI-2

λc

10.78 0.74

TIR-2 11.97 0.77

TIR-1


See details at SGLI Sensor Characterization homepage, http://suzaku.eorc.jaxa.jp/GCOM_C/data/prelaunch/index.html

11

Initial Check Outpurpose

Confirmation of the all sensor function• Works properly as designed, and as tested in pre-launch tests. • Special calibration parameters were also checked.

not only nominal configuration and signal levels but also different ones binning rate, raw resolution mode, different LED configuration, integration time dependence and intermediate tilt angle … etc.

• For example, CCD integration time is fixed for the earth observation. Check various integration time effects which includes the ground

system processing algorithms, such as a stray light correction.

Obtaining the initial sensor performance data.• SGLI performance will degrade gradually for 5 years on-orbit lifetime. • Initial performance is very important for the succeeding calibration activity. • SGLI was turned on for the first light image on Jan. 1, 2018 (Y+9days)

30 days earlier than previous GLI sensor (Y+40days).• The solar angle calibration maneuver was conduced on Jan. 4, 2018 (Y+12

days).


12

Initial Check Outresults

Initial check out activities✓ Earth Observation✓ Onboard calibrator

• LED and lamp calibration• Solar calibration• Dark signal calibration• Black body calibration

✓ Calibration maneuver• Solar angle dependency• CCD de-striping• Lunar calibration

✓ Geometric calibration

All sensor functions were confirmed. The initial calibration parameters were obtained.

Approval to proceed to the initial Cal./Val. phase on March 28, 2018. Next target is the data release in December 2018.


13

Solar Reflective bandsVNR and SWI

Solar reflective bands trend for 9 months✓ Same solar diffuser degradation at both LED and Sun Calibration is

observed for VNR wavelength.✓ Detailed analysis and a comparison with other results is ongoing.


65%

70%

75%

80%

85%

90%

95%

100%

105%

2018/01/01 2018/04/01 2018/06/30 2018/09/28

VNR LED Cal Trend

NP-L VN01 NP-L VN02 NP-L VN03 NP-L VN04 NP-L VN05


NP-L VN11 S09(+60) PL-1 S09(+60) PL-2 Monitor PD-1 Monitor PD-2

65%

70%

75%

80%

85%

90%

95%

100%

105%

VN

01

VN

02

VN

03

VN

04

VN

05

VN

06

VN

07

VN

08

VN

09

VN

10

VN

11

PL-

1

PL-

2

PD

-1

PD

-2

PD

-3

PD

-4

NP-L S09(+60) Monitor

VNR LED Trend

65%

70%

75%

80%

85%

90%

95%

100%

105%

2018/01/01 2018/04/01 2018/06/30 2018/09/28

VNR SunCal Trend



NP-L VN11 S10(±0) PL1 S10(±0) PL2 Monitor PD-1 Monitor PD-2

65%

70%

75%

80%

85%

90%

95%

100%

105%

VN

01

VN

02

VN

03

VN

04

VN

05

VN

06

VN

07

VN

08

VN

09

VN

10

VN

11

PL1

PL2

PD

-1

PD

-2

PD

-3

PD

-4

NP-L S10(±0) Monitor

VNR SunCal Trend

65%

70%

75%

80%

85%

90%

95%

100%

105%

2018/01/01 2018/04/01 2018/06/30 2018/09/28

SWI Halogen Trend

Halogen Trend SW1 Halogen Trend SW2

Halogen Trend SW3 Halogen Trend SW4

65%

70%

75%

80%

85%

90%

95%

100%

105%

SW1 SW2 SW3 SW4

Halogen Trend

SWI Halogen Trend

14

Thermal band (TIR) performance

Two key technologies for TIR✓ 55K cooler system ✓ PV-MCT detectors

55K cooler system✓ 50W class Stirling cycle mechanical linear cooler ✓ Open type cryogenic dewar✓ Contamination control from manufacturing until launch✓ Outgas and cooler activation✓ Life time prediction

TIR observation performance✓ Gain stability✓ Low noise✓ Background thermal emission✓ Deselection of poor performance sub-pixel✓ Gain trend


15

55K Cooler SystemWith 50W class cooler

3:00:000.125

3:00:000.125

0

50

100

150

200

250

300

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Rep

lace

men

tH

eate

rLo

ad[m

W]

,Co

ole

r P

ow

er [

W]

,Dew

arte

mp

[deg

C]

Days from Cool Down (2018/01/28)

ReplacementHeater Load[mW] Cooler Power

Adjustment @ Y+3years (TBD)

▽

△2018-09-08 (7months)

Required Lifetime(> 5 years)

▽

Cooler Power[W]

Dewar temp.[deg C]

36 W

37 W

38 W

39 W

40 W

life time preditionsbased on cooler power tunning

0

50

100

150

200

250

300

350

06:00:00 07:00:00 08:00:00 09:00:00

IR0593 IRS CCE TMP1 K IR0594 IRS CCE TMP2 K

Dewar Temp[K]

▽CoolDown Start

45

50

55

60

08:00:00 08:20:00 08:40:00 09:00:00


IR0565 IRS LWIRD TMP1 K

Cold Stage

Cold Chip

09:00:00 12:00:00 15:00:00 18:00:00 21:00:00


IR0565 IRS LWIRD TMP1 K

LWIRD Temp

0

50

100

150

200

250

300

350

400

450

06:00:00 07:00:00 08:00:00 09:00:00

IR0597 IRS CCE HTR PWR MON mW

ReplacementHeater Load[mW]

0

50

100

150

200

250

300

350

400

450

08:00:00 08:20:00 08:40:00 09:00:00


09:00:00 12:00:00 15:00:00 18:00:00 21:00:00


LWIRD Turned On

▽

0

10

20

30

40

50

06:00:00 07:00:00 08:00:00 09:00:00

IR0589 IRS CCE STC PWR MON W

Cooler Power[W]

0

10

20

30

40

50

08:00:00 08:20:00 08:40:00 09:00:00


09:00:00 12:00:00 15:00:00 18:00:00 21:00:00


Cooler system initiated on January 21, 2018. ✓ Continuous cooling starts on January 28, 2018.✓ All performance is fine. Enough margin for 5 years operation.


16

TIR performanceOrbit cycle

TIR-1 GAIN

0.45% p-p

Deep Space

Offset 1.30 Kp-pDeep Space Noise

1σ = 0.06KBlackbody

Offset 3.12 Kp-p

Blackbody Noise

1σ = 0.06K

TIR-2 GAIN

0.21% p-p

Deep Space

Offset 1.44 Kp-pDeep Space Noise

1σ = 0.08KBlackbody

Offset 3.17 Kp-p

Blackbody Noise

1σ = 0.08K

1 rev = 100min,

14 rev. (= 1day) plot for an orbit cycle repeatability for 250m mode✓ Gain is corrected and stable as designed.✓ Noise is low as tested in pre-launch test.


17

TIR performanceGain trend for 7 months

7months gain trend for 250m mode✓ Small degradation is observed

(TIR-1/11micron : 0.2%, TIR-2/12micro : 0.5%)✓ Enough margin for 5 years operation✓ Deselection technique to eliminate a poor performance sub-pixels works as

designed with periodical health check (3months : TBD)


18

Lunar Calibration

Lunar Model✓ GIRO/ROLO model✓ Earth-Moon distance, phase angle effect, liberation effect✓ Full Disc irradiation calibration

Sensor radiometric performance✓ Traceability to the national standards through pre-launch IS calibration✓ Sensor stability, offset correction, noise, radiation effects (protons)✓ Wavelength response function

Sensor geometric performance✓ Attitude rate, off-nadir attitude profile✓ Solid angle of each observation sample✓ VNR-CCD signal integration time effect✓ Optical distortion, MTF effects✓ IRS wisk broom scan profile with 45deg folding mirror effect✓ Low pass filter (LPF) effects


19

37. 16 msec

↑

Orbi t Cycl e 6,057 secOrbit Vel. 5.944E-2 deg/sec

7.444 km/secRaw Det 13 μmfocal len 166 mm

Overlap 76.3% Overlap 0.0%

Manouver Pitch Rate Equivalent obs angle rate

1.499E-1 deg/sec 4.829E-4 deg/sec (Note 2)

　　Note 1) Int Time = 255 case 　　Note 1) Int Time = 255 case

　　Note 2) Calc. of sat movement, not angle rate calc.

radius 1,738km 37.164 msecdiameter 3,476km 1.499E-1 deg/sec

92. 9 line

28. 8 pix

Full Disc Irrradiance

21. 17arcsec 125. 0met er

5. 01ar csec 62. 5m

AT 4pix BINNING AT 4pix BINNING

msec

69. 2 meter

16. 15 arcsec

9. 291

Moon

Ear t h

798km

0. 52deg

( 356,565 ～ 384,873km = 7.4% ̂2 = 14.2 %)

384, 873km( 796 ～ 836km )

Moon SGLI

AT di r ect i on

Earth ObsSolidAngle

Lunar CalSolidAngle

CentroidCentroid

Movement

RAW Pix

0 10 20 30 40

arcsec

Before BINNing

After Binning

0 100 200 300 400

meter

Before BINNing

After BINNing

a) Less MTF performancecomaring to Earth Obs.

250m Pix

0.00 0.01 0.02 0.03 0.04

[deg]

Integral irradiance

Square Response

b) Integral response is equivalent to the square reponse assumption.c) Actual preceise solid angle calcuration is required to get the full disc irradiance.

Solid angle of each obs. sampleVNR-CCD signal integration time effect


20

EO case:(0.35 deg / scan)

LUCA case:(0.1 deg / scan)

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

40.340.440.540.640.740.840.9

AT[deg]

CT [deg]

SWI-01 Sample-1 SWI-01 Sample-2 Next Scan

1st Sample

Scan

Next Scan

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

-0.3-0.2-0.10.00.10.20.3

AT[deg]

CT [deg]


Det-01

Det-05

Scan Scan

0.05

0.15

0.25

0.35

0.45

0.55

0.65

-41.4-41.3-41.2-41.1-41.0-40.9-40.8

AT[deg]

CT [deg]


Last Sample

Scan

Next Scan

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

40.340.440.540.640.740.840.9

AT[deg]

CT [deg]


1st Sample

Scan

Next Scan

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

-0.3-0.2-0.10.00.10.20.3AT[deg]

CT [deg]


Det-01

Det-05

Scan Scan

0.05

0.15

0.25

0.35

0.45

0.55

0.65

-41.4-41.3-41.2-41.1-41.0-40.9-40.8

AT[deg]

CT [deg]


Last Sample

Scan

Next Scan

Simple NearestNeighbor methodcause a significanterror because ofcomplexed geometry.The precise solid angle and overlap calculation should be used.

the scanning overlap effects by 0.74sec scanning cycleEO case : sat. moves 0.74sec x 7.4km/sec ÷ 798km 0.35 deg/scanLUCA case : sat. att. rate 0.1499deg/sec x 0.74sec 0.1 deg/scan

Difference between earth observation (EO) and lunarcalibration (LUCA) geometry for 45deg folded wisk broom


21

Solid Angle CorrectionUsing optical distortion model and satellite attitude model

GIRO/ROLO model comparison

Lunar Calibration Analysis


22

Preliminary results✓ VNR observed irradiance is 5-10% higher than GIRO model.✓ Small degradation (～1%) is observed in short wave length (380nm

and 412nm)✓ Calibration Difference in dual band channels (RED and NIR) Comparison with other results and PL/SWI calculation is ongoing.

Preliminary ResultsFor 7 months trend


102%

107%

112%

VN01 VN02 VN03 VN04 VN05 VN06 VN07 VN08 VN09 VN10 VN11

Irr_Obs ÷ Irr_ROLO

380nm & 412nm

O2A absorption

channel

Dual Gain

channels

RED

NIR

short wave

degradation?~ 1%

102%

107%

112%

VN01

VN02

VN03

VN04

VN05

VN06

VN07

VN08

VN09

VN10

VN11roll=+1deg

Int. Time is longer

roll=0deg0.00

0.10

0.20

300nm 400nm 500nm 600nm 700nm 800nm 900nm 1000nm

refl

ecta

nce

[-]

ROLO_smooth_spectra ROLO spectr VN01VN02 VN03 VN04VN05 VN06 VN07

VN

1

VN

2V

N3

VN

4

VN

5V

N6

VN

7/V

N8

VN

10

/VN

11

VN

9

Conclusion On-orbit commissioning activities of SGLI during the first several

months to confirm the system integrity.

Technical aspects of the lunar calibration and the thermal infraredperformance.

All SGLI observation performance is confirmed as designed and astested in pre-launch test campaign.

Detailed calibration factor is under analysis.

The observation data will be delivered to the public after its reviewboard approval, in December 2018.

SGLI related information can be found at:

http://suzaku.eorc.jaxa.jp/GCOM_C/index.html


Acknowledgement SGLI Lunar calibration data was evaluated using the GSICS lunar

calibration tool (GIRO: GSICS Implementation of the Robotic LunarObservatory).

The authors would like to thank the GIRO implementationagencies led by EUMETSAT and GSICS lunar calibrationcommunity for GIRO usage and technical assistance.


first year on-orbit activities of sgli on gcom-c...first year on-orbit cal activities of sgli, sep...

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