Development status of theSecond - generation GlobalImager (SGLI) on GCOM-C1

September 2, 2009SPIE Europe, Berlin
Kazuhiro Tanakaa, Yoshihiko Okamuraa,
Takahiro Amanob, Masaru Hiramatsub,
Koichi Shiratamaba Japan Aerospace Exploration Agency(JAXA)b NEC TOSHIBA Space Systems Ltd.

Contents
 Global Change Observation Mission (GCOM) SGLI on GCOM-C1 Satellite BBM Test Result of SGLI VNR
 BBM Test Result of SGLI IRS Current Status
 Conclusion
Development status of SGLI at SPIE Europe, Berlin 20092

Global Change Observation Mission(GCOM) Global observation satellite system as JAXA’s GEOSS contribution.
 2 satellite series for 5 years, total 13 years observation.
9 GCOM-WMicrowave radiometer observation for WATER CYCLE
using AMSR2 (AMSR-E follow on)
9 GCOM-C Optical multi-channel observation for RADIATIONBUDGET and CARBON CYCLE using SGLI (GLI follow on)
GCOM-C(CLIMATE)
GCOM-W(WATER)

SensorAMSR2Advanced Microwave Radiometer 2(AMSR2)
Passive Microwave Observation
Water vapor, soil moisture etc

SGLISensor

Development status of SGLI at SPIE Europe, Berlin 2009Second Generation Global Imager(SGLI)
Optical Observation 380nm – 12 micron
Cloud, Aerosol, Vegetation, Chrolophl etc

3

GCOM Mission
GCOM observation
GCOM-W

Model prediction
GCOM observation

GCOM-CRadiation budget•Surface albedo•Snow ice
•Cloud/ aerosol•SST/ LST

Input

Carbon cycle

Comparison•Vegetation cover•Primary production•Coastal environment
Frequent and longterm (>10yer) global
observation system

Prediction results

Climate system model

Water cycle•Water vapor, cloud,precipitation•Soil moisture•Sea ice, snow
•SST, windImproveaccuracy• Improvement of parameterization
about radiation budget and carbon
cycle, etc. in climate prediction
model.
• Verification and improvement ofprediction of the earth environmentchange including the water cycle bycomparison with the satellite
observation.

•Surface temperature•Sea level•Snow and sea ice area
•Environmental change•Rain/drought
distribution•Extreme weather
frequency•Land cover
Air temperature prediction

3°C

Data application

Knowledge

Future prediction

Operational use for fishery, searoute, weather forecast, etc.

monitoring and understanding ofthe earth environment change

Policy design throughprediction improvement

Development status of SGLI at SPIE Europe, Berlin 20094SGLI
Second Generation Global Imager
TIR-DET→
Non Polarized
Observation Telescopes(24deg FOV x 3)

SolarDiffuser

Polarized
Observation
Telescopes(55deg FOVx 2)←Optics

EarthView Window
Sun Cal.
Window←Scan Mirror

About
1.4m

About
1.3m

About
1.7m

Visible and Near Infrared Radiometer(SGLI-VNR)

About
0.6m

Deep
SpaceWindow

SGLI IRS
Bread Board Model

Infrared Scanning Radiometer(SGLI-IRS)

Sensor Unitfeatures

SGLI VNR

Non Polarized Observation （11ch）, IFOV 250m, Swath 1150km
Polarized Observation（2ch）, IFOV 1km, Swath 1150km

SGLI IRS

Shortwave Infrared （SWI 4ch）, IFOV 250m/1km, Swath 1400km
Thermal Infrared （TIR:2ch）, IFOV 500m, Swath 1400km

Development status of SGLI at SPIE Europe, Berlin 20095SGLI Specification• The SGLI features are 250m (VNI) and 500m (T) spatial resolution andpolarization/along-track slant view channels (P), which will improve land,
250m over the Land or coastal
coastal, and aerosol observations.
area, and 1km over offshore
GCOM-C SGLI characteristics
Sun-synchronousOrbit(descending local time: 10:30)
Altitude 798km, Inclination 98.6deg
Mission Life 5 years (3 satellites; total 13 years)
Push-broom electric scan (VNR)
Scan
Wisk-broom mechanical scan (IRS)
1150km cross track (VNR: VN & P)
Scan width
1400km cross track (IRS: SW & T)
Digitalization 12bit
Multi-angle
Polarization 3 polarization angles for P
obs. for674nm andAlong track Nadir for VN, SW and T,
869nm
direction+45 deg and -45 deg for P

On-board
calibration

VN: Solar diffuser, LED, Lunar cal
maneuvers, and dark current bymasked pixels and nighttime obs.
SW: Solar diffuser, LED, Lunar, and darkcurrent by deep space window
T: Black body and dark current by deepspace window

SGLI channels
Lstd
Lmax SNR at Lstd IFOV
VN, P:
VN, P, SW:
VN, P, SW: nm
2
SNRm
W/m /sr/μm
T: μm
T: Kelvin
T: NEΔT
380
1060
210
250
250
412
1075
250
400
250
443
10
64
400
300
250
490
1053120400
250
530
2041350
250
250
565
20
3390
400
250
673.5
202362
400
250
673.5
2025210
250
250
763
840
350
1200
250/1000868.520830400
250
868.5
2030300
200
250673.52025250250
1000
868.5
2030300
250
1000
1050
2057248500
1000
1380
2081031501000
1630
200
35057250
2210
50
1.9202111000
10.80.7300
3400.2250/500
12.00.7300
340
0.2
250/500
λCH
VN1
VN2
VN3
VN4
VN5
VN6
VN7
VN8
VN9
VN10
VN11
P1
P2
SW1
SW2
SW3
SW4
T1
T2

Development status of SGLI at SPIE Europe, Berlin 2009

Δλoption

6

Bread Board Model (BBM) Activity

Visible and Near infrared radiometer (VNR)
CriticalTechnologies- To Validate
feasibility of
the criticalcomponents

BBM System
Design-To establish SGLI

system design toachieve observation
requirement

BBM Component Tests- To assess and demonstrate theobservation performances by componentlevel<Major BBM component>
・11line CCD

・Optics

・Bandpass filters- To assess and demonstrate
the observation performancesby system level

Radiometric Tests

・Bandpass filter Assembly

VNR-NP・Polarization filter Assembly

Geometric Tests

非偏光観測機能
非偏光観測機能（鏡筒３本）

太陽光拡散板・Readout Circuit
VNR-PTests with onboard
calibrators

偏光観測機能（鏡筒２本）・CCD
約1.3m

Complete

BBM System Tests

約1.7m

Complete

Complete

Development status of SGLI at SPIE Europe, Berlin 2009

Complete7Bread Board Model (BBM) Activity
Infrared Scanning radiometer (IRS)

CriticalTechnologies- To Validate
feasibility of
the criticalcomponents

BBM
System Design-To establish SGLI

system design toachieve observation
requirement

BBM Component Tests- To assess and demonstrate theobservation performances by component
level<Major BBM component>
・SWIR Detector

・TIR Detector

BBM System Tests- To assess and demonstrate
the observation performancesby system levelSWIR Radiometric Tests

BBM用
SWI検知器・Optics
・Mechanical Cooler
地球観測窓
太陽光校正窓・Mirror Sample
約0.6m

深宇宙校正窓約1.4m

TIR Radiometric Tests(Vacuum condition)

・Scan Mirror Assembly

観測光SWI検出器

走査モータ

光学
ベンチ

・CCD
・TIR detector

機械式冷凍機黒体・Readout Circuit

Geometric Tests

・Blackbody

Tests with onboard
calibrators

TIR検出器Complete

Complete

Complete

Development status of SGLI at SPIE Europe, Berlin 2009

Complete
8BBM test results of VNR
Dynamic Range VNR dynamic range requirement is set based on careful study of target
characteristics.
 VNR uses CCD. Integration time can be easily changed by command.
 This means dynamic range adjustment is possible.
9 Difference between design and manufacturing results such astransmittance of optics can be adjusted
9 Dynamic range modification can be changed even after launch
9 Calibration technique using different integration time.

Development status of SGLI at SPIE Europe, Berlin 2009

9

BBM test results of VNR
CCD Integration Time
Previous GLI design

SGLI VNR design

Development status of SGLI at SPIE Europe, Berlin 200910

BBM test results of VNR
Linearity

linearity error

test result of VN10 non-polarized observing telescope
4%
3%
2%
1%
0%-1%-2%-3%-4%

test result
linearity req
0linearity error [%] Linearity is very important forradiometer because it leads toaccuracy dependencies to input
radiance level.
 Also, the test methodology
using integration time above
mentioneduses
theassumption that sensor is very
linear.
 VNR BBM linearity is checkedfor
both
input
radiance
dependencies and integration
time dependencies.
 Test result is very good andfurther detailed analysis isconducted to find the major
non-linear element to improve.

109876543210Development status of SGLI at SPIE Europe, Berlin 2009

102030input radiance [W/m^2/str/μm]
test result of non-polarized observing telescope

400deg+12deg-12degreq

VN1 VN2 VN3 VN4 VN5 VN6 VN7 VN8 VN9 VN10 VN1111

BBM test results of VNR
Noise SGLI noise performance is required as Signal to Noise Ratio(SNR) at standard signal observation radiance (Lstd) for eachobservation channel.
 Both integration time dependence and input radiance for SNR waschecked.
 The all channels noise level met the sensor specification.
Test Result

6Development status of SGLI at SPIE Europe, Berlin 2009

Ｐ1

VN11

VN10

VN08

VN07

VN06

0VN05

25

1

VN04

10
15
20
iinput radiance [W/m^2/str/μm]

2VN03

53VN02

04VN01

SNR
Lstd
fitting curve
Req at Lstd

Req

5VN09

1000
900
800
700
600
500
400
300
200
10007

rms noise [count]

SNR

test result of non-polarized observing telescope (VN10)

12

BBM test results of VNR
Polarized Light Observation
 The special polarization unit is set to the collimator light source. The collimatorpolarization characteristic is canceled with de-polarizer filter and polarized unit
can be rotated around the optical axis to realize the desired polarized direction forboth linear and partially polarized light.
 As the result of BBM test, approximately 4% polarization observation accuracy(ΔP/Pstd) and 1.3deg polarization direction error is confirmed for the 670nm
polarization observing telescope with standard 5% polarized light (Pstd).
Polarization
Unit

VNR BBMtest result of 670P polarization observing telescope

Collimator
SystemRotating
StagePolarization AccuracyΔP/P

7%
6%

Design Target

5%

Input Angle

4%+27.5deg

3%+0.5deg

2%-27.5deg

1%
0%
250

500

750∞

SNR

Development status of SGLI at SPIE Europe, Berlin 200913

BBM test results of IRS
Scanning PerformanceBecause very stable rotating speed is important for sensor observation geometry,the centroid position error and product of inertia should be minimized.
Manufacturing error and assembly process were carefully studied and confirmed.
The friction learning technique in the rotation speed control loop is also applied.
The selection of the bearing unit is another key issue for the IRS 5years operationrequirement. The bearing lifetime test under the vacuum condition was
successfully completed for required 2.7 x 10^8 revolution operation and still under
the test for the further design margin.

Position error [deg]Development status of SGLI at SPIE Europe, Berlin 200914

BBM test results of IRS
SWI Radiometric Performance

Test Result

60.6K

20.2K

10.1K

00.0K
T20.3K

T1

3SW40.4K

SW34

SW20.5KSW15left axis

Development status of SGLI at SPIE Europe, Berlin 2009

ReqTIRrmsnoise NEdT [K]0.7K

7
SWI rmsnoise [count]

SNR performance
9 high transmittance of telescopeand filters
9 detector sensitivity
9 dark current of 2.2μm channel
at operating -30deg C
9 System SNR performanceDynamic Range
9 adjustment at analog signal
processor (ASP)
EMC allowance limit
9 Trans Impedance Amplifier (TIA)
for detector readout.
9 EMC test in the shield room forboth RF radiation and conductive
noise allowanceright axis

15

BBM test results of IRSTIR Radiometric Performance Detector temperature & performanceÆ special dewar for 55K
Æ spectral characteristics at 55K
Æ detector linearity
 Effects of sensor temperature around
optical pathÆ dynamic range design considering
sensor temperature range
Æ Thermal vacuum test to confirm
the design.
Observation
light

SecondarymirrorPrimarymirror Dynamic range adjustment
methodology
Æ integrating capacity at ROICÆ integration timeÆ post amplifier gain (fixed)
 TIR system level test meets the noise
requirement (NEdT). (previous page)

SWIDetectorTIRDetector
ScanMirror

Dichroic
filterRitchey-Chretien telescope

Development status of SGLI at SPIE Europe, Berlin 200916SGLI Current Status Based on the BBM successful test result the sensor Engineering Model (EM)design is on going.
 The manufacturing of EM starts soon. EM test will be conducted in next year,and sensor PFM manufacturing starts.
 The target launch of GCOM-C1 is JAN 2014.
Japanese
Fiscal Year

FY2006

FY2007

FY2008FY2009FY2010

GCOM-W1 Project start

FY2011GCOM-W1
LaunchMilestone
GCOM-C1 Project start

SDR

GCOM-W1

Phase-A

PDR

Phase-B

Pre-Phase-A

Phase-C

Phase-A

FY2013GCOM-C1
Launch(TBD)

CDR
Phase-D

SDR

GCOM-C1

FY2012

PDR
Phase-B

Development status of SGLI at SPIE Europe, Berlin 2009

Phase-C

CDR
Phase-D17

Conclusion
 GCOM is JAXA’s GEOSS contribution of global observation
for water cycle, radiation budget and carbon cycle.
 SGLI is the optical sensor on GCOM-C1 satellite.
 Bread Board Model (BBM) design and test activity has
successfully completed last year.
 The Engineering Model (EM) design is currently conducted.
 The EM testing including environmental test and I/F testwith satellite system is planned in next year.

Development status of SGLI at SPIE Europe, Berlin 200918