1. Progress of in-flight Calibration of HJ-1A/HSI Li Chuanrong Invited expert of NRSCC Professor and Vice President Academy of Opto-Electronics,CAS Phuket, Nov 03, 2009 1 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 2009

2. Contents Brief introduction of HJ satellite and HSI senor CAL/VAL activities of HJ-1A/HSI Challenges Prospect 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 20092

3. Introduction 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 20093 “2+1” 2 optical moonlets 1 radar-moonlet first-stage “4+4” 4 optical satellites 4 radar satellites second-stage On 2008.09.06, the small satellite constellation HJ -1A/1B were launched by a single LM-2C (CZ-2C) launch vehicle. On 2009.03.30, HJ -1A/1B were ready for operational applications. HJ -1C will launch soon.

4. Introduction 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 20094 satelliteHJ-1AHJ-1B payload 2 CCDs HSIIRS orbital typesun-synchronous orbit orbital height （ km ） 649.093 orbital inclination97.9486 orbital period (minute)97.5600 circles per day14+23/31 revisiting period (hour) CCD96 (48 with HJ-1A/1B combination) HSI96 IRS96 coverage period (day)31 coverage period circles457 local time at descending node10:30 AM ± 30min

5. The small satellite for environment and disaster ( HJ- 1A) in China carried a hyper- Spectral Imaging (HSI) sensor, designed by Academy of Sciences, CAS HJ-1A Spectral range: 450nm-950nm Band number: 115 Spatial resolution: 100m Swath: 50km Side-looking: ±30° Revisiting: 4-31days Introduction

6. Principles of HSI 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 20096  The imaging approach used by HSI is a spatially modulated Fourier transform method based on a Sagnac interferometer.  Onboard inner calibration mode and earth observation mode can be switched by a swing mirror. Introduction

7. 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 20097 Principles of HSI Introduction

8. Imaging Parameters of HSI Parameters HJ-1AEO-1 CCDHSIALIHyperion Spectral Range430-900nm450-950nm400-2400nm400-2500nm Spatial Resolution30m100m30m Swath Width360km50km36km7.5km Spectral Resolution--~4.3nm--~10nm Number of Bands411510220 Comparison of Parameters Between HJ-1A and EO-1 Introduction 8 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 2009

9. Calibration requirement to HSI:  New imaging system and mechanism — We have less experiences  We have not carried out on board calibration with consideration of instrument safety  With the issues above we do need more sites and more experiments to study the way to calibrate this new kind of sensor CAL/VAL activities of HJ-1A/HSI 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 20099

10. Vicarious calibration activities Dunhuang Site (twice after launch) – 40.08N, 94. 38E – Altitude: 1200m – 2008.10.14-2008.10.22 (Gain level 1) – 2009.08.19-2009.08.29 (Gain level 2) Inner Mongolia (once for validation) – 2009.09 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200910 CAL/VAL activities of HJ-1A/HSI

11. Measure Target Surface Properties Measure Atmospheric Properties Radiative Transfer Model - Modtran; 6S Predicted At-Sensor Radiance (L) Illumination + Viewing angles Sensor Signal (DN) DN L Gain=dL/dDN offset Sensor’s spectral response function Vicarious calibration at Dunhuang Site 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200911

12. Radiometric vicarious calibration results of HSI （ Gain1) WL(nm)GainWL(nm)GainWL(nm)GainWL(nm)GainWL(nm)Gain 460.040.2927513.561.0333581.181.7071669.292.9618788.894.4275 462.140.3050516.171.1463584.521.7016673.733.0574795.074.6644 464.250.3447518.811.1874587.901.7869678.233.0978801.344.6438 466.380.3786521.481.1288591.331.9722682.793.1684807.724.5858 468.530.4018524.171.1658594.792.0156687.413.4454814.204.9406 470.710.4296526.891.2008598.301.9759692.104.3658820.786.4526 472.900.4713529.641.2321601.851.9553696.853.9148827.475.5252 475.110.5059532.421.2460605.441.9843701.663.8392834.275.3826 477.350.5022535.221.3309609.072.0150706.543.8968841.184.5829 479.600.5239538.061.2698612.742.1141711.503.7569848.204.3767 481.880.6020540.921.4228616.462.2630716.523.7909855.354.4874 484.180.6329543.821.3548620.232.1945721.615.8620862.624.2436 486.500.7557546.751.3759624.042.1912726.775.1258870.014.3057 488.840.7367549.711.4898627.902.3906732.015.5057877.534.1998 491.200.7456552.701.4741631.812.4263737.334.3242885.184.1541 493.590.8194555.731.4915635.762.4634742.734.1700892.964.0919 496.000.7721558.791.5827639.772.4562748.203.9960900.895.7221 498.440.8276561.881.5462643.822.5488753.753.9403908.955.6478 500.900.8993565.001.5896647.932.7137759.393.8426917.166.2722 503.380.9542568.161.6073652.092.9064765.1111.5210925.524.7639 505.890.9832571.361.6783656.312.9426770.924.5856934.047.7071 508.421.0366574.601.5987660.582.9840776.824.0644942.7112.8335 510.981.0400577.871.6443664.902.8501782.814.1707951.5410.0017 12

13. Cross comparison at Dunhuang site Between HJ-1A/HSI channels and corresponding MODIS bands 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200913

14. HJ-1A/HSI and Terra/MODIS Image Pairs MODIS channel 1 UTM 04:25 May 29,2009 HSI channel 73 UTM 04:41, May 29,2009 870 pixels 180 pixels Cross-comparison at Dunhuang site 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200914 CAL/VAL activities of HJ-1A/HSI

15. MODIS channel 1HSI channels 57-74 MODIS channel 2HSI channels 98-109 MODIS channel 3HSI channels 1-11 MODIS channel 4HSI channels 34-43 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200915 Cross-comparison at Dunhuang site CAL/VAL activities of HJ-1A/HSI

16. MODIS observed radianceHSI-convolved radiance MODIS channel 1112.6021109.5861 MODIS channel 274.0045865.9016 MODIS channel 3126.2463135.7682 MODIS channel 4120.6291123.0256 distinction of observing geometry and atmosphere due to different acquisition time Discrepancy MODIS calibration accuracy HSI calibration accuracy 1 23 16 Cross-comparison at Dunhuang site CAL/VAL activities of HJ-1A/HSI

17. Current challenges  Uncertainties in radiometric vicarious calibration  Radiometric cross-calibration method based on other well-calibrated satellite data is to be studied  Spectral calibration is to be expected 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200917

18. Prospect  Invited by former WGCV group chair Dr. Cao Changyong, we will take part in Antarctic Dome C project on behalf of NRSCC  The actions including confirmation of coverage area of Antarctic region and planning of data acquisition in Dec. of this year has been carried out  By working on this project, AOE, as technical and operational facilitator of NRSCC, is willing to join the actions of CEOS WGCV.  AOE will also be pleasant to technically bridge the action cooperation between CEOS and China related agencies, such as data democracy, calibration, validation, virtual constellation etc. 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200918

19. Anticipated agency participation HJ-1A/HSI image over Dome C area for example 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200919 2009-09-13 23:59 scene Center Latitude: S74.676132° scene Center Longitude:E124.513398° solar altitude angle: 5.5°

20. Anticipated agency participation Near-term plans  Provide related HJ-1A/HSI data and technical parameters support, so as to enrich datasets about the Dome C site.  In accordance with the procedure of CEOS/WGCV, carry out the cross-calibration studies between HJ-1A/HSI and other well-calibrated visible/near infrared sensors based on the Antarctic Dome C calibration site.  Invite foreign calibration experts including those work for CEOS to go to China for scientific discussion periodically. 23 rd CEOS Plenary I Phuket, Thailand I 3-5 December 200920

21. Thank you !