1. Lunar observation data set preparation
Terra / ASTER
Toru Kouyama
National Institute of Advanced Industrial Science and Technology
(AIST), Japan
Collaborating with Japan Space Systems (JSS)

2. Terra ASTER General description of “Terra” and “ASTER”
Sensors: ASTER, MODIS, MISR, CERES, MOPITT
1999~
Orbit Type
Polar, Sun Synchronous
Mean Altitude
705 km +/-5km
Orbit Period
98.8 minutes
Orbit Inclination
98.2 degrees
Equatorial Crossing
10:30 AM +/- 15 minutes
Ground Track Repeat
16 days (233 orbits)
From JSS’s brochure
ASTER
Ground track repeat cycle:16 days, i.e. every 16 days (or 233 orbits) the pattern of orbits repeats itself
(Advanced Spaceborne Thermal Emission and Reflection Radiometer)
operated by METI/JSS & NASA
Push broom sensor composed of three instruments
(VNIR, SWIR, TIR)
VNIR has nadir and backward cameras for taking stereo images

3. ASTER 21.5 15 60 8 18.6 42.6 30 128 90 12 Sensor Band Wavelength (μm)
Res. (μrad)
GSD
(m)
Swath
(km)
Quantization (bit)
VNIR
(Visible & Near Infrared) 1
21.5 15 60 8 2 3N 3B
18.6
SWIR
(Short wave Infrared) 4
42.6 30 5 6 7 9
TIR (Thermal Infrared) 10
128 90 12 11 13 14

4. Spectral Response Functions
ASTER
Spectral Response Functions 3N 3B
Band 1
Band 2
Band 3N/B
0.4
0.5
0.6
0.7
0.8
0.9
Wavelength [μm]

5. Description of the Moon acquisition (maneuver)
360 degree rotation maneuver of the satellite (April 14, 2003)
[Chamoun et al., 2004]
ASTER observed the Moon
Satellite position
TLE + SPICE
Because of the narrow FOV, ASTER cannot observe the Moon in regular operation.  Terra/MODIS
The Moon observation has been conducted only once due to the risk for Terra. => ASTER has taken the Moon only once..

6. Example of ASTER images
Oversampling ratio: 4.57
Moon Diameter:
Cross track ~450 pix
Along track ~2100 pix
Observation period: ~5 sec
around :09:34
Along track
Nadir
Backward
Cross track

7. L0B L1A L1B Example of ASTER images Radiance = a*DCL1B + b Raw data
I prepared
L0B
L1A
L1B
Raw data
(non-calibrated)
Raw data
(non-calibrated)
Calibrated Data
+ Calibration
parameters
Dark signal level
Non-linearity
Sensitivity degradation…
Radiance = a*DCL1B + b

8. The lowest count = 0 radiance
Dark signal correction
Absolute calibration (calibration methods)
L1B
Dark signal correction:
Routinely night side observations for obtaining dark signal level.
The lowest count = 0 radiance
Absolute calibration:
Based on “Onboard calibration” results using onboard lamps for
- non-linearity
- sensitivity degradation, etc..
Because at this time JSS has only radiometric calibrated Moon data, my analysis has been based on other calibration activities of ASTER.
Radiance = a*DCL1B + b

9. Integration step
Moon Mask

10. Integration step I set the threshold DC = 5 for masking Moon region.
“0” is the reserved DC
for dead-pixels
“1” corresponds to
“0 radiance”.
I set the threshold DC = 5 for masking Moon region.

11. Oversampling consideration
Assuming constant rotating ratio:
Estimation of Oversampling ratio using an ellipse fitting method.
[e. g. Ogohara et al., 2012] Y X
Originally I didn’t have satellite information
Y / X = 4.57
 4.58 [Stone et al., 2003]
ASTER: Pushbroom

12. Operation of the GIRO: status and calibration results

13. Operation of the GIRO: status and calibration results
-27.7
100*(IIrr/IGIRO-1)
GIRO Irradiance
I summarized the results in one plot.

14. Operation of the GIRO: status and calibration results
[Kieffer & Stone, 2005] 5 -5 10
-10
-27.7
Band 1
Band 2
Band 3N
GIRO Irradiance

15. L1B Dark signal correction Dark signal: 0 radiance ASTER/Band 1
Moon
Deep Space
0 radiance
“0” is the reserved DC
“1” corresponds to “0 radiance”.

16. L1B Dark signal correction Dark signal: ASTER/Band 1 Deep Space Moon
“0” is the reserved DC
“1” corresponds to “0 radiance”.

17. Dark signal correction
ASTER/Band 1
Moon
Deep Space
Hand-made line noise correction using mean deep space DC in each line
Usign deep space region before and after Moon observation

18. Dark signal correction
ASTER/Band 1
Moon
Deep Space
Hand-made line noise correction using mean deep space DC in each line
ASTER/Band 1

19. Operation of the GIRO: status and calibration results
[Kieffer & Stone, 2005] 5 -5 10
-10
-27.7
Onboard calibration

20. Feedback for discussions
・ Dark signal correction:
It might be better to investigate dark signal level using deep space regions before and after the Moon if we use.
↑ In ASTER case, although dark level is expected to be “0”, I found there are significant line noises.
ASTER topic:
Japanese Lunar calibration team of ASTER has proposed the
second Lunar observation, and I will talk about this in Japan-US
ASTER Science Meeting in next week.

22. Band 1
Quantity
User Imgt
Processing
Observed Irradiance
Observed DC
DC Offset
Total number of pixels
699899

23. Band 2
Quantity
User Imgt
Processing
Observed Irradiance
Observed DC
DC Offset
Total number of pixels
698077

24. Band 3N
Quantity
User Imgt
Processing
Observed Irradiance
Observed DC
DC Offset
Total number of pixels
693576

25. [Tsuchida, 2012]

26. [Tsuchida, 2012]

27. [Tsuchida, 2012]

28. Dark signal correction
Absolute calibration (calibration methods)
Dark signal:
ASTER/Band 2
Moon
Deep Space
ASTER/Band 1

29. Dark signal correction
Absolute calibration (calibration methods)
Dark signal:
ASTER/Band 3N
Moon
Deep Space
ASTER/Band 1

30. [Chamoun et al., 2004]
ASTER observed the Moon