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)
1
Terra
General description of “Terra” and “ASTER”
Sensors: ASTER, MODIS, MISR, CERES, MOPITT
1999~
Orbit Type
Mean Altitude
Orbit Period
Orbit Inclination
Equatorial Crossing
Ground Track Repeat
Polar, Sun Synchronous
705 km +/-5km
98.8 minutes
98.2 degrees
10:30 AM +/- 15 minutes
16 days (233 orbits)
From JSS’s brochure
ASTER
(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
2
ASTER
Sensor
VNIR
(Visible &
Near
Infrared)
SWIR
(Short
wave
Infrared)
TIR
(Thermal
Infrared)
GSD
(m)
Swath
(km)
Quantiz
ation
(bit)
15
60
8
42.6 30
60
8
128
60
12
Wavelength Res.
Band
(μm)
(μrad)
1
0.52-0.60
2
0.63-0.69
3N
0.76-0.86
3B
0.76-0.86
4
1.600-1.700
5
2.145-2.185
6
2.185-2.225
7
2.235-2.285
8
2.295-2.365
9
2.360-2.430
10
8.125-8.475
11
8.475-8.825
12
8.925-9.275
13
10.25-10.95
14
10.95-11.65
21.5
18.6
90
3
Spectral Response Functions
ASTER
3N
3B
Band 1
0.4
0.5
Band 2
0.6
0.7
Band 3N/B
0.8
0.9
Wavelength [μm]
4
Description of the Moon acquisition (maneuver)
360 degree rotation maneuver of the satellite (April 14, 2003)
[Chamoun et al., 2004]
2003.04.14
7
6
ASTER observed the Moon
5
Satellite position
TLE + SPICE
2
1
3
4
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
5
for Terra. => ASTER has taken the Moon only once..
Example of ASTER images
Oversampling ratio: 4.57
Moon Diameter:
Cross track ~450 pix
Along track ~2100 pix
Along track
Observation period: ~5 sec
around 2003.04.14 22:09:34
Nadir
Cross track
Backward
6
Example of ASTER images
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
7
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..
Radiance = a*DCL1B + b
8
Integration step
Moon Mask
9
Integration step
“0” is the reserved DC
for dead-pixels
“1” corresponds to
“0 radiance”.
I set the threshold DC = 5 for masking Moon region.
10
Oversampling consideration
Assuming constant rotating ratio:
Estimation of Oversampling ratio using an ellipse fitting method.
[e. g. Ogohara et al., 2012]
Y
X
Y / X = 4.57
 4.58 [Stone et al., 2003]
ASTER: Pushbroom
11
Operation of the GIRO: status and calibration results
12
Operation of the GIRO: status and calibration results
-27.7
100*(IIrr/IGIRO-1)
GIRO Irradiance
0.52-0.60
0.63-0.69
0.76-0.86
0.76-0.86
13
Operation of the GIRO: status and calibration results
-27.7
10
Band 1
5
0
-5
-10
Band 2
Band 3N
[Kieffer & Stone, 2005]
GIRO Irradiance
14
Dark signal correction
L1B
Dark signal:
ASTER/Band 1
Moon
Deep Space
0 radiance
“0” is the reserved DC
“1” corresponds to “0 radiance”.
15
Dark signal correction
L1B
Dark signal:
ASTER/Band 1
Moon
“0” is the reserved DC
“1” corresponds to “0 radiance”.
Deep Space
ASTER/Band 1
16
Dark signal correction
Moon
Deep Space
ASTER/Band 1
Hand-made line noise
correction using mean
deep space DC in each line
Usign deep space region
before and after Moon
observation
17
Dark signal correction
Moon
Deep Space
ASTER/Band 1
Hand-made line noise
correction using mean
deep space
DC in
ASTER/Band
1 each line
18
Operation of the GIRO: status and calibration results
-27.7
10
5
0
-5
-10
[Kieffer & Stone, 2005]
Onboard calibration
19
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.
20
21
Band 1
Quantity
User Imgt
Processing
Observed Irradiance
0.002660296010277499
0.002660232910753413
Observed DC
40028272
40028270
DC Offset
1.02087569017662
1.01001450699612
Total number of pixels
699899
699899
22
Band 2
Quantity
User Imgt
Processing
Observed Irradiance
0.002315433433013099
0.002315556390154567
Observed DC
33534728
33534727
DC Offset
1.09474562654714
1.00000000000000
Total number of pixels
698077
698077
23
Band 3N
Quantity
User Imgt
Processing
Observed Irradiance
0.001877600541649895
0.001877508610671119
Observed DC
22405770
22405770
DC Offset
1.01760252980047
1.00000000000000
Total number of pixels
693576
693576
24
[Tsuchida, 2012]
25
[Tsuchida, 2012]
26
[Tsuchida, 2012]
27
Dark signal correction
Absolute calibration (calibration methods)
Dark signal:
ASTER/Band 2
Moon
Deep Space
ASTER/Band 1
28
Dark signal correction
Absolute calibration (calibration methods)
Dark signal:
ASTER/Band 3N
Moon
Deep Space
ASTER/Band 1
29
[Chamoun et al., 2004]
2003.04.14
7
6
ASTER observed the Moon
5
2
1
3
4
30