MRO CRISM Derived Data Record (DDR)
Instrument: Compact Reconnaissance Imaging Spectrometer for Mars
PDS Data Set ID: MRO-M-CRISM-6-DDR-V1.0
For more information about CRISM products, go to the CRISM Product Primer.
For more information about DDRs, see the CRISM Data Product SIS.
A Derived Data Record (DDR) accompanies each observation pointed at Mars’ surface, and includes information needed to map project data calibrated to units of radiance or I/F, or to process them further to Lambert albedo corrected for photometric, atmospheric, and thermal effects.
There are two types of information in DDRs: geometric information (latitude, longitude, incidence, emission, and phase angles) and information on surface physical properties (slope magnitude and azimuth, thermal inertia).
Once image data are assembled into EDRs and calibrated into TRDRs, DDRs are created for the data. DDRs contain multiple-band images with the same spatial dimensions as a scene EDR or the resulting TRDR. There is one DDR per VNIR TRDR or scene EDR, and one DDR per IR TRDR or scene EDR. The DDR is indexed to the wavelength bands of EDRs and TRDRs that are closest to 610 nm (VNIR) or 2300 nm (IR).
CRISM Observing Modes Used
Mode |
Pointing |
Description |
Coverage |
---|---|---|---|
Targeted (hyperspectral) |
Tracking as shown, once per target |
Full resolution (FRT) Spatial pixels unbinned for target – 18 m/pixel @ 300 km, 10x binned for EPF |
~6500 per Mars year |
Half resolution short (HRS) Spatial pixels 2x binned for target – 36 m/pixel @ 300 km, 10x binned for EPF; same swath length as above |
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Half resolution long (HRL) Spatial pixels 2x binned for target – 36 m/pixel @ 300 km, 10x binned for EPF; twice swath length as above |
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Full resolution short (FRS) Spatial pixels unbinned for target – 18 m/pixel @ 300 km; half swath length as above |
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Along-track oversampled (ATO) Spatial pixels unbinned for target – 18 m/pixel cross-track, up to ~3 m/pixel downtrack, requires special processing for increased resolution; half swath length as above |
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Along-track undersampled (ATU) Spatial pixels unbinned for target – 18 m/pixel cross-track, 36 m/pixel downtrack; half swath length as above |
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Atmospheric (hyperspectral) |
Tracking as shown but only center of target measured |
EPFs Spatial pixels 10x binned (~200 m/pixel @ 300 km) |
Lat./lon. grids every ~9° of Ls |
Nadir-pointed |
Tracking Optical Depth (TODs) Spatial pixels 10x binned (~200 m/pixel @ 300 km) |
Between other scheduled observations |
|
Limb scans |
Limb scan measurements (LMBs) Spatial pixels 10x binned; ~200 m vertical sampling |
2 orbits every 2 months |
|
Mapping (selected wavelengths) |
Nadir-pointed |
Multispectral survey (MSP or MSV) 73/74 or 94/94 selected channels, spatial pixels 10x binned (~200 m/pixel @ 300 km) |
~80% of Mars |
Multispectral windows (MSW) 73/74 or 94/95 selected channels, spatial pixels 5x binned (~100 m/pixel @ 300 km) |
Select areas plus sampling of seasonal variation at polar cap |
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Hyperspectral survey (HSP or HSV) 262 channels, spatial pixels 10x binned (~200 m/pixel @ 300 km) |
Select areas plus sampling of seasonal variation at polar cap |
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Radiometric Calibration (CAL) |
- |
Observations of onboard integrating sphere |
Daily |
Bias Calibration |
- |
Dark observations at multiple exposure times |
Daily |
Flat-Field Calibration (FFC) |
Nadir-pointed |
Observations of bland regions of Mars |
Every month |
Contents of each type of CRISM observation
Class of observation |
Frame rate, Hz |
Activity |
Pixel binning |
# |
Wave-lengths |
Frames (typical) |
---|---|---|---|---|---|---|
Full resolution targeted (FRT) |
3.75 |
central scan |
1 |
1 |
545 |
390 |
EPF scans |
10 |
10 |
15 |
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dark sets |
1 |
4 |
12 |
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Half resolution short targeted (HRS) |
3.75 |
central scan |
2 |
1 |
545 |
243 |
EPF scans |
10 |
10 |
15 |
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dark sets |
2 |
4 |
12 |
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Half resolution long targeted (HRL) |
3.75 |
central scan |
2 |
1 |
545 |
487 |
EPF scans |
10 |
10 |
15 |
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dark sets |
2 |
4 |
12 |
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Full resolution short (FRS) |
3.75 |
half central scan |
1 |
1 |
545 |
195 |
dark sets |
4 |
12 |
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Along-track oversampled (ATO) |
3.75 |
half central scan |
1 |
1 |
545 |
195 |
dark sets |
4 |
12 |
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Along-track undersampled (ATU) |
3.75 |
half central scan |
1 |
1 |
545 |
195 |
dark sets |
4 |
12 |
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Atmospheric survey (EPF) |
3.75 |
EPF scans |
10 |
11 or 13 |
545 |
15 |
dark sets |
4 |
12 |
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Limb scan (LMB) |
3.75 |
Individual scans |
10 |
variable |
545 |
540 |
dark sets |
same |
12 |
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Tracking optical depth (TOD) |
3.75 |
3-second segments |
10 |
12 |
545 |
12 |
dark sets |
4 |
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Multispectral survey (MSP or MSV) |
15 |
3-minute segments |
10 |
8 |
73/74 or 94/95 |
2700 |
dark sets |
9 |
12 |
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Hyperspectral survey (HSP or HSV) |
15 |
3-minute segments |
10 |
8 |
262 |
2700 |
dark sets |
9 |
12 |
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Multispectral window (MSW) |
30 |
1 3-minute segment |
5 |
1 |
73/74 or 94/95 |
5400 |
dark sets |
2 |
12 |
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Radiometric calibration (CAL) |
1 (VNIR), 1 (IR) |
sphere background |
1 |
2 |
545 |
12 |
sphere frames |
1 |
32 |
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1 (VNIR), 3.75 (IR) |
sphere background |
2 |
12 |
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sphere frames |
1 |
32 |
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1 (VNIR), 15 (IR) |
sphere background |
10 |
2 |
73 |
12 |
|
sphere frames |
1 |
32 |
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1 (VNIR), 30 (IR) |
sphere background |
5 |
2 |
12 |
||
sphere frames |
1 |
32 |
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Bias calibration |
1 |
dark frames, several integration times |
1 |
4 |
438 (IR only) |
10 |
3.75 |
5 |
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15 |
10 |
4 |
55 (IR only) |
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30 |
5 |
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Flat field calibration (only 1 frame rate at a time) (FFC) |
1 |
dark sets |
1 |
2 |
545 |
12 |
3-minute segments |
1 |
180 |
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3.75 |
dark sets |
2 |
12 |
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3-minute segments |
1 |
675 |
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15 |
dark sets |
10 |
2 |
73 |
12 |
|
3-minute segments |
1 |
2700 |
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30 |
dark sets |
5 |
2 |
12 |
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3-minute segments |
1 |
5400 |
CRISM DDR products have the following file names:
tttnnnnnnnn_mm_DEbbbc_DDRv.IMG (with detached PDS label)
where:
ttt = class type
FRT = Full Resolution Targeted Observation
HRL = Half Resolution Long Targeted Observation
HRS = Half Resolution Short Targeted Observation
FRS = Full Resolution Short Observation
ATO = Along-track Oversampled Observation
ATU = Along-track Undersampled Observation
EPF = Atmospheric Survey EPF
TOD = Tracking Optical Depth Observation
MSV = Multispectral Survey, lossy compressed
MSP = Multispectral Survey, losslessly compressed
HSP = Hyperspectral Survey, losslessly compressed
HSV = Hyperspectral Survey - VNIR only, losslessly compressed
MSW = Multispectral Window
FFC = Flat Field Calibration
nnnnnnnn = observation ID, unique for the whole CRISM mission, expressed as a hexadecimal number
mm = ordinal counter carried through from the source EDR ID, expressed as a hexadecimal number
bbb = macro #
c = sensor ID
S = VNIR
L = IR
v = version, 0-9, a-z
In ODE, TRDR products have the following Product IDs:
TTTNNNNNNNN_MM_DEBBC_DDRV