1. Lunar Observation Data for GIRO Landsat–8 Operational Land Imager
Thomas C. Stone
U.S. Geological Survey, Flagstaff, AZ USA
GSICS Lunar Calibration Workshop
EUMETSAT
02 December 2014

2. Landsat–8 Operational Land Imager (OLI)
Landsat Data Continuity Mission satellite launched 11 Feb. 2012
Renamed Landsat-8 at operational phase, 30 May 2013; flight operations handed off to USGS
Sun-synchronous orbit at 705 km altitude; 10:00 a.m. descending node crossing time; 16-day repeat cycle
OLI instrument:
9 bands
Pushbroom imager
185 km cross-track swath
Accommodated with 14 Focal Plane Modules (FPMs)
Multispectral bands 494 pixels wide; Pan band 988 pixels wide

3. OLI Moon Image Acquisition
Typically once per month, at ~8° phase angle
Raster scan over the Moon in all 14 FPMs
Requires 2 orbits; repeat FPM 7 or 8 (FPM 7 used for GIRO data)

4. Example OLI image of the Moon
Level-1r image data: radiometrically corrected, geometrically raw
approximately 8.25× oversampled
Moon image size ~230×1860 pixels (Pan band images double size)
radiometric calibration: pre-launch, done at Ball Aerospace (BATC)
The same image at level-1g: geometrically corrected (incl. rotation)

5. Moon image integration: Threshold of pixel (radiance) level
space background level presumed zero
Pixel angular size from Calibration Parameter File, available online
Satellite Position:
Obtained from ancillary (telemetry) data files
interpolated to Moon center scanline
provides position in ECEF coordinates
Oversampling:
Computed from ancillary data — line-of-sight vector for Moon scans
proportional to: (pixel angular size×sampling rate) ⁄ (LOS slew rate)
must account for satellite motion during scan

6. OLI line-of-sight (LOS) for lunar scan
LOS angle relative to the center of the focal plane

7. Operation of the GIRO 3 OLI Moon acquisitions: March, April, May 2014
lunar irradiance for all 9 bands; radiance imagettes for 30m bands only
FPM 07 only
Satellite positions determined for each band, but the GIRO requires one value for all bands
use center of FPM = Red band
change in phase angle over the complete Moon scan (~8 sec) ≈0.04%
Radiance imagettes: 494×2001 pixels, centered on the Moon
DC imagettes not available (using Level-1r data)
GIRO-generated lunar irradiances show bias compared to OLI operational calibration