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THE LANDSAT DATA CONTINUITY MISSION 
OPERATIONAL LAND IMAGER (OLI) SENSOR 


1 2 2 2 2 2 

Brian L. Markham , Edward J. Knight , Brent Canova , Eric Donley , Geir Kvaran , Kenton Lee , 

Julia A . Barsi \ Jeffrey A. Pedelty 1 , Philip W Dabney 1 and James R . Irons 1 

^ASA/GSFC, Greenbelt, MD 20771; 2 Ball Aerospace & Technology Corp., Boulder, CO 80301; 

3 SSAI/GSFC, Greenbelt, MD 20771 

1. INTRODUCTION/STATUS 

The Landsat Data Continuity Mission (LDCM) is being developed by NASA and USGS and is currently planned 
for launch in January 2013 [1]. Once on-orbit and checked out, it will be operated by USGS and officially named 
Landsat-8. Two sensors will be on LDCM: the Operational Land Imager (OLI), which has been built and 
delivered by Ball Aerospace & Technology Corp (BATC) and the Thermal Infrared Sensor (TIRS)[2], currently 
being built and tested at Goddard Space Flight Center (GSFC) with a planned delivery of Winter 2012. The OLI 
covers the Visible, Near-IR (NIR) and Short-Wave Infrared (SWIR) parts of the spectrum; TIRS covers the 
Thermal Infrared (TIR). This paper discusses only the OLI instrument and its pre-launch characterization; a 
companion paper covers TIRS. 


2. INSTRUMENT DESCRIPTION 

The OLI is an all-reflective pushbroom radiometer that images a 185 km swath like the whiskbroom TM and 
ETM+ instruments (Figure 1,2). The OLI has 7 spectral bands (Table 1) that are similar to the reflective bands 
on the ETM+, though refined in bandwidth and location. In addition, it has a band centered at 443 nm that is 
intended to provide additional information about coastal regions and the atmosphere, and a band centered at 1373 
nm for detection of cirrus clouds. As per the ETM+, all spectral bands, with the exception of the panchromatic 
band are 30m IFOV; the pan band is 15 m. The dynamic range of OLI is set that it will not saturate for non- 
specular targets across all solar zenith angles observed on orbit. OLI data are transmitted at 12-bit radiometric 
resolution. 

The OLI is designed to achieve 5% uncertainty in radiance calibration and 3% uncertainty in reflectance 
calibration. To assist in maintaining this calibration, two full aperture Spectralon™ solar diffusers are part of the 
instrument as well as internal lamps. The solar diffusers will be used about every week, the lamps every day. 
The OLI will also observe the moon monthly. Detector to detector normalization within a band is required to be 
better than 0.5%; the diffuser observations will be key in maintaining this relative calibration. 



FPA (Focal 
Plane) Radiator ^ 
& Earthshield 


Entrance Aperture 


X (Velocity 
Direction) 



Calibration Asseml 
Assembly (Diffuser) 


FPE (Focal Plane 
Electronics) Radiator 

Shutter Assembly 


Calibration 

Aperture 



Baseplate Struts to 
Spacecraft Interface 


Optic Bench 


Focal Plane 
System (FPS) 


Baseplate Assembly 

ISE Assy (Instrument 
Support Electronics) 


3. 


Telescope Subsystem 


of 


to 



Figure 1. Operational Land Imager 

Table 1: OLI Spectral Bands 


Instrument Support 
Electronics (ISEI— — — 
, Subsystem Surwal 

Mecft/ 

TIM 

Boards 



Spare 

Board 

Controller 

Board 



Heater 

Controller 

Boards 

1; Data 

LV 

Power 

Supply 

’ Link 

Back- 

piane 


Figure 2. OLI Block Diagram 

PRE-LAUNCH TESTING AND RESULTS 


3.1. Spatial/Geometry 

The principal spatial and geometric characterizations 

(rsc, . the OLI instrument were performed in a thermal 

vacuum chamber using the BATC horizontal 
collimator assembly (HCA). The HCA includes 
various targets at the focus of the collimator that are 
***** used to test edge response, bright target recovery, 
ghosting and line of sight. Edge response as opposed 
modulation transfer function was used as the primary 

LD< 

hlo< measure of spatial response for the OLI. Figure 3 


shows samples of the OLI edge response, where all requirements were met. 






Figure 3. OLI edge response for the 30-meter band 

3.2. Spectral/Radiometry 

Spectral and radiometric testing of the OLI was performed at BATC with the OLI in a thermal vacuum chamber 
and with the spectral and radiometric sources outside. Testing included in-band relative spectral response, 
linearity, stability, noise, and absolute calibration. Band average relative spectral responses are shown in Figure 
4, and have been released to the web: http://ldcm.nasa.gov/spacecraft_instruments/oli_band_average.html . In 
Figure 5 are shown the median Signal to Noise ratios of the OLI bands at typical radiance levels (L^p), i.e., about 
a 10% reflectance at a 45° solar zenith angle. 


4. SUMMARY 

The OLI for LDCM has been completed, delivered and integrated onto the LDCM spacecraft. It meets the vast 
majority of its performance requirements with a few minor exceptions. 



Vegetation - Bare desert — CA ^^Blue Green —Red — Nl R * — Pan ^—SWIRl ^—SWIR2 Cirrus 


Figure 4. OLI band average relative spectral responses. 


OU Sfgnal-fo- Noise Performance at (.typical 

4M 



bind 

• OU SNR Requirement (median At Uypf ■ QU S*rR Performance (12-blt median At Lr^p] 


Figure 5. OLI Signal to Noise Performance 

5. REFERENCES 

[1] J.R. Irons and J.L. Dwyer, “An Overview of the Landsat Data Continuity Mission,” Proceedings of the SPIE, Vol. 7695, 12 May 2010. 

[2] D. Reuter et al., “The Thermal Infrared Sensor on the Landsat Data Continuity Mission,” IGARSS 2011, p 754-757, Honolulu, HI.