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Landsat Calibration & Validation

While Landsat satellites are well-designed and calibrated prior to launch, continuous calibration is required to offset degradation that may be caused by mechanical or electrical effects, or exposure to UV radiation. Calibration requires a comparison between the measuring instrument and an absolute reference standard of known accuracy. Validation of Landsat data is an ongoing effort.

Maintaining the Gold Standard in Earth Observations

Continuity with the past is key to meeting future land imaging science needs. The Landsat program is the longest continuous record of satellite-based Earth imaging. Landsat data quality is viewed by the remote-sensing user community as the "Gold Standard" (National Geospatial Advisory Committee, 2020).

To ensure the continued excellent quality of Landsat data, the USGS Earth Resources Observation and Science (EROS) Center has identified the following key strategic pillars: 

  1. Maintain a well-calibrated multidecade remote-sensing archive for science applications and Earth observation advancement. 
  2. Develop and understand land remote-sensing requirements and land imaging solutions. 

Understanding the land imaging requirements of current and future users, along with an ability to assess the capabilities of current and future systems for meeting those requirements, is key to meeting future land imaging science needs. 

In the past, the Cal/Val activities addressing the pillars noted above were spread across multiple groups. The EROS Cal/Val Center of Excellence (ECCOE) was established in 2018 to enable the USGS to more efficiently address national and global land remote-sensing needs.

The ECCOE Landsat Cal/Val Team continually monitors the radiometric performance of active Landsat missions and makes calibration adjustments as needed. Continual geometric corrections are made to ensure Landsat data are of the highest quality. 

 

Landsat 9 pre-launch, commissioning, and early on-orbit performance highlighted in journal

A recently published Remote Sensing Special Issue provides information on the calibration and validation activities performed that ensure the gold standard of geometric, radiometric, spatial, and spectral resolutions are upheld, and lead to known and expected superior Landsat 9 data quality. Topics cover pre-launch characterization, testing, commissioning, and early on-orbit performance for the OLI and TIRS instrument and Landsat 9 spacecraft. Visit the Remote Sensing webpage to view the published papers within this issue.


Radiometric Calibration/Validation

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Railroad Valley Playa
Landsat 9 image of Railroad Valley Playa, Nevada acquired July 2024. A portion of the playa is used as a vicarious radiometric calibration and validation site for various satellite sensors.

 

Factors like sensor artifacts, viewing and illumination angles, or atmospheric conditions affect Landsat data's digital number (DN) values. 

Monitoring and regular characterization of sensor data are required to maintain radiometric calibration and stability of Landsat products and improve algorithms and processes used in product generation.

Access the Landsat Radiometry webpage to learn more. 

 

 

 

 

 

 


Geometric Calibration/Validation 

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Landsat 9 image of the Phoenix Metropolitan Area - The Valley of the Sun
Landsat 9 image of the Phoenix, Arizona metropolitan area acquired July 2024. 

 

Accurate geometry ensures that Landsat data pixels are aligned and that the data can be used easily in time series analysis through the use of ground control points, processing levels, and spatial performance tests. 

The exceptional geometric qualities of Landsat 8 and Landsat 9 OLI/TIRS data are used to improve the reference database used to precisely and accurately geolocate all Landsat Level-1 data products. 

Access the Landsat Geometry webpage to learn more.

 

 

 

 

 

 

Calibration Files Used in Landsat Product Generation

    • Landsat Calibration Parameter Files Landsat Calibration Parameter Files

      Calibration Parameter Files (CPFs) provide radiometric and geometric coefficients needed for processing of raw, uncorrected Landsat image data. Each timeframe specific CPF contains calibration coefficients that have been adjusted to correct for the time varying performance of the sensor.
      Landsat Calibration Parameter Files

      Landsat Calibration Parameter Files

      Calibration Parameter Files (CPFs) provide radiometric and geometric coefficients needed for processing of raw, uncorrected Landsat image data. Each timeframe specific CPF contains calibration coefficients that have been adjusted to correct for the time varying performance of the sensor.
      Learn More
    • What are Landsat Response Linearization Look Up Tables? What are Landsat Response Linearization Look Up Tables?

      Landsat Response Linearization Look Up Tables (RLUT) are additional files that accompany Calibration Parameter Files (CPFs) and contain a mapping lookup table to linearize the output of the Landsat 8 and Landsat 9 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) detectors. Learn more (and download RLUT files): Landsat Response Linearization Look Up Tables

      What are Landsat Response Linearization Look Up Tables?

      What are Landsat Response Linearization Look Up Tables?

      Landsat Response Linearization Look Up Tables (RLUT) are additional files that accompany Calibration Parameter Files (CPFs) and contain a mapping lookup table to linearize the output of the Landsat 8 and Landsat 9 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) detectors. Learn more (and download RLUT files): Landsat Response Linearization Look Up Tables

      Learn More

Landsat Mission Underfly Opportunities

Cross-calibration between instruments is the best method to standardize Landsat sensors.  As a newly launched satellite makes its way to its final orbit, opportunities to acquire imagery near-coincidentally in tandem with an earlier mission sensor allows USGS and NASA Landsat Cal/Val staff to ensure the new sensors are accurately calibrated and characterized.   Underfly opportunities have been successful since Landsat 4 and Landsat 5 flew in tandem during an underfly campaign on March 15-16, 1984 following the Landsat 5 launch. 

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Landsat 9 Underfly with Landsat 8 over Puerto Vallarta, Mexico
Landsat 9 underfly with Landsat 8 over Puerto Vallarta, Mexico on November 11, 2021. The left image shows the Landsat 8 OLI image and the right image is from Landsat 9 OLI. 

Visit the Landsat Mission Underfly Opportunities webpage for details and to view pictures from each of the historic underfly events. 
 

Additional Calibration Information

    • Test Sites Catalog Test Sites Catalog

      The number of Earth-observing sensors and their derived science products continue to grow rapidly. Without characterization and calibration of these sensors, the products they provide could not be reliably used by scientists and decision makers.
      Test Sites Catalog

      Test Sites Catalog

      The number of Earth-observing sensors and their derived science products continue to grow rapidly. Without characterization and calibration of these sensors, the products they provide could not be reliably used by scientists and decision makers.
      Learn More
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