Landsat Missions

Landsat Thematic Mapper No-Payload Correction Data

Payload Correction Data (PCD) provides critical information when correcting for geometric distortions inherent to the Landsat Thematic Mapper imaging system and temperature values used to estimate per-scan gains and biases necessary for the radiometric calibration of the instrument's thermal band data. 

No-PCD Radiometric Calibration

No-PCD Radiometric Calibration
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No-PCD Geometric Calibration

No-PCD Geometric Calibration
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What is Payload Correction Data?

PCD contains critical information needed to correct geometric distortions, as well as temperature values used to estimate per-scan gains and biases necessary for the radiometric calibration of the instrument's thermal band data. PCD contains information on the spacecraft ephemeris, gyros, gyro drift, angular displacement sensor (ADS), and star tracker. The gyros, ADS, and star tracker allow for the correction of the low-to-high frequency attitude disturbances that are present within the data. The spacecraft position and velocity data provided in the PCD ephemeris information can sometimes be replaced by other entities such as the mission Flight Operations (Flight Ops) team using tracking data, such that this “definitive” post-pass ephemeris can be substituted for the missing PCD ephemeris.  

In cases where the satellite tracking information is not present, a method has been developed by the USGS to generate a set of Two Line Elements (TLEs) that can be used for determining an approximate spacecraft position.  Mean pointing offsets and very low frequency attitude disturbances may be corrected using ground control points, with bias and first order corrections being applied through the precision correction process. The magnitude of the uncompensated attitude disturbances cannot be routinely measured within the Landsat TM Level-1 products. There is no method for determining the spacecraft’s mid-to-high frequency attitude variations, so these disturbances will remain within the data.   __________________________________________________________________________________________________________________________

Over 260,000 Landsat 5 Thematic Mapper (TM) scenes acquired between January 1986 and December 1999, originally downlinked to international ground stations, lack the necessary PCD. 

The green dots on this map denote the coverage of Landsat Thematic Mapper (TM) no-Payload Correction Data (PCD)

The green dots on this map display the coverage of Landsat Thematic Mapper (TM) no-Payload Correction Data (PCD). 

Until recently, these scenes failed Landsat Level-1 data processing and could not be added to the Landsat data archive. However, as of early February 2018,  processing algorithm changes make it possible to process these scenes into the Landsat Collection 1 Level-1 data inventory and make them available for download from EarthExplorer. Adding these unique scenes significantly enriches the Landsat archive and improves the scope of time series analysis.

46 percent of the scenes processed within the required root square mean error (RMSE) of 12 meters or lesss, and were placed into the Tier 1 collection category. The remaining 54 percent of the scenes are cataloged as Tier 2.

No-PCD scenes are included in EarthExplorer's Landsat 4-5 TM search results. The majority of these scenes are cataloged as Tier-2 data. A new metadata field  "DATA_ANOMALY" is visible on EarthExplorer's metadata information for each scene, and is also listed in the metadata (.MTL.txt) file that accompanies the Level-1 product. The value "NO_PCD" identifies these scenes.

As the USGS receives and ingests data from international cooperators in support of the Landsat Global Archive Consolidation (LGAC) effort, more TM scenes may be identified, categorized, and processed  as no-PCD.

Geometric distortions and radiance value differences may be evident in these data.