LSDS-1927 Version 2.0 Department of the Interior U.S. Geological Survey Landsat 7 (L7) Data Users Handbook Version 2.0 November 2019 Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Landsat 7 (L7) Data Users Handbook November 2019 Document Owner: ______________________________ Vaughn Ihlen Date LSRD Project Manager U.S. Geological Survey Approved By: ______________________________ Karen Zanter Date LSDS CCB Chair U.S. Geological Survey EROS Sioux Falls, South Dakota - ii - LSDS-1927 Version 2.0 Executive Summary The Landsat 7 Data Users Handbook is prepared by the U.S. Geological Survey (USGS) Landsat Project Science Office at the Earth Resources Observation and Science (EROS) Center in Sioux Falls, SD, and the National Aeronautics and Space Administration (NASA) Landsat Project Science Office at NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Maryland. The purpose of this handbook is to provide a basic understanding and associated reference material for the Landsat 7 Observatory and its science data products. In doing so, this document does not include a detailed description of all technical details of the Landsat 7 mission but focuses on the information needed by the users to gain an understanding of the science data products. This handbook includes various sections that provide an overview of reference material and a more detailed description of applicable data user and product information. This document includes the following sections: • Section 1 describes the background for the Landsat 7 mission, as well as previous Landsat missions • Section 2 provides a comprehensive overview of the Landsat 7 concept of operations, the Observatory, including the spacecraft, the Enhanced Thematic Mapper Plus (ETM+) instrument, the Landsat 7 ground system, as well as various institutional services • Section 3 provides information on radiometric and geometric instrument calibration, as well as a description of the Calibration Parameter File (CPF) • Section 4 includes information about the Landsat 7 Long-Term Acquisition Plan (LTAP) and documents the changes in data acquisition scheduling since launch • Section 5 includes a description of Level 1 data products and product generation, as well as conversion of Digital Numbers (DNs) to physical units • Section 6 provides an overview of data search and access using various online tools • Appendix A contains a list of known issues associated with Landsat 7 data • Appendix B includes information about the CPF content • Appendix C contains historical information pertaining to Landsat 7 ETM+ and Landsat 5 Thematic Mapper (TM) cross-calibration • Appendix D includes historical information about Level 0 Reformatted (L0R) and Level 1 Reformatted (L1R) data products • Appendix E details the differences between Level 1 Product Generation System (LPGS) and National Land Archive Production System (NLAPS) products This document is under Land Satellites Data Systems (LSDS) Configuration Control Board (CCB) control. Please submit changes to this document, as well as supportive material justifying the proposed changes, via a Change Request (CR) to the Process and Change Management Tool. - iii - LSDS-1927 Version 2.0 Note: This document contains information specific to Landsat 7 ETM+ Pre-Collection data only. Landsat 7 ETM+ Pre-Collection data is no longer available from USGS EROS. As of October 1, 2017, Landsat Collection data is the standard Landsat Level 1 data product available from USGS EROS. While Landsat Pre-Collection and Collection data share basic foundational qualities, there are important differences between the datasets that users must be aware of. For up-to-date information on Landsat Collection data, visit the Landsat Missions Website. - iv - LSDS-1927 Version 2.0 Document History Document Document Publication Change Number Version Date Number LSDS-1927 Version 1.0 June 2018 CR 13992 LSDS-1927 Version 2.0 November 2019 CR 15145 - v - LSDS-1927 Version 2.0 Contents Executive Summary ..................................................................................................... iii Document History ......................................................................................................... v Contents ........................................................................................................................ vi List of Figures ............................................................................................................... x List of Tables ............................................................................................................... xii Section 1 Introduction .............................................................................................. 1 1.1 Foreword.......................................................................................................... 1 1.2 Background ....................................................................................................... 2 1.2.1 EOSAT Era and Basis in Law for Landsat ................................................. 2 1.2.2 Previous Missions ...................................................................................... 3 1.2.3 Operations and Management .................................................................... 6 1.3 Landsat 7 Mission ............................................................................................. 7 1.3.1 Overall Mission Objectives ......................................................................... 7 1.3.2 Initial System Performance Requirements ................................................. 7 1.3.3 Current System Capabilities ...................................................................... 8 1.3.4 Global Survey Mission ............................................................................... 9 1.3.5 Rapid Data Availability ............................................................................... 9 1.3.6 Enhanced IGS Access ............................................................................... 9 1.4 Document Purpose ......................................................................................... 10 1.5 Document Organization .................................................................................. 10 Section 2 Observatory Overview ........................................................................... 12 2.1 Concept of Operations .................................................................................... 12 2.1.1 Orbit ......................................................................................................... 12 2.1.2 Swath Pattern .......................................................................................... 13 2.1.3 Worldwide Reference System (WRS) ...................................................... 14 2.1.4 Scheduling ............................................................................................... 15 2.1.5 Tracking and Spacecraft Control ............................................................. 16 2.1.6 Orbit Maneuvers ...................................................................................... 16 2.2 Enhanced Thematic Mapper Plus (ETM+) ...................................................... 18 2.2.1 Detector Geometry .................................................................................. 19 2.2.2 ETM+ Sample Timing .............................................................................. 20 2.2.3 ETM+ Subsystems ................................................................................... 22 2.3 Spacecraft Overview ....................................................................................... 29 2.4 Solid State Recorder (SSR) ............................................................................ 31 2.5 Ground System ............................................................................................... 32 2.5.1 Overview .................................................................................................. 32 2.5.2 Unique Landsat Ground System Components ......................................... 33 2.5.3 NASA Institutional Ground System Components ..................................... 37 Section 3 Instrument Calibration ........................................................................... 39 3.1 Radiometric Characterization and Calibration Overview ................................. 39 3.1.1 Radiometric Characteristics ..................................................................... 39 3.2 Pre-Launch Radiometric Characteristics ......................................................... 40 - vi - LSDS-1927 Version 2.0 3.2.1 Spectral Characterization ......................................................................... 40 3.2.2 Radiometric Calibration............................................................................ 41 3.2.3 Spherical Integrating Source (SIS) .......................................................... 42 3.3 Post-Launch Radiometric Characteristics ....................................................... 43 3.3.1 On-Orbit Calibration Methods .................................................................. 43 3.3.2 Internal Calibrator (IC) ............................................................................. 44 3.3.3 Full Aperture Solar Calibrator (FASC) ..................................................... 46 3.3.4 Partial Aperture Solar Calibrator (PASC) ................................................