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Remote Sensing Landsat 1,2,3. Major Remote Sensing Systems. 1. Introduction of Satellite Systems. Land observation satellite systems vehicles - spacecraft devices - electro-optical sensors images - digital images target - earth resources. Landsat 1,2,3.
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1. Introduction of Satellite Systems • Land observation satellite systems vehicles - spacecraft devices - electro-optical sensors images - digital images target - earth resources
Landsat 1,2,3 1972, 1975, 1978 http://hosting.soonet.ca/eliris/remotesensing/bl130lec11.html
1. Orbits • Sun-synchronous • Altitude 919km • Inclination 80o 80oN - 80oS • 103 minutes per cycle, 14 times each day • Because of the earth's rotation, each successive N/S pass is offset to the west by 2,875km • Distance between the adjacent tracks (at the Equator) is 159km • Passes over the same place every 18 days
Orbits .. http://rst.gsfc.nasa.gov/Intro/Part2_15.html
Orbits .. http://rst.gsfc.nasa.gov/Intro/Part2_15.html
http://edcsgs9.cr.usgs.gov/glis/graphics/guide/landsat/figure3.gifhttp://edcsgs9.cr.usgs.gov/glis/graphics/guide/landsat/figure3.gif
2. Return Beam Vidicon (RBV) • Generates high resolution television-like images • Landsat 1,2 consists 3 cameras sensitive to green, red, NIR, respectively • Forms a 3-band multispectral image (Bands 1, 2, and 3) • Landsat 1 and 2 RBV were hardly used due to technical failures • Landsat 3 RBV was modified but did not perform as expected
3. Multispectral Scanner (MSS) • A scanning system of a oscillating mirror to scan from W to E • The reflected energy is directed to 24 detectors that are sensitive to 4 bands with 6 detectors per band(Bands 4, 5, 6, and 7)
MSS .. http://rst.gsfc.nasa.gov/Intro/Part2_16.html
MSS .. A: Rotating MirrorB: DetectorsC: Instantaneous Field of ViewD: Ground Resolution CellE: Angular Field of ViewF: Swath http://hosting.soonet.ca/eliris/remotesensing/bl130lec11.html
Resolutions of MSS • Spectral resolution band4: 0.5-0.6mm (green) band5: 0.6-0.7mm (red) band6: 0.7-0.8mm (near infrared) band7: 0.8-1.1mm (near infrared) band8: 10.4-12.6mm (far infrared, Landsat 3 only)
MSS4 MSS5 MSS6 MSS7 http://rst.gsfc.nasa.gov/Intro/Part2_17.html
Resolutions of MSS .. • Radiometric resolution: 6 bits, 64 levels and re-scaled to 7 bits, 128 levels • Spatial resolution: 79x79m, re-sampled into 79x56m • Temporal resolution: 18 days for Landsat 1-3,
5. MSS scene • Ground swath: 185x185km • 5% overlap and 14-85% sidelap • 2340 scan lines, 3240 pixels per line • After skew correction, rectangle image becomes parallelogram due to spacecraft movement and the earth rotation
Skew Correction http://rst.gsfc.nasa.gov/Intro/Part2_15.html
6. Worldwide Reference System (WRS) • The nominal center of a Landsat scene is identified by combination of - Path: N-S along satellite orbital tracks (total 223 paths) - Row: E-W along latitudinal center lines (total 119 rows) • The three satellites retired in 1978, 1983, and 1983, respectively
7. Landsat 4,5,6,7 1982, 1985, 1993, 1999 http://rst.gsfc.nasa.gov/Intro/Part2_15.html
Orbit • - 705km, a lower altitude for finer spatial resolution and retrievable by space shuttle - inclination 98.20 - 99 minutes per cycle, 14.5 times each day - image swath 185km
影像镶嵌图 影像边界矢量图 Orbit
Orbit .. • The gap between successive passes at the equator is 2752km • The gap is filled in 16 days • Distance between the adjacent tracks (at the Equator) is 172km • Sidelap at the equator 7.6% • Adjacent swaths are acquired every 7 days • Landsat 4 and 5 are 8 days out of phase • New path system in WRS and less paths (233)
Orbit .. http://edcsgs9.cr.usgs.gov/glis/graphics/guide/landsat/figure4.gif
Second generation of Landsat MSS • On board landsat 4,5,6,7 are both MSS and TM • MSS band 1,2,3,4 are equivalent to band 4-7 on Landsat 1,2,3 • Spatial resolution 82m
Thematic Mapper (TM) • Spectral resolution • 7 bands and narrower bands
Thematic Mapper (TM) .. • Band1: 0.45-0.52mm (blue-green, water, soil & vegetation) • Band2: 0.52-0.60mm (green, chlorophyll reflection) • Band3: 0.63-0.69mm (red, chlorophyll absorption) • Band4: 0.76-0.90mm (near infrared, vegetation biomass, ) • Band5: 1.55-1.75mm (mid infrared, vegetation moisture, cloud, snow, ice) • Band6: 10.4-12.5mm (far infrared, temperature) • Band7: 2.08-2.35mm (mid infrared, geologic rock formation, plant heat stress)
Biophysical Sensitivity of Spectrums .. Upper epidermis Palisade Spongy mesophyll Lower epidermis http://www.cstars.ucdavis.edu/projects/modeling/
Landsat Band 6 http://rst.gsfc.nasa.gov/Intro/Part2_20.html
Resolutions of TM • Radiometric resolution: 8 bits, 256 levels of brightness • Spatial resolution: 30x30m, 120x120m for band6 • Temporal resolution: 16 days
TM Operation • Scanning • Tracking and Data Relay Satellites
Scanning • Each scan of TM mirror acquires 16 lines of data (4 lines for band 6) • The mirror is active in both E->W and W->E directions • Allows a slower mirror speed for better brightness response
TM detectors http://rst.gsfc.nasa.gov/Intro/Part2_20.html
Tracking and Data Relay Satellites • Landsats are teamed with two TDRS • TDRSs are geo-synchronous and transmit sensor data to central ground receiving station near White Sand, New Mexico • TDRSs relay commands from mission control to the Landsats and telemetry from the Landsat to the ground
Landsat 4, 5 • Landsat 4 retired in 2001 after near 20 years service • Landsat 5 retired June 5, 2013 after 29 years service
Metternicht, G. I., and J. A. Zinck. "Evaluating the Information Content of JERS-1 SAR and Landsat TM Data for Discrimination of Soil Erosion Features." Photogrammetry and Remote Sensing 153rd ser. 53.143 (1998): 143-53. 15 Feb. 1998
Landsat 6 • Lost on October 5, 1993 • Same orbit as Landsat 4 and 5 • Enhanced Thematic Mapper (ETM) • An eighth panchromatic band 0.5-0.9mm with 15m resolution • Improved radiometric sensitivity
Landsat 7 http://www.crisp.nus.edu.sg/~research/tutorial/landsat.htm
French SPOT French SPOT French SPOT Landsat 7 Landsat 7 Landsat 7 DS DS - - 1260 1260 DS - 1260 AVIRIS AVIRIS AVIRIS 2.0 m m 1.0 1.0 1.0 m m m m m 2.0 2.0 m m m m m Landsat 7 • Launched on April 15, 1999 • ETM+, Enhanced Thematic Mapper Plus • Design continuity with Landsat 4 and 5 • An eighth 15m-resolution panchromatic band • 60m spatial resolution for the thermal band
Landsat 8 • Launched on February 11, 2013 • Landsat Data Continuity Mission (LDCM) • Orbit 705 km • Inclination 98.20 • 98.9 minutes per cycle • Image swath 185km http://www.youtube.com/watch?feature=player_embedded&v=2pnqFHXoA1c http://landsat.usgs.gov/about_ldcm.php
Landsat 8 .. • Two sensor systems on board - Operational Land Imager (OLI) - Thermal Infrared Sensor (TIRS)
Landsat 8 .. • Operational Land Imager (OLI) Band 1 (0.43-0.45µm) 30m Coastal/Aerosol Band 2 (0.45-0.51µm) 30m Blue Band 3 (0.53-0.59µm) 30m Green Band 4 (0.64-0.67µm) 30m Red Band 5 (0.85-0.88µm) 30m NIR Band 6 (1.57-1.65µm) 30m SWIR 1 Band 7 (2.11-2.29µm) 30m SWIR 2 Band 8 (0.50-0.68µm) 15m Pan Band 9 (1.36-1.38µm) 30m Cirrus
Landsat 8 .. • Thermal Infrared Sensor (TIRS) Band 10 (10.6 - 11.19 µm) 100m Thermal 1 Band 11 (11.5 - 12.51 µm) 100m Thermal 2
Readings • Chapter 6