1. Earth resource satellites operating in the optical spectrum
Chapter 6
Earth resource satellites operating in the optical spectrum
Introduction to Remote Sensing
Instructor: Dr. Cheng-Chien Liu
Department of Earth Sciences
National Cheng-Kung University
Last updated: 28 May 2003

2. 6.1 Introduction
Remote sensing + space exploration (RS+SE)  interest and application over a wider range of disciplines
Current application
New technology  new or improved satellite/sensor  new application
The most important outcome of RS+SE
 observing earth  earth system

3. 6.1 Introduction (cont.) This chapter  optical range  0.3 m m~14 m m
Landsat
Spot
NOAA series

4. 6.2 Early history of space imaging
Ludwig Bahrmann (1891): New or improved apparatus for obtaining Bird’s eye photographic views
Alfred Maul (1907): gyrostabilization
Alfred Maul (1912): 41kg, 200mm x 250 mm, 790m
1946~1950: V2 rockets
1960~ : TIROS-1, early weather satellite
Not just look at but also look through

5. 6.2 Early history of space imaging (cont.)
1960s: Mercury, Gemini, Apollo
Alan Shepard, 1961, 70 mm, 150 photos
John Glenn, 1962, 35 mm, 48 photos.
Later Mercury missions: 70 mm, 80 mm
Gemini GT-4 mission: formal experiment directed at geology
Tectonics, volcanology, geomophology.
1:2, photos
Apollo 9: 4 camera array, electrically triggered. 140 sets of imagery

6. 6.2 Early history of space imaging (cont.)
Skylab 1973
Earth Resources Experiment Package (EREP)
6-camera multi-spectral array
A long focal length “earth terrain” camera
A 13-channel multispectral scanner
A pointable spectroradiometer
Two microwave systems.
35,000 images
U.S.-USSR Apollo-Soyuz Test Project (ASTP)

7. 6.3 Landsat satellite program overview
Earth Resources Technology Satellite (ERTS) 1967
ERTS-1, 1972~1978
Nimbus weather satellite  modified
Experimental system  test feasibility
Open skies principle
Landsat-2, 1975 (ERTS-2)

8. 6.3 Landsat satellite program overview (cont.)
Table 6.1: Characteristics of Landsat 1~6
Return Beam Vidicon (RBV) camera systems
Multispectral Scanner system (MSS)
Thematic Mapper (TM)
Enhanced Thematic Mapper (ETM)
Table 6.2: Sensors used on Landsat 1~6 missions

9. 6.4 Orbit characteristic of Landsat-1, -2, and –3
Fig 6.1: Landsat –1, -2, and –3 observatory configuration
3m x 1.5m, 4m width of solar panels, 815 kg, 900 km
Inclination = 90
To= 103 min/orbit
Fig 6.2: Typical Landsat-1, -2 and –3 daily orbit pattern
Successive orbits are about 2760km
Swath: 185km
Orbital procession  18 days for coverage repetition 20 times of global coverage per year

10. 6.4 Orbit characteristic of Landsat-1, -2, and –3 (cont.)
Sun-synchronous orbit
9:42 am  early morning skies are generally clearer than later in the day
Pros: repeatable sun illumination conditions on the same day in every year
Cons: variable sun illumination conditions with different locations and seasons  variations in atmospheric conditions

11. 6.5 Sensors onboard Landsat-1, -2 and –3
3-Channel RBV
185km x 185 km
Ground resolution: 80m
Spectral bands: 1: mm~0.575 mm (green)
2:0.580 mm~0.680 mm (red)
3: mm~0.830 mm (NIR)
Expose  photosensitive surface  scan  video signal
Pros:
Greater cartographic fidelity
Reseau grid  geometric correction in the recording process

12. 6.5 Sensors onboard Landsat-1, -2 and –3 (cont.)
3-Channel RBV (cont.)
Landsat-1: malfunction  only 1690 scenes
Landsat-2  only for engineering evaluation  only occasionally RBV imagery was obtained.
Landsat-3
Single broad band (0.505~0.75 u mm)
2.6 times of resolution improved: 30m  double f
Two-camera side-by-side configuration with side-lap and end-lap. (Fig 6.4)
Fig 6.5: Landsat-3 RBV image

13. 6.5 Sensors onboard Landsat-1, -2 and –3 (cont.)
4 Channel MSS
185km x 185km
Ground resolution: 79m
Spectral band:
Band 4: 0.5 mm ~ 0.6 mm (green)
Band 5: 0.6 mm ~ 0.7 mm (red)
Band 6: 0.7 mm ~ 0.8 mm (NIR)
Band 7: 0.8 mm ~ 0.9 mm (NIR)
Band 8: 10.4~12.6 um  Landsat-3, failed
Band 4~7  band 1~4 in Landsat-4, -5
Fig 6.6: Comparison of spectral bands

14. 6.5 Sensors onboard Landsat-1, -2 and –3 (cont.)
4 Channel MSS (cont.)
Fig 6.7: Landsat MSS operating configuration
Small TFOV  use an oscillating scan mirror
A-to-D converter (6 bits)
Pixel width: 56m x 79m  set by the pixel sampling rate (Fig 6.8)
Each Landsat MSS scene  185km x 185km
2340 scan lines, 3240 pixels per line, 4 bands
Enormous data
Fig 6.9: Full-frame, band 5, Landsat MSS scene
Parallelogram  earth’s rotation
15 steps
Tick marks  Lat. Long.
Annotation block
Color composite: band 4 (b), band 5 (g), band 7(r) (Fig 6.6)

15. 6.5 Sensors onboard Landsat-1, -2 and –3 (cont.)
Data distribution
Experiment  transitional  operational
NASA NOAA NASA
USGS EOSAT USGS
Landsat-1,-2,-3 Landsat-4,-5,-6 Landsat-7
Department of Interior Department of Commerce Department of Defense
Data receiving station
Data reprocessing
Data catalogue

16. 6.6 Landsat MSS image interpretation
Applications:
agriculture, botany cartography, civil engineering, environmental monitoring, forestry, geography, geology, geophysics, land resources analysis, land use planning, oceanography, water resource analysis
Comparison of Landsat & airborne image
Table 6.4
Resolution
Coverage
Complementary not replacement
2-D, non-stereo mode

17. 6.6 Landsat MSS image interpretation (cont.)
Characteristics of MSS image
Effective resolution  79m, (30m for Landsat-3) but linear feature with sharp contrast can be seen
1-D displacement relief (in E-W direction)
Limited area can be viewed in stereo  study topographic
High altitude + low TFOV  little RD  planimeter map
E.g. World Bank, USGS. DMA, petroleum company

18. 6.6 Landsat MSS image interpretation (cont.)
Characteristics of MSS image (cont.)
Band 5 (red)  better atmospheric penetration  detecting cultural features
Band 4 (green)  deep, clear water penetration
Band 6, 7  lineating water bodies (dark)
The largest single use of Landsat MSS data  geologic studies  band 5.7

19. 6.6 Landsat MSS image interpretation (cont.)
Fig 6.10 : four Landsat MSS bands
Extent of the urban area (B4, 5, light)
Major road (B4, 5 light, not B6, B7 dark)
Airport
Asphalt-surfaced runways
Four major lakes and connected river (B6, 7 dark)
mid-July  algae  green  B4: similar to the surrounding agricultural land
Agricultural field. (B5, 6, 7)
Forest (B4, 5 dark)  winter images are preferred

20. 6.6 Landsat MSS image interpretation (cont.)
Fig 6.11: Landsat MSS band 5
December image
20 cm snow covered  all water bodies are frozen
Snow covered upland and valley floors  light tone
Steep, tree-covered valley sides  dark tone
September image
Identify forest area

21. 6.6 Landsat MSS image interpretation (cont.)
A hit-or-miss proposition
Some events leave lingering trace
Fig 6.12: Landsat MSS band 7
July image  200 m3/sec
March image  1300 m3/sec  once every four years
Fig 6.13: Mississippi River Delta
Silt flow but vague boundary  band 5
Delineation of the boundary  band 7
Fig 6.14: short-lived phenomena
Active forest fire in Alaska
Volcanic eruption on Kunashir Island

22. 6.6 Landsat MSS image interpretation (cont.)
A hit-or-miss proposition (cont.)
Fig 6.15: Extensive geologic features visible on MSS
San Andreas fault, Six solid dots  earthquake > 6.0
Fig 6.16: Landsat MSS band 6
66-km-wide Manicouagan ring  212-million-year-old meteorite impact crater
Fig 6.17: Landsat MSS images of Mt. St. Helens before and after its 1980 eruptions
Fig 6.18: Landsat MSS image of Maritoba, Canada, showing tornado and hail scar
Fig 6.19: Landsat MSS image of East kalimantan, Indonesia, showing tropical deforestation

23. 6.7 Orbit characteristics of Landsat-4 and -5
Fig 6.20: Sun-synchronous orbit of Landsat-4 and –5
Altitude: 900  705km
Retrievable by the space shuttle
Ground resolutions
Inclination T=99min  14.5 orbit/day
9:45 am
Fig 6.21: adjacent orbit space = 2752km
16-day repeat cycle
8-day phase between Landsat-4 and –5 (Fig 6.22)

24. 6.8 Sensors onboard Landsat-4 and -5
Fig 6.23: Landsat-4 and –5 observatory configuration
MSS, TM
2000 kg, 1.5x2.3m solar panels x 4 on one side
High gain antenna  Tracking and Data Relay Satellite system (TDRSS)
Direct transmission  X-band and S-band
MSS: 15 Mbps
TM: 85 Mbps

25. 6.8 Sensors onboard Landsat-4 and –5 (cont.)
MSS
Same as previous except for larger TFOV for keeping the same ground resolution (79m  82m)
Renumber bands TM
7 bands (Table 6.4)
DN: 6  8 bits
Ground resolution: 30m (thermal band: 120m)
Geometric correction  Space Oblique Mercator (SOM) cartographic projection

26. 6.8 Sensors onboard Landsat-4 and –5 (cont.)
TM (cont.)
Bi-directional scan  the rate of oscillation of mirror dwelling time  geometric integrity signal-to-noise
Detector:
MSS: 6x4=24
TM: 16x6+4x1=100
Fig 6.24: Thematic Mapper optical path and projection of IFOV on earth surface
Fig 6.25: Schematic of TM scan line correction process

27. 6.9 Landsat TM Image interpretation
Pros:
Spectral and radiometric resolution
Ground resolution
Fig 6.26: MSS vs TM
Fig 6.27: All seven TM bands for a summertime image of an urban fringe area
Lake, river, ponds: b1,2 > b3 > b4=b5=b7=0
Road urban streets: b4  min
Agricultural crops: b4  max
Golf courses

28. 6.9 Landsat TM Image interpretation (cont.)
Fig 6.27 (cont.)
Glacial ice movement: upper right  lower left
Drumlins, scoured bedrock hills
Band 7  resample from 120m to 30m
Plate 12 + Table 6.5: TM band color combinations
(a): normal color  mapping of water sediment patterns
(b): color infrared  mapping urban features and vegetation types
(c)(d): false color

29. 6.9 Landsat TM Image interpretation (cont.)
Fig 6.28: Landsat TM band 6 (thermal infrared) image
Correlation with field observations  6 gray levels  6T
Plate 13: color-composite Landsat TM image
Extremely hot  blackbody radiation  thermal infrared
TM bands 3, 4 and 7

30. 6.9 Landsat TM Image interpretation (cont.)
Fig 6.29: Landsat TM band 5 (mid-infrared) image
Timber clear-cutting
Fig 6.30: Landsat TM band 3, 4 and 5 composite
Extensive deforestation.
Fig 6.31: Landsat TM band 4 image map
13 individual TM scenes + mosaic

31. 6.10 Landsat-6 planned mission
A failed mission
Enhanced Thematic Mapper (ETM)
TM+ panchromatic band (0.5~0.9 mm) with 15m resolution.
Set 9-bit A-to-D converter to a high or low gain 8-bit setting from the ground.
Low reflectance  water  high gain
Bright region  deserts  low gain

32. 6.11 Landsat ETM image simulation
Fig 6.32: Landsat ETM images

33. 6.12 Landsat-7 Launch: 1999 Web site: http://landsat.gsfc.nasa.gov
Landsat 7 handbook
Landsat 7 in orbit
Depiction of Landsat 7

34. 6.12 Landsat-7 (cont.) Landsat 7 Orbit Landsat data Orbital paths
Swath
Swath pattern
Landsat data

35. 6.12 Landsat-7 (cont.) Payload Enhanced Thematic Mapper Plus (ETM+)
Dual mode solar calibrator
Data transmission
TDRSS or stored on board.
GPS  subsequent geometric processing of the data
High Resolution Multi-spectral Stereo Imager (HRMSI)
5m panchromatic band
10m ETM bands 1~4
Pointable  revisit time (<3 days) Stereo imaging.
00~380 cross-track and 00~300 along-track

36. 6.12 Landsat-7 (cont.) Application Monitoring Temperate Forests
Mapping Volcanic Surface Deposits
Three Dimensional Land Surface Simulations

37. 6.13 SPOT Satellite Program
Background
French+Sweden+Belgium
1978
Commercially oriented program
SPOT-1
French Guiana, Ariane Rocket
1986
Linear array sensor+pushbroom scanning+pointable
Full-scene stereoscopic imaging

38. 6.13 SPOT Satellite Program (cont.)
1990
SPOT-3
1993

39. 6.14 Orbit characteristics of SPOT-1, -2 and -3
Circular, near-polar, sun-synchronous orbit
Altitude: 832km
Inclination: 98.70
Descend across the equator at 10:30AM
Repeat: 26 days
Fig 6.33: SPOT revisit pattern at latitude 450 and 00
At equator: 7 viewing opportunities exist
At 450: 11 viewing opportunities exist

40. 6.15 Sensors onboard SPOT-1, -2 and -3
Configuration (Fig 6.34)
223.5m, 1750 kg, solar panel: 15.6m
Modular design
High Resolution Visible (HRV) imaging system
2-mode
10m-resolution panchromatic mode (0.51~0.73mm)
20m-resolution color-infrared mode. (0.5~0.59mm, 0.61~0.68mm, 0.79~0.89mm)

41. 6.15 Sensors onboard SPOT-1, -2 and –3 (cont.)
HRV (cont.)
Pushbroom scanning
No moving part (mirror)  lifespan
Dwell time 
Geometric error 
4-CCD subarray
6000-element subarray  panchromatic mode, 10m
Three 3000-element subarrays  multi-spectral mode, 20m
8-bit, 25 Mbps
Twin-HRV instruments
IFOV (for each instrument)  4.130
Swath: 60km  2 - 3km = 117km (Fig 3.36)
TFOV (for each instrument)  270=0.6045 (Fig 3.35)

42. 6.15 Sensors onboard SPOT-1, -2 and –3 (cont.)
HRV (cont.)
Data streams
Although 2-mode can be operated simultaneously, only one mode data can be transmitted  limitation of data stream
Stereoscopic imaging
Off-nadir viewing capability (Fig 6.37)
Frequency  revisit schedule (Fig 6.33)
Base-height ratio  latitude
0.75 at equator, 0.5 at 450
Control
Ground control station  Toulouse, France  observation sequence
Receiving station  Tordouse or Kiruna, Sweden
Tape recorded onboard
Transmitted within 2600km-radius around the station

43. 6.16 SPOT HRV image interpretation
Fig 6.38: SPOT-1 panchromatic image
10m-resolution
Cf: Landsat MSS 80m
Cf: Landsat TM 30m (Fig 6.26)
Cf: Landsat ETM 15m (Fig 6.32)
Fig 6.39: SPOT-1 panchromatic image
Plate14: merge of multispectral & panchromatic data
Fig 6.40: SPOT-1 panchromatic image stereopair
Plate 15: Perspective view of Alps
SPOT stereopair + parallax calculation
Plate 23
Fig 6.41: before and after the earthquake

44. 6.17 SPOT –4 and –5 SPOT –4 Launched 1998
Vegetation Monitoring Instrument (VMI)
Swath: 2000km  daily global coverage
Resolution: 1km
Spectral band: b(0.43~0.47mm), g(0.5~0.59mm), r(0.61~0.68mm), N-IR(0.79~0.89mm), mid-IR(1.58~1.75mm)

45. 6.17 SPOT –4 and –5 (cont.) SPOT – 5 Launched 2002
Vegetation Monitoring Instrument (VMI)
Swath: 2000km  daily global coverage
Resolution: 1km
Spectral band: b(0.43~0.47mm), g(0.5~0.59mm), r(0.61~0.68mm), N-IR(0.79~0.89mm), mid-IR(1.58~1.75mm)

46. 6.18 Meteorological Satellite
Metsats
Coarse spatial resolution  land-oriented system
Very high temporal resolution of global coverage
NOAA satellites  sun-synchronous
GOES  geostationary  36,000km altitude
DMSP

47. 6.18 Meteorological Satellite (cont.)
NOAA satellites
Advanced Very High Resolution Radiometer (AVHRR)
NOAA –6 ~ -12. (N-S)
Even: 7:30AM crossing time
Odd: 2:30 AM crossing time
Table 6.6: characteristics of NOAA-6 ~ -12
Fig 6.42: Example coverage of the NOAA AVHRR
Ground resolution: 1.1km at nadir
AVHRR data
LAC
GAC
Fig 6.43: Comparison of Spectral sensitivity

48. 6.18 Meteorological Satellite (cont.)
NOAA satellites (cont.)
Fig 6.44: AVHRR images
A: distortion  wide angle of view
B: geometric correction
Plate 16: NOAA AVHRR band 4 thermal image of the Great Lakes
Fig 6.45: AVHRR images of the Mississippi Delta
(a): present and past channels, future  Atchafalaya
(b): Channel–1 (red), silky material  visible
(c): Channel–2 (Near-IR), light tone  higher & drier
(d): Channel–4 (thermal –IR) light tone  cooler
Plumes of cooler river water

49. 6.18 Meteorological Satellite (cont.)
NOAA satellites (cont.)
Plate 17: springtime NOAA-8 AVHRR color composite
Applications of AVHRR in monitoring vegetation
Use Ch-1 (0.58~0.68 mm) and Ch-2 (0.73~1.10 mm)
A simple vegetation index VI=Ch2-Ch1
Normalized difference vegetation index NDVI = (Ch2-Ch1)/(Ch2+Ch1)
Vegetated areas  large VI
Clouds, water, snow  negative VI
Rock, Bare soil  VI  0
For global vegetation  NDVI preferred  compensate the charging illumination conditions
Plate 18: color-coded NDVI
Select the highest NDVI during that period

50. 6.18 Meteorological Satellite (cont.)
NOAA satellites (cont.)
Applications of AVHRR in monitoring vegetation (cont.)
Applications: vegetation seasonal dynamics at global and continental scale, tropical forest clearance, leaf area index measurement, biomass estimation, percentage ground cover determination, photosynthetically active radiation estimation
Other factors that might influence NDVI
Incident solar radiation
Radiometric response of the sensor
Atmospheric effect and viewing angle  need further research

51. 6.18 Meteorological Satellite (cont.)
GOES (Geostationary Operational Environmental Satellites)
NOAA + NASA
1974
36,000km
USRS, ESA, NSDA
Fig 6.46: GOES –2 visible band (0.55~0.7 mm)
Frequency: 2/hour
VI (daytime), IR (day and night)

52. 6.18 Meteorological Satellite (Cont.)
Defense Meteorological Satellite Program (DMSP)
1973
0.4~1.1 mm (VI+N-IR)
Nighttime visible band  tune the amplifiers
Fig 6.47: DMSP nighttime image
Fig 6.48: Maps of population distribution

53. 6.19 Ocean monitoring satellites
Ocean  Land
2/3, but comparatively little is know
Seasat (see §8.9)
Nimbus –7
CZCS (Coastal Zone Color Scanner) 1978~1986
Proof of concept mission
Table 6.7: CZCS bands  narrow bandwidth
825m resolution at nadir, 1566km swath
Map phytoplankton concentrations and inorganic suspended matter
N-IR  separate water from land

54. 6.19 Ocean monitoring satellites (cont.)
Japan
Marine Observation Satellite (MOS)-1: 1987
MOS-1b: 1990
Table 6.8: Instruments included in MOS-1 and MOS-1b
4-Channel Multi-spectral Electronic Self-Scanning Radiometer (MESSR)
4-Channel Visible and Thermal Infrared Radiometer (VTIR)
2-Channel Microwave Scanning Radiometer (MSR)
909km altitude, revisit period:17days

55. 6.19 Ocean monitoring satellites (cont.)
Sea-viewing Wide-Field-of-View Sensor (SeaWiFS)
8-channel across-track scanner (0.402~0.885 mm)
Ocean biogeochemistry
NASA-orbital science corporation (OSC)
1998 – date
Data
LAC: 1.13km
GAC: 4.52km
705km altitude, 2800km swath

56. 6.20 Earth Observing System
Mission to Planet Earth (MTPE)
Aims: providing the observations, understanding, and modeling capabilities needed assess the impacts of natural events and human-induced activities on the earth’s environment
Data and information system: acquire, archive and distribute the data and information collected about the earth
Further international understanding of the earth as a system

57. 6.20 Earth Observing System (cont.)
EOS (Table 6.9)
ASTER
CERES
MISR
MODIS
MOPITT
MODIS (Table 6.10)
Table 6.10
Terra: 2000
Aqua: 2002

58. 6.21 Fine-resolution satellite system
CORONA
1960 – 1972, declassified in 1995
KH-1 ~ KH-4B ~ KH-5
Camera + film
Band and resolution
Web site:
Impacts

59. 6.21 Fine-resolution satellite system (cont.)
IKONOS
1999 by Space imaging
Bands and resolution
1m-resolution
0.45 – 0.90 mm
4m-resolution
0.45 – 0.52 mm
0.52 – 0.60 mm
0.63 – 0.69 mm
0.76 – 0.90 mm
Orbit: sun-synchronous
Repeat coverage: 1.5 (1m) ~ 3 (4m) days

60. 6.21 Fine-resolution satellite system (cont.)
OrbView–3 and –4
OrbView-2: SeaWiFS
Will be launched soon!
Similar bands and resolution as IKONOS
OrbView–4
200 spectral channels in the range 0.45 – 2.5 m m at 8m resolution

61. 6.21 Fine-resolution satellite system (cont.)
QuickBird
2001 by EarthWatch Inc.
Bands and resolution
61cm-resolution
0.45 – 0.89 mm
2.44m-resolution
0.45 – 0.52 mm
0.52 – 0.60 mm
0.63 – 0.69 mm
0.76 – 0.89 mm