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Celebrating 25 Years of Achievement 17 August 2000 Dr. Charles Randell P.Eng TransCanada Transmission & Colonial Pipeline Company EO Satellite Primer.

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Presentation on theme: "Celebrating 25 Years of Achievement 17 August 2000 Dr. Charles Randell P.Eng TransCanada Transmission & Colonial Pipeline Company EO Satellite Primer."— Presentation transcript:

1 Celebrating 25 Years of Achievement 17 August 2000 Dr. Charles Randell P.Eng TransCanada Transmission & Colonial Pipeline Company EO Satellite Primer

2 Celebrating 25 Years of Achievement 2 Main Categories of Satellites Geostationary satellites: - stationary above a fixed point on the equator - “footprint” does not change - orbits very high (1000s of km) above earth - typically communications and weather satellites GOES Image km orbit km resolution

3 Celebrating 25 Years of Achievement Polar (near polar) orbiting satellites: - lower orbits (100s of km) - orbit follows a pattern that takes it near the poles - “footprint” moving continuously in periodic pattern. Repeats every days. - “earth observation” (EO) satellites 2 Main Categories of Satellites Celebrating 25 Years of Achievement

4 Spacecraft parameter: orbit period serviceable life Sensor parameters type of sensor temporal resolution (tied to orbit) spatial resolution radiometric resolution spectral resolution Satellite Specifications

5 Celebrating 25 Years of Achievement Temporal resolution: Revisit time, or how often you can “see” the same area on earth Many sensor have overlapping swaths so it is possible to see the same spot on earth every days. Seeing the same spot from the same perspective, or point in space depends on repeat period of the spacecraft. This is important for certain subtle change analyses. Use more than one satellite to increase revisit frequency

6 Celebrating 25 Years of Achievement Spatial resolution: Minimum spacing between two points for which they can be individually distinguished. Generally accepted “working definition”: area on the ground covered by each pixel

7 Celebrating 25 Years of Achievement Satellite imagery is digital: Numerically it is a matrix where each matrix element contains a number corresponding to the image picture element - pixel The number may be real or complex For optical images, the number represents intensity of the pixel For radar images, the number represents a magnitude and phase

8 Celebrating 25 Years of Achievement Image with 25 m resolution Spatial resolution:

9 Celebrating 25 Years of Achievement Image with 5 m resolution Spatial resolution:

10 Celebrating 25 Years of Achievement Image with 1 m resolution

11 Celebrating 25 Years of Achievement 8 bit multispectral image green + red + blue = Spectral resolution

12 Celebrating 25 Years of Achievement Reduced radiometric resolution - 3 bit image

13 Celebrating 25 Years of Achievement Panchromatic (grayscale) image

14 Celebrating 25 Years of Achievement Currently 2 Types of Imaging Sensors on Satellites 1. Synthetic Aperture Radar (SAR) 2. Optical - panchromatic - multispectral

15 Celebrating 25 Years of Achievement SAR Satellites SAR is an active radar Penetrates cloud & fog penetrates darkness very reliable coverage RADARSAT Fine Beam Image (this clip 9 km × 11 km)

16 Celebrating 25 Years of Achievement Radar not optical image prone to noise interpretation not “intuitive” “complex” data permits very power techniques for information extraction SAR Satellites

17 Celebrating 25 Years of Achievement Oil slick in false colored SAR Image

18 Celebrating 25 Years of Achievement RADARSAT Receiving Stations

19 Celebrating 25 Years of Achievement SAR Satellites SAR SatelliteMission DateFrequency (GHz) Resolution (m) Seasat1978 June – October1.3 L-band25 SIR-A1981 November1.3 L-band40 SIR-B1984 October1.3 L-band17–58 Almaz March – S-band15–30 JERS February – L-band18 ERS July – 1996 (1999)5.3 C-band20–30 SIR-C/X-SAR1994 April1.3 L-band 5.3 C-band 9.6 X-band 25–200 SRTM2000 February5.3 C-band 9.6 X-band 30 ERS April –5.3 C-band20–30 RADARSAT November –5.3 C-band8–100 ENVISAT2001 June5.3 C-band30–150 RADARSAT C-band3–100 PALSAR TerraSAR 2001 Q1 J-band10– L/X-band1

20 Celebrating 25 Years of Achievement Optical Satellites Optical equipped satellites are passive imaging systems. Effectively cameras in space. Interpretation more intuitive Subject to usual visibility limitations Multiple spectral bands permit detection/classification of numerous phenomena Subject to “usual” visibility limitations Interpretation more intuitve Multiple bands permit reliable detection of numerous phenomena IKONOS 4m multispectral image

21 Celebrating 25 Years of Achievement Multispectral and hyperspectral imagery good for detecting color and anomalous regions such as stressed vegetation, moisture changes, temperature change, and local atmospheric anomolies Hyperspectral image of oil from underground pipeline serving Chaulk Point Generating Station, MD. Ruptured April 7, 2000

22 Celebrating 25 Years of Achievement Optical Satellites Optical satellites have recently passed a milestone in commercial capability “Taskable” satellites with 1 meter resolution Multiple bands permit reliable detection of numerous phenomena IKONOS 1m panchromatic image Sawmill & lumber yard

23 Celebrating 25 Years of Achievement Satellite Revisit Data Launch Time Delivery Date IKONOS-2 2 days 1+ days operational EROS-A1 2-3 days - Q4 ‘00 (1 st of 8) Orbview-3 < 3 days - Jan '01 Quickbird 1-5 days-2001 Encroachment and Gas Detection Optical Satellites (1m / 4m resolution)

24 Celebrating 25 Years of Achievement Summary: Two types of EO satellites: SAR & optical Highest resolutions range from 1 m to 30 m Data can be available within hours EO satellites where traditionally for scientific and government use Current and future satellite missions designed with commercial/industrial applications in mind


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