Remote Sensing 4

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Remote Sensing Satellites

Dr P.K. GARGCivil Engg Deptt

IIT Roorkee

Highlights of RS Satellites • Before 1972 - primarily aerial photographs• 1972 - First Landsat satellite by US

launched• 1978 - SPOT satellite by France launched• 1988 - Indian Remote Sensing Satellite

launched• 1995 - Radarsat by Canada launched• 1999 - IKONOS satellite by US launched

and NASA launched Terra satellite• Today many new satellite and airborne

instruments are being developed and launched

LANDSAT Satellites

Landsat – The Beginning ofSpectral Imagery Age

• 1965 – NASA Earth Resources Survey initiated• 1972 – ERTS 1 launched (July 23) with RBV, MSS• 1975 –Landsat 2 launched (January 22) (RBV,

MSS)• 1978 – Landsat 3 launched (March 5) (RBV, MSS)• 1982 – Landsat 4 launched (July 16) with MSS, TM• 1984 – Landsat 5 launched (March 1) with MSS,

TM • 1993 – Landsat 6 launches (October 5) with MSS,

ETM but fails to achieve orbit• 1999 – Landsat 7 launches (April 15) with ETM+

http://landsat.gsfc.nasa.gov/

http://landsat7.usgs.gov/index.php

Summary

Summary• Landsats 1, 2 and 3 altitude 923 km• Landsats 4, 5 and 7 altitude 705 km. • All Landsats pass between 9:30 and 10:00 AM

over the equator• Make 14 passes per day taking about 103

minutes for a complete one orbital • Landsats 1, 2 and 3 repeat period 18

days• Landsats 4, 5 and 7 repeat period 16 days• About 11,000 scenes fully cover the Earth's

land surface.

LANDSAT Ground Receiving Station

Each zone covers about 3000-4000 km radius

Return Beam Vidicon (RBV) Sensor in LANDSAT

• System of cameras designed to take high-spatial accuracy pictures of areas collected by Landsat

• Consisted of 3 cameras (Landsats 1 and 2) or 2 cameras (Landsat 3)

• Landsat 1 RBV turned off after less than one month due to electrical failure

• Landsat 2 RBV turned off shortly after launch for similar reason

• Landsat 3 had technical problems that precluded routine use

RBV Image

Multispectral Scanner (MSS) in LANDSAT

• Unidirectional whiskbroom scanner• Image earth surface cross-track

using oscillating mirror• Along-track provided by satellite

motion• Six scan lines imaged

simultaneously; each scan line collects four spectral bands (6-bit resolution)

• Landsat 1-3; MSS onboard Landsat 3 included an extra thermal band (designated band 8)

• Typical scene size 185kmx185 km

Configuration - MSS

LANDSAT 4, 5 & 6

• Area imaged on the ground.• Imaging swaths for spaceborne

sensors vary between tens and hundreds of km wide.

Thematic Mapper (TM)in LANDSAT

• Bi-directional whiskbroom scanner • TM provides:

– Better resolution (spatial and spectral)– Improved geometric fidelity– Improved radiometric accuracy

• Collects 7 spectral bands (8-bit resolution) simultaneously

• Employed in Landsat 4-5; 30 m pixels (except for band 6, which is either 120 for Landsat 4 or 60 for Landsat 5) with typical image size of 185x172 km

Landsat - 7

Landsat-7• 705-km altitude• 16-day repeat cycle• 185 km swath width• Descending node at 10:00 - +15 min• Whisk-broom scanner• Radiometric resolution: 28 (256 levels)

• ETM+ sensor– 30-m XS (for 6 bands) & 60-m

thermal– 15-m pan band

• Image data (185 km by 185 km)– $475 – raw data; $600 – corrected

data– NASA developing a global

archive of ETM+

Landsat-7

Enhanced Thematic Mapper (ETM) / ETM Plus (ETM+)

• ETM was an evolution of TM onboard ill-fated Landsat 6

• ETM+ is an evolution of ETM onboard Landsat 7

• Bi-directional whiskbroom scanner

• Collects 8 spectral bands simultaneously (8-bit resolution)

• 30 m pixels (except for Band 6 which is 60 m, and the pan band which is 15) with typical image size of 183x170 km

Band Wavelength (µm)

Spectral Location

Resolution (m)

Pan 0.52-0.90 Pan 15

1 0.45-0.52 Blue 30

2 0.53-0.60 Green 30

3 0.63-0.69 Red 30

4 0.76-0.90 Near IR 30

5 1.55-1.75 Mid IR 30

6 10.4-12.5 Thermal IR

7 2.07-2.35 Mid IR 30 7

ETM Plus (ETM+) characteristics

Band Principal Applications

1 Coastal water mapping, soil/vegetation discrimination, forest type mapping, cultural feature identification

2 Measures green reflectance peak of vegetation for vegetation discrimination & vigor assessment, cultural feature identification

3 Senses a chlorophyll absorption region aiding in plant species differentiation, cultural feature identification

4 Determine vegetation types, vigor & biomass content, delineate water bodies, soil moisture discrimination

5 Indicative of vegetation moisture content & soil moisture, differentiate snow from clouds

6 Useful for vegetation stress analysis, soil moisture discrimination, thermal mapping applications

7 Discrimination of mineral & rock types, sensitive to vegetation moisture content

Pan Detailed mapping, useful in sharpening multispectral images

Landsat ETM+ band 1 (0.45-0.52 µm, blue-green)

• Penetrates water better than the other bands so it is often the band of choice for aquatic ecosystems

• Used to monitor sediment in water, mapping coral reefs, and water depth

• The “noisiest” of the Landsat bands since short wavelength blue light is scattered more than the other bands

Landsat ETM+ band 2 (0.52-0.60 µm, green)

• Similar qualities to band 1 but not as noisy.

• Matches the wavelength for the colour green.

Landsat ETM+ band 3 (0.63-0.69 µm, red)

• Since vegetation absorbs nearly all red light (it is sometimes called the chlorophyll absorption band) this band can be useful for distinguishing between vegetation and soil and in monitoring vegetation health

Landsat ETM+ band 4 (0.76-0.90 µm, near infrared)

• Since water absorbs nearly all light at this wavelength water bodies appear very dark. This contrasts with bright reflectance for soil and vegetation so it is a good band for defining the water/land interface

• Sensitive to vegetation cover

• Less affected by atmospheric contamination

Landsat ETM+ band 5 (1.55-1.75 µm, mid-infrared)

• Very sensitive to moisture and is therefore used to monitor vegetation water stress and soil moisture.

• Useful to differentiate between clouds and snow

Landsat ETM+ band 6 (10.40-12.50 µm, thermal infrared)

• Measures surface temperature.

• Geological applications • Differentiate clouds from

bright soils since clouds tend to be very cold

• The resolution is twice as course as the other bands (60 m instead of 30 m)

Landsat ETM+ band 7 (2.08-2.35 µm mid-infrared)

• Can detect high surface temperatures

• Also used for vegetation moisture although generally band 5 is generally preferred for that application

• Commonly used in geology

Landsat Image - View of Mt. St. Helens, Post-Eruption

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Image Data Band combination Colour Composite

Selected bands are superimposed to get the output image in colour.

Image display

Natural colour composite3, 2, 1 Bands

False colour composite4, 3, 2 Bands

Certain bands or band combinations are better than others Certain bands or band combinations are better than others for identifying specific land cover features.for identifying specific land cover features.

Landsat TM Red= band 3, Green = band 2, Blue = band 1

Landsat TM Red= band 7, Green = band 5, Blue = band 4

Landsat ETM+ bands 3,2,1 Landsat ETM+ bands 3,2,1 – Penetrates shallow water – Penetrates shallow water and shows submerged and shows submerged shelf, water turbidityshelf, water turbidity

Landsat ETM+ bands Landsat ETM+ bands 4,3,2 – Peak chlorophyll, 4,3,2 – Peak chlorophyll, land/water boundary, land/water boundary, urban areasurban areas

•This dataset covers 5.4 million square kilometers. Eight scenes of data were unavailable from this system.

•The original projection data is UTM with datum WGS84.

•The data amount of the mosaic image from 105 Landsat scenes (composed of 4 bands) is around 40 GB.

Landsat MosaicLandsat Mosaic

SPOT Satellite

SPOT system

• SPOT - Satellite Pour l’Observation de la Terre• Designed by CNES (Centre national d’études

spatiales) and built in partnership with Astrium and Spot Image.

• Currently includes three operational in-orbit satellites, Spot 2, 4 and 5.

Volcanic Activity

Dec. 22, 2000

SPOT 4 HRV

SPOT 5

– Launched in 2002– visual 5 meter land observations– high-resolution mapping, infrastructure

identification, terrain analysis, crop identification

SPOT 5- Summary

Orbit Altitude 822 Km

Orbit Inclination 98.7º, sun-synchronous

Speed 7.4 Km/second – 26,640 Km/hour

Equator Crossing Time 10:30 a.m. (descending node)

Orbit Time 101.4 minutes

Revisit Time 2-3 days depending on Latitude

Swath Width 60 Km x 60 Km to 80 Km at nadir

Geometric Accuracy <50-m horizontal position accuracy (CE90%)

Radiometric Accuracy 8 Bits

HRG Sensor in SPOT 5• Spot 5 payload comprises two

identical Haute Resolution Geometrique (HRG) instruments capable of acquiring data at four resolution levels with the same swath of 60 km:– images in the SWIR band at a resolution

of 20 meters;– multispectral images at 10 meters;– panchromatic images at 5 meters;– supermode panchromatic images at 2,5

meters.

HRG bands in SPOT-5

Pan: 480 - 710 nm 2.5m, 5m

Green: 500 - 590 nm 10m

Red: 610 - 680 nm 10m

Near IR: 780 – 890 nm 10m

Short Wave IR: 1,580 – 1,750 nm 20m

SPOT-5• The SPOT imaging instruments’ oblique viewing

capability means they can acquire imagery of any point on the globe within less than five days at the Equator, and in less than three days at temperate latitudes (45o).

• The SPOT system’s three satellites are thus able to observe any area of interest almost daily.

High Resolution Stereoscopic (HRS) Sensor

• Acquires images almost simultaneously in front of and behind the satellite to allow acquisition of stereo pair images in a single pass.

• Swath: 120 km centred on the satellite ground track

• Repeat cycle of 26 days• Resolution: 10 metres in panchromatic

mode • DEM accuracy better than 15 metres• Allows orthorectification of HRG (High

Resolution Geometric) images

Vegetation Sensors

• VEGETATION 1: passenger aboard SPOT 4, launched on March 24, 1998

• VEGETATION 2: passenger aboard SPOT 5, launched on May 3, 2002

• To observe the Earth's biosphere and crops on a regional and global scale

• Long-term environmental change at regional and global scales

• Cover almost all of the globe’s land masses in one day

Vegetation Sensors

• Resolution: 1 km• Swath: 2250 km• 4 spectral bands

– Red: 0.61 to 0.68 µm – Near-infrared: 0.78 to 0.89 µm – Mid-infrared: 1.58 to 1.75 µm – Blue: 0.43 to 0.47 µm (for atmospheric corrections)

Vegetation SensorsProducts• Primary products (P),

extracted from a single image segment

• Daily (S1) or ten-day (S10) syntheses - mosaics of acquired image segments, for 24h periods and for the last 10 days respectively

• Vegetation indices (NDVI) calculated from daily or ten-day syntheses

Vegetation Sensors

Other Applications• Production and updating of forest maps to help

manage local resources, and for long-term continental and global studies of climate change

• Monitoring of crop acreage to aid yield forecasting

• Observation of ocean colour to aid fishing vessels

• Daily monitoring of specific areas to help combat locust swarms effectively and prevent forest fires.

Indian Remote Sensing Satellites (IRS)

• The first satellite in the IRS series was launched by a Soviet Vostock booster on March 17, 1988.

• By Dec. 1997, seven more had been launched.• Series of eight satellites namely; IRS-1A,-1B,-

1E,-P2,-1C,-P3,-1D.• 2 more ( IRS-P4 and –P6) were launched

between 1999 and 2003 respectively.• IRS-P5 came to being in 2005

IRS Series• The launch of India's first civilian remote sensing satellite

IRS-1A in March 1988, marked the beginning of a successful journey of the Indian Space Programme.

• The two LISS sensors (LISS I and LISS II) aboard IRS-1A captured valuable data for large scale mapping.

• IRS-1B , having similar sensors, was launched in August 1991, and together, they provided better repetivity.

• IRS-1C (launched in December 1995) carried LISS-III, PAN and WiFS sensors.

• IRS-1D (September 1997) further strengthened the scope of remote sensing, with increased coverage.

Indian Remote Sensing Satellite (IRS)

• IRS-1A launched in March 1988 • IRS-1B launched in August 1991 • IRS-1C launched in December 1995 • IRS-1D launched on September 29,1997. • IRS-P3 and IRS-1D launched by India's Polar Satellite

Launch Vehicle (PSLV). • OCEANSAT-1 with an Ocean Colour Monitor (OCM) and a

Multi-frequency Scanning Microwave Radiometer (MSMR) • RESOURCESAT-1 (IRS P6) for agricultural applications

launched on October 17, 2003. • CARTOSAT-1 (IRS P5) with a Very High Resolution

Panchromatic camera for cartographic applications launched on May 5, 2005

Indian Remote SatellitesSatellite Launch date Uses Sensors

IRS-1B Aug. 29, 1991 Cartography, digital terrain models

LISS-I, LISS-II

IRS-P2 Oct. 15, 1994 Ocean biology, physical oceanography

LISS-II

IRS-1C Dec. 28, 1995 Cartography, digital terrain models

PAN, LISS-III, WiFS

IRS-P3 March 21, 1996

Ocean chlorophyll, vegetation assessment, snow studies, geological mapping for minerals

WiFS, MOS

IRS-1D Sept. 29, 1997 Vegetation index mapping PAN, LISS-II, WiFS

IRS-P4 May 26, 1999 Oceanography OCM (8 bands)

IRS-P6 Oct. 17, 2003 Agricultural applications LISS-IV, LISS-III, WiFS

IRS-P5 May 5, 2005 Cartography, digital terrain models

2 PAN cameras

Sensor – Panchromatic Camera (PAN)• Good for urban planning,

detecting urban fringe or updating transportation infrastructure

• Resolution of 5.2 (IRS-1D), and 5.8 (IRS-1C)

• Swath 65-80 Km • Spectral bands 0.50 – 0.75 um

Sensor – LISS-III• Contains Bands:

– 2 – vegetation reflectance curve

– 3 – centered in the chlorophyll absorption region

– 4 – high reflectance plateau region

– 5 – sensitive to leaf water content

• Good for vegetation studies

• Swath 141 km (bands 2,3, 4) and 148 km (band 5)

Sensor – WiFS Camera• Also useful for

vegetation studies– Larger swath (770 Km)– High repetivity (5 days)

• Contains spectral bands– 3 (0.62-0.68 um), red– 4 (0.77-0.86 um), near IR

• Resolution 188 m

Ground Receiving Station at Shadnagar, Hyderabad

IRS Images

IRS-1C IRS-1D

IRS Applications

IRS-P6 (RESOURCESAT-1)• The tenth satellite in IRS series, IRS-P6 (launched in October 2003) is

intended to continue the services provided by IRS-1C and IRS-1D, and also to vastly enhance the data quality of 10-bit.

• The 1360 kg IRS-P6 is launched into an 817 km high polar orbit. Orbit inclination : 98.7 deg. Repetivity (LISS-3) : 24 days, (LISS-4) : 5 days.

• IRS-P6 carries three cameras similar to those of IRS-1C and IRS-1D but with improved spatial resolutions _ – A high resolution Linear Imaging Self Scanner (LISS-4) operating in

three spectral bands in the Visible and Near Infrared Region (VNIR) with 5.8 metre spatial resolution and steerable up to+_ 26 deg across track to obtain stereoscopic imagery and achieve five day revisit capability; a medium resolution

– LISS-3 operating in three spectral bands in VNIR and one in Short Wave Infrared (SWIR) band with 23.5 metre spatial resolution; and

– An Advanced Wide Field Sensor (AWiFS) operating in three spectral bands in VNIR and one band in SWIR with 56 metre spatial resolution.

RESOURCESAT

IRS-P5 (Cartosat-1)• Launched on May 5, 2005, it is a state-of-art remote

sensing satellite mainly intended for cartographic applications, large scale mapping and terrain modelling applications.

• It is 1560 kg, launched into a 618 km high polar orbit.

• It carries two Panchromatic (PAN) cameras that take stereoscopic pictures in the visible region with 30 km swath and 2.5m spatial resolution. The cameras are mounted on the satellite in such a way that near simultaneous imaging of the same area from two different angles is possible. This facilitates the generation of accurate three-dimensional maps.

CARTOSAT

IKONOS (1m) – 29 April 2002

IKONOS zoomed

ALLAHABAD JAN 23, 2001

WTC ON JUNE 30, 2000

WTC ON SEPTEMBER 15, 2001

PENTAGON ON DECEMBER 28, 2000

PENTAGON ON SEPTEMBER 12, 2001

EarlyBird

• launch scheduled October 1997• visual 3 meter land observations• high-resolution mapping, infrastructure

identification, terrain analysis

QuickBird

• launch scheduled for 1998• visual 1 meter land observations• high-resolution mapping, infrastructure

identification, terrain analysis

QUICKBIRD (Singapore)

QuickBird, 60 cm, Paris

“False” Color Composites

B & W images from different bands are assigned colors & combined.

Satellite Imagery for Plant Disease Detection

“Clubroot” on a cauliflower crop

Space Imaging• Carterra 1

– launch scheduled for December 1997– visual 1 meter and multispectral 4 meter land observations– high-resolution mapping, infrastructure identification, terrain

analysis• Carterra 2

– launch scheduled for 1998– visual 1 meter and multispectral 4 meter land observations– high-resolution mapping, infrastructure identification, terrain

analysis, crop identification

OrbView• OrbView-3

– launch scheduled for Mid 1998– visual 1 & 2 meter and multispectral 4 meter land

observations– high-resolution mapping, infrastructure identification, terrain

analysis, crop identification• OrbView-3B

– launch scheduled for 1999– visual 1 meter and multispectral 4 meter land observations– high-resolution mapping, infrastructure identification, terrain

analysis, crop identification

•Host remote sensing instruments including staring and spinning sensors•Data and message store and forward •Tracking assets, wildlife, billing, earth and ocean surface motion •Custom orbits, including high energy trajectories for geophysics, solar physics and astrophysics sensing •Precise orbit maintenance for sun synchronous earth sensing and satellite constellation maintenance •Space environment testing and qualification of components and materials •Launch on demand for event-driven missions including tactical communications and imaging, and environmental events including forest fires, volcano eruptions and severe weather

•Bitsy is a full-functioned, autonomous, three-axis-stabilized spacecraft in a 1 kg package

Google Earth(High resolution satellite images )

Provides scientific, industrial, civil, military and individual users with high resolution images for: • Defense & intelligence • Homeland security & asset protection• Insurance & risk management• Transportation & infrastructure planning• Natural resource assessment • Agriculture• Disaster relief• Insurance and risk management• Oil & gas exploration• Mapping

Commercial Remote SensingQuickBird .61 m color image

Remote Sensing Industry• Three U.S. Commercial Satellite Imagery

Companies

Name DigitalGlobe ORBIMAGE Space Imaging

Location Longmont, CO Dulles, VA Thornton, CO

Year Launched 2001 2003 1999

Satellite Name QuickBird OrbView-3 IKONOS

Resolution (meters)

0.61 m black/white

1m black/white 1 m black/white

@ 2.44 m color

4 m color 4 m color

• all weather 25-500 meter land and sea observations, radar and SAR

• 3 dimensional mapping, oil spill detection, flood extent, damage assessment, night coverage

RADARSAT

• all weather 10-100 meter land and sea radar observations

• all weather 18 meter land and sea observations

Indian National Satellite System (INSAT)

• Established in 1983 with commissioning of INSAT-1B. • INSAT space segment at present consists of INSAT-1D,

last of the INSAT-1 series launched in 1990 • INSAT-2A launched in July 1992, • INSAT-2B launched in July 1993 and • INSAT-2C launched on December 7, 1995. • INSAT-2E launched on April 3,1999. • INSAT-3B launched on March 22nd 2000. • INSAT-3C launched on January 24th 2002. • INSAT-3A launched on April 10th 2003. • INSAT-3E launched on September 28th 2003.

“Typical” Fixed Satellite Network

Branch Offices

Corporate Data Center/HQ

Network HUB

Corporate Offices

Gas Stations

Apartment Buildings

Residential

Internet

Applications• Credit Card Validation• ATM/Pay at the Pump• Inventory Control• Store Monitoring• Electronic Pricing• Training Videos• In-Store Audio• Broadband Internet Access• Distance Learning

Some large scale corporate networks have as many as 10,000 nodesSome large scale corporate networks have as many as 10,000 nodes

AVHRR – Mission and Function• High resolution radiometer (intensity) designed

to measure long wavelengths (low energies)

AVHRR Specifications•At 833 km IFOV 1.1 km x 1.1 km

•2x Daily global coverage per satellite (14 overlapping passes)

•10-bit digitization for higher radiometric resolution

•Primary applications are meteorology/climate/oceanography/landcover

30-day NOAA/AVHRR NDVI30-day NOAA/AVHRR NDVI

Jan 2001 Apr 2001 Oct 2001July 2001

View of Earth from Geosynchronous Orbit

Sequence of 3 Images of Hurricane Andrew (1992)Viewed from Geosynchronous Orbit

Emergency services, disaster recovery

Reduction in Antarctic Ozone Due to Chlorine Pollution of the Stratosphere

Weather Forecasting Search and Rescue

• NOAA’s operational environmental satellite system is composed of:– Geostationary Operational

Environmental Satellites (GOES): short-range warning and “narrowcasting”

– Polar Orbiting Environmental Satellites (POES): longer term forecasting

• Both are required for providing complete global weather monitoring

• The satellites carry search and rescue instruments, and have helped save the lives of about 10,000 people to date.

THANK YOU

Current Operational Satellites (as of 2002) (1 of 4)

(2 of 4)

(3 of 4)

Source: http://www.planetary.brown.edu/arc/sensor.html

(4 of 4)

Remote Sensing 4

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