Satellite Sensors Capture the Past, the Present and Aid in Our Future

Satellite images from high to medium resolution satellite sensors have captured our changing world since the 1970’s and continue to collect massive amounts of data about our planet and the many changes it has experienced.

There are dozens of remote sensing satellites orbiting the Earth collecting invaluable information about the Earth’s surface, oceans and the atmosphere and how they interact. Satellite images have been collected for scientific and technical purposes as well as just appreciating its simple beauty. These satellites collect information that our eyes cannot, collections from 30 to 0.5 meter resolution is now available.

Earth Observation Satellites

Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. Studying these satellite images and climate data collected over many years reveal the signals of a changing climate.

Scientists have been able to piece together a picture of the Earth’s climate dating back decades to millions of years ago by analyzing a number of surrogate, or “proxy,” measures of climate such as ice cores, boreholes, tree rings, glacier lengths, pollen remains, and ocean sediments, and by studying changes in the Earth’s orbit around the sun.

 GeoEye-1 Satellite (0.5m)

GeoEye1(Image credit: DigitalGlobe)

DigitalGlobe’s GeoEye-1 satellite sensor launched on September 6, 2008 from Vandenberg Air Force Base, California, USA and features the most sophisticated technology ever used in a commercial remote sensing system.

GeoEye-1 is capable of acquiring image data at 0.5 meter panchromatic (B&W) and 1.65 meter multispectral resolution. It also features a revisit time of less than three days, as well as the ability to locate an object within just three meters of its physical location.

This newly developed sensor is optimized for large projects, as it can collect over 350,000 square kilometers of pan-sharpened multispectral satellite imagery every day.

Pleiades-1A Satellite (0.5m) 

pleiades-1a(Image credit: AIRBUS Defence and Space)

Pleiades-1A satellite is the first very high-resolution satellite from SPOT. The satellite is capable of providing orthorectified color data at 0.5-meter resolution (roughly comparable to GeoEye-1) and revisiting any point on Earth as it covers a total of 1 million square kilometers (approximately 386,102 square miles) daily. Perhaps most importantly, Pleiades-1A is capable of acquiring high-resolution stereo imagery in just one pass, and can accommodate large areas (up to 1,000 km x 1,000 km).

The satellite features four spectral bands (blue, green, red, and IR), as well as image location accuracy of 3 meters (CE90) without ground control points. Image location accuracy can be improved even further — up to an exceptional 1 meter — by the use of GCPs. Because the satellite has been designed with urgent tasking in mind, images can be requested from Pleiades-1A less than six hours before they are acquired. This functionality will prove invaluable in situations where the expedited collection of new image data is crucial, such as crisis monitoring.

Pleiades-1B Satellite (0.5m)

pleiades-1b(Image credit: Defence and Space)

Pleiades-1B is the second dual-use, very-high-resolution satellite for the Pleiades constellation.

The launch of Pleiades-1B marks the third step in the formation of a constellation of four satellites combining a double daily revisit capability and an ingenious range of resolutions.

Pleiades-1A and 1B satellites will be phased 180° apart in the same near-polar sun-synchronous orbit at an altitude of 694 km, enabling daily revisits to any location on the planet which makes it ideal for mapping large scale areas including engineering and construction projects, monitoring of mining, industrial and military complexes, conflict zones and crisis/disaster areas, natural hazards, evacuation and rescue operations.

Pleiades-1A and Pleiades-1B will deliver 0.5m imagery products, and SPOT-6 and SPOT-7, designed to assure continuity of service after SPOT-5 (2.5/5m) to supply high-resolution data products at 1.5m. SPOT-6 was launched on September 9, 2012.

In addition to their high precision, the Pleiades satellites are also notable for their remarkable agility, which enables tilted imaging from nadir and operation in several acquisition modes (20 images over 1000 x 1000 km2, stereo, 3D, mosaic, corridor, etc.).

SPOT-6 Satellite (1.5m)

spot-6(Image credit: Defence and Space)

SPOT-6 is an optical imaging satellite capable of imaging the Earth with a resolution of 1.5 meter Panchromatic and 6 meter Multispectral (Blue, Green, Red, Near-IR) and will offer imaging products to customers in defense, agriculture, deforestation, environmental monitoring, coastal surveillance, engineering, oil, gas and mining industries.

SPOT-6 and SPOT-7 will ensure service continuity of SPOT- 4 and SPOT-5 satellites, which have been operating since 1998 and 2002. Moreover, both ground and space segments have been designed for improved performances compared to previous SPOT missions, especially in term of reactivity from satellite tasking to product delivery and collection capacity. The constellation SPOT-6 and SPOT-7 provide a daily revisit everywhere on Earth with a total coverage of 6 million km² per day. SPOT-6 and 7 will have a service life of 10 years.

WorldView-2 Satellite (0.5m)

worldview-2(Image credit: DigitalGlobe)

DigitalGlobe’s WorldView-2 satellite was launched on October 8, 2009, provides 0.5m Panchromatic (B&W) mono and stereo satellite image data.

With its improved agility, WorldView-2 is able to act like a paintbrush, sweeping back and forth to collect very large areas of multispectral imagery in a single pass. WorldView-2 alone is able to collect nearly 1 million km2 every day, doubling the collection capacity of  constellation to nearly 2 million km2 per day. And the combination of WorldView-2’s increased agility and high altitude enables it to typically revisit any place on earth in 1.1 days. When added to the satellite constellation, revisit time drops below one day and never exceeds two days, providing the most same-day passes of any commercial high resolution constellation.

The WorldView-2 sensor provides a high resolution Panchromatic band and eight (8) Multispectral bands; four (4) standard colors (red, green, blue, and near-infrared 1) and four (4) new bands (coastal, yellow, red edge, and near-infrared 2), full-color images for enhanced spectral analysis.

WorldView-3 (0.5m) Satellite Sensor

(Image credit: DigitalGlobe)

WorldView-3 satellite sensor is the first multi-payload, super-spectral, high-resolution commercial satellite sensor operating at an altitude of 617 km. WorldView-3 provides 31 cm panchromatic resolution, 1.24 m multispectral resolution, 3.7 m short wave infrared resolution and 30 m CAVIS resolution. WorldView-3 has an average revisit time of <1 day and is capable of collecting up to 680,000 km2 per day.

WorldView-3 bears a strong resemblance to WorldView-2 launched on October 8, 2009 in terms of its performance characteristics. The WorldView-3 satellite sensor will benefit from significant improvements including cost savings, risk reduction, and faster delivery for its customers.

QuickBird Satellite (0.6m)

quickbird(Image credit: DigitalGlobe)

DigitalGlobe’s QuickBird is a high-resolution commercial earth observation satellite was successfully launched in 2001 from Vandenberg Air Force Base, California, USA. The first satellite in a constellation of three that where scheduled to be in orbit by 2008. QuickBird uses Ball Aerospace’s Global Imaging System 2000 (BGIS 2000) that collects the fourth highest resolution commercial imagery of Earth after WorldView-1, WorldView-2 and GeoEye-1 and boasts the largest image size and the greatest on-board storage capacity of any satellite. QuickBird collects image data to 0.61m pixel resolution degree of detail. This satellite is an excellent source of environmental data useful for analyses of changes in land usage, agricultural and forest climates.

IKONOS Satellite (1m)

BOYER(Image Credit: DigitalGlobe)

The IKONOS satellite is a high-resolution satellite operated by DigitalGlobe and was launched on September 24, 1999 at Vandenberg Air Force Base, California, USA. Its capabilities include capturing a 3.2m multispectral, Near-Infrared (NIR)/0.82m panchromatic resolution at nadir. Its applications include both urban and rural mapping of natural resources and of natural disasters, tax mapping, agriculture and forestry analysis, mining, engineering, construction, and change detection. It can yield relevant data for nearly all aspects of environmental study. Its high resolution data makes an integral contribution to homeland security, coastal monitoring and facilitates 3D Terrain analysis. IKONOS comes from the Greek word for “image”.

IKONOS stereo images have the potential for creating DSM/DEM’s. The primary advantage of stereo imagery is the ability to extract cultural and geographic features in 3D such as buildings, roads and other terrain features and manmade structures. This accuracy can be consistently achieved with terrain slope conditions of <20%.

WorldView-1 Satellite (0.5m)

worldview-1(Image credit: DigitalGlobe)

DigitalGlobe’s WorldView-1 earth imaging satellite completed a successful launch on September 18, 2007 from Vandenberg Air Force Base, California, U.S.A. The high-capacity, panchromatic imaging system features half-meter resolution imagery. Operating at an altitude of 496 kilometers, WorldView-1 has an average revisit time of 1.7 days and is capable of collecting up to 750,000 square kilometers (290,000 square miles) per day of half-meter imagery. The satellite is also equipped with state-of-the-art geo-location capabilities and exhibits stunning agility with rapid targeting and efficient in-track stereo collection.

SPOT-5 Satellite(2.5m-5m)


(Image credit: ASTRIUM)

The SPOT-5 Earth observation satellite owned by Spot Image based in Toulouse, France was and was successfully launched May 4, 2002 on Ariane 4 from the Guiana Space Centre in Kourou.

Compared to its predecessors, SPOT-5 offers greatly enhanced capabilities, which provide additional cost-effective imaging solutions.  SPOT-5’s improved 5-meter and 2.5-meter resolution and wide imaging swath, the satellite provides an ideal balance between high resolution and wide-area coverage. The coverage offered by SPOT-5 is a key asset for applications such as medium-scale mapping, urban and rural planning, oil and gas exploration, and natural disaster management. SPOT-5’s other key feature is the unprecedented acquisition capability of the on-board HRS stereo viewing instrument, which can cover vast areas in a single pass. Stereo pair imagery is vital for applications that call for 3D terrain modeling and computer environments, such as flight simulator databases, pipeline corridors, and mobile phone network planning.

RapidEye Satellite (0.5m)

RapidEye(Image credit: BlackBridge)

RapidEye was successfully launched from the DNEPR-1 Rocket on August 29th, 2008 at Baikonur Cosmodrome in Kazakhstan. RapidEye built by MacDonald Dettwiler, Ltd. (MDA) will offer image users a data source containing an unrivaled combination of large-area coverage, frequent revisit intervals, high resolution and multispectral capabilities.

The RapidEye constellation of five satellites stands apart from other providers of satellite-based geospatial information in their unique ability to acquire high-resolution, large-area image data on a daily basis. The RapidEye system collects an unprecedented 4 million square kilometers of data per day at 6.5 meter nominal ground resolution. Each satellite measures less than one cubic meter and weighs 150 kg (bus + payload), and has been designed for at least a seven-year mission life. All five satellites are equipped with identical sensors and are located in the same orbital plane. BlackBridge’s satellites include the Red-Edge band, which is sensitive to changes in chlorophyll content.

LANDSAT 7 ETM+ Satellite Sensor (15m)


(Image credit: NASA)

LANDSAT 7 satellite is equipped with Enhanced Thematic Mapper Plus (ETM+), the successor of TM. The observation bands are essentially the same seven bands as TM, and the newly added panchromatic band 8, with a high resolution of 15m was added. An instrument malfunction occurred on May 31, 2003, with the result that all Landsat 7 scenes acquired since July 14, 2003 have been collected in “SLC-off” mode (Details).

LANDSAT 8 Satellite (15m)

landsat_8(Image credit: NASA)

The eighth satellite in the series of Landsat satellites, will continue and advance the collection of Landsat data with a two-sensor payload.

Landsat 8 satellite has two main sensors: the Operational Land Imager (OLI)  and the Thermal Infrared Sensor (TIRS).

OLI will collect images using nine spectral bands in different wavelengths of visible, near-infrared, and shortwave light to observe wide areas of the Earth’s landscape while providing sufficient resolution to distinguish features like urban centers, farms, forests and other land uses.

TIRS was added to the satellite mission when it became clear that state water resource managers rely on the highly accurate measurements of Earth’s thermal energy obtained by LDCM’s predecessors, Landsat 5 and Landsat 7, to track how land and water are being used. With nearly 80 percent of the fresh water in the Western U.S. being used to irrigate crops, TIRS will become an invaluable tool for managing water consumption.

ASTER Satellite

ASTER(Image credit: NASA/Japanese Space Systmes)

ASTER launched December 18, 1999 at Vandenberg Air Force Base, California, USA is one of the five state-of-the-art instrument sensor systems on-board Terra a satellite. It was built by a consortium of Japanese government, industry, and research groups. ASTER monitors cloud cover, glaciers, land temperature, land use, natural disasters, sea ice, snow cover and vegetation patterns at a spatial resolution of 90 to 15 meters. The multispectral images obtained from this sensor have 15 different colors, which allow scientists to interpret wavelengths that cannot be seen by the human eye, such as near infrared, short wave infrared and thermal infrared.

ASTER is the only high spatial resolution instrument on Terra that is important for change detection, calibration and/or validation, and land surface studies. ASTER data is expected to contribute to a wide array of global change-related application areas, including vegetation and ecosystem dynamics, hazard monitoring, geology and soils, land surface climatology, hydrology, land cover change, and the generation of digital elevation models (DEMs).


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