Database of SPOT Satellite Images
(SPOT satellites)

The SPOT (Satellite Pour I'Observation de la Terre) satellites are planned by French engineers in cooperation with Sweden and Belgian engineers. Ever since the first satellite became operational in 1986, CNES has developed the SPOT programme in keeping with two guidelines:

• to ensure continuity of customer service
• to improve data and service quality by anticipating the changing needs of key users (cartographers, farmers, forest managers, geologists etc.).

Launching date of the SPOT 1 – 5 Satellites, proposed launching date of SPOT 6 and SPOT 7

THE SPOT FAMILY

The operational SPOT Earth observation satellite system, first approved in 1978, was designed by CNES and developed by France in cooperation with Belgium and Sweden. The system comprises a series of spacecraft and associated ground facilities for satellite control, acquisition programming, data reception and imagery production.

Spot data is processed, the derived products then being marketed and distributed by SPOT IMAGE, a CNES subsidiary.

With five satellites launched, two of which – SPOT 4 and 5 - continue to operate, the SPOT system has been operational since the launch of SPOT 1 on 22 February 1986.

SPOT 1’s orbit was lowered in 2003 so that it was retained on 31 December, 1990. Likewise, SPOT 2 was moved to a re-entry orbit on 29 July 2009 after 19 years in service. SPOT 3 launched on 26 September 1993, fulfilled its mission up to 14 November 1998 as it became inoperable in 1996 due to a failure of its stabilization system.

SPOT 4, successfully launched on 24 March 1998, features an additional short wave infrared band to help discriminate between different types of land cover. It also flies the VEGETATION payload developed jointly by the European Union, Belgium, Italy and Sweden, for its first mission.

SPOT 5 was successfully launched on 4 May 2002 and provides continued service from 2002.

During the 10 years of their operation they archived about 5 million images about the earth. The unique characteristics of the SPOT images (big resolution, stereo images etc.) qualifies the images suitable to collect data according to environmental changes in as a result of land use, land cover, destruction of special territories like wood destruction, erosion, built in territories etc. In the FÖMI National Archives of Satellite Images are archived the panchromatic or multispectral images taken off by SPOT1, SPOT2, SPOT3 satellites. The panchromatic method works in one ray, in the visible region of the spectrum, in 0.51-0.73 m. It gives only black-white image, with pixels in 10 m. This method is used for recognition of fine geometrical details. The multispectral images are taken off in 3 multispectral ray:

 SPOT 5

SPOT 5 offers a greatly enhanced resolution while retaining the wide field of view, excellent operational capability and image quality of its predecessors.

The multispectral resolution is 10 m in bands B1 (green), B2 (red) and B3 (near infrared), compared with 20 m for Spot 1 to Spot 4 and 20 m in the short wave infrared (SWIR) band. In panchromatic mode (PA band) the nominal resolution is 5 m compared with 10 m for its predecessors. Spot 5 also offers a very high resolution mode produced by combining two 5 m resolution images on the ground and sampling every 2.5 m. In keeping with the aim of continued service,

SPOT 5 flies the VEGETATION 2 instrument. The latter is built to the same technical specifications as VEGETATION 1, currently aboard Spot 4. The VEGETATION payload offers a 2 250 km swath, a spatial resolution of 1 km and excellent radiometric resolution in spectral bands B0 (blue), B2 (red), B3 (near infrared) and SWIR (short wave infrared). For easier multiscale, multidata interpretation and to enable twin-instrument coupled modes, the spectral bands used by both SPOT and VEGETATION instruments to distinguish vegetation (B2, B3 and SWIR) are identical.

The precision of VEGETATION's detection capability means that very slight variations in ground reflectance may be measured, thus providing accurate, operational measurements on plant cover.

Finally, in order to facilitate the production of digital terrain models, the HRS high resolution stereoscopic imaging instrument is flown: with its 120 km swath, it takes panchromatic stereopairs during the same pass with a resolution of 10 m and a B/H (base/height) ratio of 0.8.

BASIC INSTRUMENT CHARACTERISTICS
resolution - field of view

OPERATIONAL CAPABILITIES

Spot 5 carries two HRG high geometric resolution imaging instruments. Like the instruments flown by Spot 1 to Spot 4, each HRG can be steered through a range of viewing angles, enabling the satellite to acquire imagery of any region of interest anywhere on Earth at least once every five days, or once every three days in the case of European latitudes. Spot 5's two HRG instruments can thus be used:

• independently to acquire images of isolated regions of interest scattered across much larger areas, such as Western Europe, where demand is high;
• in the twin-instrument (coupled) configuration to acquire a 120 km swath in a single pass, significantly speeding up large surveys.

Spot 5's enhanced onboard processing capabilities will make it possible to simultaneously acquire 120 km swath products in the panchromatic and multispectral modes (compared with Spot 4's 60 km swath capability for the same combination of modes).

As its data channels can be managed independently, Spot 5 also offers improved acquisition programming.

Spot 5's operational capabilities have been significantly improved through its new solid-state onboard memory (which replaces the tape recorders of its predecessors). The memory's file management system offers greater flexibility during data recording and playback, allowing resource optimisation.

Acquisition programming is further optimised by combining long- term cloud forecasts based on climatological statistics tailored to Spot needs with short-term forecasts based on daily global cloud forecasts.

The HRS instrument takes along-track stereopair images with its two cameras, one facing forward and the other backward.

MARKETING SPOT IMAGERY

Since 1986, imagery gathered by Spot satellites has been market worldwide by Spot Image.

Thus it is that over 6.5 million images have already been acquired by SPOT satellites. Such imagery, which constitutes a unique record of our planet, together with all marketed products, are archived in a computerised catalogue accessible via Internet (http://www.spotimage.fr).

By setting up a commercial network spanning five continents (with subsidiaries in the United States, Australia, Singapore and China, 80 distributors and 23 receiving stations), Spot Image has made this wealth of geographic information accessible to an ever-increasing number of users through either its archive or through programming new acquisitions.

Due to its complete operational system (from reception of images through to processing then production), highly efficient customer services (satellite acquisition programming, access to archived imagery etc.), and its growing product range, Spot Image caters to the need for geographic information in markets such as cartography (generation and updating of topographical maps), monitoring, urban planning, rural development and telecommunications.

Alongside such major applications, there are developing markets concerned with managing agricultural and renewable resources, monitoring major hazards and updating cadastral maps.

Spot Image also proposes undertakings tailored to meet specific customer needs. These include the design and management of projects from start to finish, delivery of data, equipment and software and even the training of technicians. Indeed, such solutions (depending on the nature of the project itself) may in themselves constitute technology transfers.

The higher resolutions offered by Spot 5, combined with its 2 x 60 km coverage and frequent revisit capability, will enable Spot Image to continue to develop products better tailored to customers' needs.
Thus, the fifth satellite of the Spot family will not only ensure continued service but will also make a significant contribution to the appearance of new applications.