Satellite Spot

The satellite Spot ( Probatory System of Observation of the Satellite Earth or For the Observation of the Earth ) are a satellite series of civil of observation of the terrestrial ground.

History

Decided in 1978 by the France, the Spot program is carried out by CNES (National center of space studies) in collaboration with the Belgium and the Sweden. It is composed of a series of satellites and infrastructures terrestrial for control and the programming of the satellites like for the production of the images.

The Spot images are marketed by the company Spot Image.

Orbit: quasi polar, heliosynchronous circular, and phased;
Altitude: 822 km.

One of the large assets of the system SPOT is its capacity of dépointage of its instrument principal imagor on both sides of the trace on the ground of the satellite, of +31,06° with -31,06°. This confers a very great flexibility of acquisition to him, while in particular bringing back the repetivity of acquisition (temporal frequency or frequency of revisits) to 2-3 days.

1st generation: Spot 1,2,3

Resolution of the images of instrument HRV (Visible High-resolution):

10 meters into panchromatic (channel covering the visible field of the electromagnetic spectrum)
20 meters into multispectral (three bands in the green, the red and the infra-red one near)

Launching:

Spot-1, launched the February 22nd 1986 (ARIANE 1)
Spot-2, launched the January 22nd 1990 (ARIANE 40)
Spot-3, launched the September 26th 1993 (ARIANE 40), end of operation in November 1996)

2nd generation Spot-4

Conceived in synergy with Photogravure 1.

Resolution of the images of instrument HRVIR (Visible and Infra-red High-resolution):

10 meters in monospectral in the red channel, SPOT4 does not have true panchromatic a
20 meters into multispectral (four bands in the green, the red, the infra-red one near and the infra-red means)

Momentary:

PASTEL (Momentary Spot of Laser Telecommunication), one of the two visual display terminals constitutive of the communication system space FLINT (Semi conductor Intersatellite Link EXperiment).
VEGETATION-1 consists of a system imagor functioning in 4 spectral bands (blue: 443-470nm, red: 610-680nm, close infra-red: 780-890nm, and average infra-red: 1580-1750nm). It uses telecentric optics ensuring a space resolution about 1km for a cover on ground the 2.250 km broad and a daily repetitivity with the moderate latitudes.

Launching:

Spot-4 was launched the March 23rd 1998 (ARIANE 40, Vol 107)

3rd generation Spot-5

Conceived in synergy with Photogravures 2.

Resolution of the images of instrument HRG (Geometrical High-resolution):

The innovation of Spot-5 is the introduction of the Super-Mode which allows the creation of an image 2,5 meters of resolution starting from two images with 5 meters acquired simultaneously with a half-pixel of shift. Their combination is carried out by techniques of treatment and restoration of image advanced.

2,5 meters in panchromatic super-mode
5 meters into panchromatic
10 meters color
Capacités of acquisition of stereoscopic couples improved thanks to instrument HRS (Stereoscopic High-resolution)

SPOT-5 also carries VEGETATION-2, successor of VEGETATION-1 on board SPOT-4
Lancement:

Spot-5 was launched the May 3rd 2002 (ARIANE 42P, Vol 151)

Stations of reception on the ground

30 stations out of the 5 continents.

Interests and uses of the images Spot

The images resulting from the space teledetection (Spot or other satellites) have the following advantages: world cover, capacity of synthesis thanks to the dimension of covered surfaces, repetitivity.

One of the assets of Spot has been its bank of images covering planet for more than 20 years with similar sensors. This bank makes it possible to study phenomena easily evolving/moving in time and space (deforestation, etc).

Some examples of use:

Defense:

use of the stereoscopic images for the realization of model digital of ground,
information in times of peace, without violation of the airspace of the zone observed
use of mobile stations of reception to feed the command on the theater of operation.

Agriculture:

the European Community uses the Spot images for the control of the declarations within the framework of the common agricultural policy (the infra-red sensor allows the identification of the plants and the stage of maturation),
evaluation of the damage caused by important bad weather (wind, spindly, etc).

Cartography:

Spot 5 and its panchromatic sensor (resolution of 5 m and 2,5m in super-mode) allows the realization of charts 1:50 000.

Suivi environment

the images of the sensor VEGETATION are used to follow the evolution of the continental ecosystems. Indeed, by the inversion of models of radiative transfer which reproduce the interactions between the solar radiation and the various elements present on continental surface, one can extract from these images the vegetation and soil properties physics. Those are represented by variables such as the fraction of vegetable cover, the foliar index or the fraction of radiation absorptive by the plants for the Photosynthèse. The Center of Service POSTEL treats the images of the sensor VEGETATION acquired since 1999 to generate series for more than one year of these variables and to distribute them to the scientific community for applications related to the Météorologie, with the Climatologie, the Cycle of carbon, the Cycle of water, the forecast of harvests.

Evolution of the space systems of observation of the Earth

France committed itself with Italy developing a dual system of observation of the Earth (civilian and soldier) named ORFEO and having two components. France develops an optical component, Pléiades project under control of work of the National center of Space studies (CNES), made up of two identical satellites called PHR1A and PHR1B (Pleiads High-resolution). Italy develops a component radar, Cosmo-skymed project entrusted to the Italian space agency (ASI).

PHR1A will be drawn at the end of 2008. Of a mass of a ton, it will evolve/move in heliosynchronous orbit to 694 km of altitude. It will have a capacity of acquisition of 450 images per day. It will be able to cover annually 2.500.000 km ² per annum. This satellite, built around a central telescope, will be equipped because of position with its center of gravity of exceptional capacities of operation. Its resolution is metric.

Notes and references of the article

Random links: