August 10, 2016

Satellites

The two Vegetation instruments are passengers on board the Spot 4 and Spot 5 satellites.


Vegetation instrument

The two Vegetation instruments are nearly identical. The only differences are:

  • A few improvements of the optics: minimization of the stray light and modification of the SWIR sensor (Short Wave InfraRed).
  • Improvement of the calibration system: supply of a reliable ground reference.
  • Modification of the attitude restitution: Spot 5 winding.
  • Use of 'star tracker' which ensures accurate location without Ground Control Points.

Acquisition simultanee par VGT1 et VGT 2
Simultaneous acquisition on 6 May 2002

A few characteristics of the Vegetation instrument:

Mass160 kg
Size0.7 x 1.0 x 1.0 m³
Consumption< 200 W
Reliabilityredundant equipment
4 camerasCCD + telecentric objective
4 spectral bandsBlue (B0), red (B2), near infrared (B3) and short wave infrared (SWIR)
Swath2250 km
Nearly constant resolution in the field of view
High geometric quality (no scanning mechanism)
Long integration time -> very good Signal/Noise ratio
Single video electronics
Calibration device
Mass memory2.25 Go
On-board calculator (autonomous management)
X-band transmission chain
L-band transmission chain + dedicated antenna