BEYOND SPOT 5: PLEIADES, PART OF THE FRENCH-ITALIAN PROGRAM ORFEO 
A. Baudoin 
CNES, 2 place M. Quentin 75039 Paris France (alain.baudoin(@cnes.fr) 
Commission I 
KEY WORDS : High resolution, Stereoscopic, SPOT, User, Performance, Small/micro satellites, Development, Future 
ABSTRACT 
This paper presents how Pleiades HR, the next French Earth Observation system which will succeed to SPOT 5, complementing it 
without replacing it, has been defined and decided. It describes the characteristics and performances of the system which will serv 
civilian and Defence applications and should be a key element for GMES and GEO initiatives., at European and International levels. 
From an user's analysis 10 new systems, based on small satellites, have been identified to fulfil most of the needs. After comparison, 
the highest priority was given to the development of high resolution systems, either with optical sensors or SAR instruments. 
Within a cooperative program, ORFEO, settled between France and Italy, high resolution SAR data should be provided by COSMO- 
SkyMed developed under Italian responsibility whilst high resolution optical images will be acquired by Pléiades HR, developed 
under French responsibility.. 
With its two satellites, to be launched in 2008-2009, Pléiades HR will provide high quality images, not only in terms of resolution 
(0.7 meter at nadir) but also in terms of MTF (0.2 at system level) and geometrical accuracy: Even without using any Ground Control 
Point absolute location accuracy should be better than 10 m. Orthorectified images will be produced as standard products for easier 
integration in Geographical Information Systems (GIS). The high agility of the platform and sensor will optimize acquisition of 
images either in stereoscopic or monoscopic mode on areas of very diversified sizes and shapes. 
A Preparatory Program has been undertaken with scientists, image processing specialists and end users in order to develop 
operational tools and methods for 2D or 3D applications of high resolution SAR and optical images. 
e 
RÉSUMÉ 
Ce papier présente la genése de Pléiades HR, le prochain systéme qui succédera, sans le remplacer, à SPOT 5. Il décrit les 
caractéristiques et les performances du systéme qui servira des applications civiles et de défense, constituera un outil adapté à 
l'initiative européenne GMES et qui pourra s' intégrer dans le GEOSS préconisé au niveau international par le GEO. 
Une étude utilisateurs a permis d'identifier 10 composantes spatiales, des constellations de petits satellites, pour satisfaire la plupart 
de leur besoins. Aprés comparaison, la plus haute priorité à été donnée au développement des systémes à haute résolution, aussi bien 
dans le domaine optique que dans celui du radar. 
Dans le cadre du programme ORFEO fruit d'une coopération entre la France et l'Italie des données haute résolution radar seront 
fournies par COSMO-SkyMed, développé sous responsabilité italienne, alors que des données optique à haute résolution seront 
fournies par Pléiades HR développé sous responsabilité francaise. 
Avec ses deux satellites, qui doivent étre lancés en 2008 et 2009, Pléiades HR fournira des images de haute qualité, non seulement en 
termes de résolution (0,7 m au nadir) mais également en termes de FTM (0,2 au niveau systéme) et de précision géométrique : méme 
sans utiliser de points d'appui la précision de localisation absolue doit étre meilleure que 10 m. Les images orthorectifiées seront 
produites en tant que produits standard pour permettre une utilisation plus facile dans des Systémes d'Information Géographique 
(SIG). La grande agilité de la plate-forme et du capteur permettra d'optimiser l'acquisition des images soit en mode stéréoscopique 
soit en mode monoscopique sur des zones de forme et de taille trés variées. 
Un Programme Préparatoire a été engagé avec des scientifiques, des spécialistes du traitement d'images et des utilisateurs finaux 
pour développer les outils et les méthodes nécessaires aux applications 2D et 3D de ces images haute résolution radar et optique. 
1. INTRODUCTION mid nineties, with the development of high resolution 
systems such as Ikonos from Space Imaging or Quick Bird 
In spite of the technological and operational success of the from Digital Globe, and also with the new Landsat policy. 
SPOT program from the launch of Spot 1 in 1986 up to now 
with its three satellites in orbit (Spot 2, Spot 4 and the last From a technical point of view the feasibility of small 
one Spot 5) commercial benefits from the image market had satellites has been proven. Two new Earth Observation 
been less than expected. This is due, on one hand, to more systems, called 3S (Spot System Successors) has been 
competition with new image providers, and on the other hand defined by CNES to provide both high resolution (about 80 
to a lower development than expected of new applications. cm with 3S1) and wide field (as for SPOT 5 with 3S2) with 
much smaller and cheaper satellites than the previous SPOT 
Even if for SPOT 5 some private investments were possible (Baudoin 1999) 
on the Ground Segment and on the HRS instrument, a fully 
market driven approach could not be pursued after SPOT 5 New objectives were proposed in 1999: 
and new objectives and solutions had to be found. - Looking to more innovation with smaller and cheaper 
satellites for developing constellations of mono-sensor 
Several programmatic scenarios had been envisaged, taking satellites instead of larger multi-sensors satellite: 
into account the new Earth Observation background from the 
   
   
   
    
   
    
   
  
   
   
  
    
   
  
  
   
   
  
   
  
  
  
  
  
   
   
    
   
    
    
   
   
   
   
    
   
   
      
   
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