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PREPROCESSING OF SPOT DATA AT THE TWO CENTRAL GROUND STATIONS 
by Ph. COUILLARD - SPOT PROJECT MANAGER 
CNES 
FRANCE 
COMMISSION NUMBER II 
ABSTRACT 
SPOT a polar orbiting earth observation satellite will transmit high reso- 
lution data taken all around the world, These data will either be recorded 
on board of the spacecraft or transmitted to ground receiving stations loca- 
ted in different countries. 
Two stations are directly controlled 5y Centre National d'Etudes Spatiales 
(CNES) and will constitute the central network. The first is located near 
TOULOUSE, FRANCE, and the second near KIRUNA, SWEDEN, is operated by a 
subsidiary of Swedish Space Corporation. 
The paper describes the harware installed at the preprocessing Center of 
these two central stations. It describes too the procedures used to trans- 
form the raw data into usable photographic or digital products. 
Production time and throughput will be given in the case of standard pro- 
ducts. 
1 - PREPROCESSING CENTERS FUNCTIONS IN THE SPOT SYSTEM 
  
The SPOT system, conceived and designed by the French Centre National d'Etu- 
des Spatiales (CNES) is being built by French industry working in assocía- 
tion with European partners (BELGIUM and SWEDEN), It consists essentially of 
an Earth Observation satellite and of a ground segment. 
The SPOT ground segment is divided in two separate parts. The Mission and 
Control Center is in charge of : 
. Sending the telecommand orders and in particular monitoring and program- 
ming the payload, 
. receiving housekeeping telemetry, 
. computing the orbital parameters, 
The Image Ground Segment includes two central receiving stations in TOULOUSE 
(FRANCE) and KIRUNA (SWEDEN) and severa] foreign receiving stations al] 
around the world. Inside a receiving station, there are two main subsystems 
- the receiving subsystem (SRIS) recording the image telemetry signal sent 
by the satellite, when it passes inside the circle of visibility of the 
station. Raw data obtained are recorded on high density tapes. 
- The preprocessing center (CRIS) in charge of archiving and transforming