# SYSTEM EXPLOITATION

# Toulouse facilities

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### SRIS: TOULOUSE SPACE IMAGERY RECEIVING STATION

The Toulouse Space Imagery Receiving Station (SRIS) is located at Issus-Aussaguel, 20 km from Toulouse. It can receive image telemetry whenever the satellite is within range (i.e. within a circle about 2 500 km in radius centred on Issus-Aussaguel). This occurs five times a day (two south-bound passes during the night and three north-bound passes during the day, or vice versa). The average pass duration is 10 minutes, the longest 15. SRIS-Toulouse comprises:

1. A 9-m-diameter, Cassegrain-type, parabolic antenna driving; a parametric amplifier. This is mounted on a 6-m-high concrete tower housing an antenna equipment room containing power supplies and servo-systems controlling antenna pointing and tracking in elevation and azimuth. Signal acquisition is by automatic tracking as soon as the satellite rises above the horizon.
2. Receiver equipment proper including a step-down converter (8 GHz to 720 MHz), an antenna multicoupler, a demodulator and a bit synchronizer. The complete receiver chain operates at 2 x 25 million bits/second when receiving SPOT data.
3. High-density cassette recorders
4. Operator's console for control and monitoring of all SRIS operations.

The Toulouse SRIS station was produced entirely by French industrial firms working under the prime contractorship of MCS (Matra Cap Systèmes). It is operated by staff provided by the Worldwide Networks and Services of FRANCE TELECOM. During regular operation, the SRIS is fully automated.

For each pass, the procedure is as follows:

- one hour before the pass: switch on equipment and check that all is operating correctly;
- next: aim antenna at point where the satellite will rise above the horizon (coordinates provided by MCC);
- a few seconds before rise time: switch on recorder (automatic tracking begins as soon as the satellite comes into view);
- at end of pass, antenna automatically returns to survival position and equipment is either switched off or switched to standby. /DL>

The high-density cassettes (D1-format) contain all image data generated by the spacecraft. It is these data that go to the SPOT archive. These data are not, however, suitable for direct use by users. A 10-minute pass permits the transmission of about 150 SPOT scenes of 60 km x 60 km each. It is the job of the Spot Image Archiving and Processing Centre (CAP) to process the raw image data to yield products of commercial quality.

### SPOT IMAGE ARCHIVING AND PROCESSING CENTRE (CAP)

The Spot Image CAP Centre receives raw data recorded on D-1 high density type cassettes from the SRIS station. The cassettes can record an input data stream of 50 Mbits/sec.
The main functions performed by the CAP Centre are: systematic archiving and image production to commercial quality standards.

#### Systematic archiving

Systematic archiving begins with the automatic `locating' of the raw image data. Next, the 60-km-wide strip (for vertical viewing) acquired by each HRV instrument is divided into scenes. Each scene is assessed to determine cloud cover, snow cover and image quality. The scene descriptors and quick looks are then transferred to the DALI catalogue.

#### CAP image production

The aim is to convert raw data recorded on cassettes into standard SPOT products. Processing consists of the radiometric and geometric correction of raw image data. Several preprocessing levels are offered on different media.

### IMAGE MAP WORKSHOP

Spot Image has completed its new integrated SPOTView production facility, significantly increasing imagemap production capacity. The "image oriented" system generates image blocks of the SPOTView® range. Completed image blocks are passed to the finishing facility, a special-purpose geographic information system (GIS) that combines raster-format image data with vector data from various sources. Flexibility and throughput were the watchwords during workshop design and development. The turn-around time for SPOTView® products is now down to two weeks or less.

#### Image processing system

The SPOTView IP system was supplied by French firm RFI (Réalisations Françaises en Imagerie). Built around an 12S (International Imaging Systems) core, it comprises:

- two "operator" workstations in the form of SUN stations with 64 Mbyte of RAM, A0-format flat-bed digitizers, and IVAS displays;
- one SUN station with 32 MB memory, and BITE processor used as a "development" workstation for development work, database management and background task processing;
- 25 Gbytes of disc storage shared by the three workstations;
- full range of I/O peripherals including tape, CD-Rom, 150-MB cartridge and Exabyte optical tape drives;
- one monochrome printer + one colour printer.

The PRI2SM image processing software suite runs hand-in-hand with the Ingres database management system (DBMS) used for project tracking, map and GCP library management, etc.

#### Publishing System

The SPOTView publishing system, is designed around an Intergraph core comprising:

- a prototyping and development workstation in the form of an InterPro 6450 station with 32 MB of memory, 1 GB of disk storage, and a 19-inch, 256-colour display;
- a publishing workstation in the form of an InterView 6450 station with 32 MB of memory, 1 GB of disk storage, two 19-inch, 256-colour displays and an A0 format flat-bed digitizer;
- an image manipulation workstation in the form of an InterPro 6480 station with 64 MB of memory, 1 GB of disk storage, and a 27-inch, 24-bit colour display capable of displaying 16 million colours;
- a server designed around an InterServe 6405 station with 64 MB of memory and 1 GB of disk storage.

The Microstation 32 software suite includes Microstation GIS Environment (Projection Manager, Map Finicher, Imager), Ingres DBMS, Interplot, DP Studio and DP Studio and DP Color Separation for the various phases of finishing and output.