2. System Description and Product Definition 
The SAR Processing and Archiving Facility is functionally devided into several subsystems executing proc- 
essing tasks and performing monitor and control functions as outlined in Figure 1. The major processing tasks 
are Preprocessing, Geocoding and Data Management. 
  
  
  
Facility Management 
  
  
  
  
  
  
  
  
Preprocessing Geocoding Data Management 
- HDDT-Transscrip. - Registration with GCP — Product Generation 
— SAR Processing -Rectification with DEM . - Archival/ Retrieval 
— Simulation - Map Generation 
  
  
  
  
  
  
  
  
Figure 1. The SAR Data Processing Chain 
The Preprocessing task comprises several functions such as the transcription of HDDT's, the SAR processing 
and the simulation of raw SAR data. The major of these tasks is the SAR processing. Depending on the 
selected processing parameters, image data sets with different characteristics will be generated and passed to 
the other subsystems for further processing and handling. The Preprocessing subsystem in itself is complex 
enough to require operations control support using an expert system. Accordingly the subsystem is called 
Intelligent SAR Processor ISAR. 
The Geocoding task accepts the earth located preprocessed data sets as input and performs geometric manip- 
ulations. The major subtasks are the optional rectification of SAR data with Ground Control Points (GCP) 
and/or Digital Elevation Models (DEM) - and the subsequent resampling to a geocoded grid in different map 
projections. 
The Data Management task finally comprises product generation and all related archival and retrieval functions. 
The Product Generation step converts the annotated data sets which are generated during Preprocessing and 
Geocoding into physical products that can either be archived or distributed to the user who has requested it. 
Products are either digital products such as Computer Compatible Tapes (CCT) or different kinds of optical 
disks or photographic images on film or paper in various formats. 
The above described processing subsystems for Preprocessing, Geocoding and Data Management form the SAR 
Data Processing Chain. This chain represents a distributed processing system with the subsystems executing 
their tasks in parallel, often in a pipeline configuration. All subsystems are attached to a high performance 
Local Area Network (LAN) which enables 
* the exchange of large data sets among the different subsystems and 
* the operations control of the integrated system. 
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