| | | 
| Wavelength (C-band) | 0.057m | 
| Pulse repetition frequency | 1690 Hz | 
| Range sampling rate | 16 MHz | 
| Altitude 1.793 Km | 
| Near incidence angle 18.41 | 
| Far incidence angle I^ 2543. LH 
| | | 
  
Table 1 - Radar sensor specification 
  
| | | 
| No, of range cells after compression | 4800 | 
| Azimuth replica length | 256 | 
| Azimuth resolution | 25m | 
| Ground range resolution | 25m | 
| | Swathwidth | | 80-100 Km | 
|  Radiometric resolution | 1.5 4B | 
1 "NO. ‘OF looks | 4 | 
| Dynamic range of processor output signal | 60 dB | 
| Highest sidelobe level | -20 dB | 
| Processor induced artifacts D ur 50 dE | 
| Radiometric distortions | + 0.5 d8 | 
| Output data registration errors | + 1 pixel | 
| : | | 
  
Table 2 - Image specification for a typical earth exploration 
SAR-system. 
It has been demonstrated that the most efficient azimuth compression 
algorithm for multi-look processing in terms of memory and arithmetic 
requirements is based on the "spectra! analysis" or SPECAN methods (5). 
For this reason it is considered here merely for the purpose of 
dimensioning the azimuth processor. : 
The main azimuth processing characteristics relevant to the image 
specification given in table 2 are: 
- Input data rate (burst mode) 38.4 Mbyte/s 
- Number of FFT's of length 256/sec. 42250 
- Output data rate 1,5 M pixel/s (8 bit) 
Two different implementations for achieving the azimuth processing task, 
ar? outlined below. 
2.1 Azimuth processing using the High Speed Programmable Processor (HSPP) 
  
The High Speed Programmable Processor (HSPP) concept is developed by Matra 
and Saab under ESTEC contract and is intended to provide a unified tool 
for various kinds of high speed on-board signal processing. Real time 
optical or SAR imagery are typical applications. Implementation of an 
on-board image processing application have been discussed in (1). 
Processor architecture is described in (2) and (3). 
In summary, HSPP is a bus oriented MIMD parallel processor allowing 
cooperation of various kind of processors such as general purpose 
microprocessors, digital original processors, specialised signal 
processing devices (e.g. FFT), etc. (see Fig. 1). 
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