Data Compression Unit
RUAG Space (RSA) delivers a Digital Processing Unit, which performs data compression using a modified JPEG algorithm and which interfaces signals from National Oceanic and Atmospheric Administration (NOAA) -type instruments to an European satellite bus. The Data Compression Unit contains two digital signal processor boards constituting the hardware platform for the digital signal processing algorithms and two boards containing interface and cross-strapping functions. These boards are integrated together with boards for the control computer, bus interface controller, command and control interface and power converter.
RSA has also developed the signal processing software in the programmable digital signal processor.
The hardware architecture is based on the TSC21020F Digital-Signal Processor (DSP) and supported by an Application Specific Integrated Circuit (ASIC), performing the low-level interface handling. Even with hardware support, the asynchronous interface management real-time constraints remain stringent and necessitate an interrupt driven software concept, where only low priority can be allocated to the modified JPEG algorithm. Approximately 20% of the processor's capacity are required for other tasks, which leaves an effective processing power of about 5 Mega-instructions per second (MIPS) for the compression of 0.5 Mbit of data within 1.3 seconds. Under these conditions the software has been optimized for maintainability and testability on the one hand and timing budget on the other hand. Comparisons with available other codes have shown the superior performance of the RSA code with respect to timing and memory utilization.
The product has been developed in the frame of the METOP program.