The main purpose of the self-compensating device (SCD) is to improve the Galileo signal quality, providing users with more accurate positioning information. The concept gives unique capability of real time Galileo signal quality measurements on board the spacecraft and performance improvement by state of the art digital signal processing techniques. Manufactured with European technology, the SCD concept has been studied in great detail by RUAG Space through several ESA studies and an engineering model (EM) has been designed, manufactured and tested. These activities demonstrated the SCD considerably improves the Galileo signal characteristics. 

As the satellites travel through its orbit at 23,222Km from the Earth, the SCD calculates the errors on the Galileo signals due to changes in the operating environment . The SCD makes autonomous on-board adjustments to the transmitted signals by applying the necessary corrections to the Navigation Payload. The SCD provides a high level of flexibility as the signal processing algorithms are executed in real time by a dedicated processor and can be changed by means of software updates. Currently under a new phase of development by RUAG Space AB, the unit will make use of the newly available high-performance European field programmable gate array (FPGA) technology, implement new E1-D signals and include advanced architectural analysis for future generations of Galileo Satellites.