SDR based multi-band subsampling receivers for GNSS applications

The advent in analog to digital converter technology and the available processing power of today´s digital signal processors and general purpose processors as well as the available high speed FPGAs enables the design of radio receivers to move a step closer toward the ideal software defined radio (SDR) architecture. This paper presents some of the possibilities offered by the SDR by taking the example of a subsampling multi-standard GNSS receiver. The main differences between a superheterodyne and a subsampling receiver are presented and the sampling frequency selection procedure is detailed. Finally a test setup for the GNSS receiver as well as the frequency conversion results are shown.