Bandpass-sampling based GNSS sampled data generator — A design perspective

This paper presents the design methodology and simulation results of a sampled data generator (SDG) designed to operate over the whole range of Global Navigation Satellite System (GNSS) frequencies (1164MHz to 1615.5MHz). An SDG is actually a radio front-end (RF FE) that generates digital samples at intermediate frequency (IF), which can be recorded and used in the future as test input to a baseband processing unit. The proposed SDG is based on the bandpass-sampling principle and works over combined (but overlapping) frequency bands of all three GNSS constellations (American Global Positioning System (GPS), European Galileo system and the Russian GLONASS system). It is observed that there is currently no commercially available multi-system multi-frequency GNSS SDG. This paper hopes to fill this gap. First, the overall architecture of the proposed SDG is described, followed by the detailed design of each block, namely, the bandpass & bandstop filters, and the frequency planning for the bandpass-sampling analog to digital converter (ADC).