A fully digital direct-sequence spread-spectrum receiver architecture for GNSS applications

Global navigation satellite systems (GNSS) based on the direct-sequence (DS) spread-spectrum technology are the most recent of the fully operational radio-navigation systems. The GNSS receiver designs have evolved over the last twenty years from analog to digital architectures. Due to the technological progress in silicon technologies, digital signal processing and especially in DS code division multiple access (CDMA) spread-spectrum receiver architectures, the next logical step in the evolution of GNSS receivers is the direct digitization. In this paper we will introduce a fully digital architecture for DS spread-spectrum based receivers well suited for GNSS satellite navigation and other spread-spectrum applications. The overall structure of the direct digitisation DS spread-spectrum architecture is discussed with particular attention given to the realization of the digital GNSS receiver architecture and the presentation of test results.