A direct digitisation spread-spectrum architecture for GNSS receivers

Global navigation satellite systems 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 digitisation. We introduce a multi-band direct digitisation 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 multi-band capability in the direct digitisation approach.