While the Global Positioning System (GPS) is best known for its positioning applications, another way to use GPS is as a time reference for telecommunication networks synchronization. However, as every new communication standard is more demanding, the precision of the current single-frequency GPS based network synchronization solutions is about not to be sufficient anymore. The dominant source of error in current state-of-the-art receivers based on the L1 C/A code is due to the variations of the propagation delay through the ionosphere. Fortunately, a new GPS civilian signal, L2CS, is about to be released. Combined with the existing L1 signal, it will allow to cancel most of the ionosphere induced error and therefore offer better timing signals as compared to classical GPS receivers. In this paper, a dual-frequency front-end for long antenna-GPS receiver links is presented.