This work indicates that direct conversion can be used to implement an affordable dual-frequency GNSS receiver. The highly integrated nature of such a D/C receiver enables wideband GNSS reception at competitive cost. The performance of the D/C front-end is at least comparable to a heritage heterodyne solution. A future problem, however, can arise from the phase noise in the D/C receiver, which is currently the largest observed difference compared to the heterodyne receiver. Phase noise may be an issue for the most demanding carrier-phase-based techniques and would need attention in such receivers.rnDirect conversion is particularly appropriate to receivernBOC-modulated signals with little or no energy at the band center. The evolution of GNSS systems toward such signals will also make direct conversion more attractive for future designs. Even the heritage GPS L1 signals are scheduled to be replaced by BOC-modulated signals.rnThe next step is the integration of the direct-conversion front-end with a correlator in a standalone GNSS receiver, allowing more in-depth measurements that can be extended over a longer time than the current setup, where data-recording time is limited.rnA positive outcome of this investigation will influence future receiver designs and enable dual-band GNSS receivers based on direct conversion. Such a receiver could enhance spaceborne positioning, timing, and attitude determination capabilities. Scientific applications such as atmospheric sounding and GNSS reflectometry will also profit from dual-frequency wideband reception.
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