In South Korea, a GNSS network with high density is established. This network provides the users both real-time GNSS data in RTCM format and post-processed GNSS data in RINEX format. Many GNSS Continuous Operating Reference Stations (CORSs) participating this network are operated by National Geographic Information Institute (NGII), Korea Astronomy and Space Science Institute, National Maritime Positioning, Navigation, and Timing Office (NMPNT), and so on. Recently, Software Defined Radio (SDR) technology is introduced for the flexible design and implementation of wireless transmitters and receivers. An SDR allows direct access to signal processing to adjust frequency operating ranges, modulation schemes, and bandwidths loaded on a single platform. Due to these scalability and flexibility characteristics of SDR, it is anticipated that advanced future GNSS networks would be required to accommodate SDR-based CORSs for many purposes. In this paper, we designed an SDR-based CORS utilizing an Ettus USRP N210 module and the open-source SDR development toolkit named GNU Radio. By an experiment, it was confirmed that the designed SDR-based CORS can be utilized in a self-developed software package operating a GNSS network managing conventional GNSS CORSs. It was confirmed that the GNSS data can also be collected online by the designed SDR-based CORS.

Keywords: GNSS, GNSS network, software defined radio, continuous operating reference station