On use of low cost, compact GNSS receiver modules for ionosphere monitoring

Geodetic or special purpose Global Navigation Satellite System (GNSS) receivers are used for ionosphere monitoring and research. Dual frequency, compact, low-cost commercial GNSS modules can provide raw GNSS data and are commonly used for positioning applications. This paper presents the applicability of these compact modules for monitoring ionospheric activities. A comparative study between Javad Triumph LS, a costly geodetic receiver, and an Ublox ZED-F9P, a low-cost, dual-frequency, compact module is carried out to explore the potential of the low-cost devices for ionosphere probing. Studies are carried out on signal strength values (C/N0) and vertical total electron content (VTEC) values. From the concurrently collected GPS data, a bias of 2.2–4.9 dBHz in signal strength values are observed between the two types of receivers depending on the signal frequency band. The VTEC values calculated from the Ublox module are in close agreement with the values obtained from the Triumph LS receiver. Therefore, the compact module shows the potential for use in ionosphere monitoring with clear advantages in cost, size, and power consumption. However, the signal strength values obtained from such compact modules need to be calibrated using standard GNSS receivers. A GNSS-based Ionosphere Monitoring Unit (GIMU) is also proposed in this manuscript by the integration of a compact, low-cost GNSS module with a single-board computer and a wireless data communication module. Real-time, cost-effective, concurrent ionosphere monitoring over a geographically distributed network is possible using a network of such units.