Simultaneous Retrieval of PWV and VTEC by Low-Cost Multi-GNSS Single-Frequency Receivers

Abstract

Precipitable water vapor (PWV) and ionospheric vertical total electron content (VTEC) are two essential components of space-atmosphere parameters. The zenith troposphere delay can be converted into PWV, which plays a crucial role in meteorological studies. In the meantime, the importance of the VTEC lies in providing ionospheric corrections for single-frequency (SF) positioning, navigation, and timing users. Currently, the global navigation satellite system (GNSS) has become one of the most commonly used tools for retrieving PWV and VTEC and normally relies on dual-frequency, geodetic-grade receivers and antennas. However, this reliance also implies high hardware costs. In this paper, we propose a single-frequency ionosphere and troposphere retrieval approach that enables the simultaneous retrieval of PWV and VTEC from multi-GNSS data collected by low-cost SF receivers. The use of SF receivers can greatly reduce the cost of hardware. Furthermore, the simultaneous provision of PWV and VTEC also has a positive effect on studying the coupling mechanisms of the ionosphere and troposphere. The accuracy of the estimated zenith troposphere delay can be better than 10 mm compared with the troposphere products published by the International GNSS Service, and the PWV is no more than 3 mm compared with radiosonde-derived results. Referring to the final International GNSS Service global ionosphere map products and the Jason altimeter data, the VTEC retrieved from the single-frequency ionosphere and troposphere retrieval method can perform at roughly equal levels compared to the customary dual-frequency method.