At present,research on smartphone GNSS high-precision positioning observations mainly focuses on quality analysis and positioning algorithms,but few studies have been carried out on their atmospheric applications.In this research,the ionospheric delay using the raw GNSS dual-frequency carrier phase observations from Xiaomi Mi 8,the world’s first dual-frequency smartphone,is estimated and compared with that of Trimble Alloy geodesic receiver with ultra-short baseline.The quality of observations is controlled by considering the small ionospheric variation between successive epochs.The results show that the observations of smartphone may still be invalid when the satellite elevation or the carrier-to-noise is high.The method of setting threshold of satellite elevation or the carrier-to-noise is no longer applicable for quality control.The ionospheric delay retrieved by Xiaomi Mi 8 is in good agreement with that of Trimble Alloy geodetic receiver,with slightly higher fluctuation range.The retrieving accuracy is better than 0.2 TECU,indicating that the GNSS observations from smartphone is feasible for atmospheric application.