Research of Ionospheric Modeling based on Chip-level GNSS Data

The ionosphere contains a large number of free electrons and is one of the thorniest sources of error affecting Global Navigation satellite system (GNSS) signals. With the increasing richness of GNSS data, the application field of satellite navigation and positioning services is expanding, and further application needs are put forward for ionospheric modeling and delay correction services. On the contrary, error is also a kind of signal. GNSS data provide rich data resources with high time resolution for ionospheric inversion, and is an important technical means in space weather research. However, the estimation of ionospheric total electron concentration (TEC) using GNSS data is mainly based on the use of expensive geodesic receivers with high density deployment costs. In 2016, Google promoted the opening of GNSS raw data acquisition interface for mobile terminal Android system, which opened a new situation for low-cost GNSS research. Based on the low-cost chip-level GNSS data of the Mi 8 smartphone and the Trimble Alloy geodesy receiver data, this paper systematically analyzed the GNSS numerical quality obtained and the accuracy of skew ionospheric TEC (STEC) extraction and vertical ionospheric VTEC (VTEC) modeling. The accuracy of low cost GNSS equipment in atmospheric inversion is explored. Experiments show that: in the test area, if a good GNSS antenna is used, the ionospheric modeling accuracy of the GNSS chip data of the Mi 8 smartphone can reach the water of the geodetic receiver, indicating that the GNSS data based on low-cost chip level is expected to be used in the future for the GNSS station deployed in the ionospheric research.