Performance evaluation of low-cost GNSS receivers for extracting ionospheric TEC

Abstract

This paper aims to compare the performance of the low-cost Global Navigation Satellite System (GNSS) receiver u-blox ZED-F9P and the geodetic receiver JAVAD SIGMA G3T on vertical total electron content (VTEC) estimation, and to evaluate the impacts of different antennas on VTEC estimation. Using the undifferenced and uncombined Precise Point Positioning (PPP) algorithm to process GNSS data on April 15, September 11, and September 12, 2021. Then we compared the accuracy of VTEC and differential code bias (DCB) estimation between the low-cost GNSS receiver and the geodetic receiver. The results showed that VTEC extracted from low-cost GNSS receiver and geodetic receiver are consistent with the Global Ionospheric Model (GIM) products. However, the low-cost GNSS receiver’s VTEC accuracy is slightly lower, with the residual root mean square (RMS) values ranging from 1.07 to 1.72 TECU (Total Electron Content Unit) and the absolute mean bias ranging from −1.48 to −0.85 TECU. Additionally, satellite DCBs from the geodetic receiver were closer to CAS products than those from the low-cost GNSS receiver, with more satellites exhibiting absolute bias less than 1 nanosecond. Moreover, we analyzed the impact of different antennas (SEPCHOKE_B3E6 and JAVAD GrAnt-G3T) on VTEC estimation. For two receivers, VTEC differences between antennas are less than 1 TECU, with RMS of the biases between different antennas less than 0.35 TECU and mean biases do not exceed 0.21 TECU.