Poster Presentation

Ionospheric calibration for pulsar B0329+54 using GNSS measurements and 3D electron density model

Author(s): Decmend Fang-Jie Ling (National Taiwan University, ASIAA), Kai-Yang Lin (ASIAA)

Presenter: Decmend Fang-Jie Ling (National Taiwan University, ASIAA)

Radio signals crossing the ionosphere experience frequency-dependent delays and accurate ionospheric delay calibration is therefore essential for localization of celestial radio sources. Traditional calibration methods, while widely used, often suffer from limitations such as high cost in multi-frequency observations, computational complexity of ionospheric delay in the dual-frequency and single-frequency systems, and signal dilution when relying on numerous background sources during self-calibration. To address these challenges, we present a relatively simple and effective approach that enables estimation of the ionospheric delay term along the line of sight toward a celestial source using Global Navigation Satellite System (GNSS) measurements and a global electron density model. We have a timing measurement toward a pulsar B0329+54 between the two arrays in Fushan and Nantou stations on 2024-10-23 from 17:10 to 17:25 UTC. We derive the total electron content (TEC) in the period from two approaches, GNSS data and a 3D electron density model, and then apply it to an appropriate interpolation function to estimate differential slant TEC (STEC) between two stations along the pulsar track. We also investigate how input resolution and spline parameters affect the accuracy of STEC interpolation. Both methods yield STEC differences similar to those of nearby satellites, but trends and absolute values differ significantly between the two methods. The possible causes of inconsistency and future directions will be discussed as well.