A low ionosphere occultation observation method based on differential weight separation

Radio occultation observation has garnered significant attention owing to its low-cost, all-weather, and global coverage feature. However, traditional occultation inversion methods lead to error accumulation due to assumptions that are not entirely suitable in the real ionospheric environment, resulting in poor performance in the low ionosphere (D, E layers). In this article, we propose a new method for inverting the electron density in low ionosphere using high-precision 50 Hz occultation data. This method can eliminate the fixed constant term of 50 Hz data and obtain a sharper weighting function through epoch differencing. The inversion results have a good consistency with the results of the ionosonde, with a correlation coefficient of 0.92 and a determination coefficient of 0.85. In addition, the new method can retrieve local details of electron density profiles and capture sporadic E layer (Es), providing support for the study of Es layer morphology and structure.