Analysis of TEC Time-Frequency Characteristics of Anomalous Star Links Across the Equator

Based on the simulation TEC data of the small satellite-GNSS satellite star link, this paper has carried out the time-frequency characteristics analysis of the equatorial anomaly, which is a typical ionospheric disturbance. Based on the first-order time difference method, the second-order time difference method and discrete cosine transform method, the time-frequency variation characteristics of the typical small satellite-GNSS satellite link TEC caused by the equatorial anomaly are obtained. Such as reversal structure of first-order time gradient, multi-wave packet structure of second-order time gradient and discrete pulse structure in frequency domain with first-order and second-order time gradient. These phenomena can be used as characteristic parameters to characterize equatorial anomalous events. It is of great significance for the development of autonomous identification method of ionospheric anomalous events based on small satellite networks.