A Two-parameter Multi-frequency GPS Signal Simulator for Strong Equatorial Ionospheric Scintillation: Modeling and Parameter Characterization

A scintillation simulator is an important tool for the scientific, engineering, and GNSS applications community to study the physical mechanism and effects of scintillation and to develop advanced receiver technologies that can mitigate these effects. For users focused on the latter objective, it is desirable that the simulator be not only capable of capturing realistic scintillation effects, but also convenient and intuitive to configure and use. This paper presents a physics-based, multi-frequency, strong scintillation simulator that requires only two input parameters: the expected scintillation index S_4 and the intensity decorrelation time tau_0 . This simulator is developed based on the two-component power-law phase screen model, which is specified by five parameters and suitable for representation of strong equatorial scintillation. In this paper, by defaulting three of the model parameters to representative values, numerical mappings from the user input parameter set S_4 and tau_0 to the remaining model parameter subset of two parameters, U_0 and rho_F/V_eff , can be established through numerical evaluation. Therefore, the scintillation simulation model can be controlled by user-specified expected S_4 and tau_0. To obtain the representative values for the three default model parameters and to validate the numerical mappings for strong equatorial scintillation scenario, we first apply the irregularity estimation method (IPE) to a large group of strong scintillation data (with S_4 > 0.6) from two equatorial sites to establish the profiles of the model parameters. The representative values for the three default model parameters are then determined based on their respective profiles. Based on the estimates of U_0 and rho_F/V_eff and S_4 and tau_0 obtained from this multi-site real scintillation data set, we validated that the numerical mappings are generally accurate to represent the case in the observed strong equatorial scintillation. In addition, this paper also presents the evaluation results of the IPE method in terms of triple-frequency consistency using real scintillation data set with triple-frequency scintillation. Finally, a MATLAB implementation of the scintillation simulator has been made available.