| Summary: | 碩士 === 國立中央大學 === 太空科學研究所 === 106 === In order to precisely estimate ionospheric parameters with corresponding electron density profiles form the ionogram observed by this ionosonde system, a new algorithm is developed to scale the ionogram traces. We first remove background noise from the ionogram. We use an image processing technique to identify the observed O- and X-wave traces, then obtain preliminary ionospheric parameters based on separated O- and X-wave traces. In this study, the quasi-parabolic segment (QPS) model is exploited to obtain the electron density profile, and the IRI model is also used to generate the initial inputs. According to the scaled ionospheric parameters from the O-wave traces combined with the inputs of the IRI model, it is easy to retrieve the QPS model-based electron density profiles. From the retrieved electron density profiles, the corresponding O-wave traces can be simulated and compared with the observed one. The root mean square errors (RMSEs) between observed and simulated O-wave traces are validated and the ionospheric parameters of the constructed trace with the minimum RMSE value and the best correlation-coefficient are then selected as the final result of the ionogram scaling. The accuracy and precision of the estimated ionospheric parameters by using the proposed algorithm are also analyzed and discussed.
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