Efficient coding and resonance spike identification for topside ionogram processing

• Main Authors: Seiji Igi, Kazuhiro Aikyo, Ryo Nishizaki, Takanobu Ogata, Takashi Maruyama, Takeo Hirasawa
• Format: Report
• Language: English
• Published: Radio Research Laboratories/Radio Research Laboratories/Radio Research Laboratories/Radio Research Laboratories/Radio Research Laboratories/National Institute of Polar Research 1982
• Subjects: Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1265; http://id.nii.ac.jp/1291/00001265/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1265&item_no=1&attribute_id=18&file_no=1

This paper describes an effective coding method to eliminate the redundancy contained in digital ionograms and an algorithm to identify the resonance spikes appearing on topside ionograms. This work is a first step toward automatic profile reduction to obtain ionospheric electron density profiles. Topside sounder data recorded by ISIS-2 satellite are digitized and converted to digital ionograms. A quantitative comparison of data compression techniques, based on the run-length and predictive coding method, is made and leads the conclusion that the modified run-length coding method is most effective and useful from the practical view point. This simulation experiment results in self-consistent determination of characteristic frequencies with good accuracy except for the ionograms with obscure resonance spikes.