The ionosphere is the atmosphere layer characterized by its high concentration of ionized plasma. It has a great impact on radio communications with satellites, causing disturbances and disruptions. Therefore, it is important to understand and predict the ionosphere characteristics. The Sweeping Impedance Probe (SIP) is an instrument for characterizing the ionosphere used for many decades with great success. In this thesis, a new SIP architecture design is presented using the latest techniques and components available. The design is detailed and analyses have been performed to ensure the required performances. The new SIP will be flown in the Auroral Spatial Structures Probe (ASSP) sounding rocket mission in early 2015, and it is expected it will make the most accurate measurements to date. Lastly, the conclusions of this project are presented and future work is outlined for what will become the next generation of SIP instruments.

The high-latitude electric eld fall-o region connects convection in the polar cap to the region where ring currents modify the penetration electric field equatorward of the polar cap boundary. This region is often overlooked because it falls between the limits of low latitude and high-latitude ionospheric models. However, penetrating electric fields cause large changes in ion composition; and therefore, correctly modeling the electric fields and plasma drift in this region aids in correctly specifying the ionosphere. Many ionospheric models use the Kp index as a physical driver, and so the latitude dependence of the plasma drift in the fall-o region was investigated as a function of Kp using Defense Meteorological Satellite Program ion drift data from the 2007{2010 solar minimum. Both the dusk and dawn sectors were analyzed and t to analytical functions describing the fall-o with decreasing latitude. The latitude dependencies were found to dier in the dusk and dawn sectors with a factor of two increase in the expansion of the duskside polar cap radius and auroral region over the dawnside. Additionally, the low-Kp polar cap radius was found to be five degrees smaller than the radius currently used in simple ionospheric models.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第19133号 / 情博第579号 / 新制||情||101(附属図書館) / 32084 / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 山本 衛, 教授 津田 敏隆, 教授 佐藤 亨 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20186号 / 理博第4271号 / 新制||理||1614(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 齊藤 昭則, 教授 田口 聡, 教授 塩谷 雅人 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24422号 / 理博第4921号 / 新制||理||1703(附属図書館) / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)准教授 齊藤 昭則, 教授 石岡 圭一, 教授 田口 聡 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

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京都大学 / 新制・課程博士 / 博士(情報学) / 甲第24745号 / 情博第833号 / 新制||情||139(附属図書館) / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 山本 衛, 教授 橋口 浩之, 教授 梅野 健 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Ionospheric scintillations can cause significant amplitude and/or phase fluctuations of GNSS signals. This work presents analysis results of scintillation effects on the new GPS L5 signal based on data collected using a real-time scintillation monitoring and data collection system at HAARP, Alaska. The data collection setup includes a custom narrow band front end that collects GPS L1, L2 IF samples and two reconfigurable USRP2 based RF front ends to collect wideband GPS L5 and GLONASS L1 and L2 signals. The results confirm that scintillation has a stronger impact on GPS L2 and L5 signals than on the L1 signal. Our preliminary results also show that carrier phase and amplitude scintillations on each signal are highly correlated. The amplitude and carrier phase scintillation are also correlated among the three signals. In this study, a multi-constellation multi-band GNSS software receiver has been developed based on USRP2, a general purpose radio platform. The C++ class-based software receiver were developed to process the IF data for GPS L1, L2C, and L5 and GLONASS L1 and L2 signals collected by the USRP2 front end. The front end performance is evaluated against the outputs of a high end custom front end driven by the same local oscillator and two commercial receivers, all using the same real signal sources. These results demonstrate that the USRP2 is a suitable front end for applications, such as ionosphere scintillation studies. Another major contribution of this work is the implementation of a Vector tracking loop (VTL) for robust carrier tracking. The VTL is developed based on the extended Kalman filter (EKF) with adaptive covariance matrices. Both scalar tracking loop (STL) and VTL are implemented. Once an error in the scalar loop is detected, the results from the VTL are used to assist the STL. The performance of the VTL is compared with the traditional STL with three different data sets: raw GPS RF data with short signal outages, RF data with strong scintillation impacts collected during the last solar maximum, and high dynamic data with long interval signal outages from a GPS simulator. The results confirm the performance improvement of the VTL over scintillation impacts and show that the VTL can maintain signal lock during long intervals of signal outage if the satellite ephemerides are available and the pseudorange estimation is within one code chip accuracy. The dynamic performance improvement of the VTL is verified as well. The results show the potential of robust tracking based on VTL during scintillation and interference. / Ph. D.