Study on Ionospheric TEC Measurement by Single Frequency GPS Receivers

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06383
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Measurement engineering
• Research Institution: Kanazawa University
• Principal Investigator: Goto Yoshitaka 金沢大学, 電子情報通信学系, 准教授 (30361976)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 電離層プラズマ / TEC計測 / GPS観測網

Outline of Final Research Achievements

Continuous monitoring of ionospheric total electron content (TEC) using networks of GNSS (global navigation satellite system) ground stations has been conducted in many countries since such networks make it possible to measure the TEC distributions in high spatial and temporal resolutions. Most of the GNSS networks are, however, built in mid latitude regions. In order to understand dynamics of ionospheric plasma at equatorial regions in more detail, it is effective to expand the observation network in low latitudes. The TEC observations are generally realized by measuring two frequency signals from GNSS satellites because only ionospheric delay depends on the frequency in ranging errors. However, multi-frequency receivers are not consumer products and their costs are much higher than those of single frequency receivers. In this study, ionospheric TEC observation method using a single frequency GPS receiver was developed.

Free Research Field

計測工学

Academic Significance and Societal Importance of the Research Achievements

GPS標準測位では通常、電離層遅延に対して関数モデルを用いた低減処理がなされているが、処理後でも、数メートル程度の標準偏差の誤差が残ることが知られている。一方、日本でサービスが開始された準天頂衛星システムでは、地上のGNSS信号の観測局網（電子基準点）で得られた複数周波の測距データを利用して日本上空の電離層TEC（鉛直方向のプラズマ密度の積分値）マップを作成し、その情報を補強信号として準リアルタイムに衛星から地上に向けて放送にすることにより、数センチメートル級の測位精度の実現が目指されている。本研究成果はこうした電離層TECの観測網を拡大することにつながると期待される。