Global Navigation Satellite System (GNSS), like the GPS, the GLONASS etc., have become a powerful tool for atmosphere and ionosphere studies. In Japan, GPS data came to be used for a weather forecast system and a space weather forecast recently. A Quasi-Zenith Satellite (QZS) is launched in 2010; various technical examinations using this satellite are going to be conducted from now on. In this session, you announce the result of the latest study using GNSS data and we will discuss these studies and future plans.