Ground-Based Global Navigation Satellite System (GNSS) Quasi-Zenith Satellite System (QZSS) Broadcast Ephemeris Data (30-second sampling, hourly files) from NASA CDDIS

This dataset consists of ground-based Global Navigation Satellite System (GNSS) Quasi-Zenith Satellite System (QZSS) Broadcast Ephemeris Data (hourly files) from the NASA Crustal Dynamics Data Information System (CDDIS). GNSS provide autonomous geo-spatial positioning with global coverage. GNSS data sets from ground receivers at the CDDIS consist primarily of the data from the U.S. Global Positioning System (GPS) and the Russian GLONASS. Since 2011, the CDDIS GNSS archive includes data from other GNSS (Europe’s Galileo, China’s Beidou, Japan’s Quasi-Zenith Satellite System/QZSS, the Indian Regional Navigation Satellite System/IRNSS, and worldwide Satellite Based Augmentation Systems/SBASs), which are similar to the U.S. GPS in terms of the satellite constellation, orbits, and signal structure. The hourly QZSS broadcast ephemeris files contain one day of QZSS broadcast navigation data in RINEX format from a global permanent network of ground-based receivers, one file per site. More information about these data is available on the CDDIS website at https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/hourly_30second_data.html.

本数据集包含源自美国国家航空航天局（National Aeronautics and Space Administration，NASA）地壳动力学数据信息系统（Crustal Dynamics Data Information System，CDDIS）的地基全球导航卫星系统（Global Navigation Satellite System，GNSS）准天顶卫星系统（Quasi-Zenith Satellite System，QZSS）广播星历数据（按小时归档的文件）。
全球导航卫星系统（GNSS）可实现覆盖全球的自主地理空间定位。
CDDIS收录的地基接收机GNSS数据集，早期主要包含美国全球定位系统（Global Positioning System，GPS）与俄罗斯格洛纳斯系统（GLONASS）的数据。
自2011年起，CDDIS的GNSS档案库新增了其他GNSS相关数据，涵盖欧洲伽利略系统（Galileo）、中国北斗系统（Beidou）、日本准天顶卫星系统（QZSS）、印度区域导航卫星系统（Indian Regional Navigation Satellite System，IRNSS）以及全球各类卫星增强系统（Satellite Based Augmentation Systems，SBAS）。上述系统在卫星星座、轨道参数与信号结构层面，均与美国GPS体系相似。
按小时归档的QZSS广播星历文件，包含来自全球永久地基接收机观测网络的单日QZSS广播导航数据，文件格式为RINEX，每个观测站点对应一个独立文件。
有关此类数据的更多详细信息，可访问CDDIS官方网站：https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/hourly_30second_data.html。