QZSS (Quasi Zenith Satellite System) is a Japanese satellite navigation system operating from inclined, elliptical geosynchronous orbits to achieve optimal high-elevation visibility in urban canyons and mountainous areas. The navigation system objective is to broadcast GPS-interoperable and augmentation signals as well as original Japanese (QZSS) signals from a three-spacecraft constellation. The navigation system objective is to broadcast GPS-interoperable and augmentation signals as well as original Japanese (QZSS) signals from a three-spacecraft constellation in inclined, elliptical geosynchronous orbits.