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 QZS 1 is based on Mitsubishis ETS-8-Bus and will have a lift off weight of 4100 kg. The QZS satellites are to operate for more than 10 years.