Development of QZSS L1-SAIF augmentation signal

QZSS (quasi-zenith satellite system) is a Japanese satellite navigation program offering GPS augmentation signal, called L1-SAIF (submeter-class augmentation with integrity function), on the GPS L1 frequency. L1-SAIF augmentation will improve user position accuracy within 1 meter RMS nationwide based on wide-area differential GPS technique and provide users with the integrity information necessary for safety of mobile users. L1-SAIF augmentation messages are generated at L1-SAIF Master Station (L1SMS) and broadcast to the users. The ENRI has been developing L1SMS as a part of the national QZSS program. In this paper the authors describe the overview of L1-SAIF signal, the configuration of L1SMS, and some initial results of realtime operation test.