Japan GNSS · 1 of 6 · sources dated

QZSS (Michibiki): what is in the sky in 2026, and what it sends

If you land in Japan with a multi-GNSS receiver, it will start tracking satellites with PRN numbers in the 190s that you never saw at home. Those are QZSS, the Quasi-Zenith Satellite System, known here as Michibiki. This page is the minimum an engineer needs: what is up there as of August 2026, what each signal carries, and which parts need a dedicated receiver.

What QZSS is, in one paragraph

QZSS is a regional satellite navigation system operated by the Cabinet Office of Japan. Its satellites fly figure-eight quasi-zenith orbits (and one geostationary slot) so that at least one of them stands nearly overhead Japan at any time. That high elevation is the point: in cities and mountains, where GPS satellites are hidden behind buildings and ridges, a satellite near the zenith stays visible. QZSS signals are designed to be interoperable with GPS, so a receiver that already tracks GPS L1C/A, L2C and L5 can use QZSS as extra ranging sources with no special hardware.

What is in orbit as of August 2026

The official service has run as a four-satellite constellation since November 2018. The plan has been to grow to seven satellites, which makes positioning from QZSS alone sustainable over Japan. As of this writing the picture is:

So the constellation will settle at six satellites for now; the government has stated that further satellites are planned for the 2030s, with no direct replacement for QZS-5. Where each satellite is at this moment, and the measured shape of its orbit, are on its own page in the satellite catalogue; how many of them stand above a given point, terrain included, is in KUON SKY.

A note for anyone building a tracker: QZS-7 carries a six-digit NORAD catalogue number. The legacy TLE format holds five digits, so CelesTrak returns nothing for it in TLE form. Ingest orbital elements as OMM (JSON). KUON GEO switched on 21 August 2026.

The signals, and who can use each

The practical split is simple. Everything on L1, L2 and L5 is free bonus satellites for a receiver you already own; just make sure QZSS is enabled in its configuration, because some firmware ships with it off outside Japan. Everything on L6 is the part that is unique to Japan, and it needs hardware that can demodulate the L6 band. That is where CLAS and MADOCA-PPP live, and they get their own pages here.

What changes for you in practice

Three things. First, satellite counts: in an open field in Hokkaido or a street in Osaka you will routinely see more usable satellites than at the same latitude elsewhere, and a high one near zenith helps the vertical component. Second, SLAS on L1S gives sub-metre positioning without any internet connection, which is enough for many logging tasks. Third, CLAS on L6D gives centimetre-level positioning from the sky alone, no base station and no mobile data, inside Japan. Whether that replaces RTK for your work depends on your receiver and your tolerance for the spec; the CLAS page lays out the numbers.

Sources

Cabinet Office, QZSS is becoming a seven-satellite constellation (four-satellite service since November 2018; seven-satellite plan). The Register, 11 August 2026 (QZS-7 launch, QZS-5 loss in December 2025, 2030s plans). ESA Navipedia, QZSS (signal list). Orbital elements: CelesTrak OMM, propagated on this site.