And to finish things off, here’s the performance standard for GLONASS: https://glonass-iac.ru/upload/docs/stehos/stehos_en.pdf. On page 42-43 the global average positioning error is listed as 5 m horizontal and 9 m vertical. There’s also a worst site positioning error of 12 m horizontal and 25 m vertical, but I don’t think we’ll need to worry about that.
1 Like
You’ve been wonderful, I appreciate your help. I think the last thing that needs to be done is some kind of primary source that the Japanese military relies primarily on US’ GPS. Especially if it looks like their own system is instead a back-up.
1 Like
From what I found, it seems that the JSDF uses (or is planning to use) multiple navigation systems in tandem to increase robustness. For example, page 8 of Defense Programs and Budget of Japan, Overview of FY2021 Budget Request says that they are developing a common receiver for signals from Michibiki (Japanese name for QZSS), GPS, and Galileo. For a more recent primary source, page 33 of the references to the Defense of Japan 2024 white paper by the Ministry of Defense says that the Ministry of Defense and the Self-Defense Force “will
promote the use of multiple positioning signals including Quasi-Zenith Satellite System (QZSS) and commercial satellites”. In game this could mean that their GNSS bombs would use whichever system that has the highest accuracy (from the sources we’ve got so far, probably Galileo).
It appears that the JSDF might not have fully integrated QZSS into their systems yet, though perhaps they may be using it on a case by case basis, like the ship example mentioned earlier. For a source of them using GPS, page 292 of Defense of Japan 2019 says that “the MOD/SDF has mounted
GPS receiving terminals on a large number of equipment”. Similarly, page 4 of this briefing memo of the National Institute for Defense Studies from 2017 says that they had been using GPS since 1993, before which they used TRANSIT since 1986.
1 Like