Unfortunately, the download mechanism for CPE files used by the devices with GPS chipsets from Sony is still unknown and hence unsupported
In case this is useful for future device support or for other people
For some Garmin watches with Sony GPS chipsets here is what seems to work for downloading CPE ephemeris data (and copying to the device on Linux). No additional processing is required if wget (or perhaps curl) is used. This was from recording traffic with a Garmin Vivoactive 3.
For: Garmin Forerunner 935
From: http://www.cyber-neurones.org/tag/forerunner/?amp
Possible url for it's EPO ephemeris data. Looks like it returns JSON.
https://api.gcs.garmin.com/ephemeris/cpe/mtk/segments?segments=28
Regarding this:
In case this is useful for future device support or for other people
For some Garmin watches with Sony GPS chipsets here is what seems to work for downloading CPE ephemeris data (and copying to the device on Linux). No additional processing is required if wget (or perhaps curl) is used. This was from recording traffic with a Garmin Vivoactive 3.
Update, some other collected info from other sources too:
For: Garmin Forerunner 245 From: https://gadgetbridge.org/internals/specifics/garmin-protocol/ This returns a unix tar file with four CPE bin files of varying sizes. The
constellationsparameter selects which CPE files are included in the tar file https://api.gcs.garmin.com/ephemeris/cpe/sony/lle?coverage=WEEKS_1&constellations=GPS,GLONASS,GALILEO,QZSSFor: Garmin Forerunner 935 From: http://www.cyber-neurones.org/tag/forerunner/?amp Possible url for it's EPO ephemeris data. Looks like it returns JSON.
https://api.gcs.garmin.com/ephemeris/cpe/mtk/segments?segments=28