gps-details

COROS APEX Pro / VERTIX

Speedsurfing

3.05.0

Firmware 3.05.0 (red) captures the speed data of the Sony GNSS chipset, evident when comparing to a 5 Hz Motion GPS (blue).

This release is working as well as can be expected considering the Sony GNSS chipset and its propensity for repeated speeds / flat spots.

v-3-05-0-apex-pro-ssurf

The Garmin vivoactive 4 (red) also captures the speed data of the Sony GNSS chipset, albeit with a slightly different offset for the timestamp.

The Garmin is working as well as can be expected considering the Sony GNSS chipset and its propensity for repeated speeds / flat spots.

v-3-05-0-va-4-ssurf

3.0308.0

TODO:

Test speedsurfing using an APEX Pro that has been downgraded to 3.0308.0.

Expectations:

3.0308.0 is expected to exhibit identical behavior to 3.05.0.

3.0508.0

The COROS APEX Pro (red) now appears to be using the positional data for speeds, exhibiting spikes in the maximum speeds.

This is the non-Doppler issue that was reported to COROS on 19 Aug 2024.

v-3-0508-0-apex-pro-ssurf

The Garmin vivoactive 4 (red) is capturing the speed data from the Sony GNSS chipset, which is better than the positional data.

The Garmin is working as well as can be expected considering the Sony GNSS chipset and its propensity for repeated speeds / flat spots.

v-3-0508-0-va-4-ssurf

Outstanding Issue

Due to the observations shown above it is believed that the APEX Pro and VERTIX are now using non-Doppler speeds for speedsurfing. The suspicion is that positional data is being used to calculate speeds, instead of using the speed data from the Sony chipset.

It should also be noted that GP3S now observe more spikes being posted from the APEX Pro and VERTIX when using speedsurfing mode. These issues are consistent with what would be expected when calculating speeds using the positional data, instead of the Doppler-derived speeds.

The 3.0508.0 firmware released in July did not resolve the underlying Airoha-related issue, but instead introduced an even bigger issue for the APEX Pro and VERTIX. Thoughts and guidance regarding a resolution of the underlying issue in 3.0408.0 were documented on 22 Aug 2024.