The GPS accuracy determines at what rate your watch gets a GPS position fix. The higher the fix rate (the shorter the interval between the fixes), the more accurate your track. Each GPS fix is recorded in the log file of your exercise.
The GPS accuracy directly affects battery life. By reducing GPS accuracy, you can extend the battery life of your watch.
The GPS accuracy options are:
Best: ~ 1 sec fix rate
Good: ~ 60 sec fix rate
OK: ~ 120 sec fix rate
This means that with GPS accuracy Best, your watch will get a GPS position fix every second. With GPS accuracy Good, your watch will get a fix only every 60 seconds and with OK only every 120 seconds. In the time between these fixes your watch does not obtain GPS position data.
To improve the track accuracy when using GPS accuracy Good or OK for Running and Trail Running exercises, Suunto 9 provides FusedTrackTM. FusedTrackTM is active in the background and uses the motion sensor built in your watch to log your movement between the GPS fixes. This provides better tracking of your runs.
Note: FusedTrackTM is only available  for the sport modes Running and Trail Running and it is activated in the battery modes Endurance, Ultra and Custom with GPS accuracy Good or OK.
Note: FusedTrackTM is only available for Suunto 9 and Suunto 9 Baro.