trail-mate/docs/models/positioning-time/fix-lifecycle.md

GNSS revision 处理链

sequenceDiagram
  participant Driver as GNSS byte source
  participant Service as LocationService
  participant Parser as NmeaParser
  participant Filter as GpsJitterFilter
  participant Events as ILocationEventSink
  participant Time as ITimeAuthorityUpdater
  Driver->>Service: onGnssBytes(bytes, len, now_ms, last_motion_ms)
  Service->>Parser: parse input / observe revisions
  alt fix revision changed
    Service->>Filter: evaluate LocationFix
    Service->>Events: publish accepted fix event
    Service->>Service: update latest_fix_ and last_fix_revision_
  end
  alt time revision changed
    Service->>Time: update time authority
    Service->>Service: update last_time_revision_
  end

这不是 NoFix / Valid / Stale 状态机；当前模型以 revision、filter 与输出端口为事实。