diff options
| -rw-r--r-- | src/drivers/gps/ubx.cpp | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/src/drivers/gps/ubx.cpp b/src/drivers/gps/ubx.cpp index b0eb4ab66..91ecdb474 100644 --- a/src/drivers/gps/ubx.cpp +++ b/src/drivers/gps/ubx.cpp @@ -808,7 +808,7 @@ UBX::payload_rx_done(void) UBX_TRACE_RXMSG("Rx NAV-TIMEUTC\n"); { - /* convert to unix timestamp */ + // convert to unix timestamp struct tm timeinfo; timeinfo.tm_year = _buf.payload_rx_nav_timeutc.year - 1900; timeinfo.tm_mon = _buf.payload_rx_nav_timeutc.month - 1; @@ -818,14 +818,15 @@ UBX::payload_rx_done(void) timeinfo.tm_sec = _buf.payload_rx_nav_timeutc.sec; time_t epoch = mktime(&timeinfo); -#ifndef CONFIG_RTC - //Since we lack a hardware RTC, set the system time clock based on GPS UTC - //TODO generalize this by moving into gps.cpp? + // FMUv2+ have a hardware RTC, but GPS helps us to configure it + // and control its drift. Since we rely on the HRT for our monotonic + // clock, updating it from time to time is safe. + + // TODO generalize this by moving into gps.cpp? timespec ts; ts.tv_sec = epoch; ts.tv_nsec = _buf.payload_rx_nav_timeutc.nano; clock_settime(CLOCK_REALTIME, &ts); -#endif _gps_position->time_gps_usec = (uint64_t)epoch * 1000000; //TODO: test this _gps_position->time_gps_usec += (uint64_t)(_buf.payload_rx_nav_timeutc.nano * 1e-3f); |