handleGpsTpvUpdate(tpv) {
    if (tpv.lat && tpv.lon) {

      // Log if this is the first position fix we get
      if(this.lat == null) {
        this.logger.info(`GPSD: Got GPS position. lat=${tpv.lat} lon=${tpv.lon}`);
      }

      this.lat = tpv.lat;
      this.lon = tpv.lon;
      this.positionUpdateTime = Date.now();
    }
    if ("time" in tpv) {
      try {
        const gpsTimestamp = new Date(tpv.time);

        // Log if this is the first time fix we get
        if(this.gpsTimestamp == null) {
          this.logger.info(`GPSD: Got GPS time. gpsTimestamp=${gpsTimestamp.toISOString()}`);
        }

        this.gpsTimestamp = gpsTimestamp;
        this.timeUpdateTime = Date.now();
      } catch (error) {
        this.gpsTimestamp = null;
      }
    }
  }
The system timestamp of the last GPS timestamp fix as JavaScript Date object