code: public double[] toECEF () {
  		double lon0r = toRadians(this.longitude);
  		double lat0r = toRadians(this.latitude);
  		double height = tools.feet2Meters(altitude);
  
  		double v = a / Math.sqrt(1 - e2*Math.sin(lat0r)*Math.sin(lat0r));
  
  		return new double[] {
  				(v + height) * Math.cos(lat0r) * Math.cos(lon0r), // x
  				(v + height) * Math.cos(lat0r) * Math.sin(lon0r), // y
  				(v * (1 - e2) + height) * Math.sin(lat0r) // z
  		};
  	}
docs: Converts the WGS84 position to cartesian coordinates
  @return earth-centered earth-fixed coordinates as [x, y, z]