Action to be taken in case of GPS Failure :-
Inform Master. Switch over to GPS 2 (If fitted & working). Note down the last position obtained from GPS. Obtain the position of the vessel from Celestial or Terrestrial means . Increase the frequency of position fixing. Plot the position of the vessel in ECDIS. Inform VTS / Port Authority & Company Agent. Monitor the position of vessels in vicinity. Navigate the ship clear from any proximity to navigational hazard. Try to rectify the GPS by referring the GPS Manufacturers Manual. Keep a record of all events. Effect of GPS Failure: ECDIS gives mandatory alarm & automatically switches over to DR mode. Radar and ARPA switches to Relative motion. There are chances that Gyro may give an alarm, Since Gyro has latitude error and which needs GPS Sensor to correct the same. AIS will not transmit position of the vessel.