Automatic Dependent Surveillance (ADS)
{"Image DocumentName": "Automatic Dependent Surveillance (ADS)", "Image ImageDescription": "Prior to the implementation of ADS \u2013 all flights, FANS equipped or not, had to make position reports at approximately every 10 degrees. This took up a great deal of frequency time. Prior to 11 September 2001, traffic had been increasing in the North Atlantic at a rather dramtic rate. Many HF frequencies in the North Atlantic were at a point where they had more than they could handle. A great deal of frequency time was taken up with every one of the approximately 1,000 (Westbound and Eastbound) flights traversing through the North Atlantic being required make a Waypoint Position Report at approximately every ten degrees. With the advent of ADS in the North Atlantic, FANS equipped aircraft (about 30% of today) no longer had to make Waypoint Position Reports. After the initial transition, this saved a great deal of frequency time and allowed radio operators to spend more time with non-FANS equipped flights. Since traffic levels are starting to get back to 10 September 2001 levels, ADS makes frequency congestion in the North Atlantic manageable. On each HF Family in the North Atlantic, several radio stations are working each frequency, and certain frequencies are optimal at only certain times of the day. This limits the number of usable frequencies at high traffic times of the day. Although some radio stations (such as Iceland) have rather extensive VHF coverage, this is simply not possible for more than a fraction of the area covered.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}