Here is a link that may provide a bit more perspective on the worldwide requirements of ADS-B. Please note that the document provided from the link is not from an aviation governing body, it is from an avionics supplier in Canada so I will accept that some of the information
may be incorrect or incomplete in regards to various aviation jurisdiction requirements. So if it does feel free to point out any discrepancies, errors or omissions in it, I do feel however it should provide a good overview.
http://www.midcanadamod.com/sites/de...or_posting.pdf
Here are a few exerts from the article (my bold) that I have included for those who do not wish to trawl through it:
Page 3:
NAV CANADA has thus far adopted exclusively the 1090ES (ADS-B Out) format, as have all other countries worldwide. The only exception is the USA with their “Dual-Link” ADS-B program.
For Canadians, aircraft with a 1090ES Transponder and approved interfaces will be compliant with US operating requirements; however those who frequent US skies under 18,000’ may also opt for a UAT.
Page 4:
The European mandate, in broad terms, requires 1090ES ADS-B Out with a Diversity Mode-S transponder.
As to the future, in July of 2012, Iridium Communications and NAV CANADA announced a planned joint venture. This new relationship promises to offer worldwide ADS-B-based air traffic surveillance services using the upcoming Iridium “Next” satellite network. These satellites begin launching in 2015 and will be completed in 2017.
The Iridium-NAV CANADA joint venture is called Aireon. It will add 1090ES ADS-B receivers to each of the 66 satellites (and backups) destined to form the Iridium “Next” constellation. The low-earth-orbiting Iridium satellites will offer worldwide coverage, including Polar Regions, and with the ADS-B payloads will provide complete visibility to all aircraft everywhere. This will help ANSP’s (air navigation service providers) increase efficiencies. This new capability will extend the benefits of current radar-based surveillance systems (which presently cover less than 10 percent of the world) to entire planet coverage. Aireon is expected to become operational in 2018.
Page 5:
1090ES ADS-B Out is the globally accepted system for ADS-B compliance.
One note here though - the FAA has uniquely adopted a “Dual-Link Architecture” for ADS-B compliance in the USA. This allows for a second equipment option.
Page 6:
The second or optional system is called a UAT. It is only applicable to aircraft operating in US airspace under 18,000 feet.
Note: a 1090ES ADS-B Out System is an absolute requirement for all aircraft that operate above 18,000 feet in US airspace and internationally.
aircraft with a 1090ES Transponder and approved interfaces will be compliant with US operating requirements; however those who frequent US skies under 18,000’ may also opt for a UAT.
Page 9:
The ES format carries much more data than the basic “short squit” Mode S version. In fact, some 49 individual parameters can be sent over the extended squitter, compared to three for Mode C and seven for basic non-extended Mode S. (Note: The 978 MHz UAT “Out” has the same basic data transmission elements as ES — however, it uses a different frequency in the radio spectrum to broadcast the information.)