Aireon Space-Based ADS-B -- Before vs After coverage over the North Atlantic

Sorry...”or will it require a subscription”?

FlightAware’s terrestrial ADS-B network will remain a very vital part of our flight tracking solutions, and we will continue to make both the software and data freely available. To ensure that we continue to grow the world’s largest terrestrial ADS-B network of free and low-cost access to ADS-B data, we are significantly increasing our production of FlightFeeders and our development of PiAware software.

FlightAware will soon launch a new, free Aireon map portal for viewing space-based ADS-B data, and we are exploring a number of ways to distribute this data. But because this is an extremely expensive endeavor, our initial focus is on incorporating the data into commercial products to fund the project.

Throughout this process, we will continue to offer and improve our free network of PiAware and FlightFeeders that track aircraft via ground-based ADS-B receivers.

We are still working on all the various ways and policies for accessing space-based data.

My guess is the crossing points are fixed way-points that the trans oceanic routes are made up of. The actual routes are determined to take advantage of wind patterns - to fly with the wind where possible and try not to fly into huge headwinds. To make sure all planes follow parralel routes it's useful to superimpose the route lines onto a set of gps co-ordinates so it's just a matter of joining the dots to get the correct route.

https://en.wikipedia.org/wiki/North_Atlantic_Tracks