DALLAS — Whenever geopolitical tensions simmer, disruption to the airline industry is never far away. As airlines halt flights to trouble spots and plan detours around conflict zones, the complexities are often subtle from an operational perspective yet can be far-reaching.
Perhaps you remember the first generation of satellite navigation receivers some twenty years ago, which today would be considered unfashionable and clunky. Nowadays, barely a day passes when we don’t rely on satellite navigation technology. From sleek smartwatches to compact car navigation systems, one doesn’t have to look far to see how rapidly this technology has evolved. Similarly, the aviation industry has also embraced the advantages of satellite navigation.
You will note that so far, I have refrained from using the acronym GPS (Global Positioning System), and for good reason too. While it’s common for many to refer to satellite positioning systems simply as GPS, this is not strictly correct. In fact, GPS is one of four global satellite positioning systems that all fall under the banner of the Global Navigation Satellite System (GNSS). While GPS was created by the United States, other systems include Russia’s GLONASS, China’s BeiDou system, and finally Galileo, which is overseen by the European Union.
Supplementing these systems are a number of regional navigation systems with more limited coverage. Within the cluster of GNSS systems, there is designed to be some element of redundancy. A failure of one system should never render the entire GNSS system unserviceable.
Artist’s impression of a GPS satellite in orbit. Photo: Wikimedia Commons. Illustration provided by the United States Air Force.
Back to Basics
Before we go any further, it’s probably a good idea to review how GNSS works. Satellites broadcast radio signals that are detected by GNSS receiver units. Before a location can be determined, a receiver must detect signals from a handful of…