Old satellites signal GPS risk
This is a copy of an article I had published in The Box on Tuesday, the 26th of May 2009. This is a copy of my originally submitted text, an archive for my my records. It is a topic that has seen a bit of interest. I’ve also been interviewed on National Radio’s Panel on this topic. I will probably be writing a more detailed article about the problem in due course.
A recent report from the US Government Accountability Office has identified possible trouble ahead for the Global Positioning System (GPS). Due to governance failures of those responsible for the GPS, there is the risk that satellites may not be able to be replaced faster than the rate at which they fail over the next 10 years. Whilst replacement satellites have been ordered and developed, some technical and project management issues have delayed the launch schedule, with the next launch planned for November 2009. This doesn’t mean that the GPS will just stop working. There are currently 31 active satellites in the GPS constellation – only 24 are required for the agreed level of service. There are 13 satellites that are more than 12 years old, and are increasingly likely to fail. This happens as the solar panels age, and they produce less electricity to power the satellite. There are options for extending satellite life by turning off less critical secondary payloads that draw less power. A few satellites can fail without having a significant impact on end users. If the number of active satellites drops to 24 or below, GPS receivers will probably be less accurate as fewer satellites would be visible at any given time. Given the GPS is a strategic military asset for the US, it is highly unlikely it will be allowed to fail completely. This may drive innovation in GPS receivers to support multiple satellite navigation systems to reduce reliance on a single system.