How secure are civilian GPS signals?

　　Whereas the U.S. military uses GPS signals that are encrypted and require authentication (which protects them more from GPS jamming and spoofing), civilian GPS receivers have no such capabilities.

　　Therefore, the vast majority of civilian GPS receivers, which have a relatively weak signal already, are vulnerable because the antennae can be, for all intents and purposes, shielded from receiving the GPS satellite’s data telling it where it is or be intentionally sabotaged to transmit incorrect information.

　　The GPS signal strength that is received on Earth is relatively low. So this low powered signal is essentially at the root of the majority of the vulnerabilities we will be discussing in this article.

　　The low signal is more susceptible to all sorts of interference that can degrade and jeopardize its effective strength that is the result of both natural and human activity.

　　A helpful analogy might be to think about how easy it would be for a full-blown symphony to drown out a chirping cricket.

　　Keep this in mind when we cover jamming and spoofing next because then it’s easier to understand why it’s possible.

　　Since GPS signals are low and very sensitive, they’re therefore susceptible to jamming.

　　There are a few hackers’ websites out there describing the technical details about how to build a GPS jammers which could be a particularly nasty threat to the GPS navigation units used in aviation.

　　Essentially, a jammer operates by transmitting static on the GPS receiver’s frequency which effectively overpowers a GPS unit from receiving satellite signals.

　　Apparently, even a very low powered 1 watt jammer can jam receivers in a 100 kilometer radius.