Since the early 2000s, our dependence on satellite positioning systems has grown steadily. From defense, security, management and transportation, these systems are used today for an ever-growing range of critical applications and have become indispensable for positioning themselves accurately anywhere in the world. . However, this dependence entails risks that could hinder what we now consider as acquired. A prolonged disruption of Global Navigation Satellite Systems (GNSS) signals caused by interference maneuvers or other cybersecurity threats would result in serious disruptions involving the national security of many states and even the global economy.
The GPS system is based on a constellation of about thirty satellites that allows a user, located on any point of the globe to always have at least four satellites in range. To determine its position, the user’s terminal uses the spatial trilateration method using the signals of at least three satellites. The intersection of the three signals makes it possible to identify a single point in space. A fourth satellite is nevertheless required to determine the clocks offset and reduce the uncertainties related to other sources of signal disturbance.
Why do we have to talk about GNSS?
The multiplicity of satellite positioning systems existing today imposes the use of a generic term designating all these systems. tableau GNSS.JPG Inasmuch as the GPS jammer designation designates a particular system (the American system), a more generic term should be used to evoke the different constellations of positioning satellites (see table opposite). This is why it is now better to use the name Global Navigation Satellites System (GNSS).
A system rooted deep in our society
If the system is primarily known to the general public to locate anywhere in the world, the uses of the GPS system are in fact very varied. The satellites of a GNSS generally comprise three or four atomic clocks each, these clocks are continuously monitored and controlled to be highly synchronized and traceable. These clocks are at the heart of the operation of a GNSS and also serve as a reference for many areas around the world.
“GPS is a global catalyst for billions of users,” said Steve Whitney, director of the GPS Directorate at the US Air Force’s Space and Missile Systems Center.