In order to answer the question of how to protect GNSS signals from being jammed or spoofed, it is perhaps prudent to first define what GNSS, jamming and spoofing are.
Satellite navigation systems provide user coordinates derived from distance measurements that are based on the propagation time of the transmitted signals. Thus, all these systems rely on very accurate clocks and time standards. To meet the needs of internal time synchronization and dissemination, each GNSS maintains a specific system time. The time systems of the
Time probably is the most under-appreciated concept by many that use it. Everyone experiences it but explaining is a difficult job. The perception of time is usually associated with change and for that one needs a unit and a starting point, moreover some sort of uniformity is also required for the unit. Defining a unit