GPS / GNSS anti-jam systems provide signal security, usually using two main approaches:
Anti-Jamming (AJ) Systems: These systems are used to regain GPS / GNSS signals mixed or blocked by enemy intervention and to provide accurate location and time information. These include special algorithms and antennas that can identify and interfere with powerful jamming signals.
Anti-Spoofing (AS) Systems: Spoofing means misleading or imitating GPS / GNSS signals. Anti-spoofing systems protect against such attacks. It is especially used in military and defense applications and helps detect and block fake location information.