The Department of Homeland Security (DHS) Science and Technology Directorate (S&T) has published the Positioning, Navigation, and Timing (PNT) Integrity Library and Epsilon Algorithm Suite to protect against Global Navigation Satellite System (GNSS) spoofing, or deceiving a Global Positioning System (GPS) device through false signals. As S&T notes, GPS enables many applications for critical infrastructure sectors. The reliance on GPS, however, can make systems vulnerable, requiring users to plan for potential signal loss or take reasonable steps to verify or authenticate the integrity of the data. S&T’s resources are intended to help users understand and address the vulnerabilities, including by advancing the design of PNT systems and increasing resilience to PNT disruptions. Both tools are open source and available free of charge. Read more and access the resources at DHS S&T.