Says Jeff Shepard from Microcontroller Tips: There are alternatives to GPS in various stages of development. The U.S. Air Force, a critical user of GPS, has launched GPS III satellites that offer significantly more resilience against jamming attacks. The Europeans are also seeking to augment their satellite navigation array with 5G technologies. Among several terrestrial alternatives, one by next-gen GPS developer NextNav recently got high marks in an evaluation by the Science & Technology Directorate (S&T) of the Department of Homeland Security (DHS). The trial tested the timing redundancy of NextNav’s TerraPoiNT system in a number of scenarios, including instances of GPS outages, spoofing, and jamming, which are issues of increasing frequency and growing concern. The GPS-free network proved capable of powering critical national infrastructure in the event of a 72-hour GPS outage. “GPS is critical infrastructure, but it has its limitations,” said Ganesh Pattabiraman, co-founder and CEO of NextNav. “In working with DHS S&T, we’ve validated that TerraPoiNT can serve as an important backup to GPS and ensure the resilience and continuity of our nation’s most critical systems, including next-generation telecommunications networks, financial services, and power grids.” Using a dedicated, terrestrial network of transmitters, NextNav delivers critical positioning, navigation, and timing services where GPS can’t: indoors and in urban areas. Terrestrial transmitters deployed around a service area triangulate against a device’s location, much like a GPS satellite array. Unlike national space-based systems, however, the proximity of NextNav’s transmitters makes the signal strength 100,000 times that of GPS, resulting in fast, accurate calculations that work well in urban environments, where GPS can be finicky or nonexistent.  The successful trial builds on recent evaluations of TerraPoiNT conducted by independent bodies. Earlier this year, the Department of Transportation (DOT) evaluated 11 alternate PNT solutions, in which each was rigorously tested across applications and scenarios. As a result of the evaluation, the DOT named TerraPoiNT the top solution across all PNT categories. As development in the global positioning space increases and diversifies, we’re going to continue seeing a flurry of terrestrial-based solutions.