Study finds that a GPS outage would cost $1 billion per day June 14, 2019 https://arstechnica.com/science/2019/06/study-finds-that-a-gps-outage-would-cost-1-billion-per-day/ Study (PDF - 3.22 MB): https://www.rti.org/sites/default/files/gps_finalreport.pdf