1. J. Black. (2015, 09) The economic benefits of gps. [Online]. Available: https://www.gpsworld.com/ the-economic-benefits-of-gps/
2. W. L. Ross, “Driving space commerce through effective spectrum policy,” U.S. Department of Commerce, Tech. Rep., 03 2019. [Online]. Available: https://www.ntia.doc.gov/files/ntia/publications/ drivingspacecommerce.pdf
3. “Challenges to security in space,” Defense Intelligence Agency, Tech. Rep., 022019. [Online]. Available: https://www.dia.mil/Portals/27/Documents/News/Military%20Power%20Publications/Space Threat V14 020119 sm.pdf