1. ‘Interface Specification IS‐GPS‐200’ 2013. Available at:http://www.gps.gov
2. ‘Official U.S. Government information about the Global Positioning System (GPS) and related topics’. Available at:http://www.gps.gov
3. ‘BeiDou Navigation Satellite System. Signal in Space. Interface Control Document’ 2012 Available at:http://www.en.beidou.gov.cn/
4. Federal Space Agency Information‐Analytical Center. Available at:https://www.glonass‐iac.ru/GLONASS/
5. ‘Interface Specification IS‐GPS‐800’ 2013 Available at:http://www.gps.gov