On January 15, the Trump administration released a policy memo reflecting on the dependency of the United States on the Global Positioning System as well as the need to brace for a day when GPS could not be accessible. A constellation of 31 United States Space Force powered GPS satellites use radio navigation to supply military and civilian users around the world with positioning, navigation as well as timing information. For navigation, space situational awareness, attitude control and emerging research applications, like radio occultation, satellites in the space depend on GPS.
Space Policy Directive-7 stresses the ever-increasing reliance of the United States on space-based navigation, positioning and timing. As GPS transmissions are likely to be interrupted, it indicates that government and commercial organizations should connect to back-up the PNT technologies. In an executive order which was issued in February 2020, SPD-7 echoes several of the points and proposals made by Trump. According to SPD-7, the growing dependency on GPS for military, civil as well as commercial applications renders the device fragile.
“GPS users need to plan for possible signal loss as well as take appropriate measures to confirm or authenticate the validity of GPS data and range signal received, particularly in applications where life losses can result from even small degradations.” SPD-7 notes that the United States is ‘encouraging the production of complementary strategies to PNT services and security, which can integrate emerging technology and services as they are being developed, like relative navigation, quantum sensing and alternative PNT services which are private or even publicly owned and run.’
The policy states that the United States encourages the use of PNT systems dependent on international satellites to complement GPS. Accuracy, affordability and resilience can be enhanced with the incorporation of new services, states SPD-7. However, the U.S. government “does not guarantee the accuracy or validity of foreign PNT providers,” the policy states. “In the face of increasing cyber threats, receiver manufacturers must continue to enhance security, integrity as well as resilience.” SPD-7 was released a few hours after a study outlining the Council’s effect on civil as well as national security space operations was released by Vice President of U.S., Mike Pence, who also served at the National Space Council as the chairman for the duration of the Trump Presidency.
SPD-7 states that GPS applications were no longer limited to Earth, but range from the volume of Terrestrial Service (3,000 kilometers of Earth’s surface) to the volume of the Space Service (3,000 kilometers of the geosynchronous orbit (GSO) at about 35,800 kilometers) to the volume of the Cislunar Service (from the GSO to and including the orbit of the Moon). Space Service Volume and Cislunar Service Volume satellites both do or may depend on the GPS. The latest Directive was published shortly after a definitive report on Space Council’s actions over the last four years was published by the White House.https://hindaily.com/