GPS technology has revolutionized modern warfare. It is now regularly depended on for accurate positioning, targeting and communications. For information on how GPS and other satellite systems of the Global Navigation Satellite System (GNSS) operate, refer to our book “An Introduction to GNSS: GPS, GLONASS, Galileo and Other Global Navigation Satellite Systems”.

While the value of GPS is unquestionable, the increasing availability of jamming technology is proving problematic. GPS signals are transmitted on published radio frequencies from satellites that orbit 20,000 km above the earth. The GPS transmit levels from the satellites are extremely low power, and are only about 50 x 10^-18 W by the time they reach the surface of the Earth. This fundamental weakness makes the signals vulnerable to both accidental and deliberate interference. Although illegal, devices that jam GPS signals are easy to obtain. Simple models that plug into 12-volt car receptacle connectors can be purchased for as little as $30 online and can render GPS systems inoperable for miles around.

Instances of recent GPS jamming include:

• GPS jamming at Newark airport in early 2010
• Recent report of North Korean GPS jamming capability

Learn more about GPS Jamming:

• GPS chaos: How a $30 box can jam your life
• Warning on GPS jamming threats
• Academy report warns of over-reliance on global satellite navigation systems
• No Jam Tomorrow
• GPS Jammers Could Wreck Transport, Communications
• National PNT Advisory Board comments on Jamming the Global Positioning System - A National Security Threat: Recent Events and Potential Cures
• The Civilain Battlefield - Protecthing GNSS Receivers from Interference and Jamming
• “Managing the Integration of Space and Information Operations” Maj Daniel F. Gottrich, USAF and Michael R. Grimaila, PhD, AFIT; High Frontier, April 2006 Volume 2, Number 3
• US Department of Defense, “Global Positioning System (GPS) 2008, A Report to Congress” dated 31 Oct 08.
• KTN event: “GPS Jamming and Interference - A Clear and Present Danger” 23 February 2010, National Physics Laboratory, Teddington