I. INTRODUCTION
The Global Positioning System (GPS) is the only system today able to show you your exact position on earth at anytime, anywhere, and in any weather. GPS satellites orbit 11,000 nautical miles above earth. They are monitored continuously at ground stations located around the world. The satellites transmit signals that can be detected by anyone with GPS receivers[3]. There are presently two complementary approaches to GPS interference mitigation. The first is to detect, identify, locate, and avoid or eliminate the GPS interference source. The second is to improve the GPS system resistance to interference. Both options are under aggressive investigation as part of a comprehensive synergistic mitigation capability.