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GPS Users Conference 02 November 2000

GPS Users Conference 02 November 2000. GPS Vulnerability. LCDR Drew Williams SSC-SD, Code D315 GPS Division. NAVSTAR Global Positioning System. SATELLITES PROVIDE RF SIGNAL. UPLINK/DOWNLINK. 26 SATELLITES ON ORBIT. USER EQUIPMENT COMPUTES POSITION, VELOCITY AND TIME.

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GPS Users Conference 02 November 2000

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  1. GPS Users Conference02 November 2000 GPS Vulnerability LCDR Drew Williams SSC-SD, Code D315 GPS Division

  2. NAVSTAR Global Positioning System SATELLITES PROVIDE RF SIGNAL UPLINK/DOWNLINK 26 SATELLITES ON ORBIT USER EQUIPMENT COMPUTES POSITION, VELOCITY AND TIME CONTROL SEGMENT PROVIDES SATELLITE EPHEMERIS, CLOCK SYNCH AND COMMUNICATION INTERFACES

  3. GPS Position Error Error (Meters) Elapsed Time (Hrs:Mins)

  4. NAVSTAR GPS SATELLITE Antenna System Antenna Antenna Electronics Position Velocity Time GPS Receiver

  5. #1 REASON: Signal Interference Threat Blue-on-Blue Unintentional/Foreign Frequency Allocations Vulnerability Issues The TOP 3 Reasons for GPS Vulnerability: #2 REASON: C/A-CodeSignal Spoofing #3 REASON: Growing Dependency on GPS

  6. #1 REASON • Received Power at Earth’s Surface: • 0.0000000000000001 Watts (10-16 W) • Signal below Thermal Noise Threshold by 15 dBW

  7. JTFX 98-1 Affected Target Areas • NKC-135 at 10,000 ft. • Target at Ground Level • Power: 400W • Location: Fort Bragg, N.C. • Green Civil Receivers Affected • Yellow Civil Receivers Denied • Red Military Receivers Affected • Purple Military Receivers Denied

  8. #2 REASON Present Signal Structure L2 L1 C/A P(Y) P(Y) 1227.6 Mhz 1575.42 Mhz • Must Acquire P(Y) Code through C/A Code First • C/A & P Codes are Published in Open Literature, Worldwide

  9. GPS Jamming Environment Enhanced Tracking Goal 120 110 100 90 80 Enhanced Acquisition Goal 70 J/S (dB) 60 P-code tracking 50 100 kW 40 10 kW Direct Y Acquisition 30 1 kW 20 C/A-Code Acquisition 10 1W 0 1 10 100 1000 Range NM

  10. The “Take Away” REASON #1: -Low power signal can be easily jammed when acquiring GPS REASON #2: -Military GPS receivers are Spoof Resistant once tracking Y-Code REASON #3: -Do NOT become a GPS cripple ALWAYS OPERATE IN THE “KEYED” MODE!

  11. 1 Watt GPS Jammer

  12. Questions?

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