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There Exists a US Program to Identify, Geolocate, and Mitigate Sources of GPS Interference

There Exists a US Program to Identify, Geolocate, and Mitigate Sources of GPS Interference. But are we serious? Terry McGurn/Consultant An Informal Discussion 09/23/2010. Progress So Far. Background & Motivation. Motivation: Fact Sheet of NSPD-39, Dec 2004

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There Exists a US Program to Identify, Geolocate, and Mitigate Sources of GPS Interference

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  1. There Exists a US Program to Identify, Geolocate, and Mitigate Sources of GPS Interference But are we serious? Terry McGurn/Consultant An Informal Discussion 09/23/2010

  2. Progress So Far ...

  3. Background & Motivation • Motivation: Fact Sheet of NSPD-39, Dec 2004 • Maintain Continuity of GPS service in an interference environment • Deny hostile exploitation of this service. • NSPD-39 Actions (From Fact Sheet) • Establish a PNT EXCOM to address these issues, among others • Establish the EXCOM Advisory Board • Establish Agency Roles

  4. CONCLUSIONS • Language of the NSPD-39 Fact Sheet is vague. • Open to Various Interpretations of Assignments. • NSPD-39 Muddies the Issues (friendly protection & hostile denial). • The Program may be Headed in the Wrong Direction. • But I believe we can get back on track.

  5. The Bottom Line • No one tasked to develop sensors and array them to detect and geolocate interferers. • The Fact sheet seems to reflect a belief that we have assets in place, and the task is primarily to coordinate these assets. • There are assets available that could be netted to support the program, but these are only mentioned in passing.

  6. DHS: The Action Agency • DHS has taken action on this program. • DHS developed an IDM paper to address this issue, published in 2007. • DHS/CIP group, as part of a periodic review, also addressed this issue. • The DHS persons specifically tasked to implement a response to this program, and their contractors, have been very forthcoming on their program.

  7. So: What Can We Do Now? • DHS should address the pieces of the issue. The “one size fits all threats” approach is not practical. • Unintentional interference, intentional jamming, spoofing, are different problems. Face it: It’s a Dirty Problem • But (at present) unintentional jamming is the most frequent source of signal loss.

  8. Examples of Unintentional Jamming • Rome ADC (3 days/5 watts/ several hundred kilometers) • St. Louis Airport (1990s) • Butte, Montana (? days, spurious harmonics) • Monterey Bay (2001) Many months/ VHF/UHF TV antenna radiating above the L-band noise floor) • Mesa, Arizona (2 days before reporting, traffic steered into incoming. Interference operated for 4.5 days before shutdown. • Puerto Rico FAA Facility (? days, INMARSAT) • San Diego navy Test Center (4 hrs, 500 mw)

  9. Interference Case Study General AviationPilot Report GPS Malfunction AIS Display Console Anomaly So Let’s develop a capability to minimize the occurrence of unintentional jamming. You don’t get partial credit if you lose a critical function unintentionally. Potential for First Responder Impacts Medical Services Paging Provider Network Inoperative 1.5 Hours – 20 sites DGPS Site Inoperative 2 Hours Cell Provider Network 150 sites detected error 2 sites inoperative

  10. Recommendations • Define Specific Responsibilities for the Various Components of the Network. (An EXCOM role?) • Suggest Several Small Funded Efforts. (Requires more selective expertise/less PPT.) • Responsible Dept/Agency should have System Engineering Support. • Let’s Get a Significant Start. First Address the Unintentional Jamming Issue.

  11. Introduction - GNSS receiver front end with Digital Gain Control Antenna Analog IF J/N Meter Down Converter Digital Gain Control Digital Attenuator Preamp Digital IF ADC Gain Controlled Analog IF

  12. Final Thoughts • Mitigation: • Where possible, geolocate and prosecute • Otherwise: • Back-up Systems • Inertial (short term only. Present inertial trends are for poorer performance, low-cost systems. • Loran e: Provides high availability, good anti jam, and good timing performance (sigma about 30 nsec). • Smart receivers, for situational awareness. • Land-line for time?

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