1 / 14

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

Background

vinson
Download Presentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. There Exists a US Program to Identify, Geolocate, and Mitigate Sources of GPS Interference But are we serious? Terry McGurn/Consultant Presented to the SoCal ION Chapter Meeting of 14 September 2010

    2. 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

    3. 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.

    4. 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.

    5. 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.

    6. BUT The several high level appointees in the responsible DHS body for this program were (in late 2009) not yet in place. I believe the present DHS approach may be putting the cart before the horse. (i.e., developing a “data repository” before developing the sensors that will provide the “reposing” data.) In fact, the sensors should dictate the degree of processing to be done at the repository vice in the field.

    7. So: What Can We Do Now? DHS should address the pieces of the issue. The “one size fits all threats” approach not practical. Unintentional interference, intentional jamming, spoofing, are different problems. 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. Cause: Unintentional Interference Emission at GPS frequency due to personnel error. DoD personnel discovered error at 1445PST and secured. The exact time emission started is not known. However, data from San Diego DGPS site would indicate a start around 1230PST. This testing was not coordinated as this test was not planned to be conducted at GPS L1 frequency. Joint military and/or civil (first responders, etc.) tie: need for availability of PNT information inside buildings, urban canyons, or in the presence of electromagnetic interference. Cause: Unintentional Interference Emission at GPS frequency due to personnel error. DoD personnel discovered error at 1445PST and secured. The exact time emission started is not known. However, data from San Diego DGPS site would indicate a start around 1230PST. This testing was not coordinated as this test was not planned to be conducted at GPS L1 frequency. Joint military and/or civil (first responders, etc.) tie: need for availability of PNT information inside buildings, urban canyons, or in the presence of electromagnetic interference.

    10. 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. Situational awareness?

    11. 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.

    12. Introduction - Typical digital GNSS receiver block diagram

    13. Introduction - GNSS receiver front end with Digital Gain Control

    14. 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?

    15. Final Thoughts (Continued) “When everyone’s in charge, no one’s in charge”. (Relevance to Fact Sheet) (A retired Russian Colonel, in discussing the problems in the GLONASS program) Give a clear charter to DHS/(DOT?) This problem is: Hard Challenging Fun

More Related