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Author Topic:   GPS Spoofing, eLORAN as Alternative Positioning, Navigation, and Timing System
jimh posted 08-07-2013 10:58 AM ET (US)   Profile for jimh   Send Email to jimh  
A group of students and faculty from the University of Texas report on their successful spoofing of the Global Positioning System navigation system aboard a large yacht in an article at

jimh posted 08-08-2013 11:03 AM ET (US)     Profile for jimh  Send Email to jimh     
On a corollary topic, the Department of Transportion for the United Kingdom (UK) announced it has approved implementation of seven eLoran stations along the coastline of the UK. The use of eLoran technology is seen as a countermeasure to jamming of GPS signals. For more information, see uk-will-rollout-eloran-stations-to-backup-gps

In the USA development of eLoran technology for the existing LORAN system was said to be about 75-percent complete, when a change in administration occurred. For reasons that are still perplexing, the Obama administration halted eLoran deployment, and then began a dismantling of the entire LORAN system, include the destruction of many antenna towers. It has been reported that the cost of dismantling and destroying the existing LORAN facilities was greater than the cost of continuing to improve and operate the system. I have never seen a good explanation of this decision, and, to me, it seems to suggest some sort of political revenge. The Wikipedia article on LORAN gives some details:

jimh posted 08-08-2013 11:12 AM ET (US)     Profile for jimh  Send Email to jimh     
A prototype DGPS installation at Newark Airport was rendered unusable due to GPS jamming. After a lengthy investigation the source of the jamming was found to be from small jamming devices being carried on commercial trucks driving near the airport on a busy interstate highway. The drivers of the trucks were intentionally jamming the GPS locating devices on the trucks to maintain privacy about their location. This incident is one of several mentioned in a recent article about GNSS jamming in the name of privacy:

jimh posted 08-16-2013 05:17 AM ET (US)     Profile for jimh  Send Email to jimh     
The Federal Communications Commission has issued a NOTICE OF APPARENT LIABILITY FOR FORFEITURE of $31,875 to a New Jersey truck driver whose "personal" GPS jamming device interfered with operation of a ground-based augmentation system for GPS at Newark Airport. See 32k-penalty-proposed-use-gps-jammer-individual

for details.

A number of news stories also mention that the truck driver was fired by his employer as a result of the incident. The truck was company-owned and had a GPS tracking device installed on it. The truck driver wished to thwart the GPS tracking and bought the GPS jamming device to carry in the truck. His work took him frequently to the Newark airport and vicinity, where his "personal" GPS jammer disrupted the operation of a major airport. The FCC used radio-locating devices to discover the source of the interference, located his truck, and confirmed the source of the interference was the "personal" jammer device.

jimh posted 09-29-2013 12:24 AM ET (US)     Profile for jimh  Send Email to jimh     
Korea has announced it will join the United Kingdom (UK) in deploying an eLoran system to provide an alternative navigation and timing signal during periods of GPS jamming. South Korea has been the target of continual attacks of GPS jamming from North Korea.

This paper describes in detail the jamming attacks, their effects on ship and airplane navigation, and how eLoran will be used as a complementary navigation system with much greater immunity to jamming. ENC2013_JiwonSeo.pdf

It is also anticipated that Russia will add eLoran to their navigation systems.

jimh posted 09-29-2013 01:04 AM ET (US)     Profile for jimh  Send Email to jimh     
The PBS program News Hour covered this topic in an August segment. You can see a recording of the segment at

Buckda posted 09-29-2013 12:39 PM ET (US)     Profile for Buckda  Send Email to Buckda     
There was a TED talk on NPR about this as well. I believe it was produced before the UT team had their success the original article describes, and it is possible that the speaker I heard was actually that UT professor. In any event, it was fascinating.

You can download TED talks from the NPR site.

Buckda posted 09-29-2013 12:41 PM ET (US)     Profile for Buckda  Send Email to Buckda     
Here is the TED Talk. Todd Humphreys - at UT - was the speaker.

jimh posted 09-30-2013 10:46 AM ET (US)     Profile for jimh  Send Email to jimh     
Dave--Thanks for the mention and link of the TED talk on GPS. The presenter in the Ted Talk is Todd Humphries, who is also the professor at the University of Texas who demonstrated the spoofing with the large private yacht, as mentioned in the initial article in the thread.

Both the GPS and LORAN systems can be attacked with spoofing, but the important difference is the very significantly higher power level of the eLORAN signals. Because the eLORAN signals are so much stronger, about five levels of magnitude greater, the signal power needed to spoof or jam them is proportionally greater, and this tends to preclude being able to generate the signal with a small device running on a little battery. Also the frequency of the eLORAN signal is very low, 100-kHz, which by its very nature requires a very large antenna to produce any sort of effective signal. This again tends to work against the implementation of a small or concealable device to generate the jamming or spoofing signal.

In any event, people much more acquainted with the problem than I have determined that eLORAN was the best alternative solution. In that light, it makes no sense why in the USA our present administration continues to endorse a policy of tearing down LORAN facilities. We see other nations are embarking on expansion and modernization of LORAN to create a more robust alternative to GPS, which was precisely what was recommended to our government by its own experts.

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