Protecting GPS Satellites, Signals, and America Webinar

On 17 November 2021, the Domestic Preparedness Journal and the Resilient Navigation & Timing Foundation hosted a panel discussion on the vulnerabilities of the global positioning systems (GPS) and potential efforts to deter attacks on and interference with GPS satellites and signals. The Honorable John Garamendi, Congressman for the 3rd District of California and Chair of the House Armed Services Readiness Subcommittee, provided an introduction. Dana A. Goward, President of Resilient Navigation and Timing Foundation, and David Olive, Principal at Catalyst Partners LLC, moderated the discussion.

The panel included:

  • Dr. Scott Pace, Director of George Washington University’s Space Studies Institute and Former Executive Secretary at the U.S. Space Council
  • George Beebe, Vice President for Studies at the Center for the National Interest and author of “The Russia Trap”
  • Greg Winfree, Director of the Texas Transportation Institute and Former Assistant Secretary of U.S. Department of Transportation

Essential Asset, High-Priority Target

GPS is essential to the nation’s economy, safety, and security. Its positioning, navigation, and timing (PNT) services have been integrated into so many critical applications and infrastructure that many homeland security officials have called it a single point of failure for critical infrastructure.

This integration makes GPS a high-priority target for non-state and nation state adversaries. Government reports released this summer have discussed serious and growing threats to all U.S. space assets from Chinese and Russian anti-satellite weapons. “Kamikaze,” “Russian Doll,” and “Kidnapper” satellites, as well as terrestrial lasers, have all been added to ongoing concerns about signal jamming and spoofing.

Increasing the threat to the United States are terrestrial Chinese, Russian, and Iranian systems that provide their populations’ GPS-like services making those nations less vulnerable to disruption of space-based services. This has created a technology resilience gap, a strategic asymmetry that could easily lead to an escalating series of responses and armed conflict.

What the Panelists Say About GPS Vulnerabilities and Solutions

Despite being an integral part of daily life, GPS is vulnerable to numerous threats. All critical infrastructures are in some way dependent on GPS – some much more so than others. GPS signals are weak and easy to disrupt. Numerous intentional and unintentional activities can have devastating effects, including but not limited to the following: denial of service, intentional wide area jamming, spoofing, environmental threats, solar activity such as coronal mass ejections, anti-satellite lasers, kinetic threats, accidental satellite damage, and degradation.

Building resilience is the way to combat these various threats and protect GPS systems and the timing signal. For example, a terrestrial-based navigation system (e.g., eLoran systems) could provide a solution because satellite systems (high-frequency, low power) are more vulnerable to spoofing than eLoran (low-frequency, high power). Although diversity in systems and having an alternative source for GPS are key to resilience, the limiting factor is the ability of the nation to build systems fast enough and at scale to outpace the threats.

Of course, it is not only a question of what needs to be done, but who should do it – the public or the private sector. It can be problematic trying to separate the civilian and military responsibilities because any private-sector threat can become a national security concern. In many cases, it is necessary for industry to work with government to reach common goals. Private sector industries can generally innovate at a faster pace but may lack the resources. The federal government may have the resources but moves slowly.

Panelists Answer Additional Questions

The 60-minute panel discussion share a lot of information from subject matter experts on protecting global positioning systems and building national resilience. However, not all the questions could be addressed in that timeframe. Below are additional questions that were submitted by participants and answered by the experts.

Question 1:

Which three sectors are not using GPS as stated by Greg Winfree?

Answer from Greg Winfree:

Great question, and thanks for asking! As we discussed on the panel, it is hard to imagine any critical infrastructure not using some service from GPS, and they all do.

At one time the Department of Homeland Security (DHS) determined that the National Monuments and Icons, Water and Wastewater Sector, and Agriculture and Food critical infrastructure sectors did not use GPS timing. We now know that is not true. GPS timing enables wireless networks and SCADA systems which enable a wide variety of services for all those sectors. GPS is especially important in precision farming, as I mentioned.

So, an old soundbite that I won’t use again! Thanks for making me take a look at it! 

Question 2:

If the U.S. were to commit to building a terrestrial alternative to GPS (covering both military and civilian uses), how long might that take?

Answer from Dana Goward:

It depends upon how the U.S. went about it. If the administration decided to build a government owned and operated system, it would likely take eight to twelve years as discussed on the panel. Not only would money have to be appropriated, but the responsible department would have to create a major systems acquisition staff and follow an extensive set of formal procedures.

On the other hand, there are numerous mature technologies available today from commercial entities that could provide services to complement and backup GPS. If the government decided to contract for these services, it could take only two or three years for the funding to be approved, contracts to be let, and to have the services up and running.

Question 3:

What other ground-based location systems are there besides LORAN?

Answer from Dana Goward:  

There are a number of mature technologies that are available. In January, the Department of Transportation reported to Congress on a demonstration of some of these. That report is available here. The demonstration was not all inclusive, though, and other systems are in operation and more are being developed. As examples, two of RNT Foundation’s corporate supporters, Locata and iPosi, did not participate in the demonstrations.

These systems vary greatly in what they do and how they do it. Some provide location only, some timing only, and others provide both. Some provide highly precise information over limited areas, some are slightly less precise but cover much larger areas.

The RNT Foundation recently published a white paper discussing requirements and evaluation criteria for timing services the government might be interested in as ways to complement and backup GPS. This paper also that also applies to location services and is available here.

Question 4:

What are the pluses and minuses to e-Loran?

Answer from Dana Goward:  

Every system has its pluses and minuses. Here are a few for eLoran:


  • Signal – eLoran uses a powerful, difficult to disrupt signal at least a million times stronger than GPS. The navigation and timing signal can also carry additional information. As a new build, it could incorporate all the most modern encryption, authentication, and cyber protocols.
  • Cost & Coverage – The effective range of transmissions can be a “continental” system as transmitter ranges are 800 to 1,000 miles radius over land and 1,500 miles over water. This means less infrastructure and expense per area covered compared to many other systems. The Air Force developed deployable versions of Loran in the 1960s and 1970s that they and the Coast Guard installed and operated in the United States, Vietnam, and Italy. So, conceivably coverage could be established wherever it was needed.
  • Transmission Site Maintenance and Security – Hardware on Earth can be more easily maintained and upgraded. Technology serving the homeland would be on sovereign U.S. territory and added physical security could be easily implemented if deemed necessary.
  • International Issues – Other nations, some friendly, some not, operate eLoran, or its equivalent. Having a U.S. system would make us more knowledgeable about other nations’ capabilities. This could also be the basis for apolitical international cooperation.


  • Accuracy – GPS accuracy, depending upon conditions and receiver quality, is often around two feet. Some terrestrial systems can achieve centimeter accuracy. eLoran, in its current configuration, has only been demonstrated to an accuracy of 15 to 30 feet.
  • Coverage – At the current state of the technology, it cannot provide global coverage. Land-based Loran coverage can only serve land masses and ocean areas within about 1,500 miles of land.
  • Existing Infrastructure – While the federal government still owns most of the former Loran sites within the U.S., most of the towers have been taken down or are no longer serviceable.

Click to watch this 60-minute panel discussion on protecting global positioning systems and building national resilience.

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