Satellite systems have become an integral part of our businesses for precise navigation and timing services. Yet GPS/GNSS jamming, spoofing, and other forms of interference appear to be growing in frequency and severity. Recently, the Senate Armed Services Committee (SASC) asked Pentagon to provide Combatant Commander’s alternate position, navigation and timing (PNT) systems to GPS within two years.
We caught up with Dana Goward, a member of the National PNT Advisory Board, and President & Director of RNT Foundation, an independent, member-supported non-profit that works in the area building awareness about the importance and vulnerabilities of navigation and timing systems, encourages development and implementation of resilient terrestrial systems, and advocates for policies to deter spoofing and jamming. Goward is retired from the federal Senior Executive Service having served as the maritime navigation authority for the United States. He has represented the US at IMO, IALA, the UN anti-piracy working group, and other international forums. He is also a Senior Adviser to Space Command’s Purposeful Interference Response Team.
Why is there so much concern around vulnerabilities of GPS?
It’s not just about GPS; all GNSS signals are weak. They are 20,000 km above the Earth, powered by solar panels, and are transmitting all the time, after all. Just as a matter of physics, it’s very easy to block a relatively weak signal. That is what GPS jamming is. Also, because the different global navigation satellites systems want to increase their user base, they release all the information about their signals so they can be integrated into other systems. But if you know exactly what the signals look like, you know how to imitate them. This makes the signals open to spoofing as well. That is another significant challenge, because, in many ways spoofing is worse than jamming — instead of no information, spoofing can give you hazardously misleading information.
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All GNSS are relatively the same signal strength and in same general frequency band, and they are all in space. Naturally, they are subjected to same kind of vulnerabilities — severe solar activity, malicious high-power electro-magnetic pulses, local jamming, spoofing, etc. Even urban canyons and downtown cities are a challenge as the signals tend to bounce off buildings and can cause problems for receivers. Using multiple GNSS systems at the same time does protect users a bit if one of the systems suffers a cyberattack or an equipment failure. So, it does offer some measure of additional resilience. But, generally, they all have similar vulnerabilities and are subject to the same threats, so the added resilience and security is marginal.
These shared vulnerabilities have been a concern for some time. There are all kinds of incentives for individuals and organizations to interfere with GPS signals — from delivery drivers taking long breaks, to criminal organizations wanting to divert a shipment, to nations looking to counter the armed forces of another. For example, American generals have said that Syria and the Middle East have the highest intensity of electronic warfare anywhere on the face of the planet. A lot of that is GPS/GNSS jamming and spoofing.
Interestingly, a recent sampling by the European Union found 500,000 instances of transmissions on GNSS frequency that should not have been there. About 10% of them were determined to be malicious and intentional, while the others were just apparently accidental. So, there are a lot of vulnerabilities in the system, and a lot of real-world threats
From cellular networks to power grids to transport systems, GNSS is the source of accurate, synchronized time for almost everything. A 2012 Boston Consulting Group study found that the geospatial services fueled by GPS resulted in $1.4 trillion a year in savings to the US economy and another $1.6 trillion in added revenues. A London Economics study found that if GPS/GNSS went away for five days, the UK economy would suffer losses of £5.2 billion, which translates to $482 billion per year.
We are fortunate that nothing really bad has happened so far. At the RNT Foundation we encourage responsible governments to try to get ahead of things and prevent mishaps, rather than waiting for them to happen before swinging into action.
Tell us about the details of the FCC-Ligado controversy?
Ligado is really an interesting case. Ligado Networks, an American satellite communications company, claims they want to establish a low-power nationwide 5G network. And it has been allotted space in the L-band spectrum which is the same band as that of GPS and other GNSS. US government tests have shown that these transmissions will interfere with GPS reception for many users. Naturally, a lot of organizations and individuals, including the Executive branch of the government, are concerned about its possible impact on GPS and are of the opinion that we shouldn’t go ahead with this. However, the Federal Communications Commission, which is an independent agency and works on its own under a congressional mandate, is convinced that this isn’t going to be that much of a problem, approved the request, and is refusing to budge.
Ever since, the opposition to the proposal has been growing. The entire executive branch of the government, including the Department of Defense and Department of Transportation, have amplified their protest and a number of organizations including the RNT Foundation, have formerly requested that the FCC reconsider their decision. Now, there is some legislation in Congress to examine the decision. The end of that story is yet to be written.
One of my thoughts here is that the FCC is the ‘communications’ commission, not the ‘navigation’ or ‘geospatial’ commission. Radio communications are different from radio navigation in a lot of ways. In fact, they are almost opposites — in radio communications you are blasting the 1s and 0s through the surrounding noise to get the message through, while in radio navigation you look down within the background noise for the 1s and 0s. And rather than identifying the 1s and 0s as the message in communications, radio navigation precisely measures the time of the change from a 1 to a 0 so the receiver can figure out its location. There are a bunch of other differences as well.
It could well be that the radio and communications engineers at FCC didn’t have the right context to evaluate the Ligado proposal as it would affect navigation. As an example — I was on a panel with the head of Ligado who is a communications engineer. I said there were tests that found Ligado transmissions violated the government safety buffer for GPS failures. I said that, rather than using the safety buffer in its tests, Ligado had tested the GPS receivers to the point of failure. Ligado’s CEO replied that they hadn’t done that. They had just tested the receivers to where they started “giving bad information.” OK, so that’s worse. Bad information is worse than no information at all.
But it shows the difference between the way communications engineers and navigation engineers view things. In communications, a little bit of interference might not be so bad. You could probably understand the overall message. Or, if it is two-way communications, you could ask for a repeat. Not so for navigation. One of the first signs of interference with GPS/GNSS signals in many receivers is bad, potentially hazardous, information. A safety report to NASA last year detailed how a passenger aircraft nearly crashed into a mountain because of this kind of interference with its GPS receiver.
The United States is unique among the nations in this decision to allow a terrestrial broadcast on what is basically a space-only frequency band. Quite frankly, I know from my own personal experience, other people and nations are looking askance at us and saying ‘how and why did you do that?’ It makes no sense really!
I think the Federal Communications Commission should have more than just communications engineers on the staff if it has the responsibility of adjudicating all spectrum issues in the United States.
What’s the status on an alternative PNT system for US?
We need alternate PNT systems and GPS backups. We have known that for a long time. In 2004 the President of the United States mandated we have a GPS backup capability. After a lot of study and analysis, the Department of Homeland Security said in 2008 it was going to implement one. But that didn’t happen. Later, in 2015, the Deputy Secretaries of Defense and Transportation announced that they had a system they would implement, but that hasn’t happened either. Frustrated with this long history of inaction, in 2018 the US Congress passed legislation saying the Department of Transportation must at least establish a terrestrial timing system to backup GPS by the end of 2020. The department is behind schedule, but at least they are working on it.
The Congress also said this terrestrial timing system should be expandable into a navigation system. Countries like Russia, China, Saudi Arabia, South Korea, Iran – all have terrestrial navigation and timing systems, so they are not nearly as vulnerable as the United States, India, the UK, Europe, Canada and others.
Once Galileo is fully functional, since the US and Europe have been traditional allies, do you think, it will solve some of these very critical problems that US is facing with GPS?
No. As I mentioned before, being able to use multiple satellite systems is good but it’s only a marginal improvement. The big issues of user resilience, the big threats in terms of solar weather, jamming and spoofing — they all remain. People may think it’s much harder to jam two satellite systems at the same time, but that’s not true. They are in the same general frequency band, and most of the jammers you get can go across the whole frequency band and are capable of jamming every signal in that band. So that just happens automatically. I have also seen multiple academic papers and articles on how to put together a little system for just $150-160 with step by step direction on how to deceive multiple satellite systems at the same time.
How would GPS III help?
That’s an interesting question. GPS III is not going to provide any significant improvement for most users. For military users, GPS III will be slightly more difficult to jam and will provide some more security features. However, for the vast majority of users, those not in the US military, it’s going to be about the same accuracy, same signal strength and not much of difference.
Don’t get me wrong. We have to keep the GPS constellation refreshed and as modernized as possible. So, the GPS III project is a good thing.
But it is not going to solve the resilience and security problems we have been talking about.
What’s your take on BeiDou and its economic impact? Do you think BeiDou-GLONASS together will be able to end GPS dominance?
There is a lot of evidence that BeiDou is having a very positive economic impact in China. It has sparked new business lines and enabled them to be independent from GPS. A satnav system is foundational technology upon which many other things can be built.
As to the agreement between China and Russia for BeiDou and GLONASS to cooperate, I am sure that the leaders of both countries are hoping it will lead to their dominance. I have seen reports that China has very cleverly deployed BeiDou so that there are more of their satellites overhead in many capital cities at any given time than there are GPS satellites. They are clearly making an effort.
But, you know, GPS has the distinct advantage of having been first to market by a long way. So, there are many, many more systems and applications designed around GPS than there are around BieDou or GLONASS. That will likely be true for many years to come.
As interference with GPS and other GNSS signals continues to increase, it seems to me that leadership in this area is going to be depend upon who is able to successfully develop, establish and integrate terrestrial systems that have the right safeguards with satellite navigation to provide a more reliable, robust, resilient user experience.
At the moment, it seems like most satellite navigation system providers just care about putting a signal in space. Not so much about ensuring it is useable and used well when it gets to the user. Taking a holistic approach that focuses on ensuring the user always has reliable information should be the next step in this sector’s evolution.
So what’s the answer?
Like a lot of complex problems, there isn’t a silver bullet that will make everything right. These things have to be deliberately managed.
Governments must protect GPS/GNSS signals by not allowing interference and sanctioning those who cause disruptions. Users must have equipment that is better able to resist spoofing and jamming.
And we must have a complete architecture of varied sources of PNT information so that, regardless of problems with one source, users have others to draw upon for these essential services. The US has a plan for just such an architecture, but is only in the early stages of building it out.
