Rockwell T1

Blog Editor’s Note: An excellent article showing the wide variety of products available to help users resist jamming and spoofing (GPS/GNSS is a very weak signal so it will never be jam-proof). More users should employ anti-jam technology, especially if they use GPS in safety of life or critical infrastructure applications. But, surprise, surprise, anti-jam systems cost more that leaving your receiver completely unprotected. So many users go without. Could there be a role for standards bodies or even the government to exercise some leadership here?

Anti-jam systems: Which one works for you?

June 14, 2017  – By

In my April column, I introduced the basic concepts behind GPS anti-jam technology, along with a bit of history around its evolution. I knew this was a popular topic, but I didn’t anticipate the enormous amount of positive correspondence I’ve received since, including many inquiries about where to buy this technology and who is entitled to have it.

So this month we return to the controlled reception pattern antenna (CRPA) topic, to look specifically at the major suppliers of GNSS anti-jam technology in a bid to help you select the best fit for your requirements.

As mentioned in April, CRPAs can trace their roots back to military radar developments in the 1970s and 1980s. It’s no surprise, then, that the main players in the CRPA market tend to be large defense primes. But there are many smaller companies, universities and research institutions that also play in the CRPA arena these days.

What about export?

When GNSS jamming was a little-known military problem, the situation was simple: anti-jam was a military technology for military applications only. Later, as GPS evolved into a dual-use technology, critical infrastructure and civilian applications brought a new demand for anti-jam in non-military domains.

Confusion then abounded about who exactly is entitled to make use of anti-jam technology. There are two distinct factors here: security classification, and export control. Let’s clear these up.

Security classification is simple: If a product is classified, it is only available to customers who hold the appropriate level of security clearance. Usually it is the performance and vulnerabilities of a product that would attract a classified status. As you might expect for in-service military products, the military would not wish everyone to know the performance and weaknesses of its deployed technology. This is why many datasheets for CRPAs omit performance information.

The second issue is export control. This, of course, varies by country. In the U.S., a CRPA developed towards a defense program is likely to have International Traffic in Arms Regulations (ITAR) restrictions attached to it. In Canada, CRPAs are subject to the Controlled Goods Program. In the UK, CRPAs sit on the “dual-use” export control list, which recognizes that CRPAs have both military and non-military application. An export license is usually required.

Before I go any further, a little disclaimer: I am not making any product recommendations in this article. There are many things to consider when choosing anti-jam technology, and you should always consult a navigation warfare expert and carry out appropriate evaluations prior to choosing a product. You should also seek guidance from your own government regarding any restrictions on export or import.

With that out of the way, let’s look at the offerings of a few suppliers. This is by no means a complete list, but I did manage to catch up with a few of the major players to ask them about their anti-jam technology offerings.

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