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Blog Editor’s Note: If you are interested in PNT and don’t follow Logan Scott on LInkedin, you are missing a bet.

Here is one of his typically thoughtful posts discussing some of the larger PNT resilience and policy issues.


Resilient PNT for Critical Applications

Logan Scott


There has been much discussion of the need for resilient PNT over the past few years as dependencies have grown and an evolving threat matrix has become more active. As a nation, we need a measured and cost-effective response commensurate with the level of threats and the possible consequences.

What is resilience?

Do we even know what resilience is? Mostly it looks like extra cost when you don’t need it. Then, when it is needed and you don’t have it, it looks like failure —sort of like the Texas power grid back in February. Resilience has costs and budgets are bounded. My working definition for resilience is that it is about building sufficiently secure and reliable systems out of insecure and unreliable components operating in an indeterminant environment.

How do you measure resilience? You try to break it and then decide whether the protection is adequate for the domain of use. Any system will break under sufficient stress. Determining what is sufficient is a hard question but it is a key question. Resilience could end up being quantified using a series of tests like UL standards for safes. You expose the safe to a skilled safecracker and see how long it takes them to break in. Interestingly, the highest security rating, TXTL-60, only guarantees protection for 60 minutes.

The need for standards and mandates.