Successful Testing — and Why It Is More Important Than Ever

March 2, 2015  - By
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By John Pottle and Neal Fedora

John Pottle

John Pottle

Precision matters. While “accuracy” is somewhat one-dimensional, “precision” is multi-faceted. We submit to you that whatever area of GNSS-based location you are interested in, precision matters today and will matter more in the future. In this column, we’ll explain why this is.

Traditional test approaches involve taking measurements to evaluate fundamental performance, for example, time-to-first-fix. As the number of critical applications that rely on positioning, navigation and timing (PNT) increases, the list of considerations for testing also grows.

Critical applications typically require higher integrity. There are a myriad of techniques to achieve this, from adding constellations, additional frequencies, improved navigation message authentication approaches and everything in between. Examples of safety-related applications include rail, connected car and aviation. Commercially critical application examples are smartphone payment authentication and container port automation. Protecting the warfighter and ensuring mission success against growing interference and jamming are key initiatives for the military. All of these applications are becoming more sophisticated and complex, stressing the importance of precision in testing.

Neal Fedora

Neal Fedora

Testing these critical applications requires:

  • Precise and clear test objectives
  • Precise definition of test approaches to explore both nominal and off-nominal conditions
  • Comprehensive test tools that include all required signal components precisely modeled and controlled
  • Test signal precision of at least an order of magnitude better than the device under test
  • Results analysis that can quickly and effectively highlight areas of interest or concern.

Robustness against Cyber Attacks. The second area calling for more precision is the need for a more robust PNT systems in the face of increasing cyber attacks and interference. While well known in the IT world, the GNSS community is relatively unfamiliar with being targeted by hackers. Attacks on GNSS technologies are increasing in frequency and sophistication for both commercial and military users. The stakes are rising as the incidents increase from occasional (often accidental) interference to more structured and organized approaches to jamming and even spoofing.

We’re predicting a game of cat and mouse where these cyber attacks and interference threats will continually evolve to try and stay one step ahead of the protections in place. In our view, this will call for increasingly clever and proactive threat-detection techniques in navigation systems, in addition to precise, reliable test solutions to verify them.

Spirent’s test solutions address these growing demands by providing not only multi-GNSS signal simulators, but also inertial and interference simulators, anti-jamming test solutions, and record and replay of actual observed interference and even communications port vulnerability testing.

In our view, the diversity of critical applications will increase, emphasizing the need for a precise approach to test planning, execution and analysis. Robust PNT is an achievable vision, and we are excited for the future.


John Pottle is marketing director for Spirent Communications plc. Neal Fedora is director of engineering for Spirent Federal Systems Inc.

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