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Q&A on challenged PNT

July 3, 2018  - By

This editorial comes to you live from the control console of GPS World’s June webinar, “Defense PNT in Challenged Environments.”

I’m impressed, as always, by the engagement of our webinar audience. Questions are pouring in about the speakers’ presentations, in addition to knowledgable queries submitted before the webinar began. These events strike me as, hour for hour, the best professional education one can get, short of leaving the office for a week to attend ION GNSS+ or the institute’s other conferences through the year, or the European Navigation Conference or Intergeo or others of the like. And a webinar takes only an hour of your time! From the comfort of your desk! Or sofa, even.

Here are some of the questions posed, and brief digests of our experts’ answers. The panel included John Fischer, VP Advanced R&D at Orolia, assisted by Jon Sinden, product manager for Rugged PNT; Tim Erbes, CTO at Talen-X; and Carol Politi, CEO at TRX Systems.

Q: Role of Galileo Public Regulated Service (PRS) in GPS-disrupted environment? Particularly given NATO alliance and cooperation? Any more detail about use of other GNSS to make solution more robust?

A: The PRS is certainly low-hanging fruit for traditional partners to take advantage of both GPS and Galileo, and I imagine fielded solutions will soon start to show that. There are substantial benefits to be gained from use of other GNSS as well.

Q: Please discuss the hardened military aspects of coming GPS III signals and codes. How will the new GPS III constellation impact your products?

A: Block III alone is not enough to make this happen. A new M-code will eventually replace the SAASM M-code, and it will provide a true separation from the civilian signal, different from the current situation with M-code and C/A code. Already, a dozen or more IIF satellites are now transmitting it. But the upgrade has to happen in three places for it to become effective: the satellites, the user receiver — and this is a complex, extremely broad and varied picture in the military realm — and finally the ground control system. There have been some difficulties in deploying the new OCX. This is the biggest determining factor of when these new features will roll out.

Q: What is the potential role of other means of PNT: eLoran, Iridium STL, lidar, and so on?

A: ELoran a very good alternative, ideal from the point of view of diversity: terrestrial instead of satellite, high-power instead of low, other end of spectrum from GNSS. Orolia published a white paper on a holistic approach towards resilient PNT, discussing eLoran and STL; see our website.

There are additional opportunities for outside-the-box solutions, for example, the sensors aboard tanks for anti-missile defense systems. They could also be used for PNT. Networked data radios for crowdsourced PNT data.

And there’s more! See to download the webinar and get it all.

About the Author: Alan Cameron

Alan Cameron is the former editor-at-large of GPS World magazine.