Editorial Advisory Board PNT Q&A: Promising alternatives to GNSS

June 30, 2021  - By

What is the most promising development or project in alternative PNT?

Photo: Orolia

John Fischer.

“PNT from LEO (low-Earth orbit) satellites offers the most immediate alternative to GNSS because the signals are ~30 dB or more stronger, reducing jamming vulnerability. With these new constellations being launched to improve communications, PNT services can ‘piggyback’ on the secure two-way links and avoid spoofing attacks as well. Geometric dilution of precision (GDOP) will not be a problem in these large second-generation constellations with dozens of satellites in view. Wide bandwidth links should yield accuracies to rival GNSS. There may be subscription fees to get this added resiliency, but nothing worthwhile is ever free.”

John Fischer,

Bernard Gruber

Bernard Gruber

“It depends on the application. I believe that alternative PNT, and specifically systems that complement GPS/GNSS, will continue to drive forward at a very rapid pace. Quite frankly, the ‘affordability of GPS’ from a commercial and military user business case was impossible to ignore for years. Today, the threat to GNSS signals is very real. History illustrates that ‘alternative’ systems that employ environmental data (magnetic, celestial), radio navigation (Loran, VOR), sensors (gyros, accelerometers), seekers (SAL, EO/IR) and IMUs all have new and promising developments today.”
Bernard Gruber,
Northrop Grumman

Thibault Bonnevie, SBG Systems

Thibault Bonnevie

“Inertially aided GNSS solutions are now mature and provide excellent navigation performance in many challenging conditions. On the research side, there are many exciting alternative PNT projects ongoing. RF-based solutions, such as Bluetooth/Wi-Fi or LEO satellite ranging, give promising results but are still subject to jamming or spoofing. Just like GNSS. Vision-based SLAM is probably the most exciting technology as it enables navigation in a wide range of situations and does not rely on any kind of infrastructure. It only requires low-cost sensors to be operated.”
Thibault Bonnevie,
SBG Systems

Headshot: Ismael Colomina

Ismael Colomina

“We all know that predictions are hazardous, especially about the future. This said, I confess that I am particularly interested in the technical, regulatory and commercial development of the LEO-based PNT technology with either dedicated constellations, like XONA’s Pulsar, or broader scope ones such as Iridium Next, Starlink or Kuiper. While GNSS has progressed tremendously in recent times — it plays a large role in the navigation of autonomous vehicles — it is still vulnerable to intentional or unintentional jamming. Integration of LEO-based PNT with current GNSS and other motion sensors appears to be a fascinating field ahead of us..”
Ismael Colomina,

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About the Author: Tracy Cozzens

Senior Editor Tracy Cozzens joined GPS World magazine in 2006. She also is editor of GPS World’s newsletters and the sister website Geospatial Solutions. She has worked in government, for non-profits, and in corporate communications, editing a variety of publications for audiences ranging from federal government contractors to teachers.