Vulnerability of everyday life in America, through vulnerability of GPS, is not widely recognized. That gap in awareness would be filled instantly if GPS ceased to operate. Functions we take for granted, not only for transportation but also communication, affect multiple processes in ways vitally dependent on satellite navigation. Its steady improvement over recent decades has spawned increasing usage of its capabilities — and growing reliance on continuation of its spectacular success.
Far-reaching ramifications of that theme were analyzed in depth at a June 11 gathering of the National Space-Based Positioning, Navigation, and Timing Advisory Board. After kickoff by the Space Agency Headquarters Executive Director, followed by an opening presentation from the father-of-GPS, several speakers addressed a broad range of topics. Many of those involved the crucial importance of protecting and augmenting GPS, plus specific present and future steps planned to accomplish that.
Much of the discussion covered items under military or government control, i.e., the satellites or ground stations used to track and communicate with them. A minority aimed at protective measures devised for user equipment — receivers on ships, airborne, or on the ground. Toward the end of the day my own presentation expressed recommendations, some obvious and some more subtle, demonstrably capable of producing dramatic improvements in both accuracy and robustness. While those considerations revisited advocacy I’ve offered in the past, I was able to say-it-with-data. Immediately following my title slide, in-flight results showed precise velocity — in both navigation and tracking — by using the methods proposed.
An example will illustrate the effectiveness of those methods: the tracking demonstration obtained velocity accuracy a thousand times better than official ratings quoted for the latest-and-greatest Next Generation Air Transportation System — Automatic Dependent Surveillance Broadcast (ADSB). Although that test was just a first step (no all-encompassing claims are being attempted), the huge advantage in velocity — which directly affects collision avoidance capability — clearly warrants further investigation. There’s much more (my last page listed several URLs); sufficient for this summary is a reminder that monumental improvements are achievable, just through simple adjustments to receiver interfaces. A few suppliers already make measurement data available; another post will cover relevant opportunities within the industry.

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