Notes from DoT GPS Backup Demos – Part I
Government officials, advisors, and congressional staff gathered at NASA’s Langley Research Center on Friday, March 13. They were there to discuss the Department of Transportation’s (DoT’s) GPS Backup Technology Demonstration program and view the offerings of six different companies.
A second event to view and discuss technologies offered by the other five companies in the program is scheduled (as of this writing) for Friday, March 20, at Joint Base Cape Cod, Massachusetts.
View from Washington, D.C.
The day began with remarks by Karen Van Dyke from the U.S. Department of Transportation, as well as remarks prepared by Colonel Joseph Frankino, deputy director of the National Coordination Office, a multi-agency staff that supports the National Space-Based Positioning, Navigation, and Timing (PNT) Executive Committee, whose members were unable to attend.
Van Dyke provided an overview of the program and pointed out the increasing importance of resilient PNT. As just one example, improvements in autonomy and self-driving cars are entirely dependent upon consumers having confidence in the entire system, much of which is underpinned by PNT.
Col. Frankino’s remarks reflected the Defense Department’s commitment to and support of DoT’s resilient PNT efforts. He pointed out that the nation’s military depends upon the defense industrial base, which depends upon uninterrupted PNT.
Volpe Transportation Systems Center
The technology demonstration effort is being coordinated by Andrew Hansen from DoT’s Volpe Center. Dr. Hansen pointed out that the ongoing effort, the analysis and assessment of which is expected to be concluded in May, is a series of demonstrations vice tests. This means that the companies involved were showing what their systems could do, vice being measured against set criteria.
He also mentioned that the maturity of all the systems involved seems to have improved significantly over the last year. All are at Technical Readiness Level 6 or better. Also, that things so far had gone very smoothly with no need for any “re-dos.”
GPS and a cesium clock were being used as reference standards for the demos. Two of the systems, NextNav and Skyhook, were also demonstrated on a drone at Langley’s 150 acre open air site.
Report and Transparency
Data from the demos is not proprietary and belongs to the government which intends to make “as much of it available as possible.” DoT representatives mentioned several times their desire for maximum transparency.
Admiral (ret.) Thad Allen (left), chair of the National PNT Advisory Board, was among the attendees learning about DoT’s GPS Backup Technology Demonstration project at NASA’s Langley Research Center. (Photo: RNT Foundation)
Attendee Observations
After a day of viewing and discussing the six different technologies with their vendors, the group reconvened to offer feedback. All agreed the day was very worthwhile and complemented DoT and NASA on the event.
Kicking off the discussion, the DoT hosts remarked that the department is fully committed to GPS and its modernization. That said, there is broad recognition of the importance of other PNT systems. This is evidenced by the recent White House Executive Order on PNT.
Also, that there is no single solution that will fill the PNT needs of everyone. In fact, GPS does not serve the PNT needs of everyone. The need across sectors for a wide variety of sources to “backup” GPS is why the demonstration project includes some systems that only provide time, or only positioning.
Feedback from attendees included:
- The reason for this project is that we have a 20th-century GPS and 21st-century threats. New technologies need to be examined for vulnerabilities. Security must be “baked in” from the beginning. Moderators commented that the DHS Conformance Framework was one of the tools that would help with this.
- Rural and other underserved areas (such as wilderness, remote transportation networks, maritime) need PNT and should be a part of the government calculus.
- Many systems depend upon infrastructure provided by others versus being self-sufficient.
- In the view of many in Congress, it is good to see the demos going well. Overall, though, things are about two years late. Members and staff are very interested in when there will be an RFP and schedule for implementing the timing system mandated by the National Timing Resilience and Security Act of 2018.
Monty Johnson of the company OPNT demonstrates precise time transfer through 100 kilometers of spooled fiber-optic cable. (Photo: RNT Foundation)
Systems Demonstrated at NASA Langley
During the course of the day, attendees had the opportunity to interact with representatives from the following companies and their systems.
| Vendor | Service | Technology |
| TRX | Positioning | Inertial Measurement Units |
| NextNav | Positioning & Timing | Metropolitan Beacons |
| Skyhook | Positioning | WiFi, cell ranging, very large proprietary database of site locations |
| Echo Ridge | Positioning & Timing | Uses Global Star LEO constellation of 24 |
| OPNT | Timing | Timing Fiber & White Rabbit protocol |
| Seven Solutions | Timing | Timing Fiber & White Rabbit protocol |