What should the new administration’s priorities be to make PNT more resilient?
We asked Brad Parkinson, the “Father of GPS” and a GPS World Editorial Advisory Board member, what the new U.S. administration’s priorities should be to make positioning, navigation and timing (PNT) more resilient. For more answers from board members, see below.
Brad Parkinson
Protect the Spectrum. Reverse FCC authorization for relatively high-powered Ligado transmitters that have been proven to degrade GPS and other GNSS operation for thousands of PNT users. All U.S. government departments and major user groups affected have pleaded with the FCC to reverse this terrible decision. There is little benefit from it to the American public.
Protect the rapidly evaporating and self-proclaimed Gold Standard of GPS. The GPS satellite designs are showing their age. They need to go to multiple launch (three at a time) and revert to simpler designs without the spot-beams and other weighty add-ons that greatly increase complexity and cost. The Chinese have added to BeiDou (a) inter-satellite precision ranging and wide-band communications, (b) geosynchronous satellites, probably with good spot-beam acquisition aids, and (c) a WAAS-like correction directly on the satellites, which may have accuracies down to real-time kinematic (RTK, perhaps a few centimeters). Also, they claim their basic accuracies to be better than GPS (it might be true!) — I think they already have operational retro-reflectors.
Allow and encourage export of the basic and quickest fix to jamming and spoofing for high-value PNT users. More than 40 years ago, we demonstrated, in hardware, a high anti-jamming receiver that could fly directly over a 10 kW GPS jammer and not be affected. We know that high-gain, digital beam-steering antennas will create close to immunity, but our manufacturers will not move this way because we cannot sell or use them on the international market. These devices, combined with inexpensive inertial components and the newer signals, would make PNT virtually immune to current threats of interference — both jamming and spoofing.
Move the military focus from alternative PNT techniques to seriously upgrading their receivers and useful signals. No current or reasonably anticipated alternative can provide the accuracy (3D), availability or integrity of GPS. The new M-code and L1C signals have been in the queue for about 20 years. (Loran for ground operations probably is very vulnerable to direct attack in a fluid battlefield operation. Loran’s main value is to distribute time and for maritime users.) In those 20 years, we now have cellphone chips costing less than $5 that can listen to about 200 ranging signals and process RTK, as well as use all the corrections available (WAAS, EGNOS, etc.). Such capability cannot be found in military receivers. The Defense Department must improve its acquisition strategy in terms of both speed and competition, and ncorporate existing civil capability into military user equipment.
Take government actions to rapidly identify, shut down, and prosecute GPS jammers. Some believe this problem is much larger than recognized already. All cellphones should be required to report extraordinary spectrum noise levels or apparent attempts at spoofing. This should be fed to a dynamic national database, perhaps maintained by the Coast Guard. GPS users should have an automated way to find out whether there are substantial threats in their operating area.
Brad Parkinson is the Edward Wells Professor, Emeritus, Aeronautics and Astronautics (recalled) and co-director of the Stanford Center for Position, Navigation and Time at Stanford University.
Editorial Advisory Board PNT Q&A
Here are additional responses to the question from more GPS World Editorial Advisory Board members.
John Fischer
“We hope the new administration continues on the path established with the Executive Order last year for resilient PNT, supporting progress made by DHS and NIST in establishing resilient and cybersecure frameworks. It will be important for them to maintain an open market concept toward future innovative solutions and not mandate a particular PNT approach. Awareness of the criticality for trusted PNT in our mobile connected society is established and we must not lose this.”
John Fischer
Orolia
Jules McNeff
“Resilient PNT should be a national security priority. Its continuity is vital to both military and economic/social activities of all kinds. Its qualities of spatial awareness and synchronization enable the efficient functioning of the most sophisticated modern technologies in the physical and cyber worlds while also simply getting people and things from point A to point B on schedule. In that context, the elements which comprise resilient PNT should be protected from natural or hostile disruption.”
Jules McNeff
Overlook Systems Technologies
Greg Turetzky
“Truly resilient PNT requires combining multiple positioning technologies to maximize resiliency. However, the government’s influence in many of the augmentation technologies (sensors, vision, etc.) is limited. What the administration can do is make GPS itself more resilient by speeding up the launch and acquisition schedule of GPS Block III. The new signals, particularly at L5, are invaluable for improved resiliency to jamming and spoofing as well as providing a significant improvement in accuracy.”
Greg Turetzky
Consultant