What works well and what needs improvement in the GPS program regarding technology, policy, or management?
Jules McNeff
“GPS technology and operational performance continue to set the standard for GNSS, but necessary modernization is late to need, and becoming later by the day. This reflects what I see as loss of focus on ‘Job 1’ (delivering effective GPS service to the Joint Force) and a diminution in the sense of ‘GPS uniqueness and exceptionalism’ in its management as it was fragmented within the old SMC and is no longer the ‘shiny new object’ within the evolving Space Force. Even so, its value to its global user base, and particularly to U.S. and allied militaries, is stronger than ever and it remains the cornerstone among diverse complements within the Department of Defense PNT Enterprise. It is incumbent on the DOD to ensure the GPS services our warfighters will depend on can sustain that vital role.”
— Jules McNeff Overlook Systems Technologies
Ellen Hall
“What works well? There is good focus on the areas that need development: M-code, CRPA, resiliency. What needs improvement? More thorough and timely sharing of information by the government with industry.” — Ellen Hall, Spirent Federal Systems
Mitch Narins
“The ‘GPS program’ has set the standard for all other GNSS efforts, but there are always lessons to be learned. I have full confidence that USSF leadership is well equipped to deal with both the technology and management aspects of the program. As for policy, which supports military and civil uses worldwide, there is a clear distinction, based on mission areas and acceptable risk. However, risks to civil users have increased as GPS PNT services permeate all civil critical infrastructure systems. Therefore, system improvements directed at civil user PNT resilience should be given a higher priority and funded through appropriate civil channels. I encourage a policy to enable more resilient PNT services from space — and to consider that by looking both ‘up’ and ‘down’ for PNT services, unfortunate ‘situations’ might be avoided.” — Mitch Narins,
Strategic Synergies
Bernard Gruber
“One of the most consistent and enduring enablers of the GPS program is national policy. NSPD-39 re-baselined requirements buttressed by GPS being provided to the world for free, that it must be sustained and have an ever-present focus on performance improvement and robustness. Accordingly, NSPD-7 acknowledges an ever-changing world with a nod to cybersecurity, augmentations and direction to “improve NAVWAR capabilities to deny hostile use of United States Government space-based PNT services, without unduly disrupting civil and commercial access to civil PNT services.” — Bernard Gruber,
Northrop Grumman
What role do artificial intelligence (AI) and machine learning (ML) play in analyzing GNSS signals? How might that evolve?
Ellen Hall
“ML is gaining adoption across many GNSS application areas due to its ability to extract data and classify signal information often within complex operational environments. By combining ML with AI, systems are now able to characterize receiver correlator outputs and ranging residuals, and then fuse this with identified environmental features — all potentially increasing GNSS accuracy, integrity and availability. As AI and ML mature, we can expect to see new novel methods to optimize PNT sensor-fusion engines. This will include the combination of GNSS signals with other sensor signals such as inertial and vision.”
— Ellen Hall
Spirent Federal Systems
Bernard Gruber
“AI will come to the battlefield and I would like to think that AI and ML will play a large part in GNSS solutions and specifically protection from adversaries in the future. As AI can ‘anticipate’ threats (i.e., spoofing, jamming, poor coverage) based upon what it sees and knows one should be able to reduce the cycle time to combat that threat (e.g., find/fix/identify and then target, change frequencies, evade). Seeing this data, ML can adapt to morphing threats as well as ‘fuse’ data from all different domains (air, space, sea and land) to provide solutions.”
— Bernard Gruber
Northrop Grumman
Jules McNeff
“I would like to turn the question around and ask ‘How does GNSS contribute to enabling AI and ML to function in physical space?’ Many AI and ML experts don’t think about this aspect of the technologies. Of course, timing is essential to AI and ML operation, but both must be spatially oriented as well if they are to interact effectively with things in the ‘real world.’ The more complex the interactions, the higher the need for precise, continuous PNT information. Depending on the applications, the relationships can become synergistic.”
— Jules McNeff Overlook Systems Technologies
Greg Turetzky
“AI and ML have a great opportunity to fundamentally change the way GNSS signals are used for positioning. In particular, the new modernized signals with wider bandwidths and higher chipping rates create a fundamentally richer data set than classic range/range rate measurements. By analyzing the channel response and using AI/ML techniques, the entire signal environment of LOS and NLOS signals can all be used to make more accurate measurements. In fact, in deep urban canyons with appropriate training, it is even possible to accurately position using only multipath signals such that more multipath makes the position more accurate, not less.”
The U.S. military is transitioning to M-code. When the transition is complete, what will become of the SAASM P(Y) code? What should be done with it? Should the U.S. government use it as a public authenticated service?
Jules McNeff
“In my opinion (not speaking on behalf of the Defense Department), eventual use of the P(Y) code as a public authenticated service is not feasible based on both time and accessibility. Even with the transition to M-code, the legacy P(Y) code will continue to be used by the U.S. military and by U.S. allies and partner nations as long as there are military requirements for it. More importantly, public access to the encrypted P(Y) code would require general distribution of classified cryptographic keys and associated hardware/software by the DOD. That will not happen, even if the P(Y) code use is discontinued.” Jules McNeff Overlook Systems Technologies
Bernard Gruber
“Broadly speaking, GPS user equipment security architectures transition every 10 years (such as PPS-SM/AOCs to SAASM to Modernized CGM/MSI.) It can be argued that implementation of these security measures generally takes 10 years or longer to implement. SAASM P(Y) receivers will be around for a long time, implementation can be expensive, backwards compatibility is critical. Personally, I would like to see SAASM architectures evolve to support critical services within other U.S. government departments first, and then determine a path that supports a public service as threats, unfortunately, move forward.” Bernard Gruber
Northrop Grumman
John Fischer
“Why not? Authentication protects against spoofing. I don’t know all the obstacles involved, but even if an internet connection is required to overcome the one-way limitation of GPS, that isn’t a problem for most applications. Our credit card transactions are secured this way, why not our PNT information? Decades ago, the U.S. Air Force gave the world a gift with the open GPS signal; they could do it again with a secure signal. The world would be a better place.” John Fischer
Orolia
F. Michael Swiek
“It’s premature to forecast when military operations will transition from P(Y) code even after M-code operations achieve Initial and Final Operating Capability (IOC and FOC). SAASM P(Y) code will continue to support military operations for an extended period since all MGUE receivers (both increments 1 and 2) are YMCA capable, meaning they support P(Y) code, M-code and C/A code operations. As a military-encrypted signal with military utility, military leaders must carefully weigh any potential P(Y) code transition and its impact on military operations.” Michael Swiek
GPS Alliance
Ellen Hall
“If P(Y) code is offered as a new service to the public, it will have to be maintained. This carries a great cost. This is a legacy product that had a specific military need, which has been replaced and improved upon by M-code. In today’s uncertain times, we need to be wise with our tax dollars. The cost to continue both SAASM and M-code is greater than the benefit to the public, in my opinion.” Ellen Hall Spirent Federal Systems
Feature photo: U.S. Marine Corps/Capt. Joshua Hays
All four current GNSS and two regional systems have been built and are operated by public agencies. Many correction services and complementary PNT services are operated by private companies.
Going forward, what do you expect the division of labor to be between the public and private sectors in building and maintaining PNT capabilities? What should it be?
Ellen Hall
“The space race was championed by governments. Space travel, communications and other technologies were born from government exploration into space. Today we see many private companies engaged in space. Several are intent on supplementing GNSS navigation, and some envision competing. Private companies have a way to go if they plan to compete with systems like GPS, but competition is often at the center of innovation and may benefit everyone.” — Ellen Hall Spirent Federal Systems
Jules McNeff
“GNSS and regional systems are established and sustained to meet the needs of the governments and public agencies that operate them. They cover wide areas and provide services to extremely diverse user communities at levels of performance based on resources that are justified by user requirements and limited by technical affordability. When the global/regional service levels don’t meet the needs of a particular user group or require backup for security, the opportunity is opened for other agencies or private companies to create augmentations and complements to meet the additional needs. The mix is variable and will be determined by the user groups and the market.” — Jules McNeff Overlook Systems Technologies
F. Michael Swiek
“There is really no single ‘correct’ answer or specific division of labor between public- and private-sector entities in GNSS. The situation we see today is the result of decades of constructive and successful ad hoc evolution of roles among and between public- and private-sector entities. Public agencies are better suited to provide foundation technologies and infrastructure due to the large costs and long timelines associated with establishing the constellations and maintaining stable and consistent service. The private sector is better positioned to provide variety and timely flexibility in developing innovative solutions to the broad range of constantly emerging user requirements across all market segments. This unofficial and continually evolving division of labor has worked successfully and continues to adapt to the evolving world of PNT.” —Michael Swiek GPS Alliance
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
Jules McNeff, vice president, strategy & programs, Overlook Systems Technologies
I welcome the opportunity to contribute and congratulate GPS World on your 30th anniversary. Over those 30 years, I have watched GPS influence how the world works. Early on, along with its vital contributions to U.S. and allied military operations, there was great optimism that sharing civil GPS technology openly would bring improved safety and efficiency to people around the world. However, that sense of optimism has dimmed as GPS, and the GNSS construct and PNT enterprise that it spawned, confront evolving real-world events.
Several years ago, I wrote a paper positing that in terms of dual-use utility and risks, GPS and related PNT capabilities are analogous to two other technology innovations that have occurred since the Second World War: atomic energy and the internet. The paper considered GPS/PNT in the context of each, reflecting our experiences with those two dual-use extremes.
The paper concluded that, unlike atomic energy, which has been fairly well controlled, GPS/PNT more closely resembles the internet, which has for better or worse been allowed to grow into a global capability virtually without constraint. For GPS/PNT, a fixation on civil, commercial and scientific uses enabled civil authorities uncomfortable with the military side of the dual-use equation to ignore that reality and focus only on “peaceful” civil and scientific endeavors. Unfortunately, the international comity that participants had hoped for, and that appeared for a time to be real, can no longer be assured.
Where the U.S. has been open and transparent regarding a dual-use GPS, others have not. Now, the open sharing of information that has been the hallmark of the civil GNSS community over the years must be viewed seriously and candidly through the clear lens afforded by the overt actions of GNSS providers.
Collective efforts to improve GNSS for peaceful uses ignore the reality that the information shared can equally and dangerously undermine international security. As with the internet, those who have become dependent on precise GPS/PNT services must now reactively create protections and remediations to deal with increasingly real threats from those we had considered colleagues.
So, naivete and optimism must finally yield in the face of hard reality.
New players are offering GNSS correction services — pushing prices down and offering new business models. What opportunities does this open up?
Jules McNeff
“This trend is encouraging, as new entrants bring energy and new ideas, keeping the PNT technology sector fresh. GNSS corrections enhance the value of dynamic mapping coupled with grid-coordinate systems such as the U.S. National Grid in producing user-friendly geolocation values for delivery of people and things and especially enabling efficient, precise, land mobility activities such as spatial awareness for autonomous vehicle movement and command and control of emergency response operations.” — Jules McNeff Overlook Systems Technologies
Greg Turetzky
“In a 5G world where most devices regardless of size are connected, it make sense that those devices that are mobile are going to need to be located. Correction services are key to providing enhanced accuracy, and new business models are needed to address these new markets that are fundamentally different than traditional high-accuracy markets.” — Greg Turetzky Consultant
Jean-Marie Sleewaegen
“Traditional correction services rely on bidirectional communication between a user and a local correction provider. They offer centimeter accuracy over small regions. Instead, new services broadcast corrections applicable to larger areas and with flexible accuracy levels, from centimeters to decimeters. They bring benefits not only in pricing, but also in terms of accessibility, scalability and ease of use. They make accuracy transparent to the user, opening up the opportunity of high accuracy to mass-market and industrial applications.” — Jean-Marie Sleewaegen Septentrio
Which of several proposed terrestrial PNT technologies is best suited to complement and back up GPS?
Jules McNeff
“Seeking PNT resiliency for critical functions, a layered, multi-source terrestrial RF backup strategy could include eLoran for continental coverage and Locata, or similar system(s), for high-precision, localized service where needed. However, don’t forget feature-aided navigation using optical, radar, lidar, etc., and positioning/timing from ‘validated’ signals of opportunity in data-rich environments.” Jules McNeff
Overlook Systems Technologies
Terry Moore
“No single technology can provide a backup to GNSS to match the ubiquity of satellite-based PNT. However, placing inertial navigation systems at the core of our PNT solution, and focusing on bounding the growth of the positioning errors using whatever other space or terrestrial measurements are available, could provide an alternative paradigm to resilient positioning and navigation.” Terry Moore
University of Nottingham
Members of the EAB
Tony Agresta Nearmap
Miguel Amor Hexagon Positioning Intelligence
Thibault Bonnevie SBG Systems
Alison Brown NAVSYS Corporation
Ismael Colomina GeoNumerics
Clem Driscoll C.J. Driscoll & Associates
John Fischer Orolia
Ellen Hall Spirent Federal Systems
Jules McNeff Overlook Systems Technologies, Inc.
Terry Moore University of Nottingham
Bradford W. Parkinson Stanford Center for Position, Navigation and Time
Guest column by Jules McNeff Consultant and GPS World Editorial Advisory Board member
GPS World publications are evolving, as this new column confirms. And the PNT world itself is evolving, first with the emergence of GPS in the 1990s, next with its universal adoption and duplication by others, and now with its foundational role in PNT-enabled applications for technologies of the 2020s and beyond.
Millions of people have grown up in a world where GPS-enabled PNT applications pervade their daily lives, and mostly for the better. But GPS is no longer the only face of PNT around the world, though it is still the best known even as other space-based systems from international providers have joined the party.
From its infancy, GPS was married with inertial systems and clocks. For a short time, GPS emergence stymied the commercial development of both, but as the viability of the marriage was validated, development turned toward miniaturization of the combination and adding more pieces as well.
It is now clear that GPS was the spark, and a multi-faceted PNT enterprise is the new reality.
Because of its free availability, GPS has been the foundational element in most of these integrated applications, and without GPS, many will not work as well — or at all. Consequently, dependence on GPS for efficient operation of many PNT-related activities has become a de facto reality. GPS timing is at the heart of interoperable telecommunications and data networks (most notably the internet) and of modern power grids. GPS positioning was the catalyst for adoption of the U.S. National Grid as a federal spatial interoperability standard for search-and-rescue and emergency response and by the SAE as a standard for commercial land mobility as well.
However, dependencies create vulnerabilities, and over-reliance on GPS has been cited as a potential Achilles heel for both national security and economic critical infrastructure. Efforts have been under way for several years by the U.S. Air Force to strengthen all aspects of GPS and, more recently, much attention has focused on making use of complementary technologies to increase the resilience and performance of integrated PNT devices.
Smartphone and autonomous vehicle developers have used such techniques for years to augment GPS for their applications. The awareness of value from ubiquitous access to precise position and time that was awakened by GPS in 1995 has now evolved into an understanding that diverse services from a broader PNT enterprise are necessary to preserve that access with assurance into the future.
Congress and the DoD have recognized that reality, with Congress directing and DoD implementing a DoD PNT Enterprise Oversight Council to manage future acquisition of PNT capabilities for the military. In August, the Department of Defense (DoD) also released a public version of its Strategy for the DoD PNT Enterprise, highlighting the processes it has created to implement resilient PNT for the Joint Force. Congress and the White House both have also recognized that the imperative for resilient PNT must be extended to domestic critical infrastructure, and this has resulted in direction to civil federal agencies to both strengthen and back up GPS use for their constituencies. It is now clear that GPS was the spark, and a multi-faceted PNT enterprise is the new reality.
Are drones (UAVs) a disruptive or constructive technology for high-precision mapping that yields practical, actionable results for the end user/customer?
Ismael Colomina
“More constructive than disruptive. Drone mapping is opening new markets that, to a large extent, were not serviceable by conventional manned flights. On the other hand, the profound changes — and crisis — in the mapping business were not produced by drones.” Ismael Colomina GeoNumerics
Jean-Marie Sleewaegen
“Drones have dramatically reshaped the surveying and mapping industry. Combined with reliable positioning and recent advancements in high-resolution cameras, photogrammetry and computer vision, drones now enable high-accuracy mapping faster and at much lower cost than conventional mapping techniques.” Jean-Marie Sleewaegen Septentrio
Jules McNeff
“Drones can be constructive augmentations to high-precision map products because of their ready access to diverse locations. Drone imagery can document real-time physical changes that affect mapping applications during natural disasters or other events — but images alone aren’t maps without a geo-referenced grid such as the U.S. National Grid.” Jules McNeff Overlook Systems Technologies Inc.
Other members of the EAB
Tony Agresta Nearmap
Miguel Amor Hexagon Positioning Intelligence
Thibault Bonnevie SBG Systems
Alison Brown NAVSYS Corporation
Clem Driscoll C.J. Driscoll & Associates
John Fischer Orolia
Ellen Hall Spirent Federal Systems
Terry Moore University of Nottingham
Bradford W. Parkinson Stanford Center for Position,Navigation and Time
