Tag: Bernard Gruber

Editorial Advisory Board: GNSS constellations and receivers

Which GNSS constellations do most receivers currently use? How is that mix changing?

“Most modern commercial receivers today are moving to receive all GNSS signals: GPS, GLONASS, Galileo, BeiDou, QZSS, IRNSS and so forth. Also important, in which bands does the receiver operate, and how many channels does it have for optimum accuracy and quicker cold start? Application and location for local stability are also factors. If the operation is in India, IRNSS would be important, in Japan QZSS, and so forth.”

— Ellen Hall
Imminent Federal

“The current standard in commercial receivers is to exploit the interoperability between the various GNSS signals and to make use of all satellites in view, regardless of their constellation. While the L1/E1/B1 frequency band continues to be the primary frequency in almost all GNSS systems, the legacy L2 band is gradually losing its importance as most satellites are already broadcasting more advanced signals in the L5/E5 band.”

— Jean-Marie Sleewaegen
Septentrio

“The newest phones offered by Google and the largest manufacturers in the world — Apple, Samsung, OPPO and Vivo — support the following positioning systems: Google — Pixel 7 and Pixel 7 Pro: GPS, GLONASS, Galileo, BeiDou, QZSS, and other // Apple — iPhone 14: GPS, GLONASS, Galileo, QZSS, and BeiDou // Samsung — S23 and most other recent versions: GPS, Galileo, GLONASS, and BeiDou // Xiaomi — Xiaomi 13 Pro: GPS (L1+L5), Galileo (E1+E5a), GLONASS (G1), BeiDou, NavIC (L5A-GPS supplementary positioning) // OPPO — F21: GPS, A-GPS, BeiDou, GLONASS, Galileo, and QZSS // Vivo — Vivo X90: GPS, A-GPS, GLONASS, Galileo, BeiDou, QZSS, NavIC, Cell ID, Wi-Fi. // For farming, John Deere’s SF-RTK uses GPS, GLONASS, BeiDou and Galileo.”

— Bernard Gruber
Northrop Grumman

“All modern generation cell phones use virtually all GNSS signals. This includes GPS, Galileo, GLONASS and BeiDou. In addition, they receive the correction signals, such as WAAS and EGNOS. This capability is embedded in the chips that are currently used. We are told that they have the capability to track on the order of 50 satellites at once. We expect that dual frequency is close to realization and the use of the new civil L5 signal will make cell phones even more capable.”

— Bradford W. Parkinson
Stanford Center for Position, Navigation and Time

June 1, 2023
Editorial Advisory Board: The “geodesy crisis” and GNSS satellites

What are your thoughts on the “geodesy crisis” and what do you propose to address it?

Bernard Gruber

“Evidence seems to be very clear that we, as a country, need geodesists and that there has been a decline in investments, training, and research in geodesy. While our decline relative to China may be shocking, it should not be surprising. U.S. industry and government relentlessly pursues STEM graduates, or those with relevant experience, but that does not meet current needs. Besides maybe surveying, it is unclear to the public what the geodesy profession is all about, why it is needed, and quite frankly, why it is an exciting career choice.”

— Bernard Gruber
Northrop Grumman

Does crowding of low-Earth-orbit (LEO) space — with new satellites and space debris — pose any problems for the launch or operations of GNSS satellites in medium
Earth orbit (MEO)?

Ellen Hall

“This was a focused topic at SATELLITE 2022, where the discussion centered on the 6,000 tons of space debris circulating in LEO. Even the smallest piece of debris can be lethal to a satellite, so the key is to track and maneuver where possible. Add to that about 5,000 active satellites and plans to launch tens of thousands of additional ones into LEO over the next few years, and you have a serious problem to overcome. While there are treaties and plans for tracking and maneuvering these satellites, the debris is the real challenge.”

— Ellen Hall
Spirent Federal Systems

January 25, 2023
Editorial Advisory Board Q&A: Improving the GPS program

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

December 6, 2022
Editorial Advisory Board Q&A: The role of AI and ML

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.”

— Greg Turetzky
oneNav

August 3, 2022
Editorial Advisory Board Q&A: What will OCX bring?

What improvements will the Next Generation Operational Control System (OCX) bring?

Ellen Hall

“The OCX system is a part of an enormous modernization effort to enhance the ground control segment of the current GPS. This enhancement alone increases accuracy, but coupled with modernized satellites, the next generation OCX will increase and improve coverage and security of GPS. In terms of coverage, the Next Generation OCX will be able to fly twice as many satellites, including both legacy equipment as well as GPS IIIF satellites. In terms of security, the modernized receivers host anti-jam capabilities and information assurance features.”
— Ellen Hall
Spirent Federal Systems

Bernard Gruber

“The latest GPS modernization program was envisioned in the 1990s and started with the U.S. Air Force awarding the Lockheed Martin Team a $1.4 billion contract in 2008 to build the GPS III space system. As part of the modernization effort the initial OCX contract award was given to Raytheon two years later, in 2010, while a series of development contracts have been awarded, primarily Inc 1 and Inc 2, for the Modernized GPS User Equipment (MGUE) programs to L3Harris, Raytheon and then Rockwell Collins. The improvements of OCX aligned to the space and user efforts and substantially increased security protection of this world asset. Specifically, OCX controls all legacy satellites (GPS II) and civil signals (L1 C/A) and military signals (L1P(Y), L2P(Y)). It also controls the new modernized civil signal (L2C) and the aviation safety-of-flight signal (L5). Moreover, it also will have control functions for the MGUE signals (L1M and L2M (M-Code)), and the globally compatible signal (L1C). The next Block IIIF will finally upgrade capabilities to synchronize the entire system to include a worldwide network of dedicated monitoring stations, ground antennas and backup capabilities.”
— Bernard Gruber
Northrop Grumman

July 26, 2022
Editorial Advisory Board Q&A: Do we need a new PNT office?

Given that space is increasingly a congested and contested arena, should the U.S. government establish a new office to manage both space-based and terrestrial-based PNT systems?

John Fischer

“The U.S. government already has the National Executive Committee for Space-Based PNT (see gps.gov), which coordinates policy among all the branches of government. There is also a PNT Advisory Board, which includes some international members to inform the committee, and a National Coordination Office to execute the policies. This is in addition to the new U.S. military’s Space Command under which GPS operates. So, space-based issues are being addressed, but maybe more could be done to coordinate terrestrial-based PNT systems with space-based ones.”
— John Fischer

Ellen Hall

“As new technology advances, government, along with its policies and laws, struggles to keep pace. This was certainly true of the internet and cybercrime. This is also true of terrestrial-based PNT, where new technology emerges in areas not currently covered. Policy gaps and overlapping technologies need to be addressed and coordinated. It certainly seems that this would be one of those areas that could benefit from oversight. Space-based PNT is currently addressed by the National Executive Committee for Space-Based PNT, among others.”
— Ellen Hall

Bernard Gruber

“The threat to U.S. space-borne assets and the signals they generate is very real. Both commercial and military users of GPS continue to seek independent alternatives to current PNT systems that are diverse and robust. The National Coordination Office supports the National Executive Committee (NEC) for Space-Based PNT. I believe the role of the NEC should be broadened to include terrestrial and alternative PNT as a first step to charter/secure a new or expanded program office.”
— Bernard Gruber

Editorial Advisory Board

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

Bernard Gruber, Northrop Grumman

Ellen Hall, Spirent Federal Systems

Jules McNeff, Overlook Systems Technologies

Terry Moore, University of Nottingham

Mitch Narins, Consultant

Bradford W. Parkinson, Stanford Center for Position, Navigation and Time

Stuart Riley, Trimble

Jean-Marie Sleewaegen, Septentrio

Michael Swiek, GPS Alliance

Julian Thomas, Racelogic Ltd.

Greg Turetzky, Consultant

March 30, 2022
Editorial Advisory Board Q&A: The fate of the SAASM P(Y) code

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

October 28, 2021
EAB Q&A: How should we secure PNT resilience?

Two decades ago, the Volpe National Transportation System Center released its landmark report on the vulnerability of GPS. Have this study and its many successors helped move us to the necessary levels of PNT resilience? Have we done enough? What is left to be done?

Bernard Gruber

“This study and others underscore that safety must be maintained in the event of GPS loss. Among the many recommendations, I maintain that ‘systems and procedures to monitor, report, and locate unintentional [and intentional] interference should be implemented.’ Similar to GPS integrity monitoring, awareness of signal vulnerability ‘hot spots’ may allow an understanding of the RF landscape, and thus users may employ tactics, tools and techniques to combat against it. This ‘issue’ will not be solved with a singular solution; rather, continued education and urgency will produce innovative solutions over time. I just hope that a large ‘trigger event’ is not needed to do so.”
— Bernard Gruber, Northrop Grumman

John Fischer

“We have widespread awareness now, but not enough implementation of safeguards. There is no one simple solution – a single alternative system to GPS is not the answer. Rather, the integration of several diverse alternative PNT sources will provide the necessary resiliency. DHS and NIST have taken the proper initial steps to set standards for resiliency, but the next step is implementation. Twenty years without a major incident has only reinforced complacency, but we can’t keep betting our luck will continue. We have everything we need now — the technology, the standards, the exec orders — let’s implement!”
— John Fischer, Orolia

Ellen Hall

“This study was instrumental in getting the U.S. government to face the fact that GPS is vulnerable on many fronts. It seems that the first response was to focus on making signals more robust and therefore less vulnerable. The backup systems, alternatives, or simply additional sensors have come onto the scene very slowly due to factors that include funding, politics, and difficulty in deployment on all platforms, where the costs could be astronomical. I hope that it doesn’t take a catastrophic event to force all factions to come together to find best solutions, but that is sadly often the case.”
— Ellen Hall, Spirent Federal Systems

GPS World Editorial Advisory Board

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

Bernard Gruber
Northrop Grumman

Ellen Hall
Spirent Federal Systems

Jules McNeff
Overlook Systems Technologies

Terry Moore
University of Nottingham

Mitch Narins
Consultant

Bradford W. Parkinson
Stanford Center for Position,
Navigation and Time

Stuart Riley
Trimble

Jean-Marie Sleewaegen
Septentrio

Michael Swiek
GPS Alliance

Julian Thomas
Racelogic Ltd.

Greg Turetzky
Consultant

September 13, 2021
Editorial Advisory Board PNT Q&A: GNSS diminishing returns?

As the number of GNSS constellations and satellites in orbit continues to grow,
will we reach the point of diminishing returns?

Ellen Hall

“More satellites equal more data, and redundant constellation systems — through GNSS interoperability — can give us more robust PNT, as restated in the January Memorandum on Space Policy Directive 7. That said, there are always diminishing returns. Treaties place liability on the launching country if something goes wrong, but with tens of thousands of small satellites expected to be launched over the next decade, it will be getting increasingly crowded. Concerns are growing about the necessity of increased maneuvers to keep these satellites from a chain reaction of collisions, which ultimately could cause debris to fall to inhabited areas of Earth.”
— Ellen Hall / Spirent Federal Systems

Jean-Marie Sleewaegen

“With already more than 130 GNSS satellites in orbit, the benefit of new satellites decreases while the risk of satellites interfering with each other increases. However, this is only considering GNSS as we know it, in the MEO orbit (altitude about 22,000 km). The future of GNSS may well be closer to Earth, in the LEO orbit (<1,000 km), with well-known benefits in terms of convergence time and resilience to jamming. Sooner than later, we can expect constellations of hundreds or thousands of LEO satellites carrying a GNSS-like payload supporting PNT services. No worries, there is still growth potential!”
— Jean-Marie Sleewaegen / Septentrio

Stuart Riley

“With the current four GNSS constellations and a typical survey elevation mask of 10˚in North America, we average around 30 visible satellites. Far more are visible in Asia with the addition of the regional systems. In an area with a clear view of the sky, this provides more than enough satellites for precision centimeter positioning. However, most professional GNSS users do not have the luxury of operating exclusively in open areas with ideal conditions. Accessing many satellites across multiple constellations increases the probability of receiving sufficient satellites that produce high-quality measurements in obstructed areas. As the constellations expand, we observe improvement in precision position availability in these locations. The large number of satellites, coupled with independence across the four systems, improves system integrity and continuity while also helping to reduce the converge time in PPP solutions.”
— Stuart Riley / Trimble

Bernard Gruber

“In a utopian vision of navigation, data gluttons and like-users of GNSS would say that there will never be enough! If capabilities remained static, then yes, I believe we would reach the point of diminishing returns. I would offer that innovation and competition will continue to drive capability improvements via power, signal quality, coverage, integrity and clock/timing accuracy. These innovations, coupled with user equipment flexibility utilizing signals from space, will drive an ever-maturing market balance and increasing return.”
— Bernard Gruber / Northrop Grumman

June 1, 2021
Editorial Advisory Board PNT Q&A: GPS jamming and aircraft, seamless positioning

Are military tests that jam and spoof GPS signals a threat to the safety of civil aviation? If not, why? If so, who should do what about it?

Bernard Gruber

“I would offer that military tests that jam and spoof signals are a risk. The U.S. military takes great care to control tests of this nature in an informed and careful way in order not to affect civil aviation. I cannot speak for military tests that are conducted by other countries. We all recognize the worldwide proliferation of small and large jammers that can negatively affect GPS performance and satellite-born transmissions. Accordingly, GPS users should remain vigilant to these potential hazards, including spoofing, and consider alternative navigation means where risks dictate.”
— Bernard Gruber

What are the remaining obstacles to creating a seamless indoor/outdoor positioning and navigation system that integrates data from GNSS, inertial guidance, indoor positioning systems, and signals of opportunity?

John Fischer

“The primary use case for indoor navigation is the smartphone. We can create multi-sensor navigation systems today that operate indoors, but not at the very small size, weight, power, and cost targets needed for the personal phone market. IMUs and processors continue to improve over time, so there may be a breakthrough there, but signals of opportunity (SoOP) navigation is promising and offers resiliency through diversity. The most ubiquitous SoOP is cellular and with ultra-reliable low latency (URLL) features coming on-line for 5G in the next few releases, we may see reliable positioning from 5G in indoor environments very soon.”
— John Fischer

April 26, 2021
Editorial Advisory Board PNT Q&A: Lessons from Galileo and BeiDou

What is the single most valuable lesson GPS can learn from Galileo and/or BeiDou?

Bernard Gruber

“Service continuity. Given that GNSS are so ubiquitous today, similar to the electrical grid, it is imperative that GPS continue the superb system of outage reporting via NANUs, transparency via GPS.gov, and statutory commitments via U.S. Code. Aligning to the U.S. commitment, continued Open Service Signal-in-Space, such as GPS-Galileo-BeiDou, allows thousands of planned and interoperable “apps” such as Google Maps and Waze to thrive. Although not directly in line with the question, terrestrial timing backup systems, similar to what China and some other countries do, is a valuable lesson in continuity from BeiDou.”

Bernard Gruber
Northrop Grumman

Ellen Hall

“Perhaps the lesson could be, ‘It’s easier not to be first!’ Newer navigation constellations have the benefit of watching and learning from GPS — things done well and things to improve. From technology to operational procedures, a global navigation satellite system (GNSS) is difficult to execute. Would it have been easier or cost less if the United States had decided to land on the Moon after someone else had paved the way? Probably, but there is something very satisfying about being first! And, despite the fact that GPS satellites outlive their life expectancy, we keep launching new ones, with improved technology, to give the world better accuracy and more robust signals. The world of navigation welcomes Galileo, BeiDou, and all the others to follow.”

Ellen Hall
Spirent Federal Systems

Alison Brown

“GPS could benefit from lessons learned from BeiDou as to the importance of resilience in providing PNT services. BeiDou has a total of 42 satellites now in operation and open signals are broadcast on six frequencies (B1I, B1C, B2I, B2a, B2b, and B3I). In comparison, GPS has currently 29 operational satellites and provides open signals on three frequencies (L1, L2, L5). As the global threat to GPS grows, from frequency incursions by evolving 5G systems as well as deliberate interference or spoofing, the ability to operate on different frequencies to provide resilience against harmful interference will become increasingly important.”

Alison Brown
NAVSYS Corporation

Jean-Marie Sleewaegen

“While GPS remains a gold standard with decades of reliable service, the advent of BeiDou and Galileo has undoubtedly stirred up competition. While BeiDou is exceptionally fast at deploying new signals and services, Galileo is now transmitting the first ever authenticated OSNMA signals, helping secure GNSS receivers against spoofers. The main lesson is that it is better to have company than to be alone. Having multiple GNSS not only increases the number of satellites and signals, which improves positioning accuracy and reliability, but more importantly, it fosters continuous innovation, for the benefit of all users.”

Jean-Marie Sleewaegen
Septentrio

March 22, 2021
Editorial Advisory Board PNT Q&A: Advancing bathymetry

Which recent GNSS/INS innovations have been most helpful in advancing bathymetry? Which upcoming ones will be?

Miguel Amor

“Development of PPP removed reliance on shore-based RTK base stations, allowing operation almost anywhere on the oceans. Continued performance improvement in FOG and MEMS INS, along with bathymetric sensors, provide cost-effective solutions while also providing more accurate seabed maps. The future will see increased PPP accuracy with faster convergence and continued improvement in INS, coupled with increased resolution of bathymetric sensors, leading to more of the oceans mapped using autonomous platforms.”
Miguel Amor,
Hexagon Positioning

Bernard Gruber

“While GNSS has been a clear contributor to Earth mapping, it is an altogether different dilemma to solve ‘submarine topography’ mapping. Given recent developments in the IMU and lidar markets, one can readily utilize these sensors to correct for roll, pitch, and yaw, and produce digital maps, respectively. Combining these sensors with GNSS receivers, mounted on a drone for example, can allow for precise measurements in areas of tidal shifts or dynamic variations of water depth.”
Bernard Gruber,
Northrop Grumman

November 20, 2020