Photo: Xona Space Systems

Spirent has implemented Xona Space Systems’ PULSAR production signals for seamless integration into the existing SimXona product line. The PULSAR X1 production signal implementation has passed a diligent Xona certification and the PULSAR X5 signal verification process is currently underway. It is expected to pass certification during the summer of 2024. Spirent is now accepting orders for SimXona with production signals capability.

Xona is developing PULSAR, a high-performance positioning, navigation and timing (PNT) service built on a backbone of low-Earth orbit (LEO) small satellites. Xona’s smallsat signals will improve PNT resilience and accuracy by augmenting GNSS while operating with an independent navigation and timing system architecture. Xona is fully funded to launch its production class satellite, the In-Orbit Validation mission, in 2025.

Spirent is the leading provider of PNT test solutions and recently launched a sixth-generation simulation system, PNT X. Designed for navigation warfare (NAVWAR) testing, PNT X is an all-in-one solution with a native implementation of SimXona.

<p>The post Spirent accepting orders for Xona PULSAR simulator first appeared on GPS World.</p>

A Spirent user employs a portable GSS6450 attached to an antenna to record GPS, other GNSS, and complementary signals for resilient PNT testing. (Image: Spirent)

What is Spirent’s GPS origin story?

Spirent’s GPS genesis began on a rooftop in the middle of the night in the early 1980s. Engineers were attempting to acquire the new GPS signals with their receivers, scheduling their lives around the times when satellites would pass overhead, angling antennas off a roof in the dark, and hoping for favorable conditions. Those difficulties inspired an idea: since real-world conditions are never the same twice, simulating the signals in a lab would control variables and provide repeatable and trustworthy results.

That idea grew to be Spirent’s positioning division — a team of experts whose sole focus is to partner with customers to accelerate the deployment of robust PNT technology. In 1985, one of the first groundbreaking simulators provided to a customer generated six GPS L1/L2 signals. Soon after, we developed the world’s first simulator with SA-A/S capability, establishing our reputation for innovation. Today, simulation is for much more than convenience. The further upstream testing starts, the better for R&D and investment decisions. Because of that, we work across the spectrum in close partnership with constellation developers, receiver manufacturers, and OEM application integrators.

Can you share a recent breakthrough?

GPS regional military protection (RMP) is a nascent anti-jamming capability that uses a steerable, narrow-beam M-code signal, allowing U.S. and allied forces to operate much closer to interference without losing connection. Spirent supports RMP, so modernized GPS user equipment (MGUE) can be tested and integrated with RMP long before live-sky signals are available.
Another major breakthrough is in AltNav, a catch-all term that includes non-GNSS sources of RF and other complementary PNT, with recent attention focused on low-Earth orbit (LEO) constellations. Spirent has developed LEO AltNav simulators for both the military and commercial sectors that seamlessly integrate with Spirent’s extensive testbed for GNSS, threat simulation, inertial navigation systems, and additional complementary PNT.

How is your company preparing for the next 50 years of PNT with GPS and beyond?

As a trusted industry test partner, one of Spirent’s guiding principles over the past five decades has been to support PNT developers and early adopters by being first-to-market with new signals and constellations. Enabled by our flexible solutions, our dedication to that tenet will continue across the next five decades.

NAVWAR resilience testing is an area where emerging test needs will continue to demand more from the test environment. Layered PNT positioning engines — including GNSS, secure military signals, CRPA systems, multi-orbit architectures, and sensor fusion — are driving complexity in the test regimes that support them. Spirent’s purpose-built solutions are designed to meet these advancements, with deterministic simulation that delivers definitive validation and accurate test results.

Spirent pioneered the use of software-defined radios for GNSS simulation with the GSS9000, which enabled the same architecture to support new signal types, higher motion rates, user-defined waveforms, and more than double the generated signals. The next generation will extend that flexibility, capacity, and ease of integration to future complementary PNT sources while maintaining system performance across physical and virtual realms.

<p>The post From testing GPS to assuring PNT first appeared on GPS World.</p>

Image: Spirent

Spirent has concluded a review of Xona Space Systems’ PULSAR production signals, and has deemed them feasibile for integration into the SimXona product line. Spirent will integrate the Xona production signals as an evolution of the SimXona platform.

Support will become available to existing and new users throughout 2024.

Xona is developing PULSAR, a high-performance positioning, navigation, and timing (PNT) service built on low-Earth orbit (LEO) small satellites. Xona’s high-powered smallsat signals aim to improve PNT resilience and accuracy by augmenting GNSS while operating with an independent navigation and timing system architecture.

<p>The post Spirent to generate Xona PULSAR production signals via SimXona first appeared on GPS World.</p>

What are your roles?

MH: Our business is based in the UK. I am responsible for the vision and direction of the Technology portfolio required by Spirent’s Positioning Technology business unit.

RH: I am responsible for the U.S. add-on components to the simulator, the restricted signals, and support for the U.S. government labs and contractors.

How have the need for simulation or the requirements for it changed in the past five years, with the completion of the BeiDou and Galileo GNSS constellations, the rise in jamming and spoofing threats, the sharp increase in corrections services, and the advent of new LEO-based PNT services?

MH: I would say that the need for thorough and comprehensive testing has never been greater. That need is being driven on multiple fronts due to the understandable pressure on PNT systems needing to deliver enhanced accuracy, reliability and resilience, in the presence of emerging threat vectors and an expanding application space that’s utilizing ever more complex combinations of new and enhanced signals and sensors of opportunity. Underpinning Spirent’s leadership in ensuring the test needs for this evolving, challenging and increasingly diverse market are its team, its technology and its partners. That team is well-established, dedicated and highly experienced — their sole focus is designing, manufacturing and supporting PNT test solutions. The technology focuses around our pioneering dedicated SDR hardware platform and software simulation engine, which allied provide performance, scalability and flexibility, within an open accessible architecture. In addition, close collaboration with our selected partners ensures the opportunity to support and integrate new and emerging PNT technologies through their tools, applications and hardware.

You mention the advent of LEO. A key reason why Spirent was first to market and successfully supported an early LEO + GNSS receiver test-bed (through close and collaboration with Xona and NovAtel) was driven by team, technology and partners.

Two other important areas that have definitely continued to grow and evolve in importance and priority have to be increased realism and test automation. Both are areas in which Spirent continues to prioritize and invest R&D dollars.

Spirent’s integrated, software-defined wavefront simulation system for a 5-element controlled reception pattern antenna (CRPA). Spirent solutions support 16+ antenna elements. (Image: Spirent)

With all these additional signals, is it still a single simulator or do you have to somehow split it up into different modules?

MH: Good point. Again, a key element with the Spirent solution is that it is very scaleabale and flexible. Spirent has a generic SDR that can be re-purposed to simulate whatever signals are required. That way, we can compile different signals from either one radio or multiple radios coming from the same system. Together with being able to bring in multiple chassis to gradually grow the simulation solution, while also maintaining for each of those signals the fidelity, channel count, and accuracy that customers demand.

Including every signal currently available?

MH: Absolutely, sir. In fact, signals that are still on the drawing board as well. We can enable the user with effectively an arbitrary waveform simulator or ‘sandbox’ to experiment with different modulation schemes, different chipping rates, codes, bandwidths and navigation data content. So, in addition to using that architecture to generate the signals, we allow customers to experiment with it themselves. That’s certainly accelerated over these last five years, and there’s no sign of it stopping. We’re currently working with customers and partners all over the globe who are developing both brand new and emerging PNT systems, whilst also providing all the vital simulation tools to aid the R&D of existing and planned SIS evolutions.

RH: The increasing number of signals that we can support multiplies the permutations and combinations of test cases that users can do. There is a lot of emphasis also on the user interface side of things, so that from one interface you can also easily control all these interfaces with third-party tools, because proliferation of signals produces a huge possible test volume.

What are the specific challenges in realistically simulating new LEO-based signals and any new services being developed for which you don’t have any live sky signals to record yet, only ICDs and other documents?

MH: Again, great question. The key reason Spirent excels in this arena is that the core simulation engine and SDR are agnostic of the constellation and signal type that’s being generated. So, the underlying principles of accuracy, range rate, pseudo-range control, and delay, together with the RF fidelity from Spirent’s SDR+ Sim engine, can be readily manipulated to simulate the wealth of emerging signals, including LEO.

The other area that becomes very important is that if we do not have sight of the ICD, we can enable customers to use our tools to readily populate elements of that ICD themselves. That way, the best of both worlds is achieved, i.e. a turnkey SIS solution, or we can just enable the customer to do it themselves.

Are accuracy requirements or any other requirements for simulation increasing to enable emerging applications?

MH: They are. Both current and emerging test needs are continuing to drive the need for enhanced simulation realism. Always a tough nut to crack, but our hard-won experience and expertise, allied with continuing adoption of latest-generation technology, is allowing us to take some significant strides forward. Real-world testing has an incredibly important role to play and that’s why at Spirent we continue to invest in and develop the GSS6450 Record & Playback System (RPS). However, we are also on that quest for the ‘Holy Grail’ that has all the well understood and necessary advantages of lab-based testing but with the simulation environment being as true to the real world as possible.

A German Armed Forces test center, WTD-61, recently used Spirent’s new Field Simulator to conclusively demonstrate the susceptibility of some UAS to spoofing. (Image: Spirent)

A further area where both current and emerging test needs are demanding more and more from the test environment is resilience testing. Spirent now supports a multitude of vulnerability and corresponding mitigation/prevention test cases. Those test cases become increasingly complex as multiple combinations of the threat/mitigation surface evolve — including jamming, spoofing, cyber-attack and CRPA.

Many of these test cases are driving the state of the art and, especially in the case of CRPA testing, Spirent’s purpose-designed SDR comes into its own. Technology bakeoffs and corresponding customer adoption have shown that only through the use of that dedicated purpose-built technology, the simulator test bed can deliver the necessary carrier and code phase stability, very low levels of uncorrelated noise across antenna elements and high J/S that is demanded.

Again, with respect to flexibility, we also support ways to let customers generate their own IQ data. That data can be streamed into the Spirent simulator and combined sympathetically and coherently with the signals generated inside the platform. So, you can layer new signals on existing ones, or introduce a completely new dedicated IQ stream.Finally, hardware-in-the -loop (HIL) testing requirements continue to be a crucial aspect in test coverage. Whether that application is automotive, projectiles or autonomous vehicles, the need for lower latency and higher 6DOF sampling to capture as many trajectory nuances as possible continues to grow. Spirent’s 2KHz system achieves very high iteration rates (SIR) and <2msec latency.

What are the key differences between your simulators for use in the lab and those for use in the field? I assume that the latter are lighter, smaller, and less power hungry. Do they use modules so that users can pick the ones they need for a particular test?

MH: We do support in-the-field test use cases. Spirent has record-and-replay (RPS) systems to take soundings in a wide-band RF environment, record them, then bring them back into the lab for replay. They are sized to fit into a backpack, battery-powered, accessible, and easy to use.

Recently, we have also taken some of our signal generator IP and been able to create a smaller form factor portable simulator for outside use. Its footprint is considerably smaller than that of one of our lab-based simulators. It’s primarily a mechanism for testing the resilience in the field of devices under test. Armed with a Spirent simulator and the appropriate transmit licenses, a customer can put their DUT through an array of vulnerability test cases in a live real-world environment.

You mentioned licenses. As far as jamming, specifically, and maybe spoofing, I presume that you’ll need a license for a specific time and place and that you will have to be far away from, say, an airport.

Absolutely. Right. The details will vary depending on the jurisdiction, but you will need a license to transmit. And, as you rightly say, often those places will be very remote so as not to interfere with the public. We’ve had instances where we’ll work with a customer who has those appropriate licenses and then we can provide this equipment for them to be able to put it through a battery of tests.

You generate the spoofing in your simulator, of course. Do you also generate the jamming inside the same box or from a separate jammer nearby?

It could be either. We can use our simulators to generate internally wide range of interference signals supporting a wide bandwidth, high max o/p power and large dynamic range. This is especially important in instances of CRPA testing, in which it is vital to accurately reproducing a jamming wavefront commensurate with the arrival angle and delay incident at each antenna element. Correspondingly, we support turn-key solutions to connect, control and integrate 3rd party external signal generators into the test scenario.

Are you at liberty to describe any recent success stories?

We have a Xona simulator. So, this is back on the topic of LEO. We’ve recently released that in partnership with Xona. We are also working closely with Hexagon. All those things I mentioned earlier about enabling the customer to use the flexible features that we have, that is where it came into its own. That’s certainly a significant recent success.

We’re continuing to add many realism-related capabilities, including simulating the vibration and temperature effects of inertial systems. Working with a Swiss partner called Space PNT, we’ve recently introduced another LEO-based product, called SimORBIT. That tool enables us to generate incredibly representative and accurate LEO orbits that also include gravitational effects based upon the SV size. We recently introduced a new software tool to support “GNSS Assurance” requirements.

We have a newly patented cloud-based software application called GNSS Foresight that enables users to understand the GNSS coverage they would expect during a particular time, date location and trajectory inclusive of the 3D environment they would be experiencing. We continue to evolve the tool to support real-time operation to enable it to deliver aiding content to appropriately equipped systems.

We continue to be able to support more and more automation. Automation has always been important, but with ever increasing demands of test asset utilization and in a post-pandemic world of remote working, it’s more important than ever right now. The number of test cases and corner cases required and the amount of equipment, coverage, and efficiency required, which was being demanded by using our kit means that automation is vital. So, we’ve introduced several new automation tools to build up on top of our current SimREMOTE interface.

Spirent has also developed a simulation test solution for the Galileo Open Service Navigation Message Authentication (OSNMA) mechanism. SimOSNMA is designed to work with Spirent’s GNSS simulation platforms to test OSNMA signal conformance, which will bring new levels of robustness for both civilian and commercial GNSS uses. SimOSNMA provides developers with vital new simulation tools to test for OSNMA, the security protocol that enables GNSS receivers to verify the authenticity of signals distributed from the Galileo satellite constellation. Designed to combat spoofing, OSNMA ensures that the data received is authentic and has not been modified in any way. It is currently completing the test phase before its formal launch, and SimOSNMA enables developers to simulate and test OSNMA signals and features, allowing GNSS receiver manufacturers and application developers to accelerate and assure development programs.

<p>The post Faux signals for real results: Spirent Communications / Spirent Federal Systems first appeared on GPS World.</p>

Image: Safran Federal Systems

Advanced industrial societies are increasingly reliant on the fantastic capabilities of global navigation satellite systems (GNSS) — GPS, GLONASS, BeiDou and Galileo — and, therefore, increasingly vulnerable to their weaknesses. From providing our position on a map on our smartphone to timing financial transactions, cell phone base stations, and the internet; from steering tractors in the field to guiding first responders; from giving surveyors sub-centimeter accuracy to monitoring continental drift; from providing navigation to ship captains and airplane pilots, to enabling automated control of earth moving machinery, GNSS have become a critical infrastructure. Yet their well-known vulnerabilities — such as jamming, spoofing, multipath and occultation — continue to fuel the development of complementary sources of positioning, navigation and timing (PNT) data, especially for new and rapidly expanding user segments such as autonomous vehicles.

In a January 2021 report, the U.S. Department of Transportation pointed out that “suitable and mature technologies are available to owners and operators of critical infrastructure to access complementary PNT services as a backup to GPS.”¹

Several new PNT systems are being developed and deployed that are partially or entirely independent of the four existing GNSS constellations. This cover story focuses on the following companies, products and services:

• Safran Federal Systems (formerly Orolia Defense & Security) makes the VersaPNT, which fuses every available PNT source — including GNSS, inertial, and vision-based sensors and odometry. I spoke with Garrett Payne, Navigation Engineer.
• Xona Space Systems is developing a PNT constellation consisting of 300 low-Earth orbit (LEO) satellites. It expects its service, called PULSAR, to provide all the services that legacy GNSS provide and more. I spoke with Jaime Jaramillo, Director of Commercial Services.
• Spirent Federal Systems and Spirent Communications are helping Xona develop its system by providing simulation and testing. I spoke to Paul Crampton, Senior Solutions Architect, Spirent Federal Systems as well as Jan Ackermann, Director, Product Line Management and Adam Price, Vice President – PNT Simulation at Spirent Communications.
• Oxford Technical Solutions develops navigation using inertial systems. I spoke with Paris Austin, Head of Product – New Technology.
• Satelles has developed Satellite Time and Location (STL), a PNT system that piggybacks on the Iridium low-Earth orbit (LEO) satellites. It can be used as a standalone solution where GNSS signals will not reach, such as indoors, or are otherwise unavailable. I spoke with Dr. Michael O’Connor, CEO.
• Locata has developed an alternative PNT (A-PNT) system that is completely independent from GNSS and is based on a network of local ground‐based transmitters called LocataLites. I spoke with Nunzio Gambale, founder, chairman, and CEO.

Due to the limited space available in print, this article only uses a small portion of these interviews. For full transcripts of them (totaling more than 10,000 words) click here.

¹ Andrew Hansen et al., Complementary PNT and GPS Backup Technologies Demonstration Report, prepared for the Office of the Assistant Secretary for Research and Technology, Department of Transportation, January 2021, p. 195.

Locata dish antenna pointed to the European Union’s Joint Research Center in Ispra, Italy, 44 km away, just under the setting sun. The Yagi antenna above is pointed to a cell tower in Como and used to connect the system for remote control and data logging. (Image: Locata)

Complementary PNT

“Traditionally, augmentation to GNSS has been done through inertial navigation systems (INS),” Price said. “More recently, ground- and space-based augmentation systems have increased in usage. However, both technologies depend on the absolute positioning information provided by GNSS. They do not represent a true alternative PNT.”
To facilitate the development of advanced and autonomous applications, Price suggested incorporating terrestrial sources of PNT as well as ones based on LEO, medium-Earth orbit (MEO) and geostationary equatorial orbit (GEO) satellites. This, he added, would also keep costs from becoming prohibitive. “LEO brings many benefits in comparison to MEO in just about every industry to which it can be applied,” Jaramillo said.

While mass reliance on GNSS facilitates access to GNSS data and makes devices that use it increasingly cost-effective, over-reliance on a single sensor is risky, Austin pointed out.

“That’s where complementary PNT comes in: if you can put your eggs in other baskets, so you have that resilience or redundancy, then you can continue your operation — be it survey, automotive or industrial — even if GNSS falls or is intermittently unavailable or unavailable for a long time,” Austin said.

It has been said that “the only replacement for GNSS is another GNSS.” Inertial navigation, dead reckoning, lidar, and referencing local infrastructure that, in turn, has been globally referenced using GNSS, enable mobile platforms to maintain relative positioning during GNSS outages. However, absolute positioning will continue to require GNSS. “If you claim to be breaking free from GNSS you’re really saying, ‘I can navigate in this building, but I don’t know where this building is,’” Austin said.

GNSS-INS Integration

GNSS and INS have always been natural allies because they complement each other. The recent completion of the BeiDou and Galileo constellations, which has greatly increased the number of satellites in view, has made the requirement for six satellites at any one time for real-time kinematic (RTK) “a much more reasonable proposition,” Austin said. Coupled with the drop in the price of inertial measurement units (IMU), this has made it possible to “make a more cost-effective IMU than ever or spend the same and get a much better sensor than you ever could before,” he said. “Your period between the GNSS updates is also less noisy and you have less random walk and more stability.”
It used to be that the performance of an accelerometer might far outweigh that of a gyroscope, resulting in excellent velocity but poor heading. “Now,” Austin said, “we can pick a much more complementary combination of sensors and manufacture and calibrate an IMU ourselves while using off-the-shelf gyroscopes and accelerometers. That allows us to make an IMU that is effectively not bottlenecked in any one major area.”

Autonomous vehicles require decimeter accuracy to keep to their lane, while their absolute position is irrelevant to that task. It is, however, essential for map navigation and to know about infrastructure such as traffic signs and stoplights that may not be in a vehicle’s line of sight.

“That’s where the global georeferencing comes in and where GNSS remains critical,” Austin said. “One of the key things we’re examining is GNSS-denied navigation: how we can improve our inertial navigation system via other aiding sources and what other aiding sensors can complement the IMU or inertial measurement unit to give you good navigation in all environments. Use GNSS when it’s good, don’t rely on it when it’s bad or completely absent.”
Nowadays, car makers are increasingly moving their research and development tests from indoor, controlled environments to open roads. Therefore, “they are looking for a technology that allows them to keep doing those tests that they did on the proving ground, but in real world scenarios,” Austin said. “So, they rely on the INS data to be accurate all the time. In autonomy and survey, on the other hand, the INS is used actively to feed another sensor to either georeference or, in the case of autonomy, actively navigate the vehicle. So, that data being accurate is critical because an autonomous vehicle without accurate navigation cannot move effectively and would have to revert to manual operation.”

Image: Xona Space Systems

New vs. Old

Complementary PNT systems differ from legacy GNSS along several variables. One is coverage. For example, Satelles and Xona will provide global coverage, while Versa PNT and Locata are local. Another is encryption. Unlike GPS, which encrypts only its military SAASM/M-code signal, Xona’s PULSAR system will encrypt all its signals, Jaramillo said. “For autonomous applications, security is very important. If you’re riding in an autonomous car, you certainly don’t want somebody to be able to spoof the GNSS signal and veer it off course.”

Additionally, the design of Xona’s constellation includes a combination of polar and inclined orbits, which will greatly improve coverage in the polar regions compared to current GNSS coverage. This is particularly important as climate change makes the arctic more accessible. “The idea of having a LEO-based constellation is to take advantage of what can be done in LEO for GNSS,” Jaramillo said. “If you want the most resilient time and position, you need to use a combination of everything.”

Based on its architecture, Jaramillo said, Xona will provide better timing accuracy than GNSS does today. “Our satellites are designed to use GPS and Galileo signals, as well as inputs from ground stations, for timing reference and will share their time amongst themselves. We will average all these timing inputs and build a clock ensemble on the satellites. That enables much higher accuracies than just having a few single inputs.”

Satelles’ STL service can either substitute for GNSS where the latter is unavailable or supplement it where it is available. When used as a supplement, “the goal is having a solution that is resilient to an outage, interference, jamming, spoofing, those sorts of things,” O’Connor said. “In that case, the receiver card that might be provided by one of our partner companies would have both GNSS and STL capabilities and would take the best of both worlds.” Depending on the product configuration, its locational accuracy is generally in the 10- to 20-meter range, O’Connor said.

Orolia Defense & Security’s Versa PNT “is an all-in-one PNT solution that provides positioning, navigation, and very accurate timing,” Payne said. “Every type of sensor that you’re using for PNT has its strengths and weaknesses. That’s why we have a very accurate navigation filter solution that dynamically evaluates the sensor inputs.” In GNSS-degraded environments, the Versa’s software alerts users that GNSS signals are not reliable, automatically filters out those measurements, and navigates on the basis of the other sensors, such as an IMU, a speedometer, an odometer, or a camera.

Locata’s system is completely independent of GNSS because it does not require atomic clocks. At its heart is the company’s TimeLoc technology, which generates network synchronization of less than a nanosecond, Gambale said. “TimeLoc,” Locata literature states, “synchronizes the co-located signals with other LocataLites as the signals are slewed until the single difference range between it and the other LocataLites is the geometric range. This internal correction process is accurate to millimeter level.” Applications of this system include indoor positioning for consumer devices such as mobile phones, industrial machine automation for warehousing and logistics, positioning first responders within buildings, and military applications in GPS-jammed environments.

Constellations and Timelines

How long will it take to develop and/or complete these complementary PNT systems?

Xona is a start-up, and its timeline will depend on its success with investors.“We have basically locked down our signal and system architecture. Now, it’s a matter of building out the ground segment and launching satellites,” Jaramillo said.

Xona’s current target is to launch its first satellites into operation by the beginning of 2025 and to achieve full operational capability by 2027. The company will roll out PULSAR in phases. “In our first phase, we’re going to offer timing services and GNSS augmentation that only require one satellite in view,” Jaramillo said. “Then, as we roll out to phase two, we’ll be able to start to offer positioning services in mid-latitudes with multiple satellites in view. Phase three will include high-performance PNT and enhancements globally.”

Satelles’ STL is already on Iridium’s 66 active satellites, which are all relatively new, having been launched between 2016 and 2018, and cover the entire globe constantly. STL’s signal and capability are flexible, O’Connor said.

Orolia Defense & Security is now evaluating UWB computer technology from different vendors and integrating it in the Versa’s software. “We will probably begin performing full field tests in the first quarter of 2024,” Payne said.

Locata’s mission, Gambale said, “is to deliver technology advances which enable complete, independent sovereign control over PNT for companies, critical infrastructure systems, and in the future – entire nations. It’s designed for the many entities and nations which do not have – and can never afford – their own constellations”.

“Our business model,” Gambale added, “is based on enabling others – from companies through to nations – to develop their systems and products based upon our core technology developments. We do not dictate how our technology will be deployed. Locata’s technology can be available to any suitably qualified partner, to fashion our core developments for their own use.”

The Launch of a Falcon 9 rocket carrying Xona satellites. (Image: Xona Space Systems)

Business Model

It is challenging for any new commercial entrant in the PNT field to challenge a free global service, such as GPS. While all these new services are the opposite of GPS, which is a gift from U.S. taxpayers to the world, their business models vary somewhat.

“We are targeting both mass market applications and high-performance ones,” Jaramillo said. “For the mass market applications, our business model includes a lifetime fee: a customer pays a fee one time, and the service works for the life of the device. For higher performance applications that have more capabilities associated with them, there will be different tiers, each with different services.”

These will include an integrity service that will verify that the signal has a certain level of performance thresholds, for use in critical applications. “If it drops below certain performance thresholds,” Jaramillo said, “we will flag that to the device so that it knows that, even though it is receiving a signal, it should not continue to use it due to signal degradation.”

Receivers and Chipsets

Predictably, these new ventures have spawned a web of alliances.

The success of both Xona and Satelles will hinge in part on the availability of receivers for their signals. To manufacture them, Xona is “in discussions with just about every tier one manufacturer out there,” Jaramillo said. “We have a strong relationship with Hexagon | NovAtel. They have been supportive of us for a long time now and are very advanced in their development and support for our signals.” Additionally, Xona designed its signals “so that most receivers can support them with just a firmware upgrade.”

Satelles is also working with partners, including Adtran (through their Oscilloquartz product line), Jackson Labs (now VIAVI Solutions), and Orolia (now Safran Trusted 4D). “Companies like that provide the solutions that are favored by critical infrastructure providers today,” O’Connor said. “They ultimately integrate our STL capability into their solutions. They can use our reference designs or create their own custom designs based on our reference designs.”
Satelles uses a different process to take measurements of the STL satellite signals than legacy GNSS. “It’s not a single chip that’s measuring both satellites, it’s ultimately two chips that are making those measurements,” O’Connor explained. “Then, we leave it to our partners to determine how to perform the position calculation and the integration of those signals. It can be integrated loosely or tightly.”

Markets and Applications

The target markets and applications for these new PNT services also vary.

The markets in which Satelles has the highest adoption rates are data centers, stock exchanges and 5G networks, said O’Connor. He pointed out that 5G networks need about five to 10 times more nodes to cover a geographic area than 4G networks.

“GNSS has been used for years to time 4G networks, but most 5G network sites — such as femtocells and picocells — are indoors or in places where GNSS is challenged. We deliver that timing service indoors, outdoors, everywhere.” Generally, an STL-only solution is best suited for timing, O’Connor said. “It will do timing at about 100 ns, depending on what kind of oscillator is being used and the exact configuration of the product.”

Orolia provides precise position, timing, and situational awareness for different applications. “Our systems can be used for ground, air and sea-based applications,” Payne said. “At Orolia Defense and Security we market to the U.S. government, defense organizations and contractors.” Beyond those arenas, however, its systems can be used “anywhere accurate position and/or timing is needed.”

Versa PNT. (Image: Safran Federal Systems)

The Role of Simulation

Simulation plays an important role in the development of new PNT systems. “Before the Xona constellation or any other emerging constellation has deployed any satellites, simulation is the only way for any potential end-user or receiver OEM to assess its benefits,” Ackermann said. “Before you can do live sky testing, a key part of enabling investment decisions — both for the end users as well as the receiver manufacturers, and everybody else — is to establish the benefits of an additional signal through simulation.”

Then, new receivers must be validated to ensure they perform as intended. “The best way to do that is with a simulator,” Jaramillo said. “Spirent works with two levels of customers: first, the receiver manufacturers, then all the application vendors that use those receivers.”

Spirent Communications did that for Xona’s system using its new SimXona simulator. “First, we did in-depth validation ourselves,” Ackermann said. “Then, we worked in a close partnership with Xona for them to certify that against their own developments. So, we followed a proven development approach. It’s just that, in this case, the signal comes out of a LEO.” Spirent Communications’ sister company Spirent Federal Systems also provided support to Xona, said Crampton.

Validation and Adoption

The European Commission’s Joint Research Centre in Ispra, Italy, recently conducted an eight-month test campaign to assess the performance of alternative PNT (A-PNT) demonstration platforms, including Satelles and Locata. According to the final report, released in March 2023, the demonstrations “showcased precise and robust timing and positioning services, in indoor and outdoor environments. [T]ime transfer technologies over different means were demonstrated, including over the air (OTA), fiber, and wired channels. The results … showed that all A-PNT platforms under evaluation demonstrated performances in compliance with the requirements set.”

Satelles has also been working with the U.S. National Institute of Standards and Technology (NIST) to evaluate its system. “They have subjected STL to rigorous third-party, hands-off technology evaluations,” O’Connor said. “They confirmed the timing accuracy specifications to UTC and validated the operational characteristics of STL, such as the resilience in the absence of GNSS, the ability to receive the signal indoors, and having global availability.”

The industry is now focused on adoption. “All the providers of these capabilities ultimately need adoption in industry to remain active and viable,” O’Connor said.

With the recent completion of two new GNSS constellations, the growth in the number and variety of augmentation services, and the development and deployment of complementary PNT products and services, the geospatial industry is at an inflection point.

<p>The post PNT by Other Means first appeared on GPS World.</p>

Jan, what is the role of simulation in building a new GNSS with a very different constellation and very different orbits than existing ones?

J.A.: Before the Xona constellation or any other emerging constellation has deployed any satellites, simulation is the only way for any potential end-user or receiver OEM to assess its benefits. Before you can do live sky testing, a key part of enabling investment decisions — both for the end users as well as the receiver manufacturers, and everybody else — is to establish the benefits of an additional signal through simulation. Once it’s all up there and running, there are still benefits to simulation, but then there’s an alternative. Right now, there really isn’t an alternative to simulation.

With existing GNSS, you can record the live sky signals and compare them with the simulated ones. It’s a different challenge when it’s all in the lab or on paper.

JA: Yes, but it is not an entirely novel one, at least to us at Spirent. We went through it with other constellations and signals -for example with the early days of Galileo. It’s often the case that ICDs or services are published before there is a live-sky signal with which to compare them. So, we do have mechanisms in terms of first generating it from first principle, putting out the RF, running tests with that RF, and then seeing that what we put out is actually what we expect based on our inputs and the ICD. Obviously, we always work off the ICD, which is essentially our master. Then, a lot of work needs to happen to turn what’s written in the ICD into an actual full RF signal, overlay motion, and all those things. So, we have a well-established qualification mechanism to make sure that whole chain works for signals when we don’t have a real-world constellation.

Another very important check is when you work with some of the leading receiver manufacturers who have done their own implementation and you bring the two things together and see if they marry up. Then there’s always a bit of interesting conversation happening when things don’t line up, but we have a lot of experience in resolving that. So, there’s the internal (mathematical) validation of things — which we do internally, before we bring something to market — and then there is validation with partners, be they the constellation developer or a receiver manufacturer – or both.

JJ: Then, one step further from the receiver manufacturers, what we call the OEMs, want to validate that the receiver is doing what it’s supposed to do. The best way to do that is with a simulator. You can try to get a live sky signal, but it can be difficult. You must get on a roof. It may not have an optimal environment for that. The best way to prove that in a controlled environment is with a simulator. Spirent works with two levels of customers: first, the receiver manufacturers, then all the application vendors or OEMs that use those receivers.

JA: What we’ve done with the SimXona product recently follows very closely along those lines. First, we did validation ourselves. Then, we worked in a close partnership with Xona for them to certify that against some of their own developments. So, we follow that same proven development approach. It’s just that, in this case, the signal comes out of a LEO.

What is the division of labor here between Spirent Communications and Spirent Federal? In particular, which device comes into play with Xona?

PC: Spirent Federal has provided support to Xona but the equipment is the COTS equipment provided from the UK by Spirent Communications.

JA: This Xona product does not currently implement any restricted technology only accessible through Spirent Federal. That is very much the case, especially for the aspects of secure GPS, for which we have the proxy company, Spirent Federal. However, the SimXona product is a development through Spirent Communications, albeit heavily aided by Spirent Federal, from a technical perspective and others, but there are no Spirent-Federal-specific restricted elements to SimXona or the current Xona offering.

PC: If we ever had to go into a U.S. government facility to demonstrate SimXona or to sell it to them, that would be Spirent Federal that would be involved.

<p>The post PNT by Other Means: Spirent first appeared on GPS World.</p>

Why do you see the need to modernize GPS?

For many lay users, global navigation satellite systems (GNSS) are simply there, reliably guiding them and their systems to do the right thing in the right place at the right time. But with its vulnerabilities, we cannot take GNSS — GPS specifically — for granted, and it cannot remain static. Its ubiquity in commercial and defense applications demands ongoing improvements to signal quality, diversity, availability, and assurance. The GNSS signal space is increasingly contested, navigation warfare is common, and the risk to civilians and warfighters increases. For those of us focused on defense, we see the growing array of threats steadily ticking upward in novelty and number.

We applaud the ongoing efforts by the U.S. Space Force and Air Force to modernize the GPS space segment, control segment, and user equipment. GPS-contested and -denied environments are here to stay, so we must hone GPS as a tool for both the military and civil user.

Spirent’s flexible SDR-based GSS9000 Simulator supports
GPS modernization efforts. (Image: Spirent Federal Systems)

How is Spirent Federal supporting modernization efforts?

In short, by providing deterministic simulation for future signals and capabilities not yet in theater. Regional Military Protection (RMP) is a recent example. RMP is a nascent anti-jamming capability that will be available on GPS III Follow On (GPS IIIF) satellites. RMP provides military users with a steerable, narrow-beam M-code signal that greatly amplifies the power over a defined geographical area. According to the GPS IIIF satellite manufacturer, Lockheed Martin, RMP can provide up to 60 times greater anti-jamming support. This allows U.S. and allied forces to operate with accuracy and resilience much closer to interfering sources than with legacy signals. GPSIIIF satellites with RMP are in production, and the latest publicly forecasted launch date is FY2027. With Spirent’s software-defined-radio-based simulator’s ability to support RMP simulation, modernized GPS user equipment (MGUE) can be tested and integrated with RMP early in the design phase before live-sky signals are available. Adaptive antennas, other constellations, encrypted signals, and non-RF sensors can also be tested with RMP. Coupled with this, the ability to simulate a wide range of edge cases during development enables superior performance in the real world.

Image: U.S. Space Force

And beyond RMP?

Low-Earth-orbit (LEO) constellations have been a focus for several years as we look to next-generation alternative positioning, navigation and timing (PNT) methods to complement GPS. We have developed LEO simulators for both the military and commercial sectors, including modeling tools that simplify the generation of large LEO constellations with high-fidelity orbital dynamics, delivering greater realism for applications that have no margin for error.

As GPS modernizes, there is a growing movement toward software-defined radio (SDR) architectures for both receivers and transmitters. Flexible SDR-based simulation encourages experimentation: on the same platform, applications can range from standard GNSS signals to entirely new constellations and RF modulations, including interference threats. Simulation of RF signals can be done in concert with inertial and other non-RF sensors, and deterministic architecture ensures that performance is maintained.

Another focus is on spoofing — creating tools to support defense in their efforts to harden GPS. One of the latest technological advancements in simulation is an “augmented reality” range capability: the device under test (DUT) on a moving aircraft or land vehicle is attached to a portable simulator. The DUT receives live-sky signals from the antenna on the vehicle but also receives additional spoofed signals injected by the live-sky-synced simulator.* The DUT’s resilience to the spoofed signals can then be analyzed and hardened against future spoofing attempts. Without the difficulties of setting up an open-air test, the real-world dynamics are employed in the test, heightening realism — and the simulated signals augment it.

*It is the sole responsibility of the user to obtain appropriate permits.

<p>The post A simulation perspective on supporting GPS modernization first appeared on GPS World.</p>

UAV

Image: InfiniDome

Anti-Jamming Device
Provides protection from three directions of attack 

The GPSdome 2 is tailored to defend small- to medium-sized tactical UAVs as well as manned and unmanned ground vehicles. With a small form factor (500 g, 87 mm x 91 mm x 61.55 mm) and minimal power consumption, GPSdome 2 is suitable for loitering munitions as well as UAVs. Fully retrofit and completely standalone, the system is compatible with almost any off-the-shelf GNSS receiver as well as standard active GNSS antennas, meaning that it can be integrated into existing GPS systems or into new product lines, manned or unmanned. With sophisticated algorithms and a proprietary RFIC, GPSdome 2 analyzes RF interference in the environment and combines multiple antenna patterns to create and dynamically steer three nulls in the direction of any hostile signal. GPSdome 2 provides simultaneous dual-frequency protection (GPS L1 + L2 or GPS L1 + GLONASS G1), creating up to three nulls, protecting from three jamming directions within each band in real time, making it suitable for PNT applications. The GPSdome 2 is a dual-use, non-ITAR device and comes with optional mil-spec compliance.
InfiniDome, infinidome.com

Image: uAvionix

Command and Control
Designed for easy integration

The SkyLine C2 management platform and muLTElink airborne radio systems (ARS) are designed to integrate, which enables a self-healing command-and-control network capable of both path and link diversity. This eliminates lost-link possibilities over broad terrain and altitude ranges. MuLTElink ARS consists of two models — muLTElink915 and muLTElink5060, the core of the uAvionix C2 system. The muLTElink915 model combines globally licensed aviation LTE, enhanced with frequency hopping 902 MHz – 928 MHz industrial, scientific and medical frequencies capability. The muLTElink5060 model combines global LTE with aviation-protected 5,030 MHz – 5,091 MHz C-band. Each muLTElink model allows up to one external CNPC radio to be optionally connected to allow simultaneous use of all three frequency ranges, higher power C-band operation or future radio integrations.
uAvionix, uAvionix.com 

Image: Atmos

VTOL UAV
With Sony a7R mark III and IV camera 

Atmos has integrated the Sony a7R mark III and IV cameras into its vertical take-off and landing (VTOL) fixed-wing UAV, the Marlyn Cobalt. This will increase coverage and accuracy achieved in a single flight for surveyors. Both cameras have an ISO of 32,000, which is expandable to 102,400, and camera sensors with high megapixel count — 42,4 MP for the a7R III and 61 MP for the a7R IV. When combined with Zeiss’ 35 mm and 21 mm lenses, it enables UAV surveyors to achieve ground sample distance levels below one 1 cm. The integration of the two cameras enables Marlyn Cobalt users to map an area of 210 ha with centimeter-level accuracy in a single flight.
Atmos, atmosuav.com

Trueview 720. (Image: GeoCue)

TrueView 535. (Image: GeoCue)

Accuracy Star. (Image: GeoCue)

UAV and Lidar Systems
Suitable for geospatial professionals 

TrueView 535 consists of updated lidar sensors, adding a third return, increasing mapping abilities below canopy. An additional third nadir camera offers another point of view and improves photogrammetry quality. It also includes a longer, usable lidar range to increase flexibility. TrueView 720 is a fourth-generation Riegl VUX-120 with three laser beam orientations. It provides high-point density corridor mapping. Using the Riegl VUX-120 with three laser beam orientations (nadir, +10 degrees forward and –10 degrees backward) and three oblique/nadir cameras enables data collection from more surfaces in one flight path. One application of TrueView 720 is scanning power lines. Users can capture the poles vertically, front and back. The extreme range of this system means it can be integrated with UAVs, airplanes or helicopters. In addition to the two sensor payloads, GeoCue has launched its LP360 software add-on for processing and visualization — the 3D Accuracy and the Accuracy Star hardware.
GeoCue, geocue.com

OEM

Image: Microchip

Voltage Regulator
Device for LEO space application

The MIC69303RT is a radiation-tolerant power management device for space application developers. It is a high-current, low-voltage device targeting low-Earth orbit space applications. The MIC69303RT operates from a single low-voltage supply of 1.65 v to 5.5 v and can supply output voltages as low as 0.5 v at high currents. It offers high-precision and low dropout voltages of 500 mv under extreme conditions. The MIC69303RT is a companion power source solution for microcontrollers, such as the SAM71Q21RT and PolarFire field-programmable gate arrays. MIC69303RT is designed for harsh aerospace applications and remains operational in temperature ranges from -55 C to +125 C.
Microchip Technology, microchip.com

Image: Spirent Communications

LEO Satellite Device
Designed for GNSS/PNT lab testing

SimORBIT is a low-Earth-orbit (LEO) satellite solution software designed to aid developers in determining LEO orbits more accurately for GNSS/PNT lab testing. The software replicates LEO orbits so that simulations can provide the realistic environment of a LEO satellite, including gravitational and atmospheric impacts the satellite could encounter in space. Developers can create non-ICD signals via I/Q injection, or by the “Flex” feature, generating space-centered PNT signals to be developed in the lab as realistically as possible. Spirent Communications developed SimORBIT in partnership with SpacePNT.
Spirent Communications, spirent.com

Image: Sony

5G Chipset
Includes GNSS 

The ALT1350 implements GNSS, cellular and Wi-Fi-based location in a single chipset. The cellular LTE-M/NB-IoT chipset is designed to enable additional low-power, wide-area (LPWA) communication protocols; intermittent LTE and GNSS (GPS/GLONASS) navigation for low-cost applications; and concurrent LTE and L1/L5 GNSS for tracking applications. The ALT1350 incorporates a sensor hub to collect data from the sensors while maintaining ultra-low power consumption. It also provides cellular and Wi-Fi-based positioning and is tightly integrated to provide power-optimized concurrent LTE and GNSS to accommodate various tracking applications, which can be demanding with a single chip. The chip is designed to enable deployments for the internet of things (IoT), including location technologies.
Sony, altair.sony-semicon.com

Image: Linx Technologies

Embedded Antenna
Supports multiple satellite constellations

The ANT-GNL1-nSP is a surface-mount embedded GNSS antenna supporting GPS, Galileo, GLONASS, BeiDou and QZSS in the L1/E1/B1 bands. The ANT-GNL1-nSP antenna exhibits high performance in a compact size (10 mm x 8 mm x 1 mm) and features linear polarization and an omnidirectional radiation pattern. The antenna is available in tape and reel packaging and is designed for reflow-solder mounting directly to a printed circuit board for high-volume applications.
Linx Technologies, linxtechnologies.com

Image: OriginGPS

GNSS Module
Based on a MediaTek chipset

The ORG4600-MK01 dual-frequency module provides higher precision than the company’s previous modules. It has sub-1 m precision at a cost lower than that of the company’s first L1+L5 module, the ORG4600-B01, which is based on Broadcom’s chipset. The 10 mm x 10 mm ORG4600-MK01 was designed for applications deployed in challenging environmental conditions. The solution also includes RTCM, a logger and accurate orbit prediction.
OriginGPS, origingps.com

MAPPING

Image: Mapbox

Navigation Software
Includes enhancements to existing software and more

Navigation software development kit version 2.9 provides pre-built applications compatible with Android and IOS. SDK v2.9 provides the primary navigation components across a workflow using lines of code instead of starting from square one. The drop-in user interface is customizable to reflect a developer’s brand, obviating the need to manually develop a full end-to-end application. Navigation SDK Copilot — a backend analytics tool for CX on navigation applications — collects trace files of navigation sessions and search analytics data from users. Developers can use this data to gather feedback and collective user data to create touch points with users and improve application experience based on their data-drawn conclusions. Matrix API has been updated to support scheduled departure times and provide optimal driving routes, creating a more accurate estimated time of arrival.
Mapbox, mapbox.com

Image: Hexagon

Defense Platform
For developing Android applications 

LuciadCPillar is designed for the development of mobile applications for dismounted soldiers in the field. Developers can build applications with 2D and 3D views. It features military symbology and supports many geospatial data types including vector data, raster data, elevation data, point clouds and 3D meshes. It has the same capabilities found in desktops, in-vehicle and browser applications built with LuciadLightspeed, LuciadCPillar and LuciadRIA. The platform offers capabilities to match high-resolution screens, graphic processing units and multi-core processors including the ability to display 3D data in mobile applications. LuciadCPillar supports ARM processors and an application programming interface, which aligns with the Android developer experience. Impact, a French system integrator, partnered with Hexagon to test LuciadCPillar and will integrate it into its Delta Suite product, which is used by the French Special Operations Command. LuciadCPillar is part of Luciad 2022.1, which is available now globally.
Hexagon, hexagon.com

Image: Golden Software

Surface Mapping
Designed for 3D surface mapping 

The Surfer package is designed for 3D surface mapping and provides robust subsurface visualization and modeling functionality by incorporating many true 3D gridding and visualization tools. With the enhanced functionality, users can now model an additional variable, a C variable, such as a contaminant or chemical concentration, along with the traditional X, Y, Z values. Surfer also includes the ability to create a 2D map of a slice-through 3D grid, which users can move up and down through the grid, illustrating how the C value changes with depth. Part of Surfer’s enhancements is isosurface creation, enabling visualization of the 3D grid in the 3D view as an isosurface, providing another way to see how C data varies with depth or elevation. The new 3D-rendered volume functionality also allows users to visualize the 3D grid in the 3D view as a solid body by assigning colors to different C values, highlighting variations in the data.
Golden Software, goldensoftware.com

<p>The post Launchpad: Navigation software, UAV and lidar systems first appeared on GPS World.</p>