The Spirent PNT X. (Photo: Spirent Federal Systems)

Developers and manufacturers of GNSS receivers have always needed to simulate the signals from GNSS satellites to test receivers in their labs and in the field. Now, as the vital role of GNSS for critical infrastructure and the growing threat of radiofrequency attacks are increasingly recognized, simulators must keep up. In particular, they must enable users to test a variety of new positioning, navigation and timing (PNT)  signals from satellites in low-Earth orbit (LEO) and geostationary orbit (GEO), as well as realistically simulate sophisticated jamming and spoofing attacks.

In this cover story on simulators, we discuss these challenges with experts at four simulator manufacturers:

• John Clark, Vice President, Engineering, CAST Navigation
• Lisa Perdue, Product Line Director, Safran Federal Systems
• Jan Ackermann, Director Product Line Management, Spirent Communications, and Paul Crampton, Senior Solutions Architect, Spirent Federal Systems
• Avag Tsaturyan, Systems Engineer, M3 Systems.

How are the missions/applications of simulators changing?

Clark: Our customers have been requesting larger simulation systems that can support GNSS and inertial navigation systems (INS) on multiple vehicles simultaneously. Each vehicle is required to support a phased-array (CRPA) antenna sub-system, multiple INS interfaces and signal interference capabilities. This is a change from earlier times when our customers required smaller systems with less capability.

Perdue: We see a growing focus on testing NAVWAR scenarios and assessing receiver performance against diverse threats. The increasing complexity of receivers with multiple constellations and frequencies demands more advanced simulation capabilities. We provide comprehensive PNT simulators that support hybrid scenarios, in which simulated signals and threats are combined with live signals and sensors, creating a dynamic and realistic testing environment.

Crampton: For many years, simulators have been used to prove the capability of receivers and the systems into which the receivers are integrated. Testing ensures that receivers can perform as expected, including performance in boundary cases, which are tricky to recreate in live-sky conditions.

Over time, threats to navigation and timing performance began to dominate the schedules of test labs. Ensuring reliable performance in suboptimal operating environments is critical to receiver users. The workload of test labs has increased to the point where test automation has become necessary, not only in terms of increased efficiency but also just to keep pace with rapidly evolving threat profiles.

So, one of the main changes we are seeing is the need to speed up the innovation cycle with simplified, automated testing while maintaining test fidelity and robustness. Spirent simulators are enabling testing to “shift left,” to start testing earlier in the development cycle with digital twins — software-only models of receivers and devices — to shorten the time spent on R&D.

Ackermann: Increasing efficiency, flexibility and realism have been critical drivers in the simulator industry for many years and will continue to drive us forward at an ever-increasing pace. Precision and robustness requirements demand more signals and sensor fusion, which need to be supported by simulators. Greater realism and flexibility means that more representative testing can be done in the lab, saving time and money.

On the other hand, while lab testing has grown ever more realistic, there are times where in-field verification is required — simulators have had to become more flexible to address this “augmented reality” test environment and optimize field testing. Simulators are being used on ranges to enhance testing, using combinations of real and simulated signals — including resiliency tests that incorporate live-sky signals.

Are new markets for simulators emerging?

Clark: Yes, as the world evolves and circumstances change, the ability to validate proper operations of GNSS and GNSS/INS navigation systems under less-than-optimal conditions has become challenging. The use of simulators can greatly enhance your understanding of the behavior of a navigation system, thus allowing for more reliable navigation error planning and mitigation when these errors do occur. This has become a much more important area of concern as the automated navigation and integrated navigation markets mature.

Perdue: Yes, new markets are emerging in areas such as autonomous vehicles, UAV swarms, urban air mobility and space exploration, including lunar missions. Additionally, the growing focus on cybersecurity and electronic warfare has increased the demand for simulators that can replicate complex cyberattack scenarios and electronic threats.

Ackermann: New markets for simulators are constantly emerging. As PNT impacts more and more areas of our lives, the geographic and technological spread of simulator requirements continues to expand. Even in existing segments we see new market needs. In automotive, for instance, the emergence of a wide range of safety-critical functions such as intelligent speed assist (ISA) and eCall drive new simulation needs.

From the emergence of the LEO market to the development of LEO PNT constellations, these markets appear and evolve at a rapid pace. Spirent simulators can be used to generate novel and established signals from LEO PNT constellations with ultra-realistic orbital models for complex rotational effects and satellite parameters. The emerging focus on lunar missions from space agencies around the world means new test environments, more stringent requirements, and the potential for new signals outside of L-band, at S-band and beyond.

Crampton: Increasing the realism of testing continues to open new opportunities for simulator use. Spirent provides an all-in-one alternative PNT solution for ultra-realistic LEO modeling, inertial emulation, L and S-band signals, etc. — to be fused and tested in unison.

Senior Software Engineer Neil O’Brien utilizing a CAST-8000 GNSS Simulator to analyze CRPA trajectory data. (Photo: CAST Navigation)

Are simulator requirements changing?

Clark: In the past our customers were focused on the simulation of a single element of GNSS signals and a single INS output interface for the testing of vehicles that only supported single element antenna (FRPA) and a single INS capability. Our customers are now requiring simulator systems that produce multiple elements of phase-coherent GNSS signals that are commensurate with multiple INS interface outputs to drive navigation systems that can utilize a phased-array multiple-element antenna sub-system (CRPA) and multiple INS sources simultaneously.

Perdue: Yes, simulator requirements are always evolving. High signal counts are essential due to the increase in LEO constellations, and there’s a need to replicate multiple threats to create realistic environments. Built-in automation is crucial for managing these complex scenarios. The ability to add custom signals and constellations is necessary for experimenting with new technologies. Our software-defined architecture allows for quick integration of new signals, ensuring flexibility and responsiveness to changing needs. Innovations such as a radio utilizing the RFSoC to provide a high number of multi-frequency outputs from a single system and the BroadSim Duo, which offers dual-frequency capabilities in a compact form factor, demonstrate our approach to meeting these evolving requirements.

Ackermann: As new markets and use cases emerge, the simulator requirements evolve. The growing prevalence of NAVWAR threats, such as GNSS jamming and spoofing, and the range of systems these attacks are impacting is enhancing the criticality of lab testing.

Whether seeking to gain battlefield advantage or to secure civil operations (aviation, for instance), the ability to generate a wide range of NAVWAR attack vectors in complex scenarios is needed like never before. New waveforms must be incorporated quickly and realistically, while defensive technologies such as CRPAs must be exercised with a higher level of precision.

Crampton: Due to the demand for flexible attack vectors and the expanding range of available signals, simulators need to be capable of generating authentic RF environments from novel, user-defined waveforms. A time-saving method has been developed using prerecorded I/Q files. Spirent’s sixth-generation solution, PNT X, accepts raw I/Q data, analyzes the environment and the dynamic movement between receiver and transmitters, and automatically applies the correct motion effects to the generated RF signal. The simulated signal now has real-world dynamics without the need for manual inputs from the user. Realism made simple! Additionally, multiple I/Q-defined transmitters can be seamlessly integrated with native 3D terrain-modeling capabilities to create rich RF environments with multipath and obscuration.

A continuous, dynamic range is required to better replicate high-power jamming threats for controlled reception pattern antenna (CRPA) testing. With PNT X, high-power jammers can be simulated from the moment they become part of the noise floor to when a vehicle, such as an aircraft using a CRPA, passes by it. This continuous range enables CRPA developers to characterize null-steering ability with greater precision than previously possible.

Ackermann: As previously mentioned, there is also a growing need for integration and automation. Systems need to work in concert, and testing needs to happen quickly and efficiently to stay ahead of markets and threats. To this end, the ability to automate and to control remotely, and the ability to integrate seamlessly with other simulation and control systems, are core requirements for modern labs. Spirent is simplifying and automating testing with support for multiple industry-standard frameworks.

In established markets, safety requirements on devices under test drive simulator needs. For instance, functional safety requirements for automotive applications demand the ability to simulate threats and events, while the fidelity requirement of the simulation is elevated to assure conformance.

3D view of an aircraft flying a simulation. (Photo: CAST Navigation)

What mix of signals do you support?

Clark: GPS L1/L2/L5, L1C, L2C, C/A, SBAS, P, Y, SAASM, M-Code AES and MNSA, Glonass and BeiDou

Perdue: We support a wide array of signals, including GPS, GLONASS, Galileo, BeiDou, and regional systems such as QZSS and IRNSS. Additionally, we incorporate alternative navigation signals, such as those from Xona, and support inertial navigation and timing signals. Our software-defined architecture enables us to handle high signal counts and allows for extensive customization, ensuring we can simulate any required signal environment. This flexibility ensures we meet the diverse needs of various industries and applications, from aviation and maritime to autonomous vehicles and defense.

Ackermann: Spirent supports all open service GNSS signals and classified GPS testing — including M-Code Regional Military Protection — as well as PRS (through prs[ware] and our partnership with Fraunhofer IIS) on our simulation platforms.

In addition:

• Regional systems (e.g., NavIC or QZSS)
• S-band frequency signals
• Custom non-ICD signals
• LEO PNT (Xona Space System’s PULSAR and others)
• A broad range of interference waveforms, including CW, FM, PM, wideband AWGN, chirp, matched spectrum, etc.
• Generation of RF from I/Q data injection in L-band and S-band frequencies
• Correction/augmentation
• Inertial sensor emulation

Furthermore, the ability to geolocate custom RF beacons either in a range of orbits or in terrestrial locations adds huge signal flexibility.

What are the key challenges you face?

Clark: As our customers’ needs grow and evolve, some of our key challenges have been the ability to continue to evolve our product utilizing cutting-edge technology while still maintaining backwards compatibility with our older technologies. Efforts like this give our customers peace of mind when making a system purchase and enable them to take full advantage of prior purchases when requirements change and system enhancements are necessary.

Perdue: A key challenge is creating complex simulation environments that require specialized expertise. Customers often lack the knowledge to design these environments effectively. Ensuring simulation accuracy and cybersecurity are significant concerns, especially as new threats emerge alongside new technologies developed to combat existing threats. Translating performance requirements into practical specifications and meeting stringent industry standards adds another layer of complexity. We address these challenges through continuous updates and close collaboration with our customers to ensure our solutions meet their evolving needs.

Ackermann: For 40 years, we have faced a challenge that, to some degree, is being addressed. Namely, PNT is not widely standardized and therefore test requirements are highly diverse. The scale of Spirent and the empowering flexibility of our systems enables us to overcome this, but it remains challenging.

The current geopolitical situation also presents challenges, as the number of threats and the potential for negative events demand ever-increasing sophistication in testing. That’s why we built PNT X with high-power jamming and spoofing capability for greater realism and accurate test results.

Crampton: The complexity of next-gen positioning engines means that our systems have to integrate and interact with other systems, built by other companies with other protocols and specifications. Spirent maintains the precision and stability our customers expect from us while incorporating an open and controllable architecture for easier plug-and-play in complex hardware-in-the-loop environments.

M3 SYSTEMS

Please introduce your company.

Tsaturyan: We represent the Mistral Group, which includes three distinct companies: M3 Systems France, M3 Systems Belgium and Boreal. M3 Systems France teams provide GNSS simulation and test and measurements solutions and radionavigation and signal processing expertise. M3 Systems Belgium teams are experts in air traffic management (ATM) studies. Boreal teams offer beyond-line-of-sight missions for maritime surveillance, Earth observation, and scientific experiments with the BOREAL long-range unmanned aircraft. Each company extends its scope to the challenges of GNSS and UTM with an integrated approach.

What are your key markets? What challenges are you addressing?

Our customers are from different industries: we work with space agencies — such as France’s Centre National d’Études Spatiales (CNES) and the European Space Agency (ESA) — private R&D labs and automotive companies and railways. We propose GNSS simulation products such as the Stella GNSS simulator, which allows users to simulate a vehicle in a realistic environment and in real time for low latency. Our simulator is designed to reproduce the sky with high precision. The GNSS signal passes through different layers, each one of which has a different effect. First, there can be an error in the satellite clock, then there can be a delay as the signal passes through the atmosphere, then, on the ground, there is a risk of a spoofing or jamming attack and, in urban areas, multipath from buildings.

What signals does your simulator support?

Our GNSS simulator is multiconstellation and multi-frequency. It supports all the available GNSS signals and frequencies. Users can simulate multiple antennas and multiple trajectories, custom atmosphere and multipath effects. We offer several built-in models of multipath. Users also can use their own multipath models and even integrate it with an SE-NAV multipath simulation tool. We also have several built-in jamming signals that users can apply and spoof the real signal coming from the antenna or spoof the simulated signal. Our setup now also supports Galileo’s Open Service Navigation Message Authentication (OSNMA). Our Stella GNSS simulation software can run on three different products designed for specific needs: the Stella GNSS Simulator Base (based on NI’s USRP kit), the Stella GNSS Simulator Suite (based on our bundle), and the Stella GNSS Simulator Advanced (based on NI’s VST). Our VST-based solution is optimized for tests that require high performance in terms of calibration — such as simulating a CRPA antenna, where the channels need to be very tightly synchronized.

Photo: M3 Systems

What does your Stella Suite do?

The Stella GNSS Simulator offers up to two independent RF simulations, enabling simultaneous simulation and the jamming/spoofing or the simulation of multiple antennas and trajectories.

Our simulator suite is basically an all-in-one device that allows users to plug in a receiver. This single device enables  users to simulate jamming, spoofing, multiple antennas or multiple trajectories.

When did you launch this product?

We released it and demonstrated it during Emerson NI’s “NI Connect” event. They have an annual event in May in Austin, to which they invite all their partners and customers. This year, we were invited there to present our new simulator. We brought a HIL test setup to demonstrate the new configuration of our GNSS simulator: a closed-loop test of a drone autopilot system. When kinematic parameters from the flight simulator are simulated, the trajectory is sent to the Stella GNSS simulator, which then generates the GNSS RF signal and interference to assess the receiver’s performance. The receiver then passes its positioning data to the autopilot, which sends the commands to the flight control unit in the flight simulator. It’s one of the use cases, because to fully test the receiver, in addition to the nominal situation, it is also necessary to introduce some errors — such as interference, jamming, spoofing or meaconing.

What are some other use cases for this simulator?

Another use case is the test of Advanced Driver Assistance Systems (ADAS) in a 3D simulation environment. Basically, it is designed to test any unit that includes the GNSS positioning and to test the receiver’s robustness in case of jamming, spoofing, or meaconing.

Is this all done in the lab or can you put your box in a vehicle?

With this setup, it’s all done in the lab, but we also offer solutions to record the real signals from a UAV or a ground vehicle.

Are the challenges changing? Is the market changing?

Now, a GNSS simulator is no longer sufficient. Testing the receiver’s robustness against various types of attacks, particularly jamming, requires diverse methods. Consequently, there is an emerging need for simulating jamming mitigation antennas, such as Controlled Reception Pattern Antennas (CRPA).

<p>The post Simulating new GNSS signals and threats first appeared on GPS World.</p>

MAPPING

Mobile Mapping System
With integrated inertial labs INS/lidar

The Meridian mobile mapping system integrates the Mosaic X camera with Inertial Labs inertial navigation system (INS) and lidar to improve mapping accuracy.

The Meridian system offers panoramas with a 74 MP native resolution and 13.5 K resolution using precisely synchronized camera modules. The design minimizes image overlap to offer clearer and more consistent panoramas. The integrated INS system has a vertical accuracy of 2 cm to 3 cm and a precision of 2 cm to 4 cm.

It features seamless, out-of-the-box operations with fully integrated and calibrated components. The Meridian system is designed for ease of use and requires only minutes of training. In addition, it features a rugged design to ensure performance in challenging environments.

Mosaic, mosaic51.com

OEM

INS
Combines a GPS master clock with an INS

The Geo-APNT serves applications requiring precise navigation data and an accurate time reference. The Geo-APNT combines a versatile GPS master clock with an INS to
offer assured positioning, navigation and timing (PNT) under all circumstances, including temporary loss of GPS signal. It minimizes size, weight and power (SWaP) due to the integration of positioning and timing that are typically achieved by two independent subsystems.

It can be easily integrated into existing systems and supports RTK and PPK positioning and offers support for MEMS, fiber optic gyro and ring laser gyro inertial measurement units (IMUs). The system also includes GPS antenna and cables.

AEVEX Aerospace, aevex.com

Tactical-Grade IMUs

For unmanned applications

<p>The post Launchpad: Tactical-grade IMUs, Spirent simulator upgrades, atomic clocks and more first appeared on GPS World.</p>

Read more about the BroadSim Duo, Safran’s latest navigation warfare simulator.

Check out the latest news from Safran Federal Systems.

<p>The post JNC 2024: Safran Federal Systems first appeared on GPS World.</p>

When a vehicle passes through a GNSS-denied area, its navigation system might be thrown off and report an incorrect position. Conversely, INS is inherently subject to drift — the steady accumulation of errors — and therefore must be periodically re-initialized by an external source, such as GNSS. (Photo: Safran Federal Systems)

The term “original equipment manufacturer”  (OEM) is widely used, yet vaguely described. In general, an OEM product is one that a company creates and sells to be integrated into systems made by other manufacturers.

In the GNSS industry, the purchasers of OEM products typically are manufacturers of products that require precise positioning or navigation capabilities, from precision agriculture, to surveying and mapping, to UAV missions. Often, manufacturers integrate the OEM GNSS receivers with other sensors, such as inertial measurement units (IMUs) and lidar devices.

A large portion of the OEM business goes unnoticed by the end users of the equipment that utilizes OEM components. These components, such as a guidance system, are often hidden from view, due to being housed under a hood or elsewhere deep within the system.

In the following case studies, OEM products complement GNSS in air, land and marine applications. Safran Federal Systems’ INS for land vehicle navigation and Septentrio’s AIM+ anti-jamming and anti-spoofing technology tackle land and air-based defense applications, while an OxTS IMU is used in a coral reef restoration project to accurately record ship motion.

Land vehicle navigation in GNSS-denied environments
Safran Federal Systems

Ground vehicles in defense operations often navigate in challenging environments where traditional GPS signals are contested or unreliable. This includes dense urban areas, heavily forested regions, or any areas where enemies employ electronic warfare to disrupt GPS signals. Having a robust navigation system that can provide both the vehicle’s location in real time as well as its precise orientation and direction/heading is crucial for defense applications. An inertial navigation system (INS) can provide reliable position and heading data for short periods of time or distances without the aid of GPS satellite signals, allowing vehicles to stay on course and maintain awareness of their location.

Precise location and navigation capabilities are essential for mission planning, execution and coordination with other units. Inaccurate navigation can lead to mission failure, unintended engagements, or even friendly fire incidents.

Geonyx INS

Safran’s Solution

Geonyx INS with incorporated M-Code capability

Safran has developed the Geonyx INS, which provides route guidance in GNSS-denied environments. It incorporates hemispherical resonator gyroscope (HRG) technology and does not rely on external satellite signals for navigation and heading. Instead, it uses gyroscopes to detect changes in heading and accelerometers to detect changes in acceleration, then uses those data to calculate the vehicle’s position, orientation and velocity.

The Geonyx will output coordinates of the vehicle’s current location as well as the data on its intended position to the vehicle’s battle management system (BMS). It can maintain an accuracy of a couple of meters after tens of miles of pure inertial navigation.

Geonyx is a combat-proven INS solution for ground vehicles, augmenting battle management systems. It can achieve a heading accuracy as good as 0.5 mils thanks to Safran’s HRG Crystal technology. It has quick and flexible alignment, even in GNSS-denied environments.

Safran is upgrading the Geonyx to incorporate M-Code capability. This enhancement offers a fully integrated solution to tackle the challenges of GPS-denied or spoofing environments, ensuring robust and reliable navigation even in the most demanding conditions.

JammerTest in Bleik, Andøya, Norway. (Photo: Septentrio)

Resilient GNSS receiver
Septentrio

Around the world, there is an increasing demand for better resilience in positioning, navigation, and timing (PNT) systems. U.S. President Joe Biden has signed an executive order to enhance national resilience through PNT services. Geo-political tensions require a higher level of security for operations in areas of navigational warfare (NAVWAR) under contested GNSS conditions.

In countries such as Finland, companies are seeking reliable receivers that can be connected in a network to identify sources of malicious interference. In numerous GNSS applications, such as reference networks, UAV surveillance, delivery and timing synchronization, the repercussions of PNT degradation or loss can be significant.

Septentrio’s Solution

Septentrio took part in the JammerTest 2023 event organized by the Norwegian government on the remote island of Andøya, where live interference testing was conducted in a controlled environment.

While most of these test events are classified and their results cannot be shared publicly, the JammerTest represents one of the first public events of its kind where the sharing of results is encouraged.

After five days of intensive testing in Norway, Septentrio’s AIM+ anti-jamming and anti-spoofing technology proved to work well under live interference conditions. Test results revealed that under real interference, receiver technology plays a key role, while antenna technology plays a supporting role. By testing the receiver under various types of spoofing attacks, it was shown that the best spoofing protection lies in having multiple anti-spoofing mechanisms working together.

Detecting and Mitigating GNSS Jamming

This test used a “cigarette lighter” jammer, which is commonly available for purchase online. It emits signals with power between 10 dBm and 15 dBm and can disrupt GPS L1 and L2 signals. Other jamming tests involved using jammers with signals 10 million times more powerful than GNSS signals.

Over one day of intensive jamming tests, receivers with integrated AIM+ demonstrated 99.5% positioning availability under various forms of jamming from simple continuous narrow-band interference to the most complex wide-band transmissions.

The Magic is in the Receiver

For mission-critical applications, an anti-jam antenna can help achieve maximum resilience against RF interference. During the JammerTest, three receivers were tested under heavy multi-frequency wideband jamming in combination with antennas of varying sophistication. A receiver with a standard wideband helical antenna that did not have AIM+ anti-jamming technology immediately lost tracking of satellite signals during jamming. A receiver with the same antenna, but with AIM+, continued to track signals and deliver positioning. A receiver with AIM+ coupled with an anti-jam antenna displayed that the drop in signal quality is slightly less than with a standard antenna and the receiver continued to track signals and to deliver positioning.

Tests with various anti-jam antennas showed an interference reduction of about 10 dB. While AIM+ plays a role in positioning availability under jamming, an antenna plays a supporting role and can improve the chances of getting positioning in cases where the jamming is still slightly stronger than the ability of the receiver to mitigate it. While anti-jam antennas can be effective in countering wide-band “white-noise” jamming, they are less effective for other types of jamming.

Accurate and available PNT is key to successful industrial or critical operations in challenging environments. By regularly participating in live events such as the JammerTest, Septentrio anti-jamming and anti-spoofing technology is continuously being tested and improved to withstand the latest interference attacks. This technology also has been confirmed to be effective by users out in the field, who are using Septentrio receivers in places of malicious interference, such as near contested borders.

Photo: Tunatura / iStock / Getty Images Plus / Getty Images

INS Used for Coral Reef Restoration Project
OxTS

The Reef Restoration and Adaptation Program (RRAP) is an effort to help a significant ecosystem such as the Great Barrier Reef (GBR) survive climate change. Through its Cooling and Shading sub-program, RRAP’s goal is to determine whether localized cloud brightening — a technique that involves spraying droplets of sea salt into clouds to reflect sunlight and cool Earth — and/or fogging could be a temporary solution to alleviate stress on parts of the GBR during hot summer conditions, which might lead to bleaching.

The Ordnance Survey team was tasked with consistently creating precisely georeferenced point clouds that could be utilized for identifying and classifying features. The GBR is a significant source of biogenic volatile organic compounds (BVOCs), which are likely to be impacted by ocean warming in potential climate change scenarios. In turn, these BVOC emissions can influence Earth’s radiation budget by contributing to the creation of secondary organic aerosols and cloud condensation nuclei, ultimately leading to cooling.

Southern Cross University, an RRAP partner, sought an accurate method to record ship motion for this project. The team needed to measure various parameters such as velocity, acceleration, pitch/roll, angle rate, and ship heading. They approached Industrial Measurement Solutions (IMS) and OxTS to assist them in addressing this challenge. To achieve this accurately, they needed to integrate the measurements from their existing sonic anemometer, which records three-dimensional wind velocity, with the measurements from an IMU.

OxTS Takes the Challenge

Correcting wind speed for platform motion requires two high-resolution sensors to record data simultaneously: a sonic anemometer that records three-dimensional wind velocity, and an IMU that records the movement of the platform/ship. The sonic anemometer and the IMU are two very sensitive sensors, and many of the technology challenges the team faced involved setting them up correctly and getting them to work seamlessly together.

Once the project team realized that they needed an IMU to measure the ship/platform motion, one of their collaborators at the time, Airborne Research Australia (ARA), suggested an OxTS xNAV650.

After they had defined the project requirements, Southern Cross University contacted IMS who helped them navigate the commercial process.

xNAV650 is a miniature INS that uses survey-grade dual-frequency GNSS receivers and custom MEMS IMU for centimeter-level position accuracy, precise orientation and true heading. It logs the navigation data on internal storage for downloading and viewing post-mission. It can be used in many applications, such as corridor mapping and precision agriculture.

OxTS xNAV650 Inertial Navigation System. (Photo: OxTS)

IMU in Action

The xNAV650’s IMU allowed Southern Cross University to accurately measure the motion of the ship. The IMU was configured to “displace output” to the location of the 3D wind measurement instrument — the sonic anemometer. This allowed the project team to record the movement of the instrument directly, thus avoiding any additional complicated processing steps. Additionally, the IMU was configured to output a 1 pulse per second (PPS) signal via serial connection. This allowed the project team to connect the IMU to the sonic anemometer’s data logger to sync the time between the two instruments. This was vital on such a rapidly moving platform.

Once installed, the xNAV650 device was able to measure ship motion accurately and at high time resolution
(100 Hz), which was complementary to the team’s wind velocity and BVOC measurements. The PPS output option allowed for simultaneous measurement/recording, which would have otherwise needed to be corrected in post-calibration and would likely not have been as accurate.

“We managed to accurately record ship motion for the entire length of our second voyage,” said Liz Deschaseaux, RRAP’s research fellow on BVOC emissions. “The reliability and accuracy of the xNAV650 has had a real impact on our ability to collect meaningful data.”

<p>The post How OEM technology is enhancing precision applications first appeared on GPS World.</p>

Photo: Safran Federal Systems

Safran Federal Systems has launched the BroadSim Duo, its dual-frequency GNSS simulator designed specifically for testing military receivers in an unclassified environment. 

The new product integrates dual-frequency capabilities within a single compact GPS military signal testing unit. The simulator has dual-frequency capability, which is essential for testing P-Code and AES-M-Code. It features a new software-defined radio in an M.2 form factor, offering robust and reliable performance. It also seamlessly integrates with the Skydel simulation environment for improved versatility and functionality. 

<p>The post Safran Federal Systems launches navigation warfare simulator first appeared on GPS World.</p>

The IMUs include Iconyx, a high-performance HRG-based IMU that significantly outperforms legacy technologies, the company says. It offers improved accuracy and reliability for demanding navigation needs. It also features a small tactical IMU (STIM) ideal for applications requiring lower size, weight and power (SWAP). 

The company is also upgrading its Geonyx inertial navigation system (INS), which is based on HRG technology, to incorporate M-Code capability. The fully integrated solution can perform in GPS-denied or spoofing environments, offering reliable navigation in challenging environments. 

Safran Federal Systems unveiled these IMUs at the Joint Navigation Conference (JNC) 2024 in Cincinnati, Ohio. Attendees are invited to visit Safran Federal Systems at Booth A to learn more.  

<p>The post Safran Federal unveils MEMS and HRG technologies first appeared on GPS World.</p>

Attendees are invited to engage in interactive training and hands-on sessions guided by experts for PNT and NAVWAR simulation using Safran Federal’s BroadSim and Skydel software.

Training topics include:

• BroadSim fundamentals, M-Code, and automation
• GNSS jamming and spoofing
• NAVWAR simulation – bringing PNTAX to life
• How to test CRPA antennas

Each attendee will earn a certificate to recognize participation and completion of the training. Click here to learn more and register.

Only available for U.S. citizens.

<p>The post Safran Federal Systems to host simulation training seminar first appeared on GPS World.</p>

What are currently the key challenges for simulation?

One of our big challenges is determining what performance requirements are necessary for our users. Often, they can’t determine what the specs need to be. All they know is that they need it to work. “I need this receiver from one company, this IMU from another company, and the simulator I got from you guys to work together and I need the performance to match reality.” It can be very challenging to say, “What are the requirements for the simulator? How accurate does it need to be? What types of things matter in this integration?”

Often, we’re left trying to figure that out. So, that’s an interesting, maybe unexpected challenge. It’s easy to look at the datasheet and see what some specs are, but it’s a much harder thing to say, “Well, what do you need the specs to be?” So, we’ve been working with our customers to try to nail down some of those specs, particularly with Wavefront. We have some specs on such things as phase alignment and phase stability. But how do you translate that into something like “Well, I just want the CRPA to work the same in the lab as it does in the real world?” There’s not a direct, easy way to do that. We’re in the middle of trying to figure that out. That’s definitely one of our challenges.

What about the increase in jamming and spoofing threats?

In the last five years, we’ve seen a lot more open talk about jamming and spoofing in the world. The receiver manufacturers must think about this a lot more. What’s interesting from a simulator point of view is that this is not actually new for us. We have the advantage that we’ve been designing to program requirements for years and they have included jamming and spoofing for years. So, in a way, simulation is ahead of this state of the world. Jamming and spoofing are not new or hard ideas for us. In fact, spoofing is similar to simulation. So, we already know how to do that.

Image: Safran Federal Systems (formerly Orolia Defense & Security)

However, jamming and spoofing are new to programs and integration labs. So, there might be platforms where they’re now testing against jamming or spoofing requirements where in the past, maybe they didn’t do that. They certainly can use our simulators to help them do that. However, we’re not seeing a lot of new requirements coming to us saying we need new jamming or spoofing capabilities, because we already have them. Luckily, we are future oriented regarding the jamming and spoofing requirements, so those really haven’t been a challenge for us yet.

That can always change, right? If new requirements come up, such as higher data rates or wider bandwidth waveforms or different types of waveforms, then we would have to adapt and add support for that kind of stuff. As of right now, however, we aren’t really seeing that. So, luckily, we’re prepared for that. As for the industry as a whole, there has definitely been a big movement in the last few years to understand the effects of jamming and spoofing. Simulation is a big part of that.

What about the completion of the BeiDou and Galileo constellations?

For a long time, we simulated four constellations. Then that began to get fuzzy. Do you consider SBAS a constellation or is that just an augmentation? Do you count EGNOS and other supplemental constellations for the other constellations? What about NavIC and QZSS? Before you know it, you start to lose track of exactly how many you have. We just released our 8th constellation, Xona.We’re going to be demonstrating it at JNC.

Tell me more about that.

We are trying to have all the constellations and that can be a fuzzy definition. Does that mean all that are up there right now or all that will be up there in the future? We’re trying to be forward looking and add everything that is going to be up there or might be up there so that lab users can develop and test. Multi-constellation simulation is a particularly challenging problem for groups that don’t have simulators. If you’re just doing research on, say, GPS, and want a new code, you might be able to do that in a lab on your own. But as soon as you say, “I want to do research on whether this LEO constellation helps navigation on a receiver that also uses Galileo and GPS,” suddenly, your research requires a full multi-constellation simulation.
There are two choices. One is to have a simulator do the constellations that already exist, and then you have some research to add constellations. That can be very challenging, especially with time alignment and things like that. The other is to have a simulator that can do all the constellations. That would be the easy choice, right? That presents a problem with such things as LEO navigation being on the rise and these constellations that are just emerging, that are still not even fully defined.

So, we’re trying to build those into our simulation products, to help researchers and decision makers determine whether these will be useful features to add to their receivers or their systems. We have the advantage of having a software-defined architecture. We designed the software so that it is easy to add new constellations to it. Basically, once we’re given a proper ICD, we’re only a couple of months away from a first draft implementation of that new signal. Then we iterate. There used to always be a government-driven, multi-year program to develop an ICD. Now, we have this new concept of the signal manufacturers. We’re seeing private companies release signal specs. That’s a very different way of creating a signal in a constellation. So, sometimes you don’t get much time between when the ICD is available and when simulator users want to use that constellation. Having a software-defined architecture really helps us move quickly. We can add such things as Xona very fast.

Xona told me a couple of days ago that they will soon put out an ICD. What’s the difference between actual signals that you can record and play versus something that’s only on paper?

That’s a great point. Probably many people don’t realize, when they first look at this, that what’s in the ICD and what’s on live sky are sometimes very different. Is the simulator supposed to match live sky? Or is it supposed to match the intended final state of the constellation, according to the ICD? This is a huge topic for M-Code, which is ever changing, and has a very large ICD that’s been released. Space Systems Command/Military Communications & Position, Navigation, & Timing (MCPNT) controls the features and releases them incrementally. We’re constantly having to make changes to the simulator to match those releases. The same is true for the other ICDs. At the Institute of Navigation Joint Navigation Conference (JNC), we will demonstrate an expanded PRN. I think this showed up in the ICD a couple of years ago, but it’s not used by any users yet. Some of the receiver manufacturers are starting to look at using PRNs beyond 32. So, we’re adding that to the simulator. This has already happened for BeiDou as well. I think their ICD goes up to more than 60 satellites. It’s an ever-changing race. The ICDs are constantly being updated and we’re trying to update the simulator.

Image: Safran Federal Systems (formerly Orolia Defense & Security)

Meanwhile, live sky is many years behind the paper, right? This creates an interesting challenge: when you design a system, are you designing it for today or for the future? We have users in both groups. We have users that only care about what is happening today, because they need a model. Maybe you want to model a specific mission and you want to make sure that everything’s going to go properly. Or maybe you’re designing a system that you want to release in three or four years, and you want to make sure that it’s going to work with the state of the system then.

A big challenge is to make sure that we’re keeping pace with all these ICDs. There are more constellations than ever and the technology makes it easier to change signal architectures. We’re seeing signals change faster than we’ve ever seen them change before. We go to conferences and hear about such things as on-orbit reprogramming and signals that might even change specs while they’re being transmitted. Maybe they don’t even have to have a fixed bandwidth or fixed bit rate. We’re going to start talking about signals that can reprogram on the fly. That’s going to make simulation more and more challenging. The technology exists to do this.

Software-defined waveforms is a very logical step. In the software world, we have this concept of version nightmare. When you have 20 different pieces of software that are interdependent, it can get very challenging. We’re going to start to see that in simulators. We’re going to see, “Hey, what version of navigation authentication are you using? We updated it six months ago. Are you using the new one or the old one? Which one should we use?” Well, it depends on what your receiver is using. It’s going to be interesting and challenging to keep all this straight in the next few years as things evolve. Certainly, however, our goal is to be there for all of it and to be as fast and as forward thinking as we can for our customers. That means that we also need to know what our customers need. So, we’re always looking for feedback and requests, what challenges our customers face and we’re responding to those requests.

Tell me more about the difference between simulators used by receiver manufacturers in their labs as they’re tweaking receivers or developing new ones vs. simulators used for mission planning.

The simulators are the same, but they’re used in very different ways. In most lab simulation, what the constellation looks like that day doesn’t matter very much. They can just run with a default constellation for a given day. They’ll run that scenario hundreds or thousands of times and never need to change it because they’re testing parts of the receiver that don’t care a whole lot about the specifics of what’s happening.

Whereas missions are time- and location-specific.

Yeah, exactly. They want to know which satellites will be overhead at an exact time and place. It’s not so much a problem anymore, but there used to be certain days and times when you would not get enough satellites in view, or you might have very bad dilution of precision, and your mission might actually fail. We’re past those days. There are now enough satellites up there. Most receivers will navigate within their specs most of the time in most places. However, for critical missions, such as military operations or rocket launches, you might not want to just assume that any day is a good day. So, if you’re about to launch a rocket, you might want to check. “What does the constellation look like right now?” The challenges that brings is that simulators have a default constellation, but the constellations are constantly changing.

When you’re doing real day mission planning, the big problem isn’t so much how to generate a signal, it’s how to find out what’s happening today. That’s really the nature of the problem because what’s out there today is different from what was happening yesterday or what will happen tomorrow. You might have unhealthy satellites. You need to know that if you want to model them. It becomes a big challenge to get all the right data into the simulator. Once all that data is in there, then it’s the same as any other simulation.

Are there good sources for current data on GLONASS, BeiDou and Galileo?

Image: Safran Federal Systems (formerly Orolia Defense & Security)

There are a couple of websites that provide information about where the satellites currently are. However, we’ve found that each one of those sites has its own challenges. Some are maybe 30 minutes out of date, which is pretty good, but puts the satellites in slightly different spots. Some of those sites only support some of the constellations. We’re talking about multiple countries and they don’t all agree on how this should be done. So, there’s not a single point that you can visit to get all the satellite data. There are a couple of companies that try to fix this. U-blox has AssistNow; Qualcomm has an assist for its cellular receivers; Trimble, NovAtel, and a couple of other companies have their error correction services to which you can subscribe to get some of that data.

If you want real-time up-to-date ephemeris for all the constellations, that is challenging. There are one or two options we have found that seem to work, but they each have their disadvantages. Maybe they don’t have all the satellites. Again, we’re talking about versioning issues. So, if you’ve designed your system with a certain version of an ICD and they’ve added more satellites since, those new SVs maybe aren’t so important for your users, so you don’t publish them. Other users want those satellites. So, we see versioning issues in these data streams. For example, we use the CORS network to get a lot of GPS data but that whole network, as far as I know, is only running the legacy data. As far as I know, no network is distributing the L1C modernized data that we will need at some point. So, as we launch new signals and constellations, we need the networks to provide this new data.

What are some other challenges?

For us, being a software-defined simulator on a platform dependent on software-defined radio (SDR), we’re constantly looking at what’s changing in the SDR technology community. There’s always some interesting stuff happening there that we try to incorporate. We don’t have any big announcements this year, as far as new architectures or anything like that. However, the SDR community is evolving. It’s still a rather new industry. A few years ago, we were an early adopter of SDR technology for mass deployment. Now, we’re seeing some more mature SDRs starting to push such things as channel count and coherency. We will probably take advantage of that in the future.

The other interesting thing technology-wise is that we’re also a GPU-dependent technology. So, as the GPU industry continues to evolve and makes bigger and faster GPUs, we get a relatively low-cost way to upgrade. We don’t have to do a lot of R&D to upgrade to a new GPU. For our users that means that the number of signals they can generate on their simulators is always increasing even using the same hardware from one generation to the next. Our first simulator did 75 signals; the next version did 150. We could build a system that did more than 1,000 signals, but our users don’t need it.

I assume that the growth curve for GPUs is steeper than that for signals.

I think that you’re right about that. I’m sure glad they do, because then something like Xona shows up and we don’t have to rearchitect our system to generate 300 signals, right? At JNC we will show expanded PRN, 300 Xona satellites in the constellation, and a 10 fold improvement on Wavefront performance specs.. We will continue to build simulators that meet our customers’ requirements. Besides GPUs, a lot of the technology involves software R&D and signals. The stuff that we do digitally inside of our system that allows us to do things like extremely precise phase alignment on Wavefront, for example. We spent a lot of time developing that stuff.

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