The small-form-factor Galileo OS (Open Service) or PRS (Public Regulated Service) sensors are designed to enhanced GNSS receivers and resilient multi-sensor navigation systems, ensuring safer and more reliable satellite-based navigation.
The Galileo PRS core module integrates a certified, single-chip, application-specific integrated circuit (ASIC) security module that incorporates all the necessary Galileo PRS security and navigation functions. It provides dual-frequency (E1/E6) iono-free Galileo PRS positioning, velocity and timing services. It also provides pseudorange and delta pseudorange raw data, along with GPS C/A (coarse acquisition).
The low-SWaP (size, weight and power) digital solution has been designed to work with any European GNSS receiver manufacturer seeking a standardized, easy-to-integrate Galileo module with which to develop their own GNSS receivers.
Credit: Thales
The modules can meet the requirements of a wide range of applications for manned or unmanned vehicles, combat aircraft, helicopters, high-dynamic missiles, and the navy. Their small form factor also makes them suitable for platforms with size constraints, such as ground vehicles, small drones and guided munitions.
The modules feature standardized interfaces, enabling the Galileo PRS function to be easily integrated into the host system. Furthermore, the TopStar Galileo core module can be embedded with minimum impact by using the analog RF front end of the host receiver.
The Galileo OS core module version enables the early integration of Galileo functionalities into the host system, as well as export to countries not authorized to use PRS. The PRS core module version provides an easy upgrade to Public Regulated Service capability, offering greater resilience against jamming and crucial protection against spoofing.
The European Union Agency for the Space Program (EUSPA), in collaboration with the European Commission, has published a new version of the Galileo Open Service Signal in Space Interface Control Document (OS SIS ICD).
The latest version, denoted v2.1, introduces new elements supporting the improvement and enlargement of the Galileo service portfolio. OS SIS ICD v2.1 is available along with a corresponding new version of the OS Service Definition Document (OS SDD).
New elements in v2.1 include the definition of OS Extended Operation Mode (EOM) and criteria for identifying when it is activated; description of a new ARAIM Integrity Support Message (ISM), and a new annex detailing a numerical example for the computation of its 32-bit checksum; and a new annex detailing the Galileo PRN Codes Assignment process, including codes belonging to the families E1 B, E1 C, E6 B, E6 C, E5a I, E5a Q, E5b I, E5b Q are now available.
The annex dealing with the authorization of Galileo trademarks, now obsolete, has been removed.
The Galileo OS SIS ICD provides the information required by receiver and chipset manufacturers, application developers and service providers to process the open service signals generated by Galileo satellites. It specifies Galileo signal characteristics; characteristics of Galileo spreading codes; Galileo message structure and data contents; and OS Signal in Space flags.
OS SIS ICD v2.1 pertains to receiver technology developers. The availability of adapted receivers is a key requirement for translating the full range of Galileo signals into useful services, according to EUSPA. The agency added it has been engaged in regular dialogue with advanced chipset and receiver manufacturers, working to see Galileo fully integrated into the latest generation of receivers.
The previous OS SIS ICD, version 2.0, was published by the European Commission in January 2021. In the modification of the ICD, the principle of backward compatibility for Galileo receivers has, as always, been applied.
The Galileo Open Service has been upgraded with three features added to its I/NAV message, one of the four message types broadcast by Galileo satellites. These features are now available to all Galileo Open Service users.
The process of upgrading the Galileo Full Operational Capability constellation satellites has been finalized and the I/NAV improvements are openly accessible through the I/NAV message carried by the E1-B signal. If users have experienced delays when turning on a GNSS device, the recent I/NAV improvements may reduce them significantly, reported the European Union Agency for the Space Programme (EUSPA).
The I/NAV message is now faster and offers more robust positioning. The Reed Solomon Outer Forward Error Correction (RS FEC2) increases demodulation robustness, which enhances the sensitivity. It also improves the overall time to retrieve clock and ephemeris data (time to CED) with the broadcasting of additional, redundant CED information while allowing for the device to restore potentially corrupted data autonomously.
The Reduced CED (RedCED) enables fast initial positioning, with lower than nominal accuracy, by decoding a single I/NAV word, while waiting to receive the four I/NAV words carrying the full-precision CED.
The combination of RS FEC2 and RedCED enables I/NAV to obtain a first course position solution faster and to reduce the time required to obtain a first full accuracy solution (RS FEC2). This translates into a reduced time to first fix (TTFF) for the Open Service users, particularly when operating in harsh environments.
Additionally, the improvements benefit applications working in assisted GNSS (A-GNSS) mode, through the Secondary Synchronisation Pattern (SSP). In A-GNSS mode, when navigation data is received from non-GNSS channels and the receiver’s knowledge of the Galileo System Time is affected by a relatively large error, typically in the order of a few seconds, the clock uncertainty must be resolved quickly and stably.
With the I/NAV improvements, receivers will be able to do this via the new SSP feature, thus reducing the TTFF, also in A-GNSS mode.
While the I/NAV improvements are fully operational, EUSPA will launch a testing campaign open to receiver manufacturers, that will consist of several testing windows. The tests will allow the participants to have a confirmation of the correct implementation of the OS SIS ICD 2.0 — i.e., the right processing of the three I/NAV improvements in their products.
The tests will be conducted at the laboratories of the European Commission’s Joint Research Centre in Ispra, Italy, and of the European Space Agency ESA/ESTEC in Noordwijk, The Netherlands.
EUSPA will assign each applicant to one of the two laboratories depending on the specific conditions and availability.
The high-accuracy service (HAS) offered by Galileo is now available and provides sub-meter accuracy over most of the globe. It will help enable emerging technologies such as UAVs and autonomous vehicles, which require stringent levels of accuracy for better navigation, safety and efficient traffic management.
Other industries expected to benefit include transportation, agriculture, geodesy and entertainment.
Thierry Breton, European commissioner for Internal Market, announced that the service was now live during the annual European Space Conference in Brussels, Belgium, on Jan. 24.
The European Union Agency for the Space Programme (EUSPA) developed Galileo HAS along with the European Commission and the European Space Agency (ESA). The new service will become a pillar of government programs such as EU sectorial policies and national policies by EU Member States.
“This new service has been made possible thanks to the outstanding cooperation and team commitment of all involved partners,” said Rodrigo da Costa, EUSPA executive director.
“Galileo is not standing still,” said Javier Benedicto, ESA director of navigation. “This new High Accuracy Service offers a new dimension of precision to everyone who needs it, while the Open Service Navigation Message Authentication — already available — allows users to authenticate Galileo signals as they make use of it, to minimize any risk of spoofing. An upgraded integrity message of the signal rolled out last year reduces the time to first fix while enhancing the overall robustness of Galileo.”
Galileo HAS delivers horizontal accuracy down to 20 cm and vertical accuracy of 40 cm in nominal use conditions, according to ESA. The service is transmitted directly via the Galileo signal in space (E6-B) and through the internet.
With HAS, Galileo becomes the first constellation worldwide able to provide a high-accuracy service globally and directly through the signal in space.
The service is freely accessible to all users with a receiver capable of processing the HAS corrections broadcast in the E6-B signal and via the internet. The precise corrections provided by Galileo HAS will allow users to reduce the error associated with the orbit and clocks provided through the Galileo Open Service broadcast navigation messages and the GPS Standard Positioning Service navigation data.
“With the Galileo HAS we are ready to unleash the full potential of new technologies such as drones and bring autonomous driving closer to reality,’’ da Costa said. “At EUSPA, our role is to link space to user needs. With the launch of this new service, we met a clear market demand for accurate, robust, and reliable navigation.”
To bridge the gap between chipset and receiver manufacturers and GNSS simulator manufacturers, EUSPA, together with the European Commission and the Joint Research Centre (JRC), is organizing a GNSS Signal Simulator Manufacturers Forum on December 13.
The online forum will aim to help signal simulator manufacturers keep their products up to date by presenting the latest service interface control documents (ICDs), including those for the Galileo Open Service Navigation Message Authentication, the Galileo High Accuracy Service and for the I/NAV improvements. The forum will also serve as a channel for addressing GNSS signal simulator manufacturers’ needs, questions, and concerns.
Manufacturers use ICDs to access information provided from a GNSS satellite’s Signal in Space (SiS) or from such terrestrial means as the internet. However, before a manufacturer can turn this information into a new product or service, they must first test it – which is where GNSS simulators come into play.
Signal simulators play a critical role within the GNSS product pipeline. Chipset and receiver manufacturers have rapidly evolving needs. In order to keep up, GNSS signal simulators must be regularly updated. To do this, however, simulator manufacturers must know what those needs are.
“Whether it be a personal navigation system or smart watch, before a device or application that relies on GNSS signals hits the market manufacturers need to ensure it works,” says Fiammetta Diani, Head of Market, Downstream and Innovation at EUSPA. “GNSS simulators allow manufacturers to test the accuracy of their receivers by simulating such real-world factors as vehicle and satellite motion, signal characteristics and atmospheric effects.”
In addition to being a source of market intelligence, EUSPA offers the downstream market a range of funding opportunities, including the Fundamental Elements scheme. Part of EUSPA’s market uptake strategy, Fundamental Elements is an EU R&D funding mechanism supporting the development of EGNSS-enabled chipsets, receivers and antennas.
Interested parties can register for the GNSS Signal Simulator Manufacturers Forum by emailing [email protected]. The deadline for registration is December 8.
The companies will combine their experience to guarantee robust and reliable navigation thanks to the Galileo constellation
The OSNMA scheme. (Image: ESA)
UAV Navigation is participating in the OSNMAplus project consortium led by Qascom, an Italian enterprise in the domain of GNSS authentication.
The OSNMAplus project aims to develop services and technologies that make use of novel services provided by Galileo, particularly use of OSNMA and I/NAV improvements.
The OSNMA service is a data authentication function for Galileo Open Service users worldwide, freely accessible to all. OSNMA provides receivers with the assurance that the received Galileo navigation message is coming from the system itself and has not been modified. The I/NAV improvements are part of a recently released update of the Galileo Interface Control Document, aiming at optimizing the navigation performance of Galileo even further.
“With the OSNMAplus project, we’re providing technological solutions that will facilitate the adoption of OSNMA in new and existing navigation systems,” said Carlo Sarto, OSNMAplus project manager. “We’re also providing cloud-based services and multiplatform SDK that can be used in consumer devices to improve the OSNMA experience and increase the robustness of the navigation solution.”
The OSNMAplus technologies will be subject to an extensive test campaign. The OSNMA-based navigation will be tested in a flying drone to assess effective resilience against potential malicious GNSS interference.
The Galileo Open Service Definition Document (OS SDD) was updated to reflect upgrades in the Galileo system since the publication of the previous version in May 2019. The latest version, 1.2, can be found on the GSC web portal.
This is the last update foreseen before Galileo Open Service reaches Full Operational Capability (FOC).
The SDD has been updated to include improvements of the Open Service, accounting for the current constellation and updates in the ground infrastructure that increase its robustness.
The updated SDD provides better minimum performance levels (MPLs) for signal and position availability and updated definitions of some timing MPLs. It also establishes a more stringent commitment on the time to publish Notice Advisories to Galileo Users (NAGUs). In addition, the concept of auxiliary satellites has been added, while some sections have been reworded to improve clarity.
SimOSNMA provides vital test tools for Galileo’s emerging end-to-end security protocol
Spirent Communications plc and Qascom have announced 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.
The GSS9000 test system. (Photo: Spirent)
SimOSNMA provides developers with 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 the data received is authentic and has not been modified in any way. It is now completing the test phase before its formal launch.
SimOSNMA enables developers to simulate and test OSNMA signals and features, allowing GNSS receiver manufacturers and application developers to accelerate and assure development programs.
Qascom has been a significant contributor to the development of Galileo OSNMA. The company helped create the main test vectors for early testing and led the Position Authenticated Tachograph for OSNMA Launch (PATROL) project, which is the European Union Agency for the Space Program (EUSPA) procurement looking at the implementation of OSNMA into automotive and mass-market GNSS receivers.
“During the development of the first OSNMA receiver prototype, we needed a tool that would allow us to run tests in a controlled and repeatable environment, generate reference data, test corner cases and system events that seldomly occur in reality,” said Carlo Sarto, head of Security Engineering Domain Area. Qascom. “SimOSNMA will allow industries and agencies to speed up the development and qualification of their systems.”
Since the inception of the Galileo project, Spirent has provided crucial simulation and test capabilities to many of the key organizations and projects responsible for development of the European Space Agency (ESA) program.
SimOSNMA is available now for Spirent GSS7000 and GSS9000 platforms.
The European Space Agency has selected GMV to supply the radio-frequency constellation simulator (RFCS) for the Galileo second generation (G2G) program.
According to GMV, this is the multinational’s largest contract in Portugal.
From Portugal, GMV will lead a consortium to supply an RFCS covering both the first and second Galileo generations. The Galileo first generation (G1G), running since December 2016, consists of space infrastructure (26 satellites to date) and ground infrastructure.
Under the G2G RFCS contract, GMV teams in Portugal and Spain — partnering with Orolia and Tecobit — will develop an RFCS covering both Galileo generations as well as Galileo Open Service and Public Regulated Service (PRS). The RFCS will simulate the progressive deployment of the G2G with its new signals and will be key to supporting development of G2G infrastructure and testing of experimental user receivers.
The G2G aims to phase in new services, improve existing services, and boost system robustness. It also will enhance security while cutting operating and maintenance costs.
The RFCS will cover user characteristics such as dynamic behavior, signal impairments such as multipath and interference but also solution hybridization (for example, inertial sensors) and signal distortions. It will be designed to guarantee flexibility, configurability, modularity and scalability, as well as segregation of need-to-know information. For this purpose, the RFCS will be built with consumer-off-the-shelf products and follow a software-defined radio approach.
The project is closely linked with other PRS activities within GMV, identified as strategic for the maintenance of GMV’s European leadership position in the Galileo program.
OSNMA (Open Service Navigation Message Authentication) offers end-to-end authentication on a civilian signal, protecting receivers from spoofing attacks.
OSNMA is being pioneered by the Galileo Program, with Septentrio providing a testbed for this technology from the end-user point of view. The anti-spoofing capabilities of OSNMA will complement Septentrio’s already available anti-jamming technology, AIM+, and further strengthen the overall security of Septentrio GNSS receivers.
“The authentication of the Galileo signal using the OSNMA technology is yet another first that we are pleased to share with our close partner ESA [European Space Agency],” commented Bruno Bougard, R&D director at Septentrio. “Septentrio is proud and thankful to be able to contribute to the realization of one of Galileo’s key differentiators. “
With OSNMA, Galileo is the first satellite system to introduce an anti-spoofing service directly on a civil GNSS signal.
OSNMA is a free service on the Galileo E1 frequency. It enables authentication of the navigation data on Galileo and even GPS satellites. Such navigation data carries information about satellite location — if altered, it will result in wrong receiver positioning computation.
While currently in development, OSNMA is planned to become publicly available in the near future. GPS is experimenting with satellite-based anti-spoofing for civil users with its Chimera authentication system.
Within the scope of the FANTASTIC project led by GSA, OSNMA anti-spoofing protection was implemented on a Septentrio receiver.
“Septentrio is committed to providing highly accurate and secure positioning and timing solutions to industrial applications and critical infrastructure. This is another example where Septentrio demonstrates its leadership in end-to-end GNSS receiver security with its breakthrough anti-jamming and anti-spoofing technology,” said François Freulon, head of Product Management at Septentrio. “Thanks to our future proof products, we will be rolling out OSNMA in our portfolio as soon as it is available. This will further enhance the security of our receivers, ensuring robust, trustworthy and reliable operation even in the most challenging environments.”
European Galileo satellites provide an open authentication service on the E1 signal and a commercial authentication service on the E6 signal. (Image: European Space Agency)
ESA and GSA (European GNSS Agency) have now commenced the testing phase of the OSNMA authentication, which will continue during the coming months. To find out more about spoofing and OSNMA, see this article. For more information about GNSS signals and the value they bring, see Septentrio’s free webinar More GNSS signals: What’s in it for you?
New Galileo OS SIS ICD V2.0 is now fully supported by IFEN’s NCS Nova GNSS simulator
Photo: IFEN
IFEN GmbH, a manufacturer of GNSS navigation test products and services, announced that its NCS Nova GNSS simulator now fully supports the simulation of Galileo Open Service (OS) signal improvements based on the new Galileo OS SIS ICD V2.0.
The NCS Nova GNSS simulator is a high-end, powerful and easy-to-use satellite navigation testing and R&D device. It is fully capable of multi-constellation and multi-frequency simulations for a wide range of GNSS applications. It provides multiple GNSS frequencies in one box.
A key enhancement to the NCS Nova GNSS simulator is comprehensive support of new Galileo OS signal message improvements on E1B. By enabling real-time simulation of the Galileo OS message improvements, the NCS Nova GNSS Simulator expands the user’s Galileo signal capability.
The NCS Nova GNSS simulator will, in future, also fully support the new Galileo E1B OS-Navigation Message Authentication (OS-NMA) and Galileo E6B High Accuracy Service (HAS) capabilities.
The GNSS simulator enhancements were developed through ESA’s Navigation Innovation and Support Programme (NAIVSP) Element 2, within the project STX2G.
“Through a simple software update, NCS Nova GNSS Simulator customers can automatically generate the new Galileo signal capabilities,” said Günter Heinrichs, head of Client Solutions at IFEN. “Adding Galileo OS signal improvement support to our NCS Nova GNSS simulator comes at the perfect time given the recent release of the Galileo OS SIS ICD V2.0 specification.”
By Fabio Dovis, A. Minetto, A. Nardin, Politecnico di Torino Department of Electronics and Telecommunications, E. Falletti, D. Margaria, M. Nicola, M. Vannucchi, LINKS foundation
Following the issue by the Galileo Service Center of the Notice Advisory to Galileo Users (NAGU) reporting Service Outage for all the Galileo satellites, as curious Galileo users our team of researchers of the NavSAS group started an independent investigation of the received signals in space (SISs).
In fact, we observed that a commercial ublox EVK-M8T receiver, forced to use Galileo-only satellites, provided a “no-fix” indication. Three Galileo-enabled smartphones, the Xiaomi MI 8, Huawei P 10 and Samsung Galaxy S8, which use assistance from the cellular network, were also not providing a Galileo-based position solution, considering the Galileo satellites as “not usable.”
However, the investigation started exploiting our in-house developed software receiver NGene, that was used in the past for similar monitoring of the GNSS signals, for example at the time of the transmission of the first IOV Galileo satellites in 2012, and the transmission of anomalous GPS signals from SVN49 in 2009. Monitoring the Galileo SISs, which were usable until the day before, we found that they were still correctly trackable, with normal power levels and Doppler profiles within feasible limits.
At the time of the first analysis, seven satellites were visible in the sky over Torino, Italy. Figure 1 reports a screenshot of the positions computed by means of NGene between 07:14:54 and 07:24:54 UTC on July 15, plotted on Google Earth. The position estimated using the Galileo-only satellite or hybrid GPS-Galileo solutions (red dots) showed errors on the order of 500 meters or even more. The georeferenced antenna position is depicted by the green pin.
Figure 1. Misplaced Galileo and GPS+Galileo solutions. (Screenshot: Politecnico di Torino and LINKS Foundation)
The monitoring of the status flags taken from the Galileo E1B I/NAV message showed that the SIS was marked as “healthy” for all the visible PRNs apart the number 14, which is known to be “not usable” for a long time. The Signal in Space Accuracy Index (SISA) was set to 109, which is an acceptable prediction of the minimum standard deviation of an overbound of the SIS error.
According to the Galileo Open Service, Service Definition Document (OS SDD, issued 1.1, May 2019), a SIS “Healthy” means that the SIS is expected to meet the Minimum Performance Level and “a navigation solution obtained with Galileo SIS is expected to meet the Minimum Performance Levels reported in the Galileo OS SDD only if receivers comply with the assumptions reported in Section 2.4, including the use of navigation parameters within their broadcast period.”
In fact, the document specifies that “The navigation solution is expected to meet the Minimum Performance Levels only if receivers do not use navigation parameters beyond their broadcast period. The maximum nominal broadcast period of a healthy navigation message data set is currently 4 hours.”
The check of the nominal broadcast period was bypassed in our software receiver, which is indented as a research tool and not a commercial product as the one mentioned above, so that we were still able to obtain a GPS + Galileo PVT solution, since this check looked to be the only discrimination factor to validate and thus exclude the computed solution.
On July 17, the SISA flag was changed to 255: according to the OS SDD, the accuracy status was “No Accuracy Prediction Available (NAPA).” This means that the status of the broadcast SIS must be intended as “Marginal.” In this condition the EVK-M8T restarted to provide Galileo-based fixes, while the Xiaomi Mi8 Pro smartphone still excluded the Galileo satellites from its PVT fix.
The analysis of the decoded Galileo navigation message led to the conclusion that ephemerides and clock correction data were last updated around 19:00 UTC of 1July 16. For example, PRN 3 and 15 changed Issue Of Data (IOD) from 958 to 17 at Galileo Signal Time TOW 241855, which corresponds to 19:01:25.
As a final check, we used external ephemerides to process the Galileo signals during the “system outage.” Figure 2 and Figure 3 show different navigation solutions obtained by processing a data collection taken on July 12 at 10.00 UTC (12.00 Local time). The purple dots indicate few fixes obtained by demodulating the navigation message transmitted by the Galileo satellites and show a remarkable bias with regard to the reference antenna location.
Figure 2. Comparison of Galileo-only solutions using Navigation message ephemeris data and IGS ephemeris. (Image: Politecnico di Torino and LINKS Foundation)
Figure 3. Zoom on the Galileo-only positions obtained by using IGS data.(Image: Politecnico di Torino and LINKS Foundation)
In Figure 3, the green dots are the navigation solution obtained correcting the satellites positions according to precise orbits data and clock drift provided by the IGS network. The fix is a simple code based Least Mean Square solution without smoothing of the pseudoranges.
The two results were obtained by processing the same satellites signals, thus proving that their quality was still sufficient to get an acceptable positioning solution during the Galileo service outage period. This brought us to the conclusion that, during the outage, only the ephemerides updates were affected by problems, while the other SIS components appeared sound and usable.
