Introducing the Rokubun Galileo OSNMA Library: A cutting-edge solution for secure navigation. Tailored specifically for embedded platforms, this compact and reliable library guarantees seamless integration and cross-platform support.

Exciting news from Rokubun on secure navigation. We introduce the Rokubun Galileo Open Service Navigation Message Authentication (OSNMA) Library, the ultimate solution for decoding and processing Galileo OSNMA for embedded platforms. Here’s what sets it apart:

  • Perfect Fit for Embedded and Automotive: Engineered in C with meticulous attention to MISRA compliance, Rokubun’s OSNMA Library has been optimized for embedded and automotive platforms, ensuring seamless integration and reliable performance.
  • Small Footprint, Big Advantages: Maximize your platform's potential. Rokubun’s Galileo OSNMA library is just 60 KB of code, needs only 15 KB of RAM, and does not rely on dynamic memory.
  • Cross-Platform Support and Easy Integration: Say goodbye to compatibility concerns. Our OSNMA library is designed to be architecture and OS agnostic, allowing for smooth integration across various platforms.
  • Fits every build system: Compiled with a toolchain for your architecture, and packaged as a single static library and header file, adding the library to any project is a matter of minutes.

Use Cases for enhanced navigation security

Are you seeking robust authenticated navigation information in your application? Can you trust navigation information provided by the GNSS receiver in your navigation solution so that this data can be further used for billing in demand-responsive transport or surveillance applications? Should you want to have an extra trust on the authenticity of the navigation data in your application, Rokubun OSNMA Library is your solution. Add our OSNMA library in your embedded project in order to enable the use of Galileo OSNMA authenticated navigation.

In safety and security-focused sectors like UAV Traffic Management, or cadastral surveying, the risks of spoofing pose significant threats with legal and economic implications. Let’s see some use cases:

  1. Demand-Responsive Transport: New mobility paradigms, which tailor the pricing of each user according to their trajectory, are in need of trusted navigation information for operations
  2. Cadastral surveying: Precise GNSS positioning is essential for determining land coordinates play a pivotal role in taxation purposes. By leveraging OSNMA's trust-building capabilities, industries like cadastral surveying can enhance operational efficiency and scalability while ensuring authenticity.
  3. Digital Tachograph: Freight vehicles record their positions throughout the day to support road enforcers. In regulated applications, the use of authenticated GNSS and OSNMA becomes compulsory to prevent self-spoofing, ensuring reliable data for enforcement purposes.
  4. Insurance telematics: Pay-as-you-go insurance plans face the risk of vehicle owners using spoofing devices to manipulate covered distances and pay reduced premiums. Preventing self-spoofing is crucial to avoid negative economic implications and increase the credibility of operations.
  5. E-tolling and Road charging: Accurate positioning is vital for identifying chargeable journeys and calculating toll charges based on actual distance traveled. Falsified positions pose a liability to the application, emphasizing the need for OSNMA service to ensure data integrity.
  6. Maritime surveillance. OSNMA service can be used to detect vessels engaging in illegal fishing outside the regional borders, as proofed in our OSNMA demonstration for drone surveillance with EUSPA.
OSNMA use cases

Implementing Rokubun OSNMA Library

The OSNMA library project has been organized  to be as portable as possible, requiring only a working ASM and C compiler that supports ISO C99. Clean interface design ensures easy and fast integration.

In most GNSS solutions, both commercial-grade receivers like the U-Blox ZED/NEO, and survey grade receivers like the Septentrio Mosaic X-5, AsteRx series or the Novatel PwrPak, output the “raw” navigation message bits using proprietary messages / protocols. Alternatively, if the receiver supports it, the non-standard RTCM3 4075 (navigation data frame) message can be used to obtain these “raw” navigation message bits.

In order to decode the OSNMA information contained in the navigation message, the user only needs to enable the corresponding message in their receiver and forward the payload of the message with minimal to none modifications to the library.

To ensure optimal performance and validate user-specific enhancements, such as the utilization of cryptographic accelerators or other SoC/MCU specific resources, we have implemented a state-of-the-art hardware-in-the-loop (HIL) continuous integration/continuous deployment setup. This setup continuously tests the library against several reference MCU targets, assessing its performance and guaranteeing its reliability.

Demonstration on Embedded Platforms

To showcase the seamless performance and robust capabilities of our OSNMA library in embedded platforms, we have developed a testbed. The testbed consists of two key components:

  1. Host Computer: The host computer plays a crucial role in this setup by streaming Galileo navigation messages using a serial interface (UART). This could be easily replaced by a GNSS chipset evaluation board able to stream Galileo Navigation messages.
  2. Embedded Platform: Loaded with our OSNMA library, the embedded platform receives the navigation messages from the host computer via the serial interface. It then decodes the OSNMA data and authenticates the navigation data transmitted by the Galileo satellites.

The figure below illustrates the configuration used for this demonstration. An evaluation board , with an STM32F4 series MCU, is connected to the host computer through the ST-LINK UART, and runs a firmware linked with the OSNMA library. The outcome of the library’s operation is displayed on  the LCD connected to the MCU, as shown in the figure below.

In order to integrate the OSNMA library into an STM32 firmware project, the library was first compiled with gcc-arm-none, and then added to a CubeIDE project as an external artifact (.a) and a header file (.h). The host computer acts as a remote control, issuing commands to the MCU (ex. process nav bits from E21), the MCU interacts with the OSNMA library and then returns a response to the host computer.

Each response includes Key Parameter Indicators, such as elapsed clock cycles of function calls and CPU speed. These indicators provide valuable information for benchmarking and code profiling, enabling us to assess the performance of the OSNMA library effectively.

It's worth highlighting that Rokubun's OSNMA library has been successfully cross-compiled and tested for various CPU architectures. Our testing has confirmed its compatibility with X86, ARM Cortex-A (ARMv7-A), ARM Cortex-M, and Xtensa LX7 architectures. This ensures its versatility across a wide range of platforms.

Rokubun's ready-to-use OSNMA library

Rokubun has developed and demonstrated a ready-to-use OSNMA library with which to enable Galileo OSNMA service in your GNSS solutions to deliver trusted navigation and positioning information.

Our OSNMA client is a cross-platform, small-footprint library meticulously crafted for embedded solutions.  It has undergone extensive testing using official EUSPA test vectors, and our OSNMA algorithms have been validated in real conditions at the European Comission’s Galileo testing facilities at the Joint Research Center in Italy.

In conclusion, we have successfully built and packaged the Rokubun OSNMA library and seamlessly integrated it into various embedded projects. It’s now ready for you to empower your navigation solutions with authentication.

If you are interested in the OSNMA library and would like to learn more, please reach out to us at We are excited to discuss the possibilities with you!


We would like to express our gratitude to the personnel of the European Commission's Galileo testing facilities at the Unit for Technologies for Space, Security and Connectivity (Galileo sector), at the Joint Research Center in Ispra, Italy. Their expertise and support were invaluable in validating our OSNMA algorithms under real conditions. The work resulting in this article was partially funded by the European Union Agency for the Space Programme under grant agreement No GSA/GRANT/04/2019/BANSHEE.


Rokubun is a deep-tech company that develops innovative navigation technologies, oriented to fulfilling a new demand for ubiquitous, accurate, and scalable geolocation technologies.