Back-End Safety Processor: magicGNSS Back-End SAFEty

Last Updated: 22/04/2024 15:13     Created at: 22/04/2024 08:50

Final presentation of NAVISP Project EL2-074 now available: 

On Thursday, April 18th, 2024, GMV presented the results of the NAVISP EL2-074 project " magicGNSS Back-End SAFEty". Over 50 people from industry and research institutes followed the interesting presentation and the subsequent interactive Q&A session. 

High-precision solutions are increasingly favoured for modern positioning applications, with potential for advancing safety and reliability in critical domains. Identified market segments, such as autonomous vehicles, rail, maritime, agriculture, timing, and space users, demonstrate a strong demand for GNSS (Global Navigation Satellite System) services offering high accuracy and integrity.  In this context, the development of a PPP (Precise Point Positioning) Safety processor, which adds an extra layer of integrity to PPP corrections, is considered as highly beneficial for GNSS users.

Therefore, the project aimed to design, develop, and validate magicBESAFE, a Back-End Safety Processor element adding an extra layer of integrity over the PPP corrections generated by the PPP Server (Corrections Processor). The magicBESAFE processor computes error bounds and usability associated with PPP corrections within the Correction Service, ensuring compliance with safety requirements. It processes various PPP corrections, including satellite orbits, ionosphere, and biases, generating messages containing corrections and integrity data for transmission to users. These messages not only include precise positioning data but also incorporate integrity information necessary for safe and reliable operation.

More specifically, the high-level architecture of the magicBESAFE processor involves interfacing with two networks of stations through separate instances of the Corrections Processor. One network provides corrections for validation, while the other offers independent validation data, ensuring data integrity. The Operator is responsible for configuring and commanding the magicBESAFE, establishing operational protocols, particularly in automotive applications. At the core of the processor are the Integrity Monitors, which receive configuration and data, generating internal Integrity Data, subsequently converted into Integrity Messages for transmission to end-users.

Throughout the project, automotive and railway needs were central to the product development. These included high accuracy (centimetres) and high integrity to minimize risk, particularly to high level autonomous driving. Key concepts introduced within the project include:

  • Protection Level: This parameter defines the upper confidence bounds of positioning error relative to a specified Integrity Risk.
  • Integrity Risk: It represents the probability that the actual positioning error exceeds the associated Protection Level.
  • Alert Limit: The maximum allowable error threshold for ensuring the safety of applications relying on GNSS positioning solutions. This parameter is critical for safety-critical operations and desirable for non-safety applications.

The magicBESAFE Safety Processor successfully ensured the safety of corrections across all areas within the service region while maintaining availability. Furthermore, the magicBESAFE monitors underwent rigorous testing under fault-tree and faulty scenarios, proving their effectiveness in ensuring system integrity. The safety validation process confirmed that all defined integrity requirements were met, and the integration test campaign showcased the performance of magicBESAFE in urban and semi-urban environments. Future endeavours are focusing on incorporating multi-frequency usage and processing additional GNSS constellations to enhance solution availability.

This project was carried out in the scope of NAVISP Element 2, which supports the development of novel and innovative products and services aiming to maintain and improve the capabilities and competitiveness of the participating States' industry in the global market for PNT technologies and services.   

 

More detailed information can be found in the slides of the Final Presentation