Navigation System Integrity Assurance for Safety-Critical Autonomous Operations

Development of autonomous capabilities across safety-critical applications such as autonomous operation of unmanned cars, surface vessels (e.g. unmanned passenger ferries) and aerial vehicles (e.g. air-taxies and air ambulances) is increasing the demand for navigation system integrity and accuracy. To ensure safe operation of safety-critical autonomous systems, integrity i.e. detecting and alerting if a system has failed to meet the required accuracy, is the most critical and challenging performance parameter to meet. Although the process of requirements definition for autonomous systems/operations is still on-going, it can be anticipated that navigation system performance at cm to dm level accuracy with very stringent integrity error bounds will be a prerequisite. While this accuracy requirement can potentially be met by Network-RTK or PPP-RTK techniques, the expected integrity level can currently be supported only by space and ground based GNSS augmentation systems (SBAS and GBAS) designed mainly for the aviation sector. At the current moment, none of the existing systems/technologies available is capable to support such stringent integrity and accuracy requirements at the same time. The objective of the NSIA project is to investigate the feasibility of high integrity support by a high precision terrestrial GNSS augmentation system (NRTK/PPP-RTK) to enable safety-critical autonomous operations. So far, the project has been focusing on the following tasks: - Identification of the existing/anticipated user requirements for autonomous navigation system performance in different transportation sectors and preliminary definition of the system operational concept. - Identification and characterization of major potential integrity threats on the network and user levels. The threats currently analysed include short baseline ionospheric and tropospheric gradients, ionospheric scintillation, multipath and RF interference in the L-band in metropolitan areas. - Design and test of a multi-sensor navigation platform mock-up for safety performance verification as well as design, implementation, and validation of the approaches suitable for fault detection on a multi-sensor navigation platform.

Development of autonomous capabilities across safety-critical applications such as autonomous operation of unmanned cars, surface vessels (e.g. unmanned passenger ferries) and aerial vehicles (e.g. air-taxies and air ambulances) is increasing the demand for navigation system integrity and accuracy. To ensure safe operation of safety-critical autonomous systems, integrity – detecting and alerting if a system has failed to meet the required accuracy, is the most critical and challenging performance parameter to meet. Although the process of requirements definition for autonomous systems/operations is still on-going, it can be anticipated that navigation system performance at cm to dm level accuracy with very stringent integrity error bounds will be a prerequisite. While this accuracy requirement can potentially be met by network-RTK, or PPP-RTK techniques, the expected integrity level can currently be supported only by space and ground based GNSS augmentation systems (SBAS and GBAS) designed mainly for the aviation sector. At the current moment, none of the existing systems/technologies available is capable to support such stringent integrity and accuracy requirements at the same time. A wide area GNSS augmentation infrastructure providing high accuracy and extremely reliable positioning service has strong potential to advance the development, introduction and acceptance of autonomous systems to urban areas allowing society to benefit from the known advantages of autonomy as e.g. safer and more efficient/greener transportation. While it is still unclear when safe autonomous systems will enter the mass market, it is important to ensure that the infrastructure responding to the sector's safety needs is in place. This project will investigate the path towards ensuring safety for autonomous operations in Norway by leveraging prior work in aviation.