INSPIRe (Integrated Navigation System-of-Systems PNT for Resilience) is an 18-month project to define practical measures that could be implemented to indicate the confidence a user should have in their PNT solution.


Position, Navigation and Timing (PNT) is critical for safety in maritime and other sectors – but can users trust the position, speed and heading displayed by their satellite navigation systems, and the time provided by satellite derived clocks which is used by many bridge systems?

INSPIRe (Integrated Navigation System-of-Systems PNT for Resilience) is an 18-month project to define practical measures that could be implemented to indicate the confidence a user should have in their PNT solution.

Providing a level of confidence is what we mean by integrity – ensuring that the data displayed to the user is sufficiently reliable for the manoeuvres in progress at the time, and warning the user if it is not. This has two components: system level integrity – are the raw signals transmitted by the satellites compromised? – and user level integrity – have good satellite signals been degraded at the point of use by local factors?

Trustworthy positioning and timing is critical to support the growing use of such data within the maritime sector and more so when the room to manoeuvre is reduced due to increasing offshore renewable energy production and other such infrastructure.


INSPRe is funded by the European Space Agency’s (ESA) Navigation Innovation and Support Programme (NAVISP) and builds on the earlier NAVISP-funded MarRINav project. This programme started in July 2022 and will finish at the end of 2023.


Taylor Airey Limited




GLA Research and Development


Imperial College London


London Economics


Innovate UK KTN


NLA International


Project briefing and consultation hybrid event

A hybrid briefing/consultation event for the INSPIRe project took place on 27th February. The event explored the aims and content of the INSPIRe project, expert views on users’ PNT integrity needs were captured and we discussed use cases that will underpin the programme and outputs moving forwards.

View slides from the event

Programme detail

Focus areas

The INSPIRe project comprises the following themes:

  • Integrity monitoring within the satellite navigation receiver, generally known as Receiver Autonomous Integrity Monitoring (RAIM), in various configurations.
  • Monitoring additional supporting signals provided for professional satellite navigation receivers, in this case the European Geostationary Navigation Overlay Service (EGNOS).
  • Opportunistic data to aid integrity.
  • Cost benefit analysis of the techniques developed in the project.
  • Exploitation plan for these techniques.

Core activities

In more detail, INSPIRe includes these activities:

  • Develop and test algorithms for Maritime General RAIM (MGRAIM) using single-frequency GPS.
  • Develop and test algorithms for dual frequency, multi-constellation (DFMC) RAIM.
  • Develop and test DFMC RAIM algorithms extended to include dead reckoning – vessel RAIM.
  • Develop EGNOS monitoring software.
  • Develop a RAIM availability prediction tool.

Some initial results have been drafted and publication is awaiting approval from ESA. Reports will be made available on this page soon.

Project reports

  • This document includes a review and consolidation of the status of maritime integrity and previous activities that have investigated approaches for integrity in the maritime domain. The review reflects on user-level integrity for single frequency GPS, considering the two maritime scenarios: is a maritime-specific implementation of the aviation ARAIM concept and the second: which is a chi-squared fault-detection process with simple geometric screening rules to ensure safety, (Maritime General RAIM (MGRAIM)). Also included within this document are a high-level design for the GPS single frequency integrity algorithms, an overview of the experimentation plan for the evaluation of the algorithm and a summary of the results of algorithm testing and an assessment of the suitability of the algorithm and a highlight any areas for further development and investigation.

  • This document provides a description of the following:

    • Functional specification and associated test specification for single-frequency GPS and MGRAIM.
    • Software design specification for implementing the GPS MGRAIM algorithm.
    • Software test specifications for each module for integration.

    Associated with this document will be the Test Report providing the results of the functional and software design testing. These tests are designed to demonstrate that the algorithm implemented is compliant with the functional requirements defined.

  • This July 2023 report from the University of Tokyo provides a useful comparison of resilient PNT strategy and policies in 10 leading countries and the EU.


Strategic Case for Intervention report

Intelligent Supply Chains

Within supply chains, digital technologies have transformed the way that we live our lives. The purpose of this strategic case is to set the context for intervention by the UK space sector and HM Government, to address opportunities to improve the supply chains ecosystem for goods and services in the UK.

By RethinkPNT

Read report

Get involved

If you’re interested in finding out more about the programme, please get in touch with Bob Cockshott, INSPIRe stakeholder engagement work package manager.

We are particularly interested in your answers to the following questions:

  • Are you a user or a supplier of position, navigation and timing (PNT), or just interested?
  • What sector do you work in (industry, academia, government, other)?
  • How important is PNT integrity (trustworthiness) to you?
  • How could existing systems be improved?
  • What do you need from a PNT system?

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