GPS Interference, Detection and Mitigation

GNSS systems are vulnerable

It is well known amongst some sectors (military/defence integrators for example) that GNSS systems have vulnerabilities from interference. The knowledge that satellite based systems are vulnerable to many factors is becoming more widespread, assisted by the proliferance of GNSS jamming equipment on the internet.

These vulnerabilities can result in a system failure, the causes of which can be grouped into systematic, deliberate and natural failure.

Failure of safety and mission critical systems such as power systems, military operations, aircraft systems and high value transport systems as well as governmental systems like road user charging or commercial systems like pay-as-you-go insurance, can have a devastating impact on infrastructure, ecomomic stability, crime and national security (including terrorism). Early identification of the potential for system degradation or failure enables mitigation and protection measures to be implemented in advance of system failure.

Causes of Failure

The causes of failure are as varied as they are complex, understanding, detecting and analysing these causes of failure and vulnerability are at the heart of the GAARDIAN project.


The project set out to create a mesh of PNT interference detection & mitigation sensors (IDMs) to be deployed in the vicinity of PNT dependent infrastructure and applications. The sensors would monitor the integrity, reliability, continuity and accuracy of the locally received GPS (or other GNSS) and eLoran Radio Navigation signals on a 24x7x365 basis by creating an alarm network for both natural and intentional interference to GNSS signals. If the system detected an anomalous condition, users could be alerted to the problem and investigate.

The deployed IDM sensors would be configurable by requirement and location and have the ability to communicate in multiple technologies once deployed. The sensors would perform the collection, monitoring and data reduction functions alerting users to anomalous conditions as defined by the user.

GAARDIAN: GNSS Availability Accuracy Reliability anD Integrity Assessment for timing and Navigation

GAARDIAN project was the basis for the SENTINEL programme.

APCO University of Bath BT Chronos Technology
Thatcham National Physical Laboratory Ordnance Survey Research & Radionavigation    

The GAARDIAN project was a UK Government funded collaborative R&D project to develop solutions for analysing interference phenomena assiciated with Positioning, Navigation and Timing (PNT) signals, including GPS and eLoran in safety and mission critical applications.  The industrial and academic collaboration was led by Chronos Technology Ltd and included the University of Bath, General Lighthouse Authorities, BT, Ordnance Survey, National Physical Laboratory and Imperial College London.