The use of meta-surfaces and functional coatings to improve Global Navigation Satellite Systems (GNSS) Anti-Jam

Background:
Satellite Navigation, often referred to as Global Navigation Satellite Systems (GNSS), is a key technology in the 21st century, underpinning numerous industries and playing a vital role in Aerospace applications.
Despite its many benefits, GNSS is increasingly vulnerable to hostile interference (jamming) and this poses a significant risk to commercial activities, critical industries and defence applications. The most common form of GNSS jamming protection is the use of phased array antennas to steer antenna nulls towards jammers (as well as antenna beams to satellites) which result in lower received jamming power. The success of these technologies is limited by the large sizes required to implement them. Typically, GNSS anti-jam antennas require multiple antennas separated by approximately half the wavelength (approximately 10cm) and this quickly results in large subsystems that are difficult to integrate into wider systems. Reducing the inter-element spacing results in negative consequences to the performance of the antenna system; typically by increasing the mutual coupling between antenna elements.
The use of meta-surfaces has the potential to reduce the mutual coupling of antenna elements and thus allow GNSS Anti-jam antennas to be produced with a much smaller overall footprint. This would unlock the capability to implement the systems in smaller space envelopes (e.g. autonomous cars) but also allow more elements to be installed within a given area which could increase resultant anti-jam performance.
Alongside improvements to the RF characteristics of an antenna, the novel design and use of materials/functional coatings can improve the overall RF characteristics of a larger platform/vehicle. In the context of GNSS Anti-jam for aerospace applications, the RF energy from the jammers reaches the GNSS subsystem via non-line-of-sight propagation methods such as surface waves and diffraction. For an airborne vehicle, specific coatings may be able to reduce the impact of these propagation modes.

Company Background:
MBDA is jointly owned by Airbus (37.5%), BAE Systems (37.5%) and Leonardo (25%). In summary:
- it is a world forerunner in missiles and missile systems. In total, the group offers a range of 45 missile systems and countermeasures products already in operational service and more than 15 others currently in development.
- it is the only European group capable of designing and producing missiles and missile systems that correspond to the full range of current and future operational needs of the three armed forces (land, sea and air).
- it is an example of European defence industrial collaboration, with a strong presence in 5 European countries. Within the UK, MBDA is a key partner to the UK Government and Armed Forces; and a major component in the UK Defence and Aerospace industry.

Project Description:
The aim of the project is to explore different techniques to apply meta-surfaces to GNSS antennas (and RF antennas more widely) to address the integration issues that large arrays have on industrial and aerospace applications. Different meta-surfaces will be explored to assess their relative suitability for use with GNSS signals and other key RF subsystems such as communication and guidance sensors. The desired outcome will be the identification, design and proof of concept of a meta-surface integrated within a GNSS antenna array that demonstrates improved performance at small inter-element spacing's compared to conventional antenna arrays.

The project will have the ability to explore opportunistic research avenues that emerge throughout the project duration. Research into functional coatings and materials that can reduce or dampen phenomena such as surface waves is one such example. The desired outcome from this will be innovative techniques to reduce the overall RF power received at an RF subsystem in an (e.g.) airborne platform.