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

背景：卫星导航，通常称为全球导航卫星系统（GNSS），是21世纪的关键技术，支撑着众多行业，并在航空航天应用中发挥着至关重要的作用。尽管全球导航卫星系统有许多好处，但它越来越容易受到敌对干扰（干扰），这对商业活动、关键工业和国防应用构成了重大风险。GNSS干扰保护的最常见形式是使用相控阵天线将天线零点转向干扰机（以及将天线波束转向卫星），这导致接收到的干扰功率较低。这些技术的成功受到实现它们所需的大尺寸的限制。通常，GNSS抗干扰天线需要多个天线分开大约一半的波长（大约10厘米），这很快导致大型子系统难以集成到更广泛的系统中。减小元件间间距会对天线系统的性能产生负面影响;通常是通过增加天线元件之间的互耦。元表面的使用有可能减少天线元件的互耦，从而允许以小得多的总占地面积生产GNSS抗干扰天线。这将解锁在较小空间包络（例如，自主汽车）中实现系统的能力，但也允许在给定区域内安装更多元件，这可以增加所得到的抗干扰性能。除了天线的RF特性的改进之外，材料/功能涂层的新颖设计和使用可以改进较大平台/车辆的整体RF特性。在用于航空航天应用的GNSS抗干扰背景下，来自干扰器的RF能量通过表面波和衍射等非视线传播方法到达GNSS子系统。公司背景：MBDA由空中客车公司（37.5%）、BAE系统公司（37.5%）和列奥纳多公司（25%）共同拥有。总之：它是世界上导弹和导弹系统的先驱。该集团总共提供了45种已经投入使用的导弹系统和对抗产品，以及目前正在开发的15种以上的其他产品。- 它是欧洲唯一一家能够设计和生产导弹和导弹系统的集团，这些导弹和导弹系统能够满足陆、海、空三军当前和未来的全部作战需求。- 它是欧洲国防工业合作的典范，在5个欧洲国家拥有强大的业务。在英国，MBDA是英国政府和武装部队的重要合作伙伴，也是英国国防和航空航天工业的重要组成部分。项目描述：该项目的目的是探索不同的技术，将元表面应用于GNSS天线（以及更广泛的RF天线），以解决大型阵列在工业和航空航天应用中的集成问题。将探索不同的元表面，以评估其与GNSS信号和其他关键RF子系统（如通信和制导传感器）一起使用的相对适用性。预期成果将是识别、设计和验证集成在全球导航卫星系统天线阵列中的元表面概念，与传统天线阵列相比，该元表面在小元件间间距下的性能有所提高。研究功能涂层和材料，可以减少或阻尼现象，如表面波就是这样一个例子。由此产生的期望结果将是创新技术，以减少在（例如）空中平台

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.