Ionospheric Measurement, Modelling and Simulation for Future Wideband UHF Satcoms

Lead Research Organisation: University of Birmingham
Department Name: Electronic, Electrical and Computer Eng


Society is increasingly dependent on communications (both person-to-person and machine-to-machine). Where terrestrial infrastructure is under-developed, satellite communication (satcom) is often used for point-to-point communications and networked backhaul. Reliable and robust communications underpin many of the technological developments that are transforming the economic landscape and wider society in the UK. Space technology and applications (including satcom) has been identified as one of Britain's eight "Great Technologies" and the UK has expressed the ambition of capturing 10% of the global space market by 2030. This proposal spans the EPSRC RF and Microwaves Communications and Digital Signal Processing research areas of the ICT Theme. It is relevant to the Aerospace, Defence and Marine Industrial Sector and the Electronics, Communications and IT Industrial Sector.

The choice of satcom radio frequency is dependent on various factors, but ultra-high frequency (UHF) is popular because of the low cost of the user terminals, its capability to operate with small and portable antennas, and its resilience to shadowing by objects and foliage. UHF satcom continues to provide an important part of the MOD communications infrastructure. Wideband UHF satcom will also play a key role in future machine-to-machine (M2M) communications systems. This will be especially true for systems in remote areas where terrestrial networks may not be available and for systems requiring high levels of resilience. M2M communications is one of the enablers for the development of the Internet of Things (IoT) that has been identified as one of the most important technologies that will emerge over the next decade and will drive economic and social progress.

The data communications capacity of contemporary UHF satcom is low and is limited by the simple waveforms employed. Greater data capacity is required and may be provided by new, multi-carrier wideband waveforms. However, the design and optimisation of such waveforms will require realistic satcom channel emulation. Provision of such channel emulation is hindered by our poor understanding of the distorting effects of the Earth's ionosphere (an ionized region of the upper atmosphere). Such ionospheric distortions are prevalent at high and particularly at low latitudes due to ionospheric irregularities which cause rapid changes in a signal delay, phase and amplitude.

We aim to undertake the first systematic, long-term study of the impact of the ionosphere on the wideband (5 MHz) ultra-high frequency (UHF) satcom radio channel. The research programme will undertake measurements (using the upcoming COSMIC-2 UHF wideband channel probe) and modeling to understand the ionospheric impact. The final stage of the programme will be the development of a UHF satcom waveform simulator to help modem designers. This national resource will transform the current capability and allow the UK to take a lead in the design of wideband UHF satcom waveforms.

Planned Impact

The proposed research programme will make economic and societal, and academic impacts through a number of paths.

The UK space industry is an important national asset and benefits our economy in many ways. The UK space industry is worth approximately £12B and has been growing by an average of 8.6% year-on-year since 2010. The UK Space Innovation and Growth Strategy has a target of achieving 10% of the global space market, which is estimated to be £40 billion by 2030. Satellite communications will form a significant part of this and the proposed research will enable growth in this area. One clear exploitation route of the proposed research is via Airbus Defence and Space (ADS), who are one of the project partners. However, it is also important that the research is of benefit to other commercial entities. Therefore, we will ensure that the channel simulator code developed in the project will be made available so that it can be widely used. Furthermore, industry will be briefed on the research outcomes via both direct meetings and via the relevant trade conferences (i.e. Milcom) and associations (i.e. AFCEA).

One beneficiary of the proposed work is the UK MoD where this project may support the UK's security needs. UHF satellite communications is often used to provide resilient communications that can penetrate foliage. Currently, UHF satcom is provided by Skynet 5 that is provided and operated by ADS and this system is likely to remain in service until approximately 2023. The UK has not yet established requirements for a follow-on satellite. The inclusion of DSTL and ADS as project partners ensures that the results of the proposed research will be accessible to the appropriate stakeholders and policy makers for any Skynet successor.

Another impact is related to the increasing proliferation of connected devices (i.e. Internet of Things, IoT) and the continued development of machine-to-machine (M2M) applications. Although Wi-Fi deployments and terrestrial mobile networks are able to support most applications, for remote locations (i.e. real-time asset management at unmanned sites and offshore platforms) these services must be supplemented by satellite coverage. Ultra high frequency (UHF) satcom has an important role to play in these service because of its resilient operation. Industry will be briefed on the research outcomes via both direct meetings and via the relevant trade conferences and associations.

The proposed research will contribute to the ionospheric advice provided to the UK government with regards extreme space weather impacts (via the Space Environment Impacts Expert Group, SEIEG). One Co-I (PSC) regularly advises Government in this context.

This proposal seeks to develop new trans-ionospheric propagation models and simulators to support the development of future UHF satcom systems. This will include the opportunity to develop new standards for ionospheric propagation (via ITU study group 3). The PI has successfully achieved this in a different field in the past.

The research may also lead to new scientific advances in understanding the physics of how ionospheric structures develop and affect radio systems. T

A university funded studentship will start in 2016 that will run alongside the proposed work. It is our intention to initiate a further studentship in 2017. These students are our successors and, in this inevitably growing field, the satcom experts of the future. Journal and conference papers will be a major output from each WP as means to transfer the knowledge to the academic community.

The proposed project team provides academic, industrial and government collaboration. This will be further widened to include international collaboration with government research laboratories such as the US-DoD Air Force Research Laboratory, with whom we have excellent links in this research topic.
Description UHF Satcom from and to the equatorial region can be affected by ionospheric scintillation. The scintillation (fading and phase changes) is caused by small scale irregularities. This research has shown that the amplitude fading can be either flat (the same at all measured frequencies) or frequency selective (different at all measured frequencies). The analysis has shown that flat fading predominates. The coherence bandwidth is typically 10 MHz, but can be as low as 5 MHz and as high as 20 MHz. Coherence bandwidths above 20 MHz could not be measured. These results are important as they guide the design of modems.
Exploitation Route The project outcomes will be taken forward through Dstl (defence), industry and through the Space Environment Impacts Expert Group (SEiEG) which reports to the Civil Contingencies Secretariat of the Cabinet Office. Dstl are already aware of the project and have indeed facilitated US data provision. The Industry links need to be revitalised now that the re-vectored programme is generating output. SEiEG has already reported on the top level outputs from the programme through a recent review paper. The outputs from the project will shortly be submitted to the journal Radio Science and will be presented at the URSI General assembly in August 2021.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Government, Democracy and Justice

Description Ionospheric Wideband UHF Assessment
Amount £184,223 (GBP)
Funding ID DSTLX-1000122050 
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 03/2018 
End 03/2019