Publication of the system level requirements for developing an on-board spectrum monitoring capability operating in C-, Ku- and Ka-band; including to develop a suitable concept equipment architecture that can be readily adapted to the frequency band of interest and to verify the viability through demonstrating a representative engineering breadboard and test-bench implementation
Radio frequency interference management is of increasing concern in commercial satellite telecommunication systems. As ground uplink terminals and v-sats become cheaper and more freely available, the threat is ever increasing and interference is having a significant impact on satellite service performance and ultimately the income revenues of SatCom operators. Providing a commercially viable in-orbit tool requires leveraging knowledge and expertise in interference detection algorithms and producing a design that delivers improved detection performance over existing ground based systems, having features that allow effective resolution of the problem by operators. In particular, the broad spectrum bands needing to be covered and the speed of the sampling and post-process analysis needing to be achieved poses a significant challenge. Effective interference detection also relies on the implementation of techniques capable of detecting colliding signals in-band, out of band and close to the noise floor.
Currently, several complementary ground-based tools are used for interference management, but there are no in-orbit tools available for this purpose in transparent repeaters. By exploiting existing technology, an initial uplink spectral monitoring feature could be introduced at relatively low cost. In-orbit interference detection in the uplink provides a single-point solution, whereas many ground-based tools would be required to cover the same uplink spectrum. Additionally, an in-orbit system is able to monitor rogue interference from mobile transmitters outside of the monitoring capability of ground-based systems. The developed hardware could eventually also serve as a platform for future enhancements, such as sub-channel signal (interferer) suppression and interference identification.
The on-board spectrum monitoring proof-of-concept detects and characterizes interferers by analysing the radio spectrum and identifying anomalies with respect to a mask of the expected carriers
The proof-of-concept demonstration test bench comprises a collection of evaluation boards, including a RF to IF down-conversion chain, a data-converter, an FPGA and a flexible detection algorithm.
- Establish the main causes of interference and agree the magnitude of the impact of these with SatCom operators.
- Based on findings, define the operator-level requirements for a spectrum monitoring system.
- Investigate different architectures for implementing the spectral monitoring feature with existing technology. Perform trade-off analyses and recommend an architecture.
- Design, manufacture and test an engineering breadboard of the spectral monitoring hardware, including a suitable algorithm for meeting the spectral sensing requirements. Produce a suitable test strategy to prove the viability of the recommended concept design.
- Perform tests and analyse the test results, producing test reports. Provide a qualification plan and produce recommendations for further development (e.g. new features).
Causes of satellite interference are established and categorised highlighting the most significant threats to GEO missions. High-level user requirements and a set of preliminary requirements for a baseline OBSM equipment are published.
Concept architectures are traded-off with a hardware selection for a progressive design. Space-qualified components and emerging technologies offering potential, have been considered.
A recommended preliminary architecture for an OBSM equipment, including predictive performance and preliminary budgets for mass, volume, power consumption is established.
Specifications for the 'proof-of concept test-bench' required to prove the feasibility and capabilities of the baseline equipment, are also established.
Work is nearing completion on the test-bench HW and SW implementation, including the development of the spectrum monitoring algorithm.