Small satellite SIGINT payload

A history of in-orbit operation of fifteen low Earth orbit (LEO) satellites by the Surrey Space Centre has highlighted the usefulness to the civilian market of measuring and analysing the crowded RF spectrum from the LEO perspective. A desirable instrument would be a payload that performs spectral analysis of a wide frequency range rapidly and to a useful resolution, while combining a capability for further time domain analysis of particular signals. A conventional system architecture adopts a channelised approach, sampling and processing each channel in turn over some repetition period. Here, the authors propose a novel sweeping system which provides a more elegant and possibly more efficient solution. Digital chirp filter processing can be employed to achieve suitable resolution spectral analysis. An explanation of the operation of a sweeping system, including chirp filter spectral analysis, is presented along with a comparison with a channelised approach.