Analysis of RF Signatures for Space Domain Awareness using VHF radar

There is a growing need to detect and identify the multitude of space objects orbiting Earth, largely driven by the increase in space debris competing with a drive to launch more satellites into orbit. Radar sensors are arguably under-utilised for observing unique characteristics of space objects, offering well-known advantages over more commonly used optical sensors, including the capability of operating both day and night and in all weather conditions. Although radar systems are adapting to perform observations of space objects, micro Doppler analysis has the potential to provide a unique RF signature based on rotational motion. Observed satellite rotational motion is presented in this paper for the first time using a VHF radar system, and we discuss the processing requirements to extract the micro Doppler information. Using a simple computer aided design (CAD) model of a satellite and electromagnetic simulation software, we gain insight into the ideal micro Doppler signature in isolation from ionospheric effects at VHF. The simulations not only provide assistance with interpreting the real data but are also validated for the potential use in automatic classification algorithms.