Multifunction Over-the-Horizon Radar for Space Domain Awareness

The possibility of using existing planar monopole arrays of an over-the-horizon radar (OTHR) for space domain awareness (SDA) is evaluated experimentally. The International Space Station was successfully tracked by the radar over the majority of an 11-minute pass, by exploiting the full azimuth and elevation steerability of the antenna arrays. As predicted using numerical models of the arrays, signal-to-noise ratios that can exceed 40 dB were measured. Range and Doppler measurements are compared with NASA-provided truth data to identify ionospheric effects. SDA is determined to be a potential multifunction addition to existing OTHR systems for coarse orbital element measurements, but requires better ionospheric correction techniques to achieve the fine accuracies typically obtained with SDA radars operating at higher frequencies.