Single-Satellite EMI Geolocation via Flexibly Constrained UKF Exploiting Doppler Acceleration

Single-satellite geolocation achieves effective localization of ground electromagnetic interference (EMI) signals with a low cost compared to the multi-satellite counterparts. In such systems, the Doppler and Doppler rate are commonly exploited to extract the information of the ground EMI sources and the constrained Unscented Kalman filter (cUKF) is found effective to provide instantaneous EMI locations over time. In this letter, we address the benefit of exploiting Doppler acceleration in the underlying single-satellite geolocation problem, and point out that exploiting additional constraint on the altitude of the ground emitter provides enhanced EMI tracking performance. The importance of such constraint is more pronounced in the beginning of the tracking process, whereas removing such constraint after a short period of time does not compromise the performance. The effect of sampling rates on performance and the required time to converge are investigated.