Investigation of Background Clutter Removal and Impacts on Cis-Lunar Target Detection and Tracking Using DSN Open-Loop Tracking Measurements

As NASA and other space agencies are gearing up to return to the moon, there is significant interest and opportunities in detecting and tracking small objects in cis-lunar space. NASA’s Jet Propulsion Laboratory (JPL) initiates a strategic plan to develop detecting and monitoring techniques using NASA’s Deep Space Network (DSN) tracking stations and the Goldstone Solar System Radar (GSSR) This paper summarizes the work and preliminary results of detecting Cis-lunar objects in four radar experiments in 2022 - 2023 using the measurements collected with Open-Loop Receivers (OLRs) of the Deep Space Network Goldstone complex. The research aims to evaluate the feasibility of using the GSSR with OLR configuration to detect objects in the cis-lunar environment, especially investigating the background clutter impact on the near-moon object tracking. Due to its practical implementation, the time-frequency domain analysis, such as the Short Time Fourier Transform (STFT) or wavelet we demonstrated in this paper, could be a powerful tool in real-time pattern classification for distinguishing between a target’s echoes and lunar clutter interferences. We evaluate the OLR’s cis-lunar object tracking performance using the data collected from the four experiments. We also assess the performance of Cis-lunar target detection by comparing observations with the Doppler frequency estimates derived from the spacecraft’s orbital dynamics, lunar noise temperature impacts, background clutter effects, and Signal-to-Noise Ratio simulations. These research findings will improve our engineering knowledge and technical constraints for future detection and tracking of cis-lunar targets, including satellites, debris, asteroids, and surface assets on the moon.