Research progress on clock noise suppression technique for space-borne gravitational wave detection

In space-borne gravitational wave detection, each satellite is required to carry an ultra stable oscillator (USO) as a timing reference to drive the analog-to-digital converter (ADC) for digital sampling of signals. High-precision clock timing is crucial for achieving the required sensitivity in gravitational wave detection. However, the challenges posed by aperture jitter and sampling clock jitter in ADCs cannot be overlooked, as they disrupt the sampling timing, introduce clock noise, and distort the digitized signals, thereby limiting the effectiveness of space-borne gravitational wave detection. To overcome this issue, scientists have developed pilot tone correction techniques and innovatively proposed clock noise calibrated time-delay interferometry (TDI) and optical comb TDI techniques for effectively suppressing the impact of clock noise. This study delves into and comprehensively summarizes the current state of clock noise and its suppression techniques in space-borne gravitational wave detection. Through systematic review and analysis, we aim to provide theoretical and experimental technical support, as well as optimization suggestions, for the implementation of China’s space-borne gravitational wave detection missions.