Time-delay interferometry for space-borne gravitational wave detection
Abstract
Space-borne gravitational wave detection will open a new window in the 0.1 mHz–1 Hz frequency band which is difficult to detect on the ground.It is expected to provide crucial information for studying basic physics related to astrophysics and early universe processes.However, gravitational wave signals are extremely weak.Any noise during the detection process may overwhelm the gravitational wave signal.Therefore, suppressing noise is the key to successfully detecting gravitational waves.At present, the laser frequency noise and clock noise are about seven and three orders of magnitude larger than the typical gravitational wave intensity.For these two major noise sources, the physical limitations of instruments cannot be directly broken through in experimental technology in the short term.Thus, the time-delay interferometry (TDI) technique is employed for suppression through the delay and combination of the data stream.This paper will introduce methods for obtaining multiple types of TDI combinations, including the algebraic method of solving indeterminate equations and the geometric method of symbolic search.Based on multiple types of TDI, the method of constructing independent measurement data by means of clock sideband comparison technology to reduce clock noise will be analyzed.Finally, the sensitivity functions of different types of TDI combinations are given to evaluate the sensitivity limit of TDI combinations.
