Hardware-based demonstration of time-delay interferometry and TDI-ranging with spacecraft motion effects

This hardware-based experimental simulation of the Laser Interferometer Space Antenna implements a real-time electronic duplication of the time-changing inter-spacecraft laser phase delays while measuring heterodyned laser fields with cycle phasemeters. The beat note measurements are used to verify the capabilities of theorized post-processing time-delay interferometry combinations in the proper time-scaled and time-shifted linear combinations. The experiments meet the 18 pm/Hz sensitivity goal of the Laser Interferometer Space Antenna after demonstrating the cancellation of 100 Hz/Hz laser phase noise by time-delay interferometry-ranging the time-varying arm length to an accuracy better than 2. 0 m using a frequency-modulated ranging tone.