On point-ahead angle control strategies for TianQin

Abstract

Pointing-related displacement noises are crucial in space-based gravitational wave detectors, where point-ahead angle control of transmitted laser beams may contribute significantly. For TianQin that features a geocentric concept, the circular high orbit design with a nearly fixed constellation plane gives rise to small variations of the point-ahead angles within $\pm 25$ nrad in-plane and $\pm 10$ nrad off-plane, in addition to a static bias of 23 $\mu$rad predominantly within the constellation plane. Accordingly, TianQin may adopt fixed-value compensation for the point-ahead angles and absorb the small and slow variations into the pointing biases. To assess the in-principle feasibility, the far-field tilt-to-length (TTL) coupling effect is discussed, and preliminary requirements on far-field wavefront quality are derived, which have taken into account of TTL noise subtraction capability in post processing. The proposed strategy has benefits in simplifying the interferometry design, payload operation, and TTL noise mitigation for TianQin.

9 pages, 13 figures

References in corpus (9)

• TianQin: a space-borne gravitational wave detector
• LISA technology and instrumentation
• Interferometer Techniques for Gravitational-Wave Detection
• Optimizing orbits for TianQin
• Effect of Earth-Moon's gravity on TianQin's range acceleration noise
• Coupling of wavefront errors and pointing jitter in the LISA interferometer: misalignments of the interfering wavefronts
• Optical link acquisition for the LISA mission with in-field pointing architecture
• Calculating the precision of tilt-to-length coupling estimation and noise subtraction in LISA using Fisher information
• Doppler effect in TianQin time-delay interferometry

Cited by in corpus (1)

• Modeling coupled constellation dynamics for TianQin under self-gravity