Doppler pulling suppression in arm locking systems for space-based gravitational wave detection

Gravitational-wave detection provides humanity with unique access to extreme astrophysical and cosmological phenomena. In space-based missions, however, the Doppler frequency pulling induced by orbital motion severely limits the precise extraction of gravitational-wave signals. This work shows that by introducing properly designed low-pass filters into established laser arm-locking systems, it is possible to maintain a high suppression ratio of laser frequency noise while drastically reducing Doppler pulling. Moreover, with the proposed scheme, the arm-locking system can precisely predict the Doppler frequency without the need to know the real-time distance between satellites, thereby greatly simplifying the complexity of hardware implementation. These results can be generalized and applied to other arm-locking configurations operating in more complex multi-perturbation environments.