Algorithm for time-delay interferometry numerical simulation and sensitivity investigation
G. Wang, Wei-Tou Ni, Wen-Biao Han, Cong‐Feng Qiao
Abstract
We introduce a generic algorithm to determine the time delays and spacecraft positions to compose any time-delay interferometry (TDI) channel in the dynamical case and evaluate its sensitivity by using a full numerical method. We select 11 second-generation TDI channels constructed from four approaches and investigate their gravitational wave responses, noise levels, and averaged sensitivities under a numerical LISA orbit. The sensitivities of selected channels are various especially for frequencies lower than 20 mHz. The optimal channel ${\mathrm{A}}_{2}$ (or equivalently ${\mathrm{E}}_{2}$) combined from second-generation Michelson TDI channels (${\mathrm{X}}_{1}$, ${\mathrm{X}}_{2}$, and ${\mathrm{X}}_{3}$) achieves the best sensitivity among the channels, while the Sagnac ${\ensuremath{\alpha}}_{1}$ channel shows the worst sensitivity. Multiple channels show better sensitivities at some characteristic frequencies compared to the fiducial ${\mathrm{X}}_{1}$ channel. The joint ${\mathrm{A}}_{2}+{\mathrm{E}}_{2}+{\mathrm{T}}_{2}$ observation not only enhances the sensitivity of the ${\mathrm{X}}_{1}$ channel by a factor of $\sqrt{2}$ to 2, but also improves the capacity of sky coverage.