## 1 Introduction
[16] devised an imaging system featuring a tiltable beam in  
Figure 1: (**a**) Coincidingwiththe local beam, the distal incident beam is incident vertically to the center of QPD without beam walk. When beam walk exists in the pitch direction, the spot will shift in the y-axis direction. (**b**) The measurement results of the DWS technique when beam walk occurs in the incident beam. The left side indicates the interference conditions, while the right side shows the phases of each quadrant. the test mass interferometer, achieving minimized beam walk by adjusting the lens pitch. [PERSON] et al. [17] in 2021 posited that enhancing the detection range of the differential power sensing (DPS) signal is feasible by incorporating a lens to mitigate beam walk within a dual Gaussian beam interference framework. [PERSON] et al. [18,19] analyzed the linear performance of the DWS technique in the case of Gaussian beam-Gaussian flat-top beam interference, as well as the impact of DWS on the static pointing error of gravitational wave detection satellites and proposed a zero-offset reduction scheme. A technique for enhancing the sensitivity of the torsion pendulum system by employing the DWS optical readout was proposed by [PERSON] et al. [20], and the results indicated that the angular resolution of the DWS signal in optical readout mode can reach the level of 10 \(\upmu\)rad/Hz\({}^{1/2}\) over the full measurement band. [PERSON] et al. [21] derived from the theoretical model of the DWS method that increasing the wavefront curvature of the measured laser beam can significantly improve the sensitivity to lateral displacement. [PERSON] [22] built a quasi-monolithic compact interferometer bench for dihedral-angle error measurement and test by the DWS technique. The experimental results showed that a resolution of \(\pm\)0.15 \(\upmu\)rad and a nonlinear residual below \(\pm\)3 \(\upmu\)rad within a dynamic range of \(\pm\)100 \(\upmu\)rad was achieved. Few researchers have delved into the ramifications of beam walk on the DWS signal. In this work, the correlation between beam walk and DWS signals resulting from the interference of Gaussian and Gaussian flat-top beams was scrutinized via physical modeling and numerical simulation. Then, a conjugate imaging system was constructed using two plano-convex lenses to verify the effectiveness of suppressing beam walk through conjugate position imaging. Finally, a simulation experimental platform for the DWS measurement process was set up. By introducing perturbations to the distant measurement beam, the effectiveness of the imaging system in suppressing nonlinear errors caused by the beam walk was validated. The structure of this paper is delineated in the following manner: Section 2 establishes a physical model of the DWS signal, interfered by Gaussian and Gaussian flat-top beams, and delves into the linear characteristics of the DWS signal in light of the Gaussian flat-top beam walk using numerical simulations. Section 3 presents the design and creation of an inter-satellite laser link simulation system, accompanied by an experimental setup designed to rectify the beam walk through an imaging system. In Section 4, measurements of the DWS angle are taken across different lengths of beam walk, comparing outcomes with and without the imaging system. Conclusions are subsequently drawn based on the synthesis of these simulations and experimental insights.