## 5 Conclusions  
In this study, a phase discrimination method using data shifting and a discriminator with calibrated characteristic parameters is proposed, which solves the problem of mutual constraints between ranging accuracy and ranging precision in the traditional method so that the method can achieve highly accurate and precise ranging. Compared to traditional methods, the proposed approach offers two significant improvements. The first improvement is the early-late discrimination method, which shifts data according to the position of the cross-correlation peak of the punctual code. It performs cross-correlation and normalization using fixed early and late codes, ultimately obtaining a fine phase difference via a phase discrimination model that matches the actual system. The second improvement involves the calibration of the characteristic parameters of the phase discrimination model. This process adjusts the target position, refines its spatial distance, and determines the characteristic parameters of the phase discrimination model that match the system via discrete distance values. Ground validation experiments demonstrated that this method can effectively enhance the ranging accuracy while maintaining a high precision. For the same static target with different displacements, the ranging accuracies of the proposed and traditional methods were approximately 0.56 mm and 51.05 mm, respectively, indicating that the ranging accuracy of the proposed method was 91 times higher than that of the traditional method. For dynamic targets, the ranging deviations of the proposed and traditional methods were \(-\)0.38 mm and \(-\)1.26 mm, respectively. As the target distance increased, the ranging accuracy of the traditional method exhibited periodicity with a period of one chip width, reaching a maximum value before decreasing. Additionally, the accuracy and precision of the velocity measurements performed using the proposed method were 0.44 mm/s and 0.58 mm/s, respectively. Finally, the applicability of the proposed method in real inter-satellite scenarios, spanning tens of thousands of kilometers, was simulated. At a power level of 3 nW, which corresponds to a distance of 24,663 km, the proposed method can achieve a ranging accuracy of 1.51 mm. The results show great potential for the application of the method in inter-stellar ranging, and subsequent work will also validate the method in a practical environment. In addition, the application scenario for the proposed method involves a slow-moving target, while a fast-moving target is not currently involved. The ranging system is coherent, and the velocity of the target can be solved via carrier frequency shift. This velocity is used to perform Doppler compensation for local pseudo-random codes and calibrate the characteristic parameters of the early-late discriminator model to realize the distance measurement of a fast target. This is also the work that needs further improvement and in-depth research in the next steps of the proposed method. Conceptualization, C.L., F.Y. and J.S. ; methodology, C.L. ; software, C.L. ; validation, C.L. ; formal analysis, C.L., F.Y. and J.S. ; investigation, C.L. ; resources, Z.L., Y.Z., C.Q. and W.C.; data curation, C.L., F.Y. and J.S. ; writing--original draft preparation, C.L. ; writing--review and editing, F.Y. and J.S. ; visualization, C.L., F.Y. and J.S. ; supervision, J.S. ; project administration, Z.L. ; funding acquisition, F.Y. All authors have read and agreed to the published version of the manuscript. This work was supported, in part, by the National Key Research and Development Project of China (2022 YFB3902503), the Strategic Priority Research Program (XDB 43030400), the National Natural Science Foundation of China (12293033), and the Youth Innovation Promotion Association of Chinese Academy of Sciences (Y2023075). **Infrared Consent Statement:** Not applicable. **Data Availability Statement:** Dataset is available on request from the authors. * [PERSON] et al.