Real-Time LEO Satellite Clocks Based on Near-Real-Time Clock Determination with Ultra-Short-Term Prediction

Round 1

Reviewer 1 Report

The manuscript presents a novel approach to real-time Low Earth Orbit (LEO) satellite clock determination by combining near-real-time clock determination with ultra-short-term clock prediction. This approach achieves notable precision in LEO satellite clock estimates, making it a significant contribution to the field of satellite navigation and timing. However, there are a couple of areas where the paper could be improved to enhance its clarity and comprehensiveness:

1. Figure 1 - Flowchart Complexity: The flowchart intended to illustrate the real-time LEO satellite clock determination process is overly simplistic. A more detailed flowchart would significantly aid in understanding the methodology. It would be beneficial if the flowchart explicitly outlined the technical methods used throughout the process, including data acquisition, processing strategies, and the specific implementation of the Kalman filter with restarts. Adding such details would not only clarify the procedure but also allow readers to better appreciate the novel aspects of your method.

2. Discussion Section: The discussion section of the paper appears to be underdeveloped. Given the potential impact of your research on future high-precision PNT applications, a more in-depth discussion on various fronts could enhance the manuscript. A discussion on the practical challenges of implementing your method in real-world applications, including any limitations observed and suggestions for future research directions to overcome these challenges. Addressing the point would not only strengthen the paper but also provide a clearer roadmap for researchers and practitioners looking to apply these findings in the development of next-generation PNT services.

With the suggested improvements, the paper would make a valuable contribution to the literature. I support the publication of this manuscript once the above-mentioned revisions are made.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Any observation.

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

This manuscript introduces a real-time LEO satellite clock determination based on efficient high-precision near-real-time clock determination and ultra-short-term clock prediction. This method's advantage lies in hampering unnecessary bias propagation and accumulations of ancient epochs. Besides, selecting the real-time GNSS products and re-referencing the GNSS clocks is meaningful to the determination of LEO satellite clocks. This manuscript is fitted for the Remote sensing and it can be published before some minor problems addressed..

1. As shown in Table 1, the average processing time is shorter when the processing arc length is 4 h, while the STD (vs. R) seems the same as when the processing arc length is 6 h. However, 6 h is selected as the most suitable processing arc in the following part. Please explain the reason.

2. In section 2.1, clocks from 5 different analysis centers are analyzed. As shown in Figure 2, the clocks from WHU seem the best. However, in section 3, products from CNES are chosen to determine the LEO satellite clock. Please explain the reason.

3. In figure 9, the dash line beyond the frame, it should be revised.

4. Further investigation into the LEO satellite clock prediction algorithms is necessary to reduce the precision loss caused by clock prediction and improve the precision of real-time clock determination for LEO satellites.

 5. The overall structure of the manuscript is logical, the language is fluent, and the expressions are relatively clear. However, some sections could be further simplified or refined to improve readability. Additionally, ensure that the formatting complies with the journal's requirements.

Overall, I believe the manuscript has potential but requires some revisions and improvements. I hope the authors will consider my suggestions carefully and resubmit after revision.

This manuscript introduces a real-time LEO satellite clock determination based on efficient high-precision near-real-time clock determination and ultra-short-term clock prediction. This method's advantage lies in hampering unnecessary bias propagation and accumulations of ancient epochs. Besides, selecting the real-time GNSS products and re-referencing the GNSS clocks is meaningful to the determination of LEO satellite clocks. This manuscript is fitted for the Remote sensing and it can be published before some minor problems addressed..

1. As shown in Table 1, the average processing time is shorter when the processing arc length is 4 h, while the STD (vs. R) seems the same as when the processing arc length is 6 h. However, 6 h is selected as the most suitable processing arc in the following part. Please explain the reason.

2. In section 2.1, clocks from 5 different analysis centers are analyzed. As shown in Figure 2, the clocks from WHU seem the best. However, in section 3, products from CNES are chosen to determine the LEO satellite clock. Please explain the reason.

3. In figure 9, the dash line beyond the frame, it should be revised.

4. Further investigation into the LEO satellite clock prediction algorithms is necessary to reduce the precision loss caused by clock prediction and improve the precision of real-time clock determination for LEO satellites.

 5. The overall structure of the manuscript is logical, the language is fluent, and the expressions are relatively clear. However, some sections could be further simplified or refined to improve readability. Additionally, ensure that the formatting complies with the journal's requirements.

Overall, I believe the manuscript has potential but requires some revisions and improvements. I hope the authors will consider my suggestions carefully and resubmit after revision.

Author Response

Please see the attachment

Author Response File: Author Response.pdf