SISRE of BDS-3 MEO: Evolution as Well as Comparison between D1 and B-CNAV (B-CNAV1, B-CNAV2) Navigation Messages

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper did comprehensive accuray elevation on BDS-3 navigation messages for both D1 and B-CNAV. The results sound reasonable and credible.

However, the presentation on this research could be improved. Suggestions are listed but not limited as following:

1.In the "Abstract" section, quite a lot of results has been listed from line 19 to 40, but have no conclusion made for this paper. 

2.In the "Introduction" section, several references were cited with groups as "[6-11]", "[13-18]", "[19-24]", it not a rigorous writing habit.

3.In section 2.2, discription for the correction from APC to COM chould be made since it an important work for ephemeris evaluation.

4.From line 124 to 130, please simplify the equation if possile, in equations (1), both the second and third equations have only 1 parameter on both sides of the equals sign.

5.On line 141, the SISRE evaluation has no business with cutoff angle, what's the mean of "with cutoff elevation of 5" ?

6.The horizontal axis of Figure 2 could be time (DOY) instead of epoch.

7.There is no necessary for Table 1 as it has only one row, and the information was repeated in line 209.

8.In line 213, there are three direction, 3D should not be count as a direction.

9.Please make sure the results on Figure 4 and Table 2 are right, the radial direction accuracy has high correlation with clock error, if along and cross direction accuracy were zero, the radial direction should not be so distinct.

10.As mentioned on 1, the conclusions of this paper were not explicit, it's repeating the information of the abstract.

 

 

 

Comments on the Quality of English Language

Should be improved, ask help from native speaking person or professional English assistance.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This is an excellent manuscript that presents an innovative research on the performance analysis of BDS-3 MEO D1 and B-CNAV navigation messages. The annual D1 and B-CNAV navigation messages in 2022 are evaluated in orbit and clock error by COD’s precise products. This manuscript makes a valuable contribution to the advancement of technology in this field. The following suggestions are offered to enhance the quality of this manuscript.

(1) Line 124, the second formula (dti) in equation (1) is wrong, according to Lines 125-130.

(2) Line 198, the authors should explain the meaning of ‘-0.032 +/- 0.057 m, -0.001 +/- 0.273 m and 0.037 +/- 0.293m’.

(3) In Figure 2, the unit (m) should be added after the number.

(4) Lines 209-210, ‘the radical accuracy is the highest’. Not a native expression.

(5) In the subplot SISRE_ORB of Figure 7, ‘0.083+/0.040’ should be ‘0.083+/-0.040’. And the same to the Figure 2, the unit should be added.

Comments on the Quality of English Language

(1) In Line 56, ‘signals of multiple frequency points’ should be ‘signals of multiple frequencies.’.

(2) In Line 115, the format of the reference is wrong.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This paper presents an interesting topic for a new generation of ephemeris.

There are a few minor comments:

- L115: There is a reference error for [33].

- L130: 'n' is undefined. The number of satellites?

- L146: Please clarify that B-CNAV1 and B-CNAV2 have the same content as B-CNAV.

- L180: The age of the ephemeris should affect the accuracy of the ephemeris (orbit and clock). Authors should add the figure to show the relationship between age and accuracy for D1 and B-CNAV.

- L266: Please add a comment explaining why the RMS error of the H-maser is worth more than that of the Rb.

- L273: SISRE of B-CNAV is only shown in Figure 7, it is better to show in tabular form as in Table 5.

- L315-318: Please clarify the sentence. For example, "For D1, the analyzed SISRE is 0.556m, which is better than the reference value (1.0m). For B-CNAV, the analyzed SISRE is 0.508m, which is better than the reference value (0.6m)".

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

As most of the comments (Comments 1 to 6) had not get positive responses, I would like to leave the final decisions to editor or other reviewers.

 

 

Comments on the Quality of English Language

The current version has no changes on the English quality improvement.

Author Response

Please see the attachment

Author Response File: Author Response.docx