Review Reports

Round 1

Reviewer 1 Report

In this paper, the authors mainly comparing GRACE-FO KBR and LRi ranging data with focus on carrier frequency variations. In general, the work in this paper is important, and the error discussions are very helpful. However, some useful discussions should be further discussed before acceptance.

 

1. Literature review in introduction is not sufficient. The reviewer or readers cannot find the development of KBR and LRI methods in introduction. At this point, two ranging instruments including a conventional microwave system based on K(a)-band ranging (KBR) and a novel laser ranging instrument (LRI) should be comprehensively reviewed in introduction. The modification methods of KBR and LRI methods should be further reviewed. Besides, the advantages and disadvantages of various methods should be discussed.

 

2. In section 6.3, the authors use the white phase noise in the paragraph below Eq. (56). Do the authors consider other noise model not subjected to white noise, such as Middleton noise[1] and alpha noise [2].

[1]Zhang，et al．Parameter estimation of underwater impulsive noise with the Class B model．IET Radar, Sonar & Navigation，2020，Doi: 10.1049/iet-rsn.2019.0477．

[2]Mahmood, et al, “Modeling Colored Impulsive Noise by Markov Chains and Alpha-Stable Processes,” in OCEANS 2015 MTS/IEEE, (Genoa, Italy), Doi: 10.1109/OCEANS-Genova.2015.7271550.

 

3. The authors discuss many errors in this paper. The reviewer suggests that the authors list a table reporting the conclusions drawn from these error figures. With this operation, the readers can easily find the results.

Author Response

Please see attached PDF.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is well written and organized. The result is interesting and has some new findings.

Author Response

Thank you very much!

Reviewer 3 Report

Dear Authors,

please, see the attachment.

Comments for author File: Comments.pdf

Author Response

Please see the attached PDF.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors well addressed the reviewer's comments. The reviewer suggests that this paper is accepted.