Comparative Analysis of Single-View and Multi-View Airborne SAR Positioning Error and Course Planning for Multi-View Airborne SAR Optimal Positioning
Round 1
Reviewer 1 Report
The manuscript is dedicated to the comparative analysis of single- and multi-view airborne SAR positioning error and course planning to provide multi-view airborne SAR optimal positioning. The authors analyze the main factors affecting the positioning accuracy of the two positioning methods and reveal the mechanism that the multi-view air-borne SAR positioning method can improve the target positioning accuracy compared with the single-view airborne SAR positioning method. They also solve the problem of course planning for multi-view airborne SAR optimal positioning. The results obtained are new, interesting and valuable for the field. Comparing the previous version of article ‘remotesensing-1687922’, the current version looks better, the results are presented clearly, but the structure of the manuscript is still not in accordance with the journal requirements. The paper should have the following structure (see the journal template): Introduction, Materials and Methods, Results, Discussion, and Conclusions. So, the paper should be reorganized to be exactly in accordance with this structure to be published in the journal. Further corrections needed are as follows:
Figure 1 is missing. Or remunerate figures as figures numbers should start with Figure 1.
Use the following way to present information about authors in references:
«Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.».
Provide more information on Reference 7 “Konecny, Reliability of radar image data. 16th ISPRS Con, Comm 3, 1988.” as this paper has 2 authors, and page numbers.
The same is with Reference 12 “LI M K. Research of Airborne Hight Resolution SAR Imaging and Location Techniques. Xidian University, 2018.” which has a mistake in “Hight”. It should be “High”.
Also correct Reference 27 in accordance with the real information about this paper from
https://0-ieeexplore-ieee-org.brum.beds.ac.uk/document/1435821.
Author Response
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Author Response.pdf
Reviewer 2 Report
The reorganization of the content is positive, fragments of the article are presented in the form of annexes, which affects the reception of the main part. The noted editing problems have also been mostly eliminated.
I can only repeat the previous review that the article is a detailed study of an interesting research problem. It discusses the accuracy of airborne SAR system positioning from a linear Range-Doppler Algorithm (RDA) perspective and develops the multi-view airborne SAR positioning error transfer model based on the multi-view airborne SAR positioning model.
Based on the analysis it was found that the velocity errors in range and altitude are the main factors affecting the single-view airborne SAR positioning accuracy, and dual aircraft DM motion errors are the main reason for the inaccurate positioning of multi-view airborne SAR, and dual aircraft CM motion errors can restrain the influence of aircraft motion error on target
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript is poorly conceived research work. It lacks the novel or scientific contribution for a journal publication.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The manuscript established two positioning error transfer models for single-view and multi-view airborne SAR positioning modes. An effective method to analyze the influence of dual aircraft geometry configuration on target positioning accuracy was presented.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The manuscript is dedicated to the comparative analysis of single- and multi-view airborne SAR positioning error and course planning to provide multi-view airborne SAR optimal positioning. The results obtained are new, interesting and valuable for the field. Unfortunately, the form of presentation of the methods and results as well as English language usage should be improved significantly before publication of the manuscript.
Corrections suggested.
- I suggest checking the text of the paper by a native English speaker or an editor who is fluent in English. Currently, the wording sometimes obscures the intentions of the authors in my view and this makes the reading more difficult.
- Please, insert blank between the value and its dimension.
- Please, enlarge the size of Figure 8 and increase its resolution.
- The paper should have the following structure (see the journal template): Introduction, Materials and Methods, Results, Discussion, and Conclusions. Please, reorganize your paper in accordance with this structure.
- Please, prepare all the references in accordance with the journal requirements exactly with the journal template.
- Journals names in journal references should be abbreviated, e.g. “Geoscience. Remote Sensing IEEE Transactions on” should be given as “IEEE Trans. Geosci. Remote Sens.”.
- Please, reduce Abstract providing the most important information on the research performed and results obtained.
- Please, rewrite Conclusion providing clearer information on the results obtained. Also, describe in Conclusion where the results obtained can be used and further research perspective.
- The article comprises 20 pages and its type has been specified as a Technical Note. In accordance with the Instructions for Authors (https://0-www-mdpi-com.brum.beds.ac.uk/journal/remotesensing/instructions) “Technical Notes: These are short articles (less than 18 pages) on new developments, significant advances and novel aspects of experimental and theoretical methods and techniques relevant to the scope of Remote Sensing.” In this situation I suggest to reduce the article or change its type for an Article.
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
The article is very extensive, especially chapters 2 and 3. It is advisable to extend chapter 1 and avoid group citations e.g. [12-21]. Given the volume of text in Chapters 2 and 3, I would suggest some simplification of content.
The paper mainly needs editorial correction:
- variable interlines;
- missing or unnecessary spaces: 'airborne SAR data , it firstly uses', 'where , wr(τ) is the rectangular window function', 'motion error(position or velocity)', 'the range(Case1), azi-muth(Case2), altitude(Case3)', 'target positioning error. Then , aiming at";
- "under the antenna, We can figure"->we;
- section "2.2. The Position Error in Altitude" starts at the bottom of the page;
- the caption for Figure 4 is on the following page,
- degree characters are not correct;
-"Longitude/(o) latitude/(o) Altitude/m"->"Latitude".
Despite these shortcomings, the article is a detailed study of an interesting research problem. For better perception of the content, I suggest making necessary corrections before publication of the article.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
This study presents an interesting approach for multi-view SAR-based optimal target positioning. Although it has some novelties, it also has specific limitations and drawbacks:
1) The analytical description in section 2 is mostly explanation of geometric calculations, i.e., should include only Table 1 in main text and everything else summarized in an appendix as a short proof.
2) Same comment in section 3 as for section 2, i.e., too extensive geometric descriptions instead of only the absolutely necessary final equations.
3) In section 3, F1-F4 is a non-linear system, not an "equation", and Fx are not properly defined as multi-variate functions. Additionally, the difference in definition between d and d1 is unclear, thus their comparison (absolute difference) later on.
4) This system of F1-F4 is the most interesting part of the authors' work, although in practice it is a set of geometric constraints that define an optimal (smallest-error) solution for the target location. The authors should focus their experimental work there, illustrating different solution approaches with non-linear solvers, perhaps heuristic regressors, robustness, error stability, etc.
5) Two specific experimental setups, namely 'Simulated flight experiment' and 'Positioning error transfer experiment', are defined, without a specific 'Experiments' section in place. Furthermore, from the description it is unclear if actual data from real flights (non-simulated) is used in the second experiment.
6) In Table 4 there are numbers with accuracy up to five decimals or more in a scale of meters. This is obviously invalid, since the proposed model's accuracy cannot exceed the best possible actual location data of the input even if the best possible geolocation resolution is available (usually in the order of meters).
7) Since the error estimations are made upon simulated data, the multi-view approximation is assessed based on the simulation, not real-world restrictions. One such restriction is using planar geometry when in reality using km-scale distances on Earth (see Figure 3) requires non-linear topology or at least Haversive distance calculations. Hence, the assertion of 'milimeter-level error' (accuracy) is clearly invalid.
8) Section 4 is labeled 'Experiment Result and Analysis', while in practice the authors have already explained most of their experimental work previously (outside it) and in this section there are only additional comments about combining errors.
9) Overall, the manuscript is difficult to follow, especially due to extensive (unnecessary) descriptions of equation inductions and lack of proper sectioning of the material.
10) Some minor issues in the manuscript, including syntax/grammar errors, undefined abbreviations (e.g. 'DEM generation'), etc.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The author's edits in response to the issues and comments raised by the previous review are minimal and mostly addressing structuring, instead of the content. No major change in the methodology, experimental protocol, or supporting evidence of the results presented. As such, the most important pending issues from the previous review are still valid.
