ISAR Imaging of Non-Stationary Moving Target Based on Parameter Estimation and Sparse Decomposition
Round 1
Reviewer 1 Report
This manuscript proposes an ISAR imaging method for maneuvering targets based on Parameter Estimation and Sparse Decomposition. The authors make some interesting changes to the traditional maneuvering target ISAR imaging method, but the experimental part of the manuscript is not comprehensive enough to highlight the superiority of the proposed method. It is hoped that the authors will make further improvements to the manuscript. Here are my specific comments：
1. The use of time-frequency transformation to estimate the frequency and the chirp rate of echoes is common in ISAR imaging of maneuvering targets, and it is usually used in conjunction with CLEAN techniques. In this manuscript, the authors use LVD to estimate the parameters of all echo components simultaneously. This can improve the efficiency of the parameter estimation, but it also introduces some pitfalls. Due to the effect of cross terms (even if they do not focus), this operation may lead to inaccurate parameter estimation at weak scattering centers and reduced noise robustness of the algorithm. I think the authors should add theoretical analysis or relevant experiments in these two areas.
2. In the introduction, the authors mention the limitations of ISAR imaging method based on CLEAN technology. Therefore, I suggest the authors to add relevant comparison experiments in the experimental section, which might be a stronger proof of the superiority of the proposed method.
3. In the manuscript, the authors used WVD for ISAR imaging after reconstructing the echoes. However, it is possible to reconstruct the echoes using only the scattering center amplitude vector and frequency vector and use the RD algorithm for imaging. Please explain or demonstrate the superiority of the method in the manuscript.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
This paper studies the inverse synthetic aperture radar imaging problem for a non-stationary moving target and proposes a non-search imaging method based on parameter estimation and sparse decomposition. By combining LVD with the proposed sparse recovery algorithm, the received multi-component signals are resolved accurately into the sum of mono-component signals by exploiting the sparsity of the data in the CFCR domain to mitigate the trade-off constrain between time-frequency resolution and cross-term interference.
1. Ln 39, 61, and others. Should not use abbreviation on 'be verb' or 'auxiliary verb' in technical writing. Please revise the whole article.
2. Ln:41-42, in the literature review section, a more concrete algorithm summary is needed of the cited research rather than just using vague sentences, such as 'tedious procedures', and 'specific application scenarios'. It needs to have a clear statement in ‘Section I’ to lead out the necessity/contribution of the research. Please replenish more details of the cited research and how it inspired this research.
3. Ln 74 and others. Avoid the first-person position, such as 'we', or 'they' in technical writing. Third-person singular or past tense is preferred. Please revise the whole article.
4. Ln 97, 100, and others. Needs a 'comma' at the end of the equation when the sentence is not over and the next sentence starts in lowercase without an indent. Please revise all equations accordingly.
5. Ln 100, 101, and others. Needs a 'period' at end of the equation when the sentence is over and the next sentence starts with uppercase with an indent. Please revise all equations accordingly.
6. Ln 98, 102. Specify the definition of 'fast time' and 'slow time' of the waveform and the receiving signal.
7. Ln180-182. “data” uses a plural verb rather than a singular verb in the paragraph.
8. The caption of Fig2 is oversimplified. The top and the bottom plots need to ben illustrated respectively. The description in 2.2.2 is not clear associate with the top plot and the bottom plot. Need to be replenished.
9. The caption of Fig4 and Fig 5 is oversimplified. It is one of the key proposed ideas of the research. However, the content in 2.2.3 does not well illustrate/associate the structure/operation to each block.
10. Ln:364, fig 13 discussion has to be ahead of the figure presented at ln:361.
11. Specify ‘range compensation’ and ‘translation motion compensation.
12. Lack of details of simulation design/setup descriptions and scenario assumption in Ln 271-273. Is the entropy of these 120 points equal initially? It is a reasonable assumption for a sophisticated outfit object?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
This is a very well written article with an accurate text flow.
In section 3.2, results from a measured RCS data of a yak-32 aircraft are used to obtain the ISAR images but there is no reference about how this measured data is obtained (only dimensions of the aircraft with centrimetric accuracy!). Please, can you detail it in your text?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you for your reply to my comment. I note that you have made comprehensive revisions and additions to the manuscript. In my opinion, the revised manuscript is basically eligible for publication on remote sensing. Thanks again for your work!
Reviewer 2 Report
Adjust Fig 6 to a proper size for the labels and texts to be readable in an A4 printout.
