Simulation and Feature Extraction of the Dynamic Electromagnetic Scattering of a Hypersonic Vehicle Covered with Plasma Sheath

Round 1

Reviewer 1 Report

The essence of the paper is the use of the physical optics method to establish a more reliable theoretical model to simulate and analyze the dynamic electromagnetic scattering characteristics of hypersonic vehicles and extract the effective statistical features.

It is known that there are only a few reports on the dynamic scattering characteristics of hypersonic vehicles flying in near space based on the spaceborne detection platform and the interaction between electromagnetic wave and plasma sheath is not involved.

A detailed analysis of the content of the paper allows for the following comments:

1. In line 72, there is justification for selecting continuous wavelet transform to determine the features of dynamic radar cross section of hypersonic vehicle with different flying states in the time-scale matrix.
2. In line 88 et seq., incorrect placement of the dot with reference to Figure.
3. In line 125, number the formulas separately (5).
4. In line 388, after many simulation experiments were extracted 10 valid statistical features, but only 7 features are described in paper and Appendix A.
5. In line 442, I suggest formulating a mathematical sensitivity function dynamic radar cross section time series of a hypersonic vehicle covered with a plasma sheath on changes - the frequency of the incident electromagnetic wave, the detection height of space-borne radar, the flying altitude of the target spacecraft, and the flying speed, which will allow a more detailed analysis of the quality of vehicle detection and recognition in space.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The issue dealt with is of interest to scientists working on complex subjects in the radar field.  This paper deals with the extraction of dynamic electromagnetic (EM) scattering characteristics of a hypersonic vehicle covered with a plasma sheath, and this by exploiting the method of physical optics (PO). The overall structure and organization of the paper are relatively logical. However, it would be useful to answer the various questions and / or provide clarifications to the comments given below.

- it would be useful to reinforce the introduction by further specifying the problematic treated, the objectives targeted and clearly presenting the methodology adopted (by specifying the inputs-outputs of each stage of the methodology adopted to achieve the objectives). It would also be useful to clearly specify the added value of the content presented compared to the literature, by specifying the type of radar used (its characteristics including the waveform, the operating frequency, the use of pulse compression or not, its sensitivity, the type of targets that may be present by specifying an interval with regard to the RCS, the consideration of clutter and noise, ...).
- It would be useful to specify the taking into account of polarizations, even if the configuration considered is monostatic.
- Would it be useful to further justify the use of the OP (Optical Physics) method, depending on the operating frequency, the diffraction phenomena were not taken into account?
- It would be useful to specify the limits of the methodology adopted.
It would be important to specify the algorithmic complexity of the methodology adopted, in particular the computation time required in the simulations carried out.
It would be useful to specify how to implement the adopted methodology in a practical and / or operational context.
- The conclusion should be reinforced taking into account the questions below. And it would be useful to add the perspectives offered to the work presented in this version of the paper.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

This version of the paper is overall better with the answer to a majority of questions and comments. The perspectives offered to the work produced and presented in this paper need to be further clarified.    

Author Response

Please see the attachment.

Author Response File: Author Response.docx