Terminal Impact Time Control Cooperative Guidance Law for UAVs under Time-Varying Velocity

Round 1

Reviewer 1 Report

Well writen article.

Assumtions are folowed by simulations what proof the thesis.

I sugest to do some work with editor, and edit the equations, to be more clear and according to the editorial requirements.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript claims control for an impact time for multiple UAVs. There are some numerical investigations presented considering multiple UAVs and velocity variations. 

• The references in the literature review are selective - some optimization-based approaches can be added. For example, MPC applications on aerospace systems can be referred.
• Please explain what UAV refers to in this manuscript. Since there is a highlight on the aerodynamic forces, there is a need for the description of the system at hand. 
• Is there any typesetting that you are using? The size of the equations d not seem proportional to the text size. 
• What are the impacts of the differences between Section 2.2 and 2.3? The same question is also valid for Section 3.
• Could you please add a symbol list that can help to follow the equations?
• In the simulations, is it assumed that the vehicles are the same? 
• The results section and the connection to the former section need to be clarified. 
• What is the ground truth in the simulations? For example, how is the computation for Fig. 4? 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

In this paper, the authors studied the terminal multiple UAVs cooperative guidance problem with impact time control under time-varying velocity. They proposed two analytical functions of velocity with respect to time under time-varying velocity and conducted many simulations to verify their study.

However, for readers’ better understanding, more explanations should be added to explain the development of equations in more detail. In addition, many errors should be fixed and many modifications should be required as follows:

1. The presentation should be improved. The followings are some examples.
   1. The introductory statement and explanations about related work are placed together in introduction section, so it is not easy to catch the motivation of this work. I think it’s better to explain related work separately and supplement the introduction more.
   2. For better presentation, new tables are needed to present notations and their definition.
   3. In lines 173~174, the authors should explain the development of equations in more detail.
   4. In lines 180~181, the authors should explain the development of equations in more detail.
   5. In lines 249~250, the authors should explain the development of equations in more detail.
   6. In lines 270 and 276, is “==” right presentation?
   7. In line 350, “Take” -> “Taking”
2. There are so many errors in equation numbers.
   1. In line 352, is “Equations (56) and (57)” right? I think that “Equations (52) and (53)” is right.
   2. In line 363, is “Equation (59)” right?
   3. In line 379, is “Equations (60) and (62)” right?
   4. In line 381, is “Equation (64)” right?
   5. In line 383, is “Equation (65)” right?
   6. In line 385, is “Equation (66)” right?
   7. In line 387, is “Equation (67)” right?
   8. In line 395, is “Equation (68)” right?

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

No further comments - an addition of a summary paper for MPC on aerospace systems can cover the corresponding and related problems, e.g., Model predictive control in aerospace systems: Current state and opportunities. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Overall, it seems that the authors worked hard to improve the quality of the paper. However, there is still a serious point which should be addressed.

The authors explained the differences between the manuscript and their previous work [31] and described the novelty of the manuscript. However, the authors need to additionally explain the differences between the manuscript and their another previous work,

Jiang, Zhanyuan, et al. "Impact Time Control Cooperative Guidance Law Design Based on Modified Proportional Navigation." Aerospace 8.8 (2021): 231.

The manuscript and the above paper have many similar figures, equations, and explanations. Especially, it seems that Figure 10 in the above paper and Figure 6 in the manuscript look exactly the same. Thus, the authors should mention the above paper in the manuscript, clarify the differences between them, and clearly explain the novelty of the manuscript compared to the previous work.

Author Response

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Author Response File: Author Response.pdf