Position Estimation Method for Small Drones Based on the Fusion of Multisource, Multimodal Data and Digital Twins

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have discussed the challenges of maintaining positioning accuracy and stability during continuous maneuvers of small drones in complex environments. To address this, it proposes a fusion positioning method that incorporates three different sensor technologies: GPS, inertial navigation, and visual navigation.

 

 

 

Before recommendation for publication, I would suggest a few points as follows:

1. The abstract does not contain any useful information about the investigated model in this paper. However, they did not explain their meaning directly and effectively.

2.        The authors have presented some graphs without any physical explanation beside the resolution of these figures is very bad.

3.        write in symbols in equation and text in the same style. check line no. 209

4.         Check line numbers 272 and 273, t_1 and t_2 are in subscript.

5.         Authors must write the caption in detail, like what indicates each figure.

6.         Authors must relate the all results of numerical behavior with the proposed formation for better presentation.

7.         Authors need to emphasize the conclusion part to understand the overall work precisely.

8. Reference should be up to date, replace or cite the updated study.

9.      There are some typographic errors in Sections 3 and 4. Check it.

Author Response

Thank you very much for taking the time to review our manuscript. I have provided detailed responses to your suggestions and questions, and highlighted the corresponding revisions and corrections in different colors in the resubmitted manuscript. My responses are as follows, and the revised manuscript is attached.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper proposes a so-called multisource multimodal data and digital twin solution for a single small drone position estimation. The paper tested three solution versions and concluded that the solution involving the more sources, namely the solution GPS/VO/IMU, performs better than the other two solutions VO/IMU and GPS/IMU.  

The paper is organized into 5 sections, among which the introduction and the conclusion. In section 2, the authors describe the proposed solution global architecture and the physical and behavioral models of the drone. 

Il section 3 describes the multisource and multimodal fusion solutions, namely, the vision and odometry systems and the integration of GPS data using a pose graph optimization solution and finally the fusion of the real drone and its digital twin data using and extended Kalman filter.  

• The description of theoretical tools of the paper are scattered and lack to be contextualized and linked to each other's. For example, it is not clear where the model described in equations (1) and (2) is used in the overall solution. Is it used in the digital twin?  

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• In line 211, the angular velocity is said to be in rotation per minute and in table 1, it is given in rotation per second. Which one to keep? 

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• Why is it necessary to consider a positional loop and attitude loop in the behavioral model? Is it possible to unify the two? 

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• Cdot operation is not correctly written in equation (5). 

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• Same in line 284, a little latex typo, I guess. 

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• Some notation incoherence concerning the variable “u”, it is presented as the control command variable in section 2.2 and the IMU measurement in equation (8). 

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• The model in section 3.3 needs better clarification and should figure out how the real drone and the digital twin data are fused using the extended Kalman filter.  

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• In equation (20), it is not clear what “P” refers to. 

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• In equation (21), the matrix “H” should refer to the observation matrix and not the observation noise. Maybe the notation of the observation noise “W” is just missed. 

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• The experimental part should be enriched, with only one or two tests. Authors can consider simulation tests on real benchmarks and compare their solution to the existing solutions.  

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• Results should be averaged over multiple tests.  

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• Try to find some experiments to put forward the relevance or not of using multiple sources or the digital twin.  

 

Comments on the Quality of English Language

The english is quite good in my opinion.

Author Response

Thank you very much for taking the time to review our manuscript. I have provided detailed responses to your suggestions and questions, and highlighted the corresponding revisions and corrections in different colors in the resubmitted manuscript. My responses are as follows, and the revised manuscript is attached.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The overall quality is just about satisfactory. I would recommend a thorough revision.

Lines 13-16: The sentence is verbose. Please shorten it.

Line 18: Please replace the word "eliminating".

The main issue with the Abstract section is its faulty logic. It is incredibly difficult to ascertain the key point of your work. I would suggest this section be rewritten.

Line 31: Please replace the word "orderly".

All your references are incorrectly formatted!

Lines 31-33: Reference 1 - a study on indoor autonomous navigation systems - has no relevance to "urban traffic management".

Line 33: The meaning is unclear.

Line 34: The phrase "to ensure" is inappropriate as a subject.

Line 42: The word "suffice" seems ridiculous here.

The standard of your English writing is far too low, and a comprehensive revision is needed. Furthermore, I will no longer point out specific English errors in your manuscript.

This manuscript is difficult to read. I have done a general check of the figures, which appear to be worth publishing. However, I would strongly suggest that the authors first revise the manuscript to improve its readability.

Comments on the Quality of English Language

Has to revise English.

Author Response

Thank you very much for taking the time to review our manuscript. I have provided detailed responses to your suggestions and questions, and highlighted the corresponding revisions and corrections in different colors in the resubmitted manuscript. My responses are as follows, and the revised manuscript is attached.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Accept

Author Response

I sincerely appreciate you taking the time from your busy schedule to provide your valuable insights and feedback on my research.

Thank you very much for agreeing to review my manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

Some points of the contribution are improved. The proposed solution still relatively complex for the considered purpose. The authors should better highlight the interest in the use of the numerical twin.

Comments on the Quality of English Language

The english is good according to me.

Author Response

Thank you very much for taking the time to review our manuscript. I sincerely appreciate your valuable feedback and suggestions. We have carefully considered your comments and provided detailed responses to your suggestions and questions. We have also made the corresponding revisions to the manuscript, which are highlighted for your convenience.

My responses to your comments are as follows, and the revised manuscript is attached for your review.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

I doubt your English was edited by a so-called "English professor."  The English in the original submission was incredibly difficult to read. Therefore, I only carefully checked the grammar errors in the first page and provided comments to help you improve. I also expected that you could revise the rest of your manuscript (MS).

Unfortunately, I couldn't see a significant improvement during this revision. Meanwhile, NOT all my concerns were addressed. The English of the rest of your MS remains of low quality, which will hinder readers' understanding of your work. Therefore, I recommend rejecting this work due to its low readability. Unless you are willing to thoroughly revise your English.

For example, there are still many grammatical errors on your first page.

L33 it is not clear of where is the area that  " gradual opening of low-altitude airspace". Is this info really needed?

L35 how can a drones techcould be a "e a hallmark of contemporary technological progress"? 

L36 "However" is not needed.

L41 "Nevertheless" is wrong.

L43 " severe challenges during high-speed maneuvers 42 or prolonged flights." what challenges?  ref needed.

L44 This sentence is too complicate.

You NEED to carefully revise the rest of your pages. Ask real help instead of so-called "English professor."

Meanwhile, the format of refs are still wrong : ref1 to 16. 

Lot of your refs I could find them online!

Comments on the Quality of English Language

I doubt your English was edited by a so-called "English professor".

Author Response

Dear Reviewer,

Thank you for your detailed review and feedback on my manuscript. I highly value your concerns regarding the quality of the English language in the paper, and I fully understand that these issues can affect the readers' comprehension of our research findings. Therefore, I have promptly taken action by seeking professional English editing services from MDPI Author Services.

My manuscript has undergone comprehensive and meticulous language revision by MDPI's professional editorial team to ensure it meets the publishable academic English standards. Attached to this email is the certificate confirming that the article has been edited for correct grammar and technical terminology suitable for scholarly research. Additionally, I have included the revised manuscript with all changes highlighted in red for your convenience in reviewing.

I sincerely hope that this rigorously revised version meets your expectations and fully addresses the issues you have raised. I greatly appreciate your valuable comments and suggestions and am deeply grateful for the time you have taken from your busy schedule to review my paper.

Thank you once again for your patience and assistance.

Best regards,

Author Response File: Author Response.pdf

Round 3

Reviewer 3 Report

Comments and Suggestions for Authors

Good to go