Positioning Systems for Unmanned Underwater Vehicles: A Comprehensive Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents a comprehensive review on the positioning systems for UUVs. In general, the paper is well written. However, following comments need to be addressed prior to the acceptance of the paper.

1). In the introduction, the novelty of the study and the main contributions should be well highlighted. If needed contributions can be presented in point form.

2). It is said, " These autonomous or remotely operated vehicles are revolutionizing underwater exploration and monitoring by enabling the collection of data, inspection of submerged structures, and execution of complex missions without direct human involvement.". This statement should be supported by references. For example, data collection, inspection, etc. Followings are some suggestions. 

a). An Effective Data-Collection Scheme with AUV Path Planning in Underwater Wireless Sensor Networks.

b). Multi-AUV Placement for Coverage Maximization in Underwater Optical Wireless Sensor Networks.

3). The paper discusses the applications of AUVs and ROVs. It is helpful to provide some details and diagrams how they operate any components as well. 

4). Fig. 1 is not well draw. Try to draw in a professional manner. Less colors and consistent font style, with a compact diagram.

5). No results are provided in the paper. It is helpful to provide some results and provide a discussion. Specially how accurate these positioning methods. 

6). Future directions section is poor. You can provide is before the conclusion as this is a review. Also, it should be supported by possible future research opportunities and directions.

 

Author Response

Response to Reviewer

• Comment: In the introduction, the novelty of the study and the main contributions should be well highlighted. If needed contributions can be presented in point form.

 

Response: Thank you for providing further guidance. According to your proposal, we have added in the introduction the novelty of the study. Contributions are presented in point form as you advised. Additions are presented in lines 67-88.

 

 

• Comment: It is said, " These autonomous or remotely operated vehicles are revolutionizing underwater exploration and monitoring by enabling the collection of data, inspection of submerged structures, and execution of complex missions without direct human involvement.". This statement should be supported by references. For example, data collection, inspection, etc. Followings are some suggestions. 

1. An Effective Data-Collection Scheme with AUV Path Planning in Underwater Wireless Sensor Networks.
2. Multi-AUV Placement for Coverage Maximization in Underwater Optical Wireless Sensor Networks.

 

Response: Thank you for assisting us in enriching both our knowledge and the value of our paper. References have been added as appeared in Introduction line 29. After careful consideration, both references add invaluable insights regarding unmanned underwater vehicles. In the reference section, they are numbered as 1 and 2.

References added:

1. An Effective Data-Collection Scheme with AUV Path Planning in Underwater Wireless Sensor Networks.
2. Multi-AUV Placement for Coverage Maximization in Underwater Optical Wireless Sensor Networks.

 

• Comment: The paper discusses the applications of AUVs and ROVs. It is helpful to provide some details and diagrams how they operate any components as well. 

 

Response: We appreciate your comment and after our consideration indeed a diagram and its detailed explanation would be enlightening. After renumbering we added a fifth subsection at section 2. Our addition is showcased in lines 414-454. In this diagram, we present an ROV system and its systems. Furthermore, we explain how these components connect and interfere with the behaviour of the ROV.

 

• Comment: 1 is not well draw. Try to draw in a professional manner. Less colors and consistent font style, with a compact diagram.

 

Response: After carefully examining our methodology and research we concluded that the previously named Figure 1 was unnecessary. As you highlighted the figure was not well drawn with various inconsistencies regarding the color and font style.

 

• Comment: No results are provided in the paper. It is helpful to provide some results and provide a discussion. Specially how accurate these positioning methods. 

 

Response: Thank you for helping us improve our paper even further. After analysing our paper, indeed, we didn’t provide any Section about our results and we mistakenly included them in Section 4 Subsection 4.2. A new Section 5 named results and renumbering has been made. Section 5 is showcased in line 622. In this Results Section we present our findings by categorizing them in tables. Table 4 has been added regarding the accuracy of several positioning and navigation systems. Table 4 presents the accuracy of systems, the reasons behind accuracy degradation, and the error rate that emerged from simulations and tests made by the authors of the respective papers. Following our further research, we needed to provide a discussion regarding our results and especially the accuracy of these positioning systems under various conditions. Therefore, we provided more insight into our Discussion by addressing the accuracy problems. To be precise the additions were made in lines 731-809.

 

• Comment: Future directions section is poor. You can provide is before the conclusion as this is a review. Also, it should be supported by possible future research opportunities and directions.

 

Response:  Thank you for your comment. The Conclusion Section has been deleted. We included more future directions and research opportunities in the UUV field as showcased in lines 866-886. Also, the Conclusions section has been deleted and added to the Discussion Section. This addition takes place in lines 810-838.

 

 

We would like to thank you for your insightful comments and helpful suggestions. We appreciate your effort because it helps us improve the quality of our manuscript. We have tried our best to make revisions accordingly to improve the manuscript.

 

Yours,

 Sincerely,

              Christos Alexandris, Panagiotis Papageorgas, Dimitrios Piromalis

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Exploring various aspects of positioning systems used in unmanned underwater vehicles (advantages, limitations, etc.), the paper presents an extensive review based on the analysis of an impressive number of scientific works in the field. The bibliography contains a number of 127 articles, 27 of which being analyzed in detail. Based on the extensive study carried out, the paper offers a classification of these unmanned underwater vehicles (chapter 2), with an emphasis on their positioning systems (chapter 3). The article, maybe a little too long, is well written, being a good compendium for the analysis of the issues of the studied field.

 Comments, questions and recommendations for the manuscript improvement:

- In my opinion, I think that the Abstract contains too much introductory, general primary information, presenting the field of Unmanned Underwater Vehicles (what they are, their utility and role...). This information is more appropriate in an introductory chapter. The abstract should rather highlight (a little more broadly exposed) what exactly the scientific research carried out presents, as well as the contributions and novelty brought by the article. Only the last two sentences of the abstract relatively point out these aspects.

- Is such a detailed chapter 4 (especially subchapter 4.1, regarding the description of the research methodology) really necessary? For example, is the Figure 1 absolutely mandatory? These numbers are relative, and a repetition of the performed searches will surely return other results. In my opinion, the reader is more interested in the results of the review study and less in the presentation of how to obtain them.

- I think a renumbering of some paragraphs/subsections (or removal of a numbering) is necessary. If within subchapter 2.2 there is a subsection 2.2.1, where is the subsection 2.2.2? If there is no subsection 2.2.2, numbering 2.2.1 is not necessary. It can be seen that subchapter 2.4 has, correctly numbered, two other subsections: 2.4.1 and 2.4.2.

Author Response

Response to Reviewer

 

• Comment: In my opinion, I think that the Abstract contains too much introductory, general primary information, presenting the field of Unmanned Underwater Vehicles (what they are, their utility and role...). This information is more appropriate in an introductory chapter. The abstract should rather highlight (a little more broadly exposed) what exactly the scientific research carried out presents, as well as the contributions and novelty brought by the article. Only the last two sentences of the abstract relatively point out these aspects.
  
  

Response: Thank you for your insightful feedback. Your guidance has added immense value to our paper. We have revised the abstract following your suggestions and hope that it now offers more substantive information than before.

 

• Comment: Is such a detailed chapter 4 (especially subchapter 4.1, regarding the description of the research methodology) really necessary? For example, is the Figure 1 absolutely mandatory? These numbers are relative, and a repetition of the performed searches will surely return other results. In my opinion, the reader is more interested in the results of the review study and less in the presentation of how to obtain them.

 

Response: After careful reflection on our research, we decided to further streamline Section 4 by omitting certain details from Subsection 4.2. Additionally, we removed Figure 1, as per your suggestion, recognizing that repeating the searches would likely yield different results. Despite the removal of Figure 1, we felt it was important to provide numerical data related to our research. To address this, we replaced the figure with three sentences presenting the relevant numbers after each filtering stage. These additions can be found in the following lines:

• Filter 1: Line 590
• Filter 2: Lines 596-597
• Filter 3: Lines 604-605

Furthermore, we condensed the original Subsection 4.2 and created a dedicated Results Section in response to the other reviewer's comments. The Results Section now begins on line 623.

 

• Comment: I think a renumbering of some paragraphs/subsections (or removal of a numbering) is necessary. If within subchapter 2.2 there is a subsection 2.2.1, where is the subsection 2.2.2? If there is no subsection 2.2.2, numbering 2.2.1 is not necessary. It can be seen that subchapter 2.4 has, correctly numbered, two other subsections: 2.4.1 and 2.4.2.

 

Response: Thank you for pointing out the oversight. We have removed Subsection 2.2.1, as there was no corresponding Subsection 2.2.2. Similarly, Subsection 2.1.1 has also been deleted due to the absence of Subsection 2.1.2.

Thank you for your valuable insights and thorough review of our paper. Your feedback has greatly contributed to improving the clarity and structure of our work.

Sincerely,

              Christos Alexandris, Panagiotis Papageorgas, Dimitrios Piromalis

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have well addressed the comments from the reviewer. There are no major comments from the reviewer. However, there are minor typos in the paper. Please check carefully and correct.

Comments on the Quality of English Language

The use of English in the paper has been improved. However, there are minor typos in the paper. Please check carefully and correct.