Structured Urban Airspace Capacity Analysis: Four Drone Delivery Cases

Round 1

Reviewer 1 Report

The paper is well written and results are applicable and interesting. I recommend its publication as it is. 

Author Response

Thank you for reviewing the manuscript.

Reviewer 2 Report

The authors addressed the safety-important problem of drone route planning in the paper. The indicated solutions should facilitate decision-makers in the proper management of airspace. the simulations performed indicate the high usability of the proposed methods. 

Author Response

Thank you for reviewing the manuscript.

Reviewer 3 Report

The paper proposes a study to investigate strategies for the analysis of high-density very-low-level (VLL) urban airspace networks for UAV. It extended an existing algorithm to handle the use case of multiple UAVs on the VLL network. 

 

However, though the authors intended to use the study to give some intuition and support to the policymakers, urban airspace designers, and regulators, the paper has not achieved its objectives in its current form. 

 

Firstly, the proposed algorithm is a simple extension of previous algorithms proposed by the authors, which lacks novelty and is not difficult to design.

 

Secondly, the experiment should not pick an area with low-rise buildings for its experiment. UAVs can simply fly above the buildings in Oldbrook, Milton Keynes, United Kingdom and need not follow the ground road networks.

 

Thirdly, the paper is not well-organized. In Section 3.4 Line 266, the users are referred to Section 4 to understand the example for 1-to-M case.

 

Lastly, the experiment is too primitive to illustrate the effectiveness of the FCFS vs LCFS algorithm, as it contains only 100 simulations and small-scale test cases. 

Author Response

Thank you for reviewing the manuscript. Please check our response in the attached file.

Author Response File: Author Response.pdf

Reviewer 4 Report

The related works and contributions are clearly stated in Section 1. The writing stile, typo, consistency, quality of image, equation writing, should be improved. Others comments are

1) line 22, write the full form of sUASs

2) be consistent with UAS, sUASs, UASs, and explain the differences

3) line 28 Unmanned Aircraft System (UAS), however sUASs and UASs are not defined yet

4) break the paragraph with more than 8 sentences into two paragraphs

5) define M and N in line 74

6) line 92: etc.. -> etc.

7) use more variations of sentence transition logic words in paragraph lines 93 – 97

8) Put space between “Fig.” and its number: Fig.3 -> Fig. 3

9) It will great if the image is with format of EMF/WMF converted to PDF with highest quality with vector format

10) In caption Fig. 4, he closing bracket “)” is missing. \alpha is also not available in the image

11) punctuate full stop at the end of figure caption sentence

12) the are still found equations that have not been punctuated

13) in Fig.3 and Fig.4. -> in Figs. 3 and 4; apply also for Eqs., Tables, and Lines

14) Revise the sentence of (9) with complete sentence

15) CD&R (Conflict Detection and Resolution) -> revise the consistentcy

16) Revise (13), replace all word with one math symbols and then defined. Be consistent with math symbol. Do not use any words in the equation. Each letter in equations should have one unique meaning

17) In (14) and (15) shift the LCFS and FCFS from inside the bracket to the subscript

18) make it clearly and more discussion regaring Yen and Dijkstra. Provide the reason the use of Yen for finding the shortest distance. Dijkstra is algorithm for the IP Router

Author Response

Thank you for reviewing the manuscript. Please check our response in the attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

I thank the authors for taking my comments seriously and addressing them accordingly. I look forward to more publications from the author on the extension of the current study.