Remote Data Acquisition Using UAVs and Custom Sensor Node Technology
Round 1
Reviewer 1 Report
Dear Authors,
please refer to the attached document. Thanks!
Comments for author File: 
Comments.pdf
The text is reasonably clear so this reviewer recommends a moderate control of English language.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Reviewer 2 Report
This paper presents a low-cost data acquisition system applied to Precision Agriculture. A design and manufacture of sensor nodes and custom wireless receivers node were well exposed and referenced.
Comments:
1) The authors say that the system is low-cost. Can they provide the total cost of the whole system? And it can help if they can compare with existing comercial systems.
2) How are located the sensor nodes in the field? Which dimensions has the recovered field? Maybe an scheme of the real agricultural field can help to see how the system works.
3) In Figure 12, why the EC seems to decrease? It is consistent with soil moisture, maybe the weather affects it. The authors must mention meteorological conditions during these 4 days, to rule out sensor failure.
4) Comment if sensor failures are considered, or how they can be faced.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Reviewer 3 Report
The proposed solution is an automated data collection system for precision agriculture that uses a UAV as a mobile sink node. The system’s focus is to be low-cost, easy to operate, and entirely wireless, using custom sensor nodes and a wireless receiver node to collect and transmit data to a predetermined access point via Wi-Fi.
This paper's contributions include designing and manufacturing a low-cost and easy-to-operate automated data collection system for precision agriculture using a UAV as a mobile sink node. The method comprises customized sensor nodes and a wireless receiver node that transmits data wirelessly to the drone for further transmission to a predefined access point via Wi-Fi. The system underwent field testing, collecting soil data, such as soil moisture, temperature, and electrical conductivity. Additionally, the paper discusses the system's adaptability and proposes potential improvements.
Regarding limitations, the paper needs to discuss the potential impact of weather conditions on the system’s operation, which could be a limitation in specific environments. Finally, the paper needs to compare the proposed system with other existing precision agriculture technologies.
The paper can be improved further in terms of technical analysis.
o The paper talks about range but does not specify the distance radio communications can reach.
o If multiple sensor nodes were used instead of one, it would have strengthened the paper.
o The authors have used TEROS 12 sensor for soil moisture which is costly. The authors have utilized mobile sink nodes that can cover more considerable distances, which would require more of these expensive nodes. They will ultimately increase the cost of the overall system.
o Needs to talk about the impact of weather conditions on the system’s operation.
Overall Comments
o Introduction can be improved by adding more recent existing precision agriculture technologies.
o The results have been presented with sufficient analysis. However, a few more variations in the result sections are encouraged.
o The resolution of the figures must be improved.
o In general, the quality of the paper is good, and addressing the above-mentioned points is highly encouraged.
The English language and spellings are okay.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Reviewer 4 Report
The paper proposes a custom hands-on approach to validate the theoretical benefits of a UAV to ground-sensor system in comparison to traditional methods of obtaining on-field parameters such as soil temperature, humidity, etc. The authors presented solid work related to the implementation of the system (enclosures, assemblies, etc.). The authors argue that previous studies have merely taken a theoretical approach to designing and evaluating such systems. While this might be true, the sole practical design of the system does not pose any scientific merit, but rather (and only possibly) the results and conclusions obtained from it. As the current system presented in the article consists of only one sensor node and one non-autonomous drone, it falls short when it comes to implementing a real-world example that could be used for precision agriculture. As such, its results cannot be compared to traditional approaches or theoretical ones in terms of effectiveness, robustness, and cost-efficiency. Currently, it is more a piece of work in technology development than scientific work and does not contain enough novelty for journal publication.
Suggestions:
1) In the abstract, the focus should be put on the novelty of the proposed system and the results obtained from it. Currently, a major part of the abstract consists of an overview of the designed system, which will be elaborated later on anyway. Accordingly, it could be shortened.
2) The Introduction should incorporate and emphasize the authors’ hypothesis, and approach to solving the problem, as well as the novelty of the work.
3) System Overview section fits better with the Material and Methods section.
4) Line 107 – The authors mention that the proposed system “employs a low-attitude autonomous drone”. The autonomy of the drone is later never elaborated on nor mentioned again. In fact, the authors mention a drone’s pilot (lines 190, 191, 199, 200), which begs the question – is the drone autonomous in the current state of the system? If it is, then the autonomy of the drone needs to be thoroughly elaborated as it could be a crucial part of the system’s efficiency and robustness. If it isn’t, then “employs a low-attitude autonomous drone” cannot be stated, nor it can be stated that UAV is used in the system.
5) Page 8 and page 9 – the whole text is too cumbersome and full of unnecessary details not interesting to the wider audience. Main components should be listed, as well as their functions in the system, but a detailed explanation of basic components such as MOSFET, PCB, etc. does not belong in the article.
6) The Results section only shows values obtained from the sensor node over a short period of time. The efficiency of the system is only commented and it needs to be further elaborated and backed up with measurements. The authors should at least add a graph of energy consumption during the deep sleep and during the active state of the sensor node (specifically during the communication with the drone – how much energy does communication consume, are there any voltage spikes, etc.). Greater emphasis should be put on communication efficiency as well – how long does it take to make a connection and transfer the data, can it be more efficient, how would it scale for a larger network of nodes, and what would happen in a case of unsuccessful connections? Battery life should be also analyzed during a longer period of cloudy days (i.e., without constant recharging from the solar panels).
7) It could be beneficial if the software-related part of the system is introduced and explained.
8) My main concern is that there is no comparison of the results with any related solution in any terms. To give scientific merit to the article, at least one or two comparisons with related work should be given.
Author Response
Please see the attached file.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear Authors,
please refer to the comments below. Thanks!
Comments from Reviewer V_3:
The second version of the manuscript with the original title “Remote Data Acquisition using UAVs and Custom Sensor Node Technology” has been reviewed. I have read with much interest the corrected version of this manuscript and I believe that, the topic is of great interest. The authors
have taken all of my observations into consideration and have done a good job at making the manuscript more cohesive with their aim. This reviewer appreciates the efforts made by these authors therefore, in light of these results, this reviewer recommends the acceptance of this paper.
I have no comments on the English language and its style so this reviewer recommends a minimum control of English language.
Author Response
Dear Reviewer,
Thank you for your valuable feedback. The manuscript has been checked for any typos and has been updated.
Reviewer 4 Report
The authors made significant improvements in the revised version of the article. They addressed all of my concerns except the scientific merit. The authors did introduce comparisons with other (almost) related work and did a fair explanation. However, comparing the UAV flying and scanning the whole crop field against the proposed system (1 sensor node and drone sink) is not fair. Besides, comparisons in terms of cost are also not fair. It would be better to compare the systems in terms of power consumption or efficiency.
Suggestions:
Consider using some low-power wireless technologies (BLE, LoRaWAN, WiFi HaLow, or others) instead of WiFi for communication between the drone and sensor node.
Author Response
Dear Reviewer,
Thank you for your valuable feedback. The manuscript has been revised, taking into account your comments. The energy efficiency comparison has been included and discussed (Table 1). Some other wireless technologies have also been discussed under "Limitations and Future Work."
