A Pragmatic Approach to the Design of Advanced Precision Terrain-Aided Navigation for UAVs and Its Verification
Round 1
Reviewer 1 Report
The authors proposed a federated filter based INS/GNSS/TRN integrated navigation system to obtain reliable navigation information for unmanned aerial vehicles (UAVs) even if a GNSS is not available or the degree of terrain roughness is not determined. However, there are some comments and questions about their work:
- English language should be considered carefully. e.g. in lines 6-12, the word “we” was used four times (try to reduce your authorial voice), and in line 7, don’t capitalize it. In lines 42-73, repeat “in this paper/study” four times.
- The paper is too long, please make it more concise so that the reader can catch your main points easier. Following is some examples:
- Section 1: The last paragraph is only an outline of structure, so make it brief.
- Sections 2 and 3 are about the methods, so try to make sure the descriptions are complete and as concise as possible. (e.g. line 112…, state them clearly in the Introduction section instead of repeat here.)
- Line 60, authors mention 2 works on INS/GNSS/TRN integration. Add more works to emphasize the advantage of your system.
- Your Conclusions section almost repeat explaining methods which is presented above. Hence, try to improve it by adding: judgment of possible application/ indicate limitations/ suggestions for improvements/ recommendations for future work.
- Your system seem complex, do you think it will cause payload problem in real applications since people are targeting small UAV design, especially in military area?
- Since no reference system to generate reference solutions (as actual solutions) in Section 4.2, what do you think about the accuracy of your evaluations?
Author Response
Dear Reviewer 1:
Thank you very much for the constructive comments concerning our previous manuscript. We have thoroughly considered all the comments and substantially revised our manuscript. We respond point by point to your comments, which is attached at the end of this letter.
(file name: ‘Response to Reviewer 1’)
And to indicate the location in the revision clearly, we attached the revised manuscript in red text for the revised contents.
(file name: ‘remotesensing-769659-revision’)
We hope this paper is suitable for “MDPI, Remote Sensing”. We deeply appreciate your consideration of our manuscript, and we look forward to receiving comments from you.
Thank you and best regards.
Your sincerely,
Jungshin Lee
Corresponding author:
Name : Jungshin Lee
E-mail : [email protected]
Author Response File: 
Author Response.pdf
Reviewer 2 Report
A federated filter based INS/GNSS/TRN integrated navigation system is studied. Batch processing and an auxiliary particle filter are introduced to TRN processing. The performance of the proposed system is validated through software-in-the-loop (SIL) tests and captive flight tests. The paper is well written. It provides interesting information to the field of robust navigation.
It is better for all keywords to appear in the abstract.
L46 guarantees
L50 tracking mode
L69 18st state variables????
Author Response
Thank you very much for the constructive comments concerning our previous manuscript. We have thoroughly considered all the comments and substantially revised our manuscript. We respond point by point to your comments, which is attached at the end of this letter.
(file name: ‘Response to Reviewer 2’)
And to indicate the location in the revision clearly, we attached the revised manuscript in red text for the revised contents.
(file name: ‘remotesensing-769659-revision’)
We hope this paper is suitable for “MDPI, Remote Sensing”. We deeply appreciate your consideration of our manuscript, and we look forward to receiving comments from you.
Thank you and best regards.
Your sincerely,
Jungshin Lee
Corresponding author:
Name : Jungshin Lee
E-mail : [email protected]
Author Response File: Author Response.pdf
Reviewer 3 Report
Please more specify this text "The captive flight tests used a CESSNA 172 Skyhawk with a hole to mount the IRA antenna on the back of the aircraft as shown in Figure 11. To minimize the mounting errors between the IRA antenna assembly and the INS, the testbed was manufactured to be mounted on the same jig, and all other equipment were mounted inside the aircraft using a separate rack." It’s necessary specify the installation point if is on the back or on bottom of the fuselage.
It’s necessary to described and calculate the error between the antennas of GNSS/IRA and installation point of IMU. This calculation is important to the precision measuring of the positioning.
In the Figure 6. it’s not readable text, please improve the resolution of the picture.
In the conclusion its necessary more precisely defined your output from your experiment. The authors must written the his scientific opinions or relevant scientific discusion to this results.
Author Response
Dear Reviewer 3:
Thank you very much for the constructive comments concerning our previous manuscript. We have thoroughly considered all the comments and substantially revised our manuscript. We respond point by point to your comments, which is attached at the end of this letter.
(file name: ‘Response to Reviewer 3’)
And to indicate the location in the revision clearly, we attached the revised manuscript in red text for the revised contents.
(file name: ‘remotesensing-769659-revision’)
We hope this paper is suitable for “MDPI, Remote Sensing”. We deeply appreciate your consideration of our manuscript, and we look forward to receiving comments from you.
Thank you and best regards.
Your sincerely,
Jungshin Lee
Corresponding author:
Name : Jungshin Lee
E-mail : [email protected]
Author Response File: Author Response.pdf
