C2VIR-SLAM: Centralized Collaborative Visual-Inertial-Range Simultaneous Localization and Mapping
Round 1
Reviewer 1 Report
This paper designs centralized SLAM for localization and mapping. This paper can be accepted after revision.
Comment 1. There have been extensive works on SLAM. The authors are expected to review those related ones, e.g., fast and robust data association using posterior based approximate joint compatibility test. Comment 2. In recent years, there have been intensive research on relaxing centralized protocols to distributed ones by using distributed consensus filters, distributed consensus filter on directed switching graphs, distributed consensus filter on directed graphs with switching topologies, or game theoretic formulation of the problem distributed recurrent neural networks for cooperative control of manipulators: a game-theoretic perspective. Please add a remark to discuss possible ways to relax the presented scheme to a fully distributed one by similar strategies.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear Authors,
thanks a lot for the submitted text. The contents is highly relevant and the overall quality high. Nevertheless, I would like to address a few items that might be improved:
line 42: some research has proposed => some researchers have proposed
line 44-47: incomplete sentence, maybe "...has shown that robots with ..." is what you want to express
line 53: some research proposed => some researchers proposed
Fig. 1: what is the meaning of the green and black dots? Please include them in your caption.
line 75: You are using the abbreviation VIO. As not all readers might be aware of VIO, the full term should be provided once (e.g. in this line)
line 87: The meaning of the sentence remains unclear. Maybe the verb bring should be replaced by brought?
line 100: The sentence is incomplete.
line 110-113: The second sentence needs to be rewritten or you have to combine the sentences in lines 110-113.
line 113: => Recent work has shown that even one ...
line 129: challenge => challenges
line 131: Whereas => In contrast to this approach, the centralized ...
line 152: => we propose
line 154: => we propose (or something similar)
line 160: optimizes => optimize
Fig 2 is not sufficiently explained: What is a keyframe? Is Buff short for Buffer?
Fig 2: I suggest writing Pre-integration instead of Pre-integrating
line 181: => ... is the IMU state that corresponds ...
line 207: please rewrite the sentence "While the UWB..." It does not makes sense in this way. Is it a continuation of the previous sentence?
Equation (6): The upper line will always be zero as the difference on the right hand side includes the exactly the same term twice. I assume the indexes are mismatched.
line 218: "... all the agents..." Do you really mean all of them? What about missing keyframe messages, if, e.g. one of the drones is too far away?
line 227: Then RANSAC is used => Then the RANSAC algorithm is used ...
line 231-233: Please rewrite this sentence, as its meaning remains unclear in its present form
line 272: please stay in present tense
line 273: optimizes => optimize
line 293: => frequency as the camera
line 300: Maurice 600 Pro (three words, not a single one)
Figure 4: The red lines are barely visible
Caption of fig 4: (read lines) => (red lines)
line 362: =>The UWB ranging contribution ... (if I understand the sentence correctly)
line 363 => We analyze
General discussion: I assume the computation time for the central server will increase faster than O(N). Increasing the number of swarm members might be a limitation of this approach. This should be discussed in the text as you are providing examples only for the smallest configuration.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
I have no further concern about this manuscript.
