Indoor Navigation—User Requirements, State-of-the-Art and Developments for Smartphone Localization

Round 1

Reviewer 1 Report

This paper presents the user requirements as well as methods, techniques and technologies for indoor navigation with smartphones.

It is undeniable that the author has in-depth knowledge of this field but the this paper doesn’t show a clear purpose and is not well structured. As a result, the contribution seems small compared to other surveys. In order to improve this paper, a particular scope or approach should be pointed out and developed in it.

Sections are unbalanced and unrelated, some paragraphs are redundant.

After an introductory section, section two presents the user requirements with many definitions that are not used in the following sections (neither the requirements, nor the definitions). In sections three, four and five, when reviewing methods, technologies and techniques, some are very detailed with examples from the author's earlier works and others are very short.

Concluding sections seven and eight are very short (one paragraph each).

Author Response

Please see my reply in the attached document.

Author Response File: Author Response.pdf

Reviewer 2 Report

The article looks comprehensive but requires a few modifications. Firstly, a check of the English language is required. The language is not concise. The paper needs editing by a native English speaker. Secondly, the references are not sufficient for the work. The author is suggested to add more references to existing surveys and works related to the field. Finally, there is no comparison mentioned in the paper with the existing surveys that focus on indoor positioning, localization, and navigation systems though the author has done a great job in comparing the existing indoor navigation systems and the medium/sensors used in those systems.

Author Response

Please see my reply in the attached document.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper involves much information on Indoor Navigation. The sections of it are written in proper order, and include the state-of-the-art technologies. It's helpful and useful in the people darly life with the smartphones.

There are the following problems:

In the horizontal coordinate of the figure 7，it should be "time"? In the longitudinal coordinate, it's better to use the unit of meters instead of dBm?

The figure 11 is not clear.

In the caption of the figure 16, there are two dots.

Author Response

Please see my reply in the attached document.

Author Response File: Author Response.pdf

Reviewer 4 Report

This survey presents most of indoor navigation approaches. The paper is well organized and clear presented. I have only two points:

1. Since you have read a lot of papers about fusion of two or more technologies, do you know how the two technologies are merged to one coordinate? E.g inertial dead reckoning + gnss. The trajectory obtained from ins is not in the same coordinate as gnss' global coordinate. I barely see any details about how to align them. Have you found any good information? Because this is an essential problem for all the fusion approaches.

2. I dont believe i can get such good step altitude from a smartphone as shown in the figure. I believe currently only few mems pressure sensors are able to do that in some controlled environment. So i am curious which smartphone is this? :)

Author Response

Please see my reply in the attached document.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

This paper is improved compared to the first version, reducing redundancy, extending some key aspects and adding new references.

Few typo errors have to be correct.