Robust Localization for Robot and IoT Using RSSI

Round 1

Reviewer 1 Report

This paper presents the application of a robust ranging method that can be applied in elderly patients monitoring system of a nursing home whereby the RSSI method is used. Experimental results show a measured point from the application of the trilateral technique. Furthermore, the error distance between the ideal point and the measured point is smaller than other RSSI methods. I think the subject of this paper is interesting, and this paper well organized. However, I have some questions and requirements.

1. A better readability is required for this paper and revise it for a smooth reading, for example, please change We to I because the number of authors of this paper is one.

And time difference of arrive (TDOA) -> time difference of arrival (TDOA) etc.

2. please check your reference number in manuscript, for example, the reference number of equation (1) of Friis is 26.

Using Fig. 1 as a basis, we can describe the relationship between the received power and the transmitted power through equation (1), which was proposed by Friis [25], as follows:

-> Using Fig. 1 as a basis, we can describe the relationship between the received power and the transmitted power through equation (1), which was proposed by Friis [26], as follows:

3. Why did you apply only the trilateral technique for the experiment in this paper, while three algorithms are typically used to calculate the distance to the unknown node in the field?

4. The size of the space environment assumed 30 [m] × 30 [m] for the computer simulation using RSSI. However, you applied in 20 x 20 [m] because you cannot find such a size in indoor. Would it not be better to match the size of the space environment to use the results of the simulation as predictions of the experimental results?

5. Please add a discussion about different points between your RSSI in this paper and the other RSSI [16] of table 1 to reduce the RMS error in chapter 4.

Author Response

I am very appreciate for reviewer’s comment.

1. A better readability is required for this paper and revise it for a smooth reading, for example, please change We to I because the number of authors of this paper is one.

And time difference of arrive (TDOA) -> time difference of arrival (TDOA) etc.

(Answer) I changed to “it”, “this paper”, or other reasonable words instead of “We”. 

         I also changed time difference of arrival (TDOA) to time difference of arrive (TDOA).

2. Please check your reference number in manuscript, for example, the reference number of equation (1) of Friis is 26.

Using Fig. 1 as a basis, we can describe the relationship between the received power and the transmitted power through equation (1), which was proposed by Friis [25], as follows:

 -> Using Fig. 1 as a basis, we can describe the relationship between the received power and the transmitted power through equation (1), which was proposed by Friis [26], as follows:

  (Answer) I changed Friis [26] instead of Friis [25]

3. Why did you apply only the trilateral technique for the experiment in this paper, while three algorithms are typically used to calculate the distance to the unknown node in the field?

 (Answer)Generally, because trilateral technique is superior to other two method to calculate the distance to the unknown node, this paper only focus on trilateral technique. I add this sentence in line 187-190.

4. The size of the space environment assumed 30 [m] × 30 [m] for the computer simulation using RSSI. However, you applied in 20 x 20 [m] because you cannot find such a size in indoor. Would it not be better to match the size of the space environment to use the results of the simulation as predictions of the experimental results?

  (Answer)This paper applied 30 [m] × 30 [m] and 20 x 20 [m] for computer simulation and experimental location as space environment, respectively. Because this paper used value of RSSI as each node points, I think space size is not a serious problem. In this case, big serious problem is noise due to an obstacle or interference of propagation. Thus through this paper, I considered noise in computer simulation as well as real environmental situation of office in experimental environment.   

5. Please add a discussion about different points between your RSSI in this paper and the other RSSI [16] of table 1 to reduce the RMS error in chapter 4.

(Answer) I found reference number is wrong [16, 19] in table 1, thus I changed reference number [19, 18], respectively. 

And I add sentence for different point proposed method and previous method [19]

Author Response File: Author Response.docx

Reviewer 2 Report

 (Line 53-56) Please re-state comment about fusion algorithms. The language is a little bit confusing. 

In Table 1. author mentioned that, he tested three different algorithms and calculated RMS values. Please provide more details in the supplementary.

(Line 181-184) Please provide brief reasoning for choosing the trilateral technique over the other two techniques.  

Throughout the manuscript, the author used the term "elderly patients monitoring system", I think this term can be misleading to readers. The term monitoring can include various medical information of patients (ie. vital sign). The focus of this study is the tracing location of each patient. I suggest restating the term. 

(Line 320-323) The author mentioned that there is a difference between the simulation area and the experimental area. Please provide a short discussion in the result or conclusion about the effects of test field difference between the simulation and the experiment.

(Experimental, line 372-376) There are only two cases are presented in the experimental section, but the author comment at the end of the section sounds like he has 100 more measurements. Please provide more detail about this in the supplementary.     

Author Response

I am very applicate for reviewer’s comment.

1.      (Line 53-56) Please re-state comment about fusion algorithms. The language is a little bit confusing.

(Answer) I added and restate in the line 54-57 to avoid confusion. 

2.      In Table 1. author mentioned that, he tested three different algorithms and calculated RMS values. Please provide more details in the supplementary.

(Answer) I added and restate in the line 119-120 and table 1.

3.      (Line 181-184) Please provide brief reasoning for choosing the trilateral technique over the other two techniques.  

(Answer) I added and restate in the line 187-190.

4.      Throughout the manuscript, the author used the term "elderly patients monitoring system", I think this term can be misleading to readers. The term monitoring can include various medical information of patients (ie. vital sign). The focus of this study is the tracing location of each patient. I suggest restating the term. 

(Answer) I revised tracing location of each patient instead of term “elderly patients monitoring system”.

5.      (Line 320-323) The author mentioned that there is a difference between the simulation area and the experimental area. Please provide a short discussion in the result or conclusion about the effects of test field difference between the simulation and the experiment.

 (Answer) I added difference between the simulation area and the experimental area in line 401-404.

6.      (Experimental, line 372-376) There are only two cases are presented in the experimental section, but the author comment at the end of the section sounds like he has 100 more measurements. Please provide more detail about this in the supplementary.   

(Answer) In order to calculate the more exact RMS error, I try to 100 times in the real field. However, because of the limitation of page of this paper, this paper only illustrate two case. However, this paper add several measuring data as table 4 and explain in line 383-390.  

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This paper presents the application of a robust ranging method that can be applied in elderly patients monitoring system of a nursing home whereby the RSSI method is used. Experimental results show a measured point from the application of the trilateral technique. Furthermore, the error distance between the ideal point and the measured point is smaller than other RSSI methods. I think the subject of this paper is interesting, and this paper well organized.