Algorithm and Application of Foundation Displacement Monitoring of Railway Cable Bridges Based on Satellite Observation Data
Round 1
Reviewer 1 Report
The authors have presented interesting results. Below are comments for the authors to consider.
The manuscript has listed 20 references. However, they not properly cited in the manuscript. The authors should follow the guidelines to properly cite these publication in the manuscript.
Line 62: Remove the “space” between the word “de-noising” and “comma”.
Line 108: What does “sigma” represent in Equation (1)?
Line 140 to 142: Is it “r n (t)” or “r N (t)”? The “n” for “rn” in Line 140 should be formatted with a “subscript”.
Line 154: Is “Ref. [,]” for a Missing Reference?
Line 189: What is the unit for the observation time in Figure 3?
Lines 191 to 199: Any justification that the calculations were only carried out for 30 min, 1 hour, 2 hours and 4 hours?
Line 201: Figure 4: Were the observation time terminated after 8 hours? Any supporting information for the stability test of GNSS to only include 8 hours of observation?
Line 201: Figure 4: What are the “a. horizontal” and “b elevation” referring to?
Lines 232 to 237: The authors have listed several settlement prediction methods. The authors should cite them using the publisher guidelines.
Line 262: Figure 6. What represent the “Residual” and “reservation” mentioned in the flow chart?
Lines 277 and 278: Figure 8. How far apart are the observation station and the reference station? The authors mentioned a base station. Where is this base station located?
Line 285: Figure 11. There are spikes in the original data. Any explanation for those spikes in the data? Further, in Figure 11 (b), the pre-processed data showed a movement (or settlement) of 50 mm from the first day of the observation. Have the authors benchmarked it with other instrumentations?
Line 305: Add a “space” after the word “Table 1”.
Line 311: Figure 12. How was the “precise leveling” data obtained?
Line 388: Table 2. Please use the correct font size.
Line 394: Figure 16. Please use the correct font size for the figure caption. Does the
Line 407. Table 3. Please correct the font size for the Table caption.
Have the authors considered the reason to have observed a 50 mm cumulative settlement? Is it a secondary settlement?
Author Response
To reviewer 1:
The authors have presented interesting results. Below are comments for the authors to consider.
- The manuscript has listed 20 references. However, they not properly cited in the manuscript. The authors should follow the guidelines to properly cite these publications in the manuscript.
Response: We greatly appreciate the reviewer's attentive reading. The references have been accurately cited in the amended manuscript.
- Line 62: Remove the “space” between the word “de-noising” and “comma”.
Response: The “space” between the word “de-noising” and “comma” has been removed.
- Line 108: What does “sigma” represent in Equation (1)?
Response: The expression of Eq. (1) has been revised.
- Line 140 to 142: Is it “r n (t)” or “r N (t)”? The “n” for “rn” in Line 140 should be formatted with a “subscript”.
Response: Correction has been made in the revision.
- Line 154: Is “Ref. [,]” for a Missing Reference?
Response: The references have been correctly cited.
- Line 189: What is the unit for the observation time in Figure 3?
Response: The unit of observation time has been added in the revised manuscript.
- Lines 191 to 199: Any justification that the calculations were only carried out for 30 min, 1 hour, 2 hours and 4 hours?
Response: As shown in the figure, the GNSS positioning method's variation range of the monitoring data gradually shrank as the calculation length increased, leading to smaller variance among the observed data. From the accuracy and stability experiment of GNSS, it can thus be concluded that the GPS+BDS data and the 4-h calculation scheme result in higher data positioning accuracy. In general, as the time step was increased, GNSS data stability increased.
- Line 201: Figure 4: Were the observation time terminated after 8 hours? Any supporting information for the stability test of GNSS to only include 8 hours of observation?
Response: It is evident that longer periods of observation will yield better results. However, field experiments are hampered by various variables.
- Line 201: Figure 4: What are the “a. horizontal” and “b elevation” referring to?
Response: The appropriate correction has been added.
- Lines 232 to 237: The authors have listed several settlement prediction methods. The authors should cite them using the publisher guidelines.
Response: The reasonable references have been included.
- Line 262: Figure 6. What represent the “Residual” and “reservation” mentioned in the flow chart?
Response: By applying the EMD, a signal can be expressed as3, 4
where ci is IMF component of i; rn is final residue.
The EMD technique continues until the residue becomes so little that it is less than a predefined value of consequence, or the residue becomes a monotonic function.
- Lines 277 and 278: Figure 8. How far apart are the observation station and the reference station? The authors mentioned a base station. Where is this base station located?
Response: The distance from the base station to the observation station is less than 2 kilometres. We added this description in the revised manuscript and figure 7.
- Line 285: Figure 11. There are spikes in the original data. Any explanation for those spikes in the data? Further, in Figure 11 (b), the pre-processed data showed a movement (or settlement) of 50 mm from the first day of the observation. Have the authors benchmarked it with other instrumentations?
Response: The data of this study is analyzed by using the proposed method from March 14th 2018 to June 27th 2019. These phases are respectively corresponding to the concrete pouring of the 6th tower section and the concrete pouring of the 54th tower section, with a total of 63 manual measurements by precise leveling during this time.
- Line 305: Add a “space” after the word “Table 1”.
Response: Correction has been made in the revision.
- Line 311: Figure 12. How was the “precise leveling” data obtained?
Response: In this study, our group measures foundation settlement by utilizing digital level to validate the proposed approach.
- Line 388: Table 2. Please use the correct font size.
Response: Correction has been made in the revision.
- Line 394: Figure 16. Please use the correct font size for the figure caption. Does the
Response: Correction has been made in the revision.
- Line 407. Table 3. Please correct the font size for the Table caption.
Response: Correction has been made in the revision.
- Have the authors considered the reason to have observed a 50 mm cumulative settlement? Is it a secondary settlement?
Response: The data of this study is analyzed by using the proposed method from March 14th 2018 to June 27th 2019. These phases are respectively corresponding to the concrete pouring of the 6th tower section and the concrete pouring of the 54th tower section, with a total of 63 manual measurements by precise leveling during this time.
Reference:
- Griggs, E., E.R. Kursinski and D. Akos, Short-term GNSS satellite clock stability. Radio Science, 2015. 50(8): p. 813-826.
- Hesselbarth, A. and L. Wanninger. Short-term Stability of GNSS Satellite Clocks and its Effects on Precise Point Positioning. in Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008). 2008.
- Huang, N.E., et al., The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis. Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 1998. 454(1971): p. 903-995.
- Youlin, X. and C. Jun, Characterizing Nonstationary Wind Speed Using Empirical Mode Decomposition. Journal of Structural Engineering, 2004. 130(6): p. 912-920.
The work presents and interesting framework for displacement monitoring of cable bridges using satellite observation data. Although the results are consistent, the authors are recommended to highlight the significance of the method in terms of accuracy and also resource allocation compared to traditional methods.
The following comments should be considered in the review process:
General comments:
- The introduction does not provide any reference to past works within this subject and also do not have any supporting references for the observations that are made. The authors must back up their premises with solid references on the field.
Response: The references have been correctly cited.
- There must be an explanation of the framework itself before going to the theoretical parts. Why do the authors choose these methods and what are the benefits compared to existing monitoring schemes? Is this method more precise or less costly than traditional methods? The method is briefly explained from lines 247 to 259, which must be enlarged and the specific steps of the method must be highlighted, as it is the main contribution of this work.
Response: The specific steps have been added in the section 4 (from lines 265 to 274).
- The manuscript should be revised by an English native speaker. Several sentences are disconnected and minor grammar errors are found along the text.
Response: The manuscript has been revised.
Specific comments:
- Lines 64-72: The number of the chapters are not corresponding to the numbers that are listed in this paragraph.
Response: We greatly appreciate the reviewer's attentive reading. In original manuscript, the number of the chapters are incorrect. It has been corrected.
- Line 108: what is the source of this equation?
Response: There has been a reasonable reference added.
- Line 111: change “pervious” to “previous”, and what do you mean with rule of shrinkage and in what previous sections was it discussed?
Response: The manuscript has been revised.
- Line 166: Topic 3 should not start with a Figure before it has been explained and contextualized;
Response: The manuscript has been revised.
- Line 200: Figure 4 shows the stability test. Provide quantitative values of the accuracy between measurements with different durations. How much is the increase between each duration? Is its optimal to have 4 hour duration tests if the accuracy does not change significantly?
Response: It is evident that longer periods of observation will yield better results. However, field experiments are hampered by various variables.
- Line 206: The term “etc” should be avoided in formal technical writing. References should be given for the mentioned examples of these problems.
Response: The manuscript has been revised.
- Line 215: How is this precise level data being obtained and how does it integrates with the proposed methodology?
Response: In this study, our group measures foundation settlement by utilizing digital level to validate the proposed approach.
- Lines 235, 236: Include references of studies using these methods.
Response: The references have been correctly cited.
- Line 262 – Figure 6: Avoid the overuse of abbreviations in a figure. The figure should be self-explanatory so many of those abbreviations should be written in full extent.
Response: The figure 6 has been revised.
- Line 279 – Figure 8: Include a map in the figure with the location of the stations (observation and reference) and of the location of the bridge.
Response: The location of the observation and reference station have been added in the figure 7.
- Line 292: Why was three times considered for the median absolute?
Response: Outliers are defined as elements more than three scaled MAD from the median. The scaled MAD is absolute median difference of high-frequency coefficients.
- Line 358: What was the threshold of performance that was considered as acceptable?
Response: See answer of the question 14.
- Line 394 – Figure 16: What is the reason for the significant sudden drops in the settlement in the first part of the measurements (only shown in the precise levelling)?
Response: The data of this study is analyzed by using the proposed method from March 14th 2018 to June 27th 2019. These times are respectively corresponding to the concrete pouring of the 6th tower section and the concrete pouring of the 54th tower section, with a total of 63 manual measurements by precise leveling during this time.
- Line 394 – Figure 16: Why does the proposed method begins after the others?
Response: The GNSS data of left chain dotted line are used to establish nonlinear mapping to correct the de-nosing data by EMD and Wavelet.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The work presents and interesting framework for displacement monitoring of cable bridges using satellite observation data. Although the results are consistent, the authors are recommended to highlight the significance of the method in terms of accuracy and also resource allocation compared to traditional methods.
The following comments should be considered in the review process:
General comments:
1. The introduction does not provide any reference to past works within this subject and also do not have any supporting references for the observations that are made. The authors must back up their premises with solid references on the field.
2. There must be an explanation of the framework itself before going to the theoretical parts. Why do the authors choose these methods and what are the benefits compared to existing monitoring schemes? Is this method more precise or less costly than traditional methods? The method is briefly explained from lines 247 to 259, which must be enlarged and the specific steps of the method must be highlighted, as it is the main contribution of this work.
3. The manuscript should be revised by an English native speaker. Several sentences are disconnected and minor grammar errors are found along the text.
Specific comments:
4. Lines 64-72: The number of the chapters are not corresponding to the numbers that are listed in this paragraph.
5. Line 108: what is the source of this equation?
6. Line 111: change “pervious” to “previous”, and what do you mean with rule of shrinkage and in what previous sections was it discussed?
7. Line 166: Topic 3 should not start with a Figure before it has been explained and contextualized;
8. Line 200: Figure 4 shows the stability test. Provide quantitative values of the accuracy between measurements with different durations. How much is the increase between each duration? Is its optimal to have 4 hour duration tests if the accuracy does not change significantly?
9. Line 206: The term “etc” should be avoided in formal technical writing. References should be given for the mentioned examples of these problems.
10. Line 215: How is this precise level data being obtained and how does it integrates with the proposed methodology?
11. Lines 235, 236: Include references of studies using these methods.
12. Line 262 – Figure 6: Avoid the overuse of abbreviations in a figure. The figure should be self-explanatory so many of those abbreviations should be written in full extent.
13. Line 279 – Figure 8: Include a map in the figure with the location of the stations (observation and reference) and of the location of the bridge.
14. Line 292: Why was three times considered for the median absolute?
15. Line 358: What was the threshold of performance that was considered as acceptable?
16. Line 394 – Figure 16: What is the reason for the significant sudden drops in the settlement in the first part of the measurements (only shown in the precise levelling)?
17. Line 394 – Figure 16: Why does the proposed method begins after the others?
Author Response
To reviewer 2:
The work presents and interesting framework for displacement monitoring of cable bridges using satellite observation data. Although the results are consistent, the authors are recommended to highlight the significance of the method in terms of accuracy and also resource allocation compared to traditional methods.
The following comments should be considered in the review process:
General comments:
- The introduction does not provide any reference to past works within this subject and also do not have any supporting references for the observations that are made. The authors must back up their premises with solid references on the field.
Response: The references have been correctly cited.
- There must be an explanation of the framework itself before going to the theoretical parts. Why do the authors choose these methods and what are the benefits compared to existing monitoring schemes? Is this method more precise or less costly than traditional methods? The method is briefly explained from lines 247 to 259, which must be enlarged and the specific steps of the method must be highlighted, as it is the main contribution of this work.
Response: The specific steps have been added in the section 4 (from lines 265 to 274).
- The manuscript should be revised by an English native speaker. Several sentences are disconnected and minor grammar errors are found along the text.
Response: The manuscript has been revised.
Specific comments:
- Lines 64-72: The number of the chapters are not corresponding to the numbers that are listed in this paragraph.
Response: We greatly appreciate the reviewer's attentive reading. In original manuscript, the number of the chapters are incorrect. It has been corrected.
- Line 108: what is the source of this equation?
Response: There has been a reasonable reference added.
- Line 111: change “pervious” to “previous”, and what do you mean with rule of shrinkage and in what previous sections was it discussed?
Response: The manuscript has been revised.
- Line 166: Topic 3 should not start with a Figure before it has been explained and contextualized;
Response: The manuscript has been revised.
- Line 200: Figure 4 shows the stability test. Provide quantitative values of the accuracy between measurements with different durations. How much is the increase between each duration? Is its optimal to have 4 hour duration tests if the accuracy does not change significantly?
Response: It is evident that longer periods of observation will yield better results. However, field experiments are hampered by various variables.
- Line 206: The term “etc” should be avoided in formal technical writing. References should be given for the mentioned examples of these problems.
Response: The manuscript has been revised.
- Line 215: How is this precise level data being obtained and how does it integrates with the proposed methodology?
Response: In this study, our group measures foundation settlement by utilizing digital level to validate the proposed approach.
- Lines 235, 236: Include references of studies using these methods.
Response: The references have been correctly cited.
- Line 262 – Figure 6: Avoid the overuse of abbreviations in a figure. The figure should be self-explanatory so many of those abbreviations should be written in full extent.
Response: The figure 6 has been revised.
- Line 279 – Figure 8: Include a map in the figure with the location of the stations (observation and reference) and of the location of the bridge.
Response: The location of the observation and reference station have been added in the figure 7.
- Line 292: Why was three times considered for the median absolute?
Response: Outliers are defined as elements more than three scaled MAD from the median. The scaled MAD is absolute median difference of high-frequency coefficients.
- Line 358: What was the threshold of performance that was considered as acceptable?
Response: See answer of the question 14.
- Line 394 – Figure 16: What is the reason for the significant sudden drops in the settlement in the first part of the measurements (only shown in the precise levelling)?
Response: The data of this study is analyzed by using the proposed method from March 14th 2018 to June 27th 2019. These times are respectively corresponding to the concrete pouring of the 6th tower section and the concrete pouring of the 54th tower section, with a total of 63 manual measurements by precise leveling during this time.
- Line 394 – Figure 16: Why does the proposed method begins after the others?
Response: The GNSS data of left chain dotted line are used to establish nonlinear mapping to correct the de-nosing data by EMD and Wavelet.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have addressed the comments inn the revised manuscript. No additional comment.
Author Response
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