NRTK, PPP or Static, That Is the Question. Testing Different Positioning Solutions for GNSS Survey

Round 1

Reviewer 1 Report

The paper presents research on testing different positioning solutions for GNSS survey. The authors analyzed the results of NRTK, PPP and Static measurements techniques obtained with different methods and softwares. Comparison of different measurement methods is not a new kind of research for GNSS positioning, but due to a large amount of data and comprehensive analysis, the presented results may give interesting results. However, in my opinion, the work lacks an orderly way of doing analysis. The authors compare different measurement techniques (static, NRTK, PPP), methods of forming network corrections (VRS,FKP,NEA) and software (RTKLib, CSRS, Topcon Tools) without giving detailed information about the parameters of data processing in each method. As a result, the conclusions drawn do not answer which methods are more accurate and under what conditions. In my opinion, in order for the analyzes to be clear, the authors should focus on a given issue (e.g. comparing different correction methods: VRS vs. FKP or technologies: static vs PPP) and perform tests with the setting of corresponding parameters. Comparing everything with everything it is difficult to draw conclusions! In conclusion, I believe that the topic of the paper can be interesting but requires significant testing methodology improvement before publication.

Author Response

Please see attachment file.

Best regards

Gino Dardanelli 

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript made a comparison between different solutions including static,NRTK and PPP. The data analysis procedure is clear and detailed which makes the paper convincing and logical. The results show that the congruence of the solutions obtained with different methodologies and software package quantitatively. In general, the main frame of the paper is acceptable, but some adjustments are still required. I recommend that the study can be published after minor revisions.

 

Specific comments:

• Line 65: The reason why ‘only an hour of observations was considered’ is not explained. To obtain a more convincing result,more observations are needed.
• Line 77:’depending to’,’to’ should be ‘on’
• Line 125:’Fourteen oh those belong to...’,’oh’ should be ‘of’
• Line 133:’÷’should be ‘~’
• Line 143:’15 second’ should be ‘15 seconds’
• Line 149:’15 second’ should be ‘15 seconds’
• Line 216:Comparison between NRTK are not in the selected pairs.The reason why comparison between VRS, FKP and NEA is not clarified clearly.
• Fig 4: figure and its title are not at the same page.
• Table 2:tablet and its title are not at the same page.

Author Response

Please see attachment file.

Best regards

Gino Dardanelli

 

Author Response File: Author Response.pdf

Reviewer 3 Report

The article is of particular interest. However, it seems that the research was not finished: the authors say “The analyses do not give conclusive indication”. In my view, published paper should be a complete research devoted to a problem. If the authors do not answer the main questions of the article, the research requires additional experiment. Analysis of obtained results is necessary. In my view the article has potential to be published and could be useful for community.

Important issue is space weather influence on positioning. I would recommend to get familiar with articles on PPP during magnetic storm [Luo et al., 2018; Yasyukevich et al., 2020] and solar flare [Berdermann et al., 2018] as well as RTK positioning degradation [Jacobsen & Andalsvik, 2016] during storms and PPP under ionosphere scintillations [Luo et al., 2020].

I also do not understand from the article, why “normal distribution” is required.

 

Minor remarks:

• Please, increase fonts and labels in Fig. 1. Show 20-km radius.
• Make neat Fig. 2.
• Increase fonts in figures 3-7. Why do you color grey region?

 

Berdermann, J., Kriegel, M., Banyś, D., Heymann, F., Hoque, M. M., Wilken, V., et al. (2018). Ionospheric response to the X9.3 Flare on 6 September 2017 and its implication for navigation services over Europe. Space Weather, 16, 1604– 1615. https://doi.org/10.1029/2018SW001933

Jacobsen K.S., Andalsvik Y.L. (2016). Overview of the 2015 St. Patrick’s day storm and its consequences for RTK and PPP positioning in Norway. Journal of Space Weather and Space Climate. 2016. V. 6, A9. DOI: 10.1051/swsc/2016004.

Luo, X.; Gu, S.; Lou, Y.; Xiong, C.; Chen, B.; Jin, X. Assessing the Performance of GPS Precise Point Positioning Under Different Geomagnetic Storm Conditions during Solar Cycle 24. Sensors 2018, 18, 1784. https://doi.org/10.3390/s18061784

Luo, X., Gu, S., Lou, Y. et al. Better thresholds and weights to improve GNSS PPP under ionospheric scintillation activity at low latitudes. GPS Solut 24, 17 (2020). https://doi.org/10.1007/s10291-019-0924-1

Yasyukevich, Y.; Vasilyev, R.; Ratovsky, K.; Setov, A.; Globa, M.; Syrovatskii, S.; Yasyukevich, A.; Kiselev, A.; Vesnin, A. Small-Scale Ionospheric Irregularities of Auroral Origin at Mid-latitudes during the 22 June 2015 Magnetic Storm and Their Effect on GPS Positioning. Remote Sens. 2020, 12, 1579. https://doi.org/10.3390/rs12101579

Author Response

Please see attachment file.

Best regards

Gino Dardanelli

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Please find the comments in the attached file.

Comments for author File: Comments.pdf

Author Response

Please see attachment file

Best regards

Gino Dardanelli

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Compared to the previous version of the manuscript, the revised version is much better. The authors revised the manuscript in agreement with my comments and addressed the review points adequately. The paper is written correctly, and the analyses are presented in a well-organized way. I believe that the topic of the article is interesting and deserve to be published in Remote Sensing.