Evaluation of Atmospheric Phase Correction Performance in 79 GHz Ground-Based Radar Interferometry: A Comparison with 17 GHz Ground-Based SAR Data
Round 1
Reviewer 1 Report
In this paper the authors addressed the probole of APS for a w band radar and compere the results with a ku interferometric radar. This is a very good paper, well written and complete. I do not have major revision, just some questions or remarks.
After equation (8) (row 147) I don’t understand the meaning of the sentence “which should be optimized for illumination area”. Could you please clarify?
In Figure 4 and Figure 13, could you please use the same amplitude scale (not the absolute scale, but to have almost the same dynamic in dB in the two images)?
Fig. 5 and Fig. 14, why the DA of the ku radar is so poor, I expected a DA lower than 0.5 for most of the image.
Pag. 15 row 434 – 441: the differences in the amounts of absolute displacement could be related to the phase wrapping. Indeed the phase wrapping usually underestimate the cumulative displacement. You can try by a simulation.
Author Response
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Reviewer 2 Report
The manuscript focuses on the influence of the atmospheric phase screen on the accuracy of ground-based radar interferometry, which has certain practical value. The content of the manuscript is detailed, the structure is reasonable, and the result analysis is detailed, but there are some problems in some details. Therefore, it is recommended to publish after minor revisions.
L419 Figure 15 is not clear.
L442 Please explain the meaning of AOI-I, -II, -III in the figure.
L452 Section Discussion is to little.
L479 Section Conclusion needs to improved.
Author Response
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Reviewer 3 Report
The article deals with the practical verification of different methods of compensation of the Atmospheric Phase Screen (APS) when using MIMO radar for natural slope monitoring. This is a very current and important topic.
In the first experiment for the resulting comparison (Fig. 9), only data from 15:00 26th to 21:00 26th were used. Data from 21:00 26th were omitted to avoid the CR physical displacement, probably caused by thermal shrinkage. But this comparison serves to evaluate the performance of different APS compensation methods. Limiting the time interval reduced the reliability of the results.
In the second experiment, on-site meteorological data were not measured. This was probably the reason why APS compensation by meteorological data was not performed.
In the case of three selected AOIs, only results after APS compensation by model-3 are shown. Results after APS compensation by other models are missing. Likewise, a comparison of the resulting residuals (RMS and SD, similar to what is shown in Figures 9 and 16) is also missing.
The snowfall during the second part of the second experiment partially devalued the results. On the other hand, this confirmed the well-known fact that during rain or snowfall, the results of GB-SAR and GB-RAR measurements are less reliable. This should be explicitly mentioned in the conclusion.
Although the conclusions expressed in the article are in accordance with theoretical expectations, they are not fully supported by the resulting data. It is necessary to carry out a larger number of verification measurements under more different meteorological and topographical conditions.
Author Response
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Round 2
Reviewer 3 Report
I thank the authors for a more significant revision of the discussion and conclusions chapters. The article will now serve as a start for further research in the field of APC correction methods.
