Estimation of Azimuth Angle Using an Ultrasonic Sensor for Automobile
Round 1
Reviewer 1 Report
1. In line 110, “Unlike normal sound waves, ultrasonic waves move more quickly” is wrong.
2. In Table 1, it is best to give the resolution scale, such as millimeter level, centimeter level.
3. Since VEst and VSource in formula 2 are positive or negative values, there is no need to write both the positive and negative signs in the formula.
4. In section 3.1, the speed is estimated with Doppler frequency shift, which has the advantages and disadvantages compared with the existing speed vehicle device？
5. In section 3.2, the speed of each group of experimental cars is very low, and the speed difference is very small, but in reality, the speed can range from a few meters per second to tens of meters per second. Please analyze the influence of the speed on the experimental results in detail, especially at high speed, whether the experimental results are still so ideal？
Author Response
Dear Editor,
We appreciate your valuable comments and like to submit a revised manuscript entitled "Estimation of Azimuth Angle Using Ultrasonic Sensor for Automobile" by V.K. Chandrasegar et al. for publication in the journal of MDPI Engineering Remote sensing. We have addressed all the comments of the reviewers. Our response to the comments of the handling editor and both reviewers is provided below.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper proposed a novel method of ultrasonic sensor azimuth angle estimation. Overall, the structure of this paper is well organized, and the presentation is relatively clear. The idea is interesting and has potential. However, some crucial problems still need to be carefully addressed before a possible publication. More specifically,
1. Please beautify Figure 6 and Figure 8 with the background and legends.
2. Please double-check Table 4 as it is messed up.
3. You just compared your proposed method with the ground truth. It could not demonstrate the advancement of your proposed method. You should also compare it with some other classical methods.
4. In a real vehicle, the vehicle velocty is usually estimated by vehicle wheel speed IMU, and GPS sensors. There has been a lot of research in this area (Automated vehicle sideslip angle estimation considering signal measurement characteristic, IMU-based automated vehicle slip angle and attitude estimation aided by vehicle dynamics). What are the advantages of your method of estimating vehicle velocity compared with popular methods which are based on wheel speed and IMU?
5. When the vehicle's forward speed changes drastically, the pitch angle will introduce errors in the measurement data of the ultrasonic sensor. How do you deal with this problem?
6. In the introduction, the author should highlight the benefit of ultrasonic sensor in ADAS (advanced driver assistance systems) as it is pretty common in intelligent vehicles.
Author Response
Dear Editor,
We appreciate your valuable comments and like to submit a revised manuscript entitled “Estimation of Azimuth Angle Using an Ultrasonic Sensor for Automobile” by V.K. Chandrasegar et al. for publication in the Journal of MDPI Engineering Remote Sensing. We have addressed all the comments of the reviewers. Our responses to the comments of the handling editor and both reviewers are provided below.
Author Response File: Author Response.docx
Reviewer 3 Report
In this paper, a new method is described for measuring the azimuthal angle of the object under a single beam by utilizing the Doppler Effect of ultrasonic waves. The following problems need to be better addressed before it is publishable:
1. The contributions of this paper are a little blurry. Authors should further stress the improvements and challenges of the proposed algorithm compared with the traditional method.
2. The case of the picture is not normal. Some pictures are blurry and the author should adjust them appropriately.
3. The formatting of the article should be revised. Some paragraphs and tables are irregular. The format of the references is not standard. The title of “IV. CONCLUSION” is not correct.
4. I want to know how far the measurement scheme for azimuthal angle, and whether it is feasible for large distances from the facility to objects.
5. Some discussions of vehicles and path planning should be further provided in this paper, the following articles are suggested to refer and make applications:
1) Xingling Shao, Fei Zhang, Wendong Zhang, and Jing Na, “Finite-Time Composite Learning-Based Elliptical Enclosing Control for Nonholonomic Robots Under a GPS-Denied Environment”, IEEE Transactions on Systems, Man, and Cybernetics: Systems, DOI: 10.1109/TSMC.2022.3215474
2) DOI: 10.1109/TIE.2023.3243308
3) DOI: 10.1109/TIV.2023.3240855
4) DOI:10.1016/j.dt.2023.02.007
Author Response
Dear Editor,
We appreciate your valuable comments and like to submit a revised manuscript entitled “Estimation of Azimuth Angle Using an Ultrasonic Sensor for Automobile” by V.K. Chandrasegar et al. for publication in the Journal of MDPI Engineering Remote Sensing. We have addressed all the comments of the reviewers. Our responses to the comments of the handling editor and both reviewers are provided below.
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
It could be accepted after revision.
