An Accurate UAV Ground Landing Station System Based on BLE-RSSI and Maximum Likelihood Target Position Estimation
, Roberto Carrasco-Alvarez 2, Javier Vázquez-Castillo 3, Jaime Ortegón-Aguilar 3, Johan J. Estrada-López 4, Daniel D. Jensen 4, Ricardo Peón-Escalante 1 and Alejandro Castillo-Atoche 1,*
Round 1
Reviewer 1 Report
Comments to the Authors:
In summary:
Authors demonstrate a ground landing station (GLS) prototype for unmanned aerial vehicles (UAVs) landing based on bluetooth low energy received signal strength indicator (BLE-RSSI) and maximum likelihood position estimation algorithm. Their GLS consists of an inexpensive 3D printing, cutting and bending steel sheet, and acrylic, uses BLE technology, and therefore has a great potential to be applied in the UAV market.
Before I recommend to accept this manuscript for publication in Applied Sciences, several issues should be clarified, listed as below:
1. For the section 3.2. Battery Swapping Mechanism, it's better to compare the power consumption of the battery swapping mechanism per volume of the battery in this work with the refs [15, 16].
2. The line 162 mentions a master-slave fashion using I2C protocol. It’s better to figure out who is the master and the slave, like the lines 224 and 225 describing The slave modules on the GLS are named A, B, C, D, and the master module is located in the UAV.
3. Why is the RSSI fluctuation of different samples for 3.15m (red line) much larger than that for the longer distance (5.14m yellow line) in figure 9(c)?
4. Why the error is larger outside a 5m radius to the GLS? Is it because of the frequency or the intensity of the bluetooth?
5. What is the distance accuracy of the GPS that authors used?
6. Minor: BLE should be mentioned in the line 4 rather than the line 53.
Author Response
The authors would like to thank the reviewer for the analysis of our paper. The valuable feedback and suggested improvements helped make the presentation of the document more concise and detailed.
In the attached PDF file, we have include all the responses for the the reviewer suggestions.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
1. The abstract section should provide more detailed information on the core results, such as how to judge the accuracy of < 0.04m reached better expectation?
2. BLE in the abstract should give the full name.
3. I suggest the authors should provide more background information on the detailed technology gap in the current UAV study with specific quantitative values or parameters. Such as it is not clear to say ‘the RSSI has limitations (such as, what limitation? And this limitation may cause what uncertainty?)’in line 29. Similar suggestion is also for section 2.
4. The comparative analysis in Table 2 is too weak, without any Standard experimental control conditions, it is hard to judge the relative accuracy of these UAVs. This is the major concern.
Author Response
The authors would like to thank the reviewer for the analysis of our paper. The valuable feedback and suggested improvements helped make the presentation of the document more concise and detailed.
In the attached PDF file, we have include all the responses for the the reviewer suggestions.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
this paper has been partly revised, i have no question on it.
