The aim of this thesis is to develop a ranging and communication system using LoRa in the S-Band for satellites.
The thesis is comprehensive, technically mature, and overall well-written. The solution focuses on utilizing a commercial SX1280 LoRa transceiver operating at the 2.45GHz band. The work addresses a relevant and challenging topic in modern satellite engineering, especially in the context of CubeSat-based proximity operations.

The thesis includes solid background theory, a detailed derivation of system requirements, and well-argued component selection. The system-level and link budget analyses show a good understanding of real-world constraints in RF systems for space.
The student adhered to good design practices, such as using automotive-grade components, low-outgassing PCB design, and a modular architecture, which demonstrates good awareness of aerospace requirements.
The focus on modular design ensures compatibility with commonly used components in the industry and supports future extensibility.
Some technical decisions, especially the RF filter and testing methodology leave room for improvement.

The overall structure of the thesis is well written. The language level is high, the text is well-organized, and most chapters are written clearly. A few sections, likely finished at the last minute, are slightly more difficult to read, but this does not significantly impact the overall readability or quality.

The student demonstrated a high level of independence throughout the development. He actively researched applicable literature, regularly attended consultations, discussed the topic with experts in the field, and readily proposed solutions to design issues. One of the results of this is also a successfully published paper in the EEICT students conference journal. This self-driven approach reflects a strong capability for research and engineering development.

Even with the noted limitations, the work achieves its main goals and demonstrates robust engineering skills. The thesis provides a solid foundation for further development of the payload and in my opinion with a few adjustments can be effectively used. Points proposed by supervisor: 90

The thesis is clearly written and technically solid. It describes the development of a ranging system using LoRa communication in the 2.45 GHz band, with focus on possible use in space applications. The student had to deal with limited documentation from the chip manufacturer. I appreciate the effort to follow a systematic design process, including selection of at least automotive-grade components and working with relevant specifications. This shows a good understanding of requirements for more demanding applications.

Regarding the RF output filter, I have some concerns. I think the chosen band-pass filter is too complex and not easy to reproduce reliably. A lower-order low-pass filter would probably be a more practical choice. Also, the thesis doesn't mention any regulatory or mission-specific requirements for out-of-band signal limits or harmonic suppression, which makes it difficult to evaluate if the filter is really suitable. The student improved the filter performance step by step during testing, which helped, but I believe similar or better results could be achieved with a simpler solution.

The wireless tests are not very conclusive. Important information about the antennas - such as type, gain, polarization, or placement - is missing. Also, using a development board with different RF filters affects the results, and makes the calibration from cable tests invalid. The part about ranging performance is quite brief, especially considering its importance for the project.

The English is very good and the structure of the thesis is easy to follow. Ranging results are mostly shown in tables, while simple plots would make them easier to understand. Even with the mentioned issues, I consider this thesis to be a careful and high-quality work. The student reached the main goals and showed solid technical skills. Topics for thesis defence:

1. 1. Why did you decide to use the described band-pass filter topology? What kind of differences would you expect if a simpler low-pass filter was used instead?
2. 2. Which antennas did you use for the wireless tests, and how do you think their parameters (like gain, polarization, or placement) may have influenced the results?

Points proposed by reviewer: 92