Master's Thesis

Antenna array ground station integration

Final Thesis 7.86 MB

Author of thesis: Ing. Tomáš Homolka

Acad. year: 2025/2026

Supervisor: Ing. Tomáš Urbanec, Ph.D.

Reviewer: Ing. Jiří Špaček, Ph.D.

Abstract:

This thesis describes the development and validation of a five-channel coherent transceiver ground station for Low Earth Orbit satellite communications. The architecture integrates Ettus USRP B210 software-defined radios synchronized via an OctoClock reference. A custom control framework utilizing Zadoff-Chu sequence calibration resolves inherent hardware phase ambiguities to ensure multi-channel coherence. Following laboratory evaluations of synchronization and data transport limits, the system was validated in a field trial with a custom antenna array. The implemented digital beamforming algorithms successfully captured a signal from the SITRO-AIS-28 satellite, achieving a 5.71 dB signal-to-noise ratio improvement through coherent signal accumulation.

Keywords:

Software-Defined Radio (SDR), Ground Station, Low Earth Orbit (LEO) Satellites, Antenna Array, Phase Synchronization, Digital Beamforming

Date of defence

10.06.2026

Result of the defence

Defended (thesis was successfully defended)

znamkaAznamka

Grading

A

Process of defence

Státní závěrečná zkouška probíhá v anglickém jazyce. Student prezentuje výsledky a postupy řešení své závěrečné práce. Tajemník čte posudek vedoucího závěrečné práce a oponenta závěrečné práce. Student s obsahem posudků souhlasí odpovídá na otázky oponenta. Doc. Povalač: Proč jste zvolil pět antén namísto například čtyř? Student odpovídá uspokojivě. Na navazující otázky odpovídá uspokojivě.

Language of thesis

English

Faculty

Department

Study programme

Space Applications (MPA-SAP)

Composition of Committee

doc. Ing. Tomáš Götthans, Ph.D. (předseda)
doc. Ing. Aleš Povalač, Ph.D. (místopředseda)
doc. Ing. Stanislav Vítek, Ph.D. (člen)
Ing. Václav Havlíček (člen)
Ing. Tomáš Urbanec, Ph.D. (člen)
Ing. Jan Král, Ph.D. (člen)

Supervisor’s report
Ing. Tomáš Urbanec, Ph.D.

Student Tomáš Homolka was tasked with integrating and testing a functional prototype of a five-channel antenna array, with the main focus of his work being the selection and synchronization of SDR modules.
The student approached the task in an agile manner, regularly consulting with his supervisor while also working independently. Although the project covered a relatively broad range of topics, from antennas to signal processing, he quickly familiarized himself with the subject matter. This is evident from the systematic description and selection of a suitable SDR platform, the discussion of its limitations, and the design and execution of the individual tests.
Text is very well written with only minor problems, i.e. when describing the experiment in chapter 3.6 where text it describes as signal transmitted by one SDR and received by second one, whereas the Fig. 3.10 in wiring diagram shows it as single SDR is both transmitting and receiving.
From the description of some of the tests, I had the impression that the student accepted the first results obtained, even when they were not entirely satisfactory. For example, the initial test with MUSIC algorithm is described as partial success even if single graph for angle of arrival looks very well defined, even if the settings of the input filter to bandwidth of 10kHz are very questionable. However, the amount of work completed by student within a single semester is admirable.

All requirements specified in the assignment have been fulfilled. Points proposed by supervisor: 90

Grade proposed by supervisor: A

Reviewer’s report
Ing. Jiří Špaček, Ph.D.

Topics for thesis defence:
  1. Would it be possible to use the implemented system, after appropriate software modifications, for the cancellation of common-mode (local) interference?
  2. In Appendix A.4, Beam Steering Script (page 102), the caption states: “…the key equation from the Balanis book…”. Which book by Balanis are you referring to?
Points proposed by reviewer: 92

Grade proposed by reviewer: A

File inserted by the reviewer Size
Posudek oponenta [.pdf] 212,06 kB

Responsibility: Mgr. et Mgr. Hana Odstrčilová