Digital Beamforming for a Secondary Surveillance Radar: Numerical and statistical analysis of the ADS-B reception performance for an SSR system with conventional and adaptive beamforming
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
A secondary surveillance radar (SSR) is a surveillance radar system which, rather
than detecting reflected signals, relies on interrogations and replies to identify targets.
In this master’s thesis, the performance of an SSR system is analyzed. The
performance is measured by estimating the probability to detect Automatic Dependent
Surveillance-Broadcast (ADS-B) signals interfered by other signals on the
1090 MHz frequency band. The study is performed using different beamforming
techniques, with the aim of enhancing the reception in some directions while reducing
it in others. The probability of detection is estimated by performing Monte
Carlo simulations for different target positions and interference scenarios. Simulations
are performed for a system using digital beamforming, individually digitizing
the received signal in the different antenna elements in the SSR. Both conventional
beamforming, using a fixed set of beam positions, and adaptive beamforming, using
properties of the received data to optimize the reception, is analyzed. This is
benchmarked against a system using analog conventional beamforming, where the
signals are decoded in either a sum or a difference channel. The results of this study
highlight the potential of digital beamforming, significantly increasing the probability
of detection compared to the analog system, especially in an environment with
large amounts of interfering signals. Among the adaptive algorithms tested, linear
constraint minimum power (LCMP) beamforming, imposing null constraints on interfering
signals, exhibited the most promising results. There is potential to build
on this work, further analyzing the applicability of the different beamforming techniques.
Future research areas could include analyzing more adaptive algorithms, as
well as optimizing the ones studied in this thesis.
Beskrivning
Ämne/nyckelord
Secondary surveillance radar, ADS-B, Conventional beamforming, Adaptive beamforming, Statistical signal processing, Monte Carlo simulations.