CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Risk Assessment of Electromagnetic Interference in Aerospace Systems

Estudiants que han llegit aquest projecte:

Director/a: QUÍLEZ FIGUEROLA, MARCOS

Departament: EEL

Títol: Risk Assessment of Electromagnetic Interference in Aerospace Systems

Data inici oferta: 03-02-2025     Data finalització oferta: 03-10-2025


Estudis d'assignació del projecte:
    MU AEROSPACE S&T 21
Tipus: Individual
 
Lloc de realització: Fora UPC    
 
        Supervisor/a extern: Marco A. Azpúrua
        Institució/Empresa: EMC Barcelona
        Titulació del Director/a: Ph.D. in Electronics Engineering
 
Paraules clau:
Amplitude Probability Distribution, Risk Assessment, Jammers, GNSS, RAMS, Electromagnetic Compatibility, EMC, EMI, Areoespace Systems, Metrology
 
Descripció del contingut i pla d'activitats:
The Amplitude Probability Distribution (APD) is a measurement function used
to evaluate electromagnetic disturbances, particularly those with a stochastic and time-varying
distribution. Although it is defined in the CISPR 16-1-1 standard, this measurement is not commonly
used due to several limitations: the requirements for its implementation are not well defined,
calibration methods are not included in the standards, and there is no intuitive representation of the
measurement to clearly assess the measured interference.
Within the framework of the 21NRM06 EMC-STD project, EMC-Barcelona has developed methods to
perform this measurement more efficiently, accurately, and with proper calibration. This work aims to
develop a method for assessing the risks of electromagnetic emissions and apply it to RAMS analyses
for the aerospace sector.
Goals:
- Justify the use of the APD measurement for evaluating electromagnetic interference within
the framework of aerospace systems and advocate for its inclusion in MIL and ECSS standards.
- Develop a method to determine the risk of electromagnetic interference using the APD
measurement.
- Integrate the APD measurement into the RAMS framework to assess the risks of interference
in aerospace systems.
Roadmap:
- Literature Review / State of the Art
o Review the state of the art for APD.
o Examine the standards that do not include the APD measurement and identify
whether they use any similar methods for evaluating stochastic and time-varying
interference.
o Study RAMS procedures in the context of electromagnetic interference in the
aerospace sector.
- Development of the Risk Assessment Method for APD
o Create a graphical model that represents danger thresholds or impact regions based
on system characteristics.
o Adapt this model and method to aerospace systems (likely focused on satellites).
- Testing
o Perform simulations of the risk assessment procedure.
o Conduct a real-world test using aerospace equipment (likely a nanosatellite).
 
Overview (resum en anglès):
This thesis investigates statistical techniques for processing the measured
electromagnetic emissions in the time-domain to analyze the risk of electromagnetic
interference using the amplitude probability distribution (APD) as the main indicator.
The APD allows determining the probability that a signal exceeds a certain amplitude
threshold within a given frequency range. One of the main challenges in applying APD
is the lack of standardized calibration procedures, which compromises the metrological
traceability of the tests. To address this, two complementary calibration methods are
proposed: one based on deterministic signals and the other on pseudo-random signals
with known statistical properties. The first method uses pulsed and continuous wave
signals to evaluate measurement errors at specific probability and amplitude levels,
while the second employs Gaussian white noise and Gaussian mixture models to analyze
the statistical parameters of the distribution. The calibration validation demonstrates
that both methods enable verification that the APD function complies with the
tolerances established by CISPR 16-1-1, providing a reliable and traceable procedure for
its calibration. To apply APD to emission risk analysis, a procedure has been developed
to evaluate the probability of exceeding amplitude levels across a wide frequency range.
A spectrum-type graphical representation has been designed, where probabilities are
displayed using color gradients or categories, making it easier to identify regions with
the highest impact of electromagnetic interferences. These regions are defined according
to emission limits and immunity levels established by electromagnetic compatibility
standards, setting acceptable probability ranges for each impact level. The procedure
was validated by assessing the risks of three low-cost, illegally marketed GNSS jammers
with different morphologies. The devices were characterized in terms of power,
spectrum, spectrogram, and probability distribution using measurements in both the
time and frequency domains, and their potential effective range was estimated.
Furthermore, both methodologies were compared, showing that time-domain
measurements provide a more detailed view of the behavior and influence of
interferences. The results show that these jammers use chirp signals or modulated
wideband noise to disrupt pseudo-range acquisition, corrupt satellite data, mask signals,
or saturate GNSS receivers in the L1, E1, B1, and G1 bands. Regarding risk analysis,
the wideband APD measurement provides additional information about the impact of
interferences and allows determining the risks posed by jammers in devices compliant
with the MIL-STD-461G standard. The results indicate that jammers designed to affect
GNSS signals produce a medium impact on aerospace systems, whereas those intended
for cellular communications have a low effect on the GNSS band. In conclusion, APD
measurement has proven to be effective for evaluating emission risks, providing more
detailed insights into the behavior of interferences and establishing a simple and
intuitive framework for interpreting results through its wideband spectral representation.

© CBLTIC Campus del Baix Llobregat - UPC