# Radio Frequency Interference, Its Mitigation and Its Implications for the Civil Aviation Industry
## 4 Discussion and Future Work
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ref.** & **Key Technology Used** & **Area of Research** & **Gaps Identified** & **Test Equipment/Simulation Used** \\ \hline
[22] & Anomalous VHF Wave Monitoring & \begin{tabular}{c} Sporadic E \\ propagation’s impact \\ on VHF signals \\ \end{tabular} & \
\begin{tabular}{c} Automation in anomaly \\ detection algorithms \\ \end{tabular} &
\begin{tabular}{c} Software-defined radios \\ (SDRs) \\ \end{tabular} \\ \hline
[23] & GNSSs and Inertial Navigation & \
\begin{tabular}{c} Mitigation of RF in \\ GNSS receivers \\ \end{tabular} &
\begin{tabular}{c} Integration of GNSSs \\ with alternative \\ systems \\ \end{tabular} & GNSS-DME hybrid models \\ \hline
[24] & Interference & \begin{tabular}{c} Cognitive radio \\ systems in aeronautical \\ communication \\ \end{tabular} & \
\begin{tabular}{c} Effectiveness of new \\ algorithms in \\ real-world scenarios \\ \end{tabular} &
\begin{tabular}{c} Pulse Blanking, DDNE \\ Simulations \\ \end{tabular} \\ \hline
[25] & RF Combinational & \begin{tabular}{c} Mitigation of FM \\ interference in V/UHF \\ communication \\ \end{tabular} & \
\begin{tabular}{c} Limited studies on \\ compact, multi-band \\ filter designs \\ \end{tabular} &
\begin{tabular}{c} Polytetrafluoroethylene (PTFE) \\ PCB testing \\ \end{tabular} \\ \hline
[26] & Electromagnetic & \
\begin{tabular}{c} Co-site interference in \\ Aircraft \\ Simulations \\ \end{tabular} &
\begin{tabular}{c} Lack of robust \\ transmitter \\ improvements \\ \end{tabular} & S-parameter-based simulations \\ \hline
[27] & \begin{tabular}{c} Intermodulation \\ Product Analysis \\ \end{tabular} & \
\begin{tabular}{c} Impact of \\ intermodulation on \\ navigation signals \\ \end{tabular} &
\begin{tabular}{c} Better assessment \\ methods for \\ third/fifth-order IMPs \\ \end{tabular} & Frequency domain analysers \\ \hline
[28] & RF Immunity & \
\begin{tabular}{c} Testing UAVs for RF \\ interference during \\ inspections \\ \end{tabular} &
\begin{tabular}{c} Limited multi-channel \\ redundancy \\ assessments \\ \end{tabular} & RF Noise Source Analysis \\
[29] & Channel Measurement Tools & \
\begin{tabular}{c} Air-to-ground \\ communication using \\ UHF band \\ \end{tabular} &
\begin{tabular}{c} Need for extensive \\ testing in varied \\ environments \\ \end{tabular} & Channel Sounders, Path Loss \\ \hline
[30] & Frequency Domain Testing & \
\begin{tabular}{c} Instrument Landing \\ System (ILS) \\ maintenance \\ \end{tabular} &
\begin{tabular}{c} Broader training for ILS \\ maintenance personnel \\ \end{tabular} & Spectrum Analyzers \\ \hline
[31] & Near-Field Signal Modeling & \
\begin{tabular}{c} Localizer antenna \\ system signal behavior \\ \end{tabular} &
\begin{tabular}{c} Limited understanding \\ of NF vs. FF signal \\ interactions \\ \end{tabular} & 3D Phase Analysis Tools \\ \hline
[32] & C-Band Interference & \begin{tabular}{c} 5G interference with \\ Mitigation \\ \end{tabular} & \
\begin{tabular}{c} Implementation \\ radar altimeters \\ \end{tabular} &
\begin{tabular}{c} Simulations of Base Station \\ Placement \\ \end{tabular} \\ \hline
[33] & Regulatory Impact Analysis & \
\begin{tabular}{c} 5G rollout and aviation \\ safety concerns \\ \end{tabular} &
\begin{tabular}{c} Data-driven strategies \\ for spectrum allocation \\ \end{tabular} & Policy Analysis Tools \\ \hline
[43] & Structured Shielding and Filtering & \begin{tabular}{c} Multi-layer EMI \\ defense for UAV \\ gimbal systems \\ \end{tabular} & \
\begin{tabular}{c} Needs adaptation for \\ larger-scale airborne \\ platforms \\ \end{tabular} &
\begin{tabular}{c} Real-world prototype, \\ diagnostic filters \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._