Waveform-Enabled Jammer Excision Using Look-Through Windows
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Solution Overview
Problem
Existing jammer excision techniques are slow and impractical due to the need for long correlation periods, which can lead to synchronization issues and unpredictable phase rotation under heavy interference, making it difficult to obtain accurate constraint aperture vectors for effective jammer nulling.
Innovation Solution
The system employs a waveform-enabled jammer excision method using multiple antennas and radio circuits to determine a look-through window for jammer measurement, allowing for the calculation of optimal weights that maximize the signal-of-interest to jammer power ratio, enabling rapid and adaptive spatial/temporal interference cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a long correlation period is used to obtain accurate constraint aperture vectors, then measurement precision is improved, but the system response time deteriorates and synchronization reliability worsens under heavy interference
Solution Approach 1:
The patent extracts the jammer signal from the composite signal during look-through windows when the SOI is absent. By isolating and measuring only the jammer component during these specific time intervals, the system obtains accurate jammer autocorrelation matrices without requiring long correlation periods, thus resolving the contradiction between measurement precision and time loss.
Solution Approach 2:
The system performs preliminary measurements of jammer autocorrelation matrices during look-through windows before the actual SOI transmission begins. This preliminary action allows the adaptive beamformer to be pre-configured with accurate jammer characteristics, enabling rapid response without waiting for long correlation periods during active transmission.
2Measurement precision
If a long correlation period is used for jammer measurement, then measurement precision is improved, but synchronization reliability deteriorates due to phase rotation and Doppler effects
Solution Approach 1:
The patent extracts jammer measurements during look-through windows when the SOI is absent, eliminating the confounding effects of SOI motion and phase rotation. By measuring only the stationary jammer signal during these intervals, the system achieves high measurement precision without suffering from synchronization instability caused by Doppler effects and phase rotation.
Solution Approach 2:
The system dynamically identifies and utilizes look-through windows throughout the transmission sequence. By adaptively switching between measurement modes (jammer-only during look-through windows, combined SOI+jammer during active transmission), the system maintains both measurement accuracy and synchronization reliability under varying interference conditions.
3Device complexity
If traditional beamforming techniques are used for jammer nulling, then device complexity is reduced, but productivity deteriorates due to slow and impractical jammer excision
Solution Approach 1:
The system uses the transmitted waveform structure itself to create look-through windows where the SOI is absent but the jammer is present. This self-service approach allows the system to automatically identify measurement opportunities within its own transmission sequence, enabling rapid jammer characterization without external calibration signals or complex additional hardware.
Solution Approach 2:
The patent changes the temporal parameter of the transmission waveform to include look-through windows with specific patterns (e.g., silent periods or known zero-SOI intervals). By modifying the waveform time structure, the system creates opportunities for rapid jammer measurement and updates the beamforming weights in real-time, dramatically improving productivity while maintaining manageable device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for nearly instantaneous determination of optimal weights for jammer nulling and signal copying, even under heavy interference, without requiring knowledge of the array manifold or jammer direction, thus enhancing communication robustness and efficiency.
Implementation Method 1
SOI experiences phase rotation due to motion induced Doppler Effect that can result in unpredictable synchronization drift
Data Source
AI summary
A method for waveform-enabled jammer excision (WEJE) may include performing a jammer measurement during a look-through window when no signal-of-interest (SOI) is present and obtaining a jammer signal. A SOI-plus-jammer measurement may be performed and a SOI-plus-Jammer signal may be obtained when both the jammer signal and the SOI are present. Optimal weights that maximize a SOI-to-jammer power ratio may be determined. SOI-plus-jammer signals from a number of antenna elements may be optimally weighted and combined to copy the SOI and null the jammer signal based on the determined optimal weights.