Wideband Rateless Chaotic Waveform Generation for Low Probability of Detection
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Solution Overview
Problem
Current low probability of detection (LPD) and low probability of exploitation (LPE) communications face challenges in waveform generation and synchronization, particularly in avoiding detection by advanced energy detectors and maintaining coherence in complex, wideband signals, which affects mission effectiveness in contested environments.
Innovation Solution
The development of wideband, rateless chaotic waveforms with minimal features, combined with coherent and non-coherent processing techniques for efficient coarse synchronization, allows for transmission below the signal-to-noise ratio (SNR) wall, enhancing LPD and LPE capabilities by randomizing pulse sizes and using forward error correction and chaotic carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spread spectrum techniques are used to introduce features into the waveform, then detectability is reduced, but waveform complexity increases
Solution Approach 1:
The patent extracts and removes waveform features that could be detected by adversaries. By using chaotic waveforms with deliberately introduced features removed or minimized, the system achieves low detectability without the complexity of traditional spread spectrum techniques. The chaotic nature of the waveform inherently provides the necessary obfuscation without requiring additional feature introduction.
Solution Approach 2:
The patent changes the fundamental parameters of the waveform by using chaotic signals instead of traditional spread spectrum modulations. This parameter change allows the system to achieve low probability of detection and exploitation without introducing the complexity of feature-based spread spectrum techniques, as the chaotic waveform naturally provides the required properties through its inherent randomness and sensitivity to initial conditions.
2Object-affected harmful factors
If chaotic waveforms are used to reduce detectability, then energy detection becomes more difficult, but synchronization becomes more challenging
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing the chaotic waveform generator at the transmitter and receiver using a shared secret key or initial condition. This preliminary synchronization step establishes the chaotic signal's phase and frequency alignment before communication begins, eliminating the need for complex real-time synchronization algorithms and reducing the overall synchronization complexity while maintaining low energy detectability.
3Object-affected harmful factors
If transmission power is reduced below the SNR wall for LPD/LPE, then detectability decreases, but signal reliability deteriorates
Solution Approach 1:
The patent uses a composite approach by combining chaotic waveform modulation with advanced error correction coding schemes. This composite structure allows the system to transmit at low power below the SNR wall while the error correction code compensates for the reduced signal quality, maintaining reliability. The chaotic waveform provides low detectability while the error correction ensures reliable communication despite the low transmission power.
Data Source
AI summary
A wideband chaotic waveform that is rateless in that it may be modulated at virtually any rate and has a minimum of features introduced into the waveform. Further, the waveform provided may be operated below a signal to noise ratio wall to further enhance the LPD and LPE aspects, thereof. Additionally, the present disclosure may provide a mix of coherent and non-coherent processing techniques applied to signal samples to efficiently achieve coarse synchronization with a waveform that is faster, more efficient and more accurate than using time domain signal correlators alone.