Radar Warning Receiver Signal Detection Using Pseudo-Random Noise
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Solution Overview
Problem
Radar warning receivers face issues with strong signals causing measurement errors due to high signal-to-noise ratios, leading to suppressed and distorted signals, which result in inaccurate frequency measurements and require additional components and slow response times.
Innovation Solution
A radar warning receiver design incorporating a signal detection unit with limiting amplifiers and a pseudo-random noise generator to convert RF signals into pulsed outputs, allowing for accurate frequency and amplitude measurement, and using narrowband noise to linearize strong signal effects and enhance dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If mono-bit sampling technique is used to achieve gigahertz bandwidth, then bandwidth is improved, but measurement accuracy deteriorates due to strong signals causing distortion and suppression
Solution Approach 1:
A pseudo-random noise sequence is injected as an intermediary signal into the limiting amplifier to linearize the transfer function. This mediator signal prevents strong signals from causing saturation and distortion, allowing accurate amplitude and frequency measurements while maintaining gigahertz bandwidth operation.
Solution Approach 2:
The system dynamically adjusts parameters including the amplitude of the injected pseudo-random noise and the sampling clock frequency. When strong signals are detected, the noise amplitude is increased to maintain linearity, and the sampling frequency is changed to avoid bad clock-to-signal ratios, thereby maintaining measurement accuracy across varying signal conditions.
2Reliability
If log detection amplifiers are used to measure strong signal amplitudes, then dynamic range is improved, but device complexity and cost increase
Solution Approach 1:
Instead of using complex log detection amplifiers, the patent uses a pseudo-random noise sequence as an intermediary to linearize the transfer function of a simpler limiting amplifier. This approach achieves comparable dynamic range performance while maintaining a simpler, more cost-effective receiver architecture.
Solution Approach 2:
The system uses digital signal processing to adjust the amplitude of the injected noise and process the sampled signals, replacing the need for complex analog log detection circuitry. This parameter-based approach maintains dynamic range while reducing hardware complexity.
3Measurement precision
If sampling frequency is changed to avoid bad clock-to-signal ratios, then measurement accuracy is improved, but response time increases
Solution Approach 1:
The system performs preliminary detection of strong signals and pre-adjusts the sampling frequency and noise injection parameters before actual measurement. This preliminary action ensures that when a signal is detected, the system is already optimized for accurate measurement, minimizing the time delay associated with frequency changes.
Solution Approach 2:
The sampling frequency and noise injection amplitude are dynamically adjusted based on real-time signal conditions. The system can rapidly switch between different sampling frequencies and noise levels, maintaining measurement accuracy while minimizing response time through adaptive, real-time parameter optimization.
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
The solution enables reliable, high-fidelity signal detection and measurement across a wide dynamic range, maintaining sensitivity and response speed, even with high signal-to-noise ratios, and accurately identifies threat signals for timely operator alerts or evasive actions.
Implementation Method 1
a pseudo-random noise generator for injecting noise into one of the limiting amplifiers
Implementation Method 2
a pair of limiting amplifiers for converting the collected RF signals into corresponding pulsed output signals that track the actual frequency oscillations
Data Source
AI summary
A radar warning receiver is disclosed. The radar warning receiver includes an antenna, a signal detection unit, a signal identification unit and an alarm. The antenna collects radio frequency (RF) signals. The signal detection unit is configured to generate a group of frequency and amplitude signals based on the collected RF signals. Specifically, the signal detection unit includes a pair of limiting amplifiers for converting the collected RF signals into corresponding pulsed output signals that track the actual frequency oscillations of the collected RF signals, and a pseudo-random noise generator for injecting noise into one of the limiting amplifiers. Based on the frequency and amplitude signals, the signal identification unit determines whether or not any of the collected RF signals includes a threat signal. The alarm is utilized to present a threat signal to a human operator.