Universal Radar Waveform Generation Using Asymmetric Pulse Sampling
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Solution Overview
Problem
Existing radar imaging schemes require numerous resources and are incompatible for different mission modes, leading to a decrease in SAR image quality when trying to collect data for both moving target indication and detailed imaging simultaneously.
Innovation Solution
A radar transmission system that generates and processes universal radar waveforms with spatially and temporally separated pulses, using a pattern of unequal separations and Fourier transforms to maintain image quality with fewer pulses, incorporating quadratic residue and pseudo-random patterns for efficient sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If numerous radar pulses are transmitted for SAR imaging, then image quality and Doppler resolution are improved, but radar resources are consumed and time is increased
Solution Approach 1:
The patent applies asymmetric sampling intervals between radar pulses, where the time separation between consecutive pulses varies rather than being uniform. This asymmetric timing pattern allows the radar to capture sufficient Doppler frequency information for high-resolution imaging while reducing the total number of pulses required, thereby decreasing the time needed for data collection.
Solution Approach 2:
The patent employs periodic radar pulse transmission with specific repeating patterns of unequal intervals. By using periodic action with optimized pulse repetition, the system maintains the necessary temporal aperture for Doppler resolution while reducing overall transmission time compared to uniform sampling schemes that require more pulses.
2Measurement precision
If numerous radar pulses are transmitted for SAR imaging, then image quality is improved, but radar resources are consumed
Solution Approach 1:
The asymmetric sampling pattern with varying pulse intervals optimizes the distribution of radar resources by concentrating measurements at critical time points rather than uniform intervals. This allows high-quality SAR imaging to be achieved with fewer total pulses, improving productivity by reducing resource consumption while maintaining image quality.
Solution Approach 2:
The patent changes the temporal parameter of pulse transmission by using non-uniform, asymmetric time intervals between pulses. This parameter change enables the radar system to achieve the same imaging quality with fewer pulses, effectively reducing radar resource consumption and improving operational productivity.
3Adaptability or versatility
If multiple mission modes are supported simultaneously, then adaptability is improved, but device complexity is increased
Solution Approach 1:
The asymmetric sampling waveform design serves multiple mission modes universally. The same unequal pulse interval pattern can be used for both SAR imaging and moving target indication (MTI), allowing a single radar system to perform multiple functions without requiring separate specialized waveforms or processing chains, thereby avoiding increased device complexity.
Solution Approach 2:
The patent employs dynamic, adaptive asymmetric sampling patterns that can be adjusted based on the specific mission requirements. The same fundamental asymmetric approach can be tuned for different modes (SAR, MTI, etc.), providing versatility without requiring fundamentally different system configurations, thus maintaining manageable device complexity while supporting multiple mission modes.
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 high-quality SAR images to be generated using fewer radar resources, maintaining Doppler resolution and reducing sidelobe energy, enabling simultaneous imaging modes without compromising image quality.
Implementation Method 1
Radio detection and ranging (radar) technology transmit and receive pulsed electromagnetic waves to detect objects
Implementation Method 2
If the object is at a certain distance from the radar platform and is moving toward the radar platform, then the complex radar pulses may rotate in phase with a positive frequency. Similarly, if the object is moving away from the radar platform, then the complex radar pulses may rotate in phase with a negative frequency. This effect is referred to as the Doppler effect.
Data Source
AI summary
A new approach to radar imaging is described herein, in which radar pulses are transmitted with an uneven sampling scheme and subsequently processed with novel algorithms to produce images of equivalent resolution and quality as standard images produced using standard synthetic aperture radar (SAR) waveforms and processing techniques. The radar data collected with these waveforms can be used to create many other useful products such as moving target indication (MTI) and high resolution terrain information (HRTI). The waveform and the correction algorithms described herein allow the algorithms of these other radar products to take advantage of the quality Doppler resolution.