Passive SAR Receiver Assembly for Unknown RF Source Location
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Solution Overview
Problem
Current radar systems are inadequate for detecting and locating both linear and nonlinear threats, such as buried threats and RF electronics, as they require separate assemblies or units and lack the capability to process signals from unknown transmitting sources effectively.
Innovation Solution
A receiver assembly comprising multiple channels controlled by a common clock pulse, with amplifiers, band-pass filters, mixers, analog-to-digital converters, and Fourier transforms to process and display frequency components, enabling the creation of SAR images for locating unknown transmitting sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate radar assemblies are used to detect linear and nonlinear threats, then detection capability for each threat type is improved, but device complexity and the number of required units increase
Solution Approach 1:
The patent implements a universal radar system that can detect both linear threats (such as buried objects) and nonlinear threats (such as RF electronics) using a single multi-functional assembly. The system incorporates multiple receive channels with different center frequencies that can be selectively activated based on the threat type, allowing one device to perform multiple detection functions that previously required separate specialized assemblies
Solution Approach 2:
The radar system is divided into multiple receive channels, each tuned to specific frequency ranges for detecting different threat types. This segmentation allows the system to process different frequency components separately while maintaining a unified platform, enabling specialized detection capabilities within each channel while avoiding the need for completely separate radar assemblies
2Adaptability or versatility
If multiple receive channels with different center frequencies are used, then versatility in detecting different threat types is improved, but device complexity increases
Solution Approach 1:
Each receive channel is optimized with specific local characteristics - different center frequencies, bandwidths, and filtering parameters - to detect particular threat types. This local quality optimization within each channel allows the system to achieve high detection performance for specific threat categories while maintaining overall system versatility through the combination of multiple specialized channels
3Measurement precision
If passive SAR processing is implemented, then location precision of unknown transmitting sources is improved, but signal processing complexity increases
Solution Approach 1:
The passive SAR processing system utilizes the transmitting source's own signal characteristics and the natural phase information contained in the received signals to achieve precise location. The system processes the phase data from multiple receive channels through Fourier transforms and phase unwrapping algorithms to generate SAR images that reveal the location of unknown transmitting sources without requiring external reference signals or additional active components
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
Enables the detection and location of both linear and nonlinear threats using a single assembly, providing high-resolution images and increased signal-to-noise ratio through synthetic aperture radar processing, allowing for effective surveillance without the need for elaborate sensor trajectories.
Implementation Method 1
a mixer configured to combine the received signal with a signal generated by a signal generator for providing a common phase for each of the receive channels
Implementation Method 2
means for performing a Fourier Transform on the single-sideband signal to convert the signal from a signal expressed as a function of time to the frequency components of which it is composed
Data Source
AI summary
A radar assembly for receiving signals at spaced frequencies from an unknown transmitting source comprising a receiver operative to receive signals; the receiver comprising a series of channels, each channel comprising a low pass filter configured to allow passage of a signal from an unknown transmitting source, an analog to digital converter configured to transform the signal from the unknown transmitting source to a digital signal, a Hilbert transform configured to transform the digital signal from the unknown transmitting source into a single sideband signal, a Fourier transform configured to transform the single sideband signal into a plurality of regularly spaced frequency samples, and an inverse Fourier transform for extracting regularly spaced frequency samples; whereby extracted pulses form a train of pulses that are inputted into an imager which utilizes synthetic aperture radar to form an image of the area of interest containing the unknown transmitting device and method thereof.