Incoherent Millimeter-Wave Radar Imaging System
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Solution Overview
Problem
Current millimeter-wave imaging systems face challenges in providing effective imaging capabilities through obscurants like fog, smoke, and dust, and require complex beamforming and high sensitivity receivers, which are costly and power-intensive, limiting their application in autonomous driving and security.
Innovation Solution
An active incoherent millimeter-wave imaging system using a transmitter that sends spatially and temporally incoherent signals, processed by a correlation interferometer with phase-coherent receivers, reconstructs images using spatial frequency sampling, reducing the number of required modules and improving signal-to-noise ratio, allowing for all-weather imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filled microwave phased array is used for imaging, then imaging resolution is improved, but device complexity and cost increase excessively
Solution Approach 1:
The patent applies spatial frequency sampling to divide the imaging process into discrete spatial frequency components. Instead of using a complete filled phased array, the system samples specific spatial frequencies corresponding to different baseline lengths between antenna pairs, reconstructing the image through inverse Fourier transform of the sampled visibility data. This segmentation approach achieves imaging resolution comparable to filled arrays while using significantly fewer antenna elements.
2Device complexity
If passive interferometric imaging is used to reduce modules, then device complexity is reduced, but signal-to-noise ratio deteriorates due to exceedingly small thermal power
Solution Approach 1:
The patent employs active illumination by transmitting incoherent electromagnetic signals before receiving reflections. This preliminary action provides a strong known reference signal that reflects off targets and returns to the antenna array. By correlating the received signals with the transmitted reference signal, the system achieves high signal-to-noise ratio even with reduced antenna elements, eliminating the need for extremely sensitive receivers required by passive thermal imaging.
3Measurement precision
If LIDAR is used for high resolution imaging, then measurement precision is improved, but reliability deteriorates in obscurants like fog, smoke, and dust
Solution Approach 1:
The patent changes the operating wavelength parameter from optical frequencies (LIDAR) to millimeter-wave frequencies. This parameter change enables penetration through obscurants like fog, smoke, and dust that block optical signals. The system transmits incoherent electromagnetic signals in the millimeter-wave band, which can propagate through these materials, and uses spatial frequency sampling to reconstruct high-resolution images of targets behind the obscurants.
4Productivity
If current automobile radar is used for autonomous driving, then productivity is improved with simple range and angle information, but measurement precision deteriorates by lacking imaging capability
Solution Approach 1:
The patent creates a multi-functional radar system that simultaneously provides traditional autonomous driving functions (range, angle, velocity measurement) and imaging capability. The same antenna array and signal processing infrastructure used for basic radar measurements also performs spatial frequency sampling for image reconstruction. This universal system delivers both productivity benefits of simple radar measurements and measurement precision of imaging, enabling applications like identifying traffic light states and reading license plates.
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 system achieves equivalent resolution to LIDAR with reduced size, cost, and power requirements, enabling effective imaging through obscurants and enhancing signal-to-noise ratio, making it suitable for autonomous driving and security applications.
Implementation Method 1
A transmitter is configured to transmit a signal in a direction of a scene of interest. The transmitted signal is spatially and temporally incoherent at a point where the transmitted signal reaches the scene of interest.
Implementation Method 2
The system includes a receiver set including at least a first receiver and a second receiver. The first receiver and the second receiver are configured to receive a reflected signal. The reflected signal is a reflection of the transmitted signal from the scene of interest.
Implementation Method 3
An active incoherent millimeter-wave image processor configured to obtain the reflected signal and reconstruct a scene based on the reflected signal
Implementation Method 4
The system also includes a display device configured to display the scene. In other features, the first receiver and the second receiver operate as a correlation interferometer, and the first receiver and the second receiver are phase coherent.
Data Source
AI summary
An imaging system including a transmitter configured to transmit a signal in a direction of a scene of interest. The transmitted signal is spatially and temporally incoherent at a point where the transmitted signal reaches the scene of interest. The system includes a receiver set including at least a first receiver and a second receiver. The first receiver and the second receiver are configured to receive a reflected signal. The reflected signal is a reflection of the transmitted signal from the scene of interest. The system further includes an active incoherent millimeter-wave image processor configured to obtain the reflected signal and reconstruct a scene based on the reflected signal. The system also includes a display device configured to display the scene.