Automotive MIMO Radar Difference Co-Array Processing
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Solution Overview
Problem
Existing automotive radar systems face challenges in achieving high angular resolution due to size constraints, as larger apertures required for better performance are difficult to integrate into vehicles, and existing solutions for combining distributed radars are complex, costly, and computationally intensive.
Innovation Solution
A distributed aperture radar system uses a spectral-domain auto-correlation based approach with FFT hardware accelerators to construct a difference co-array with a virtual large aperture from a sparse array, performing forward and backward difference co-array processing to mitigate spurious sidelobes and achieve finer angular resolution without the need for complex calculations or shared local oscillator signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If larger aperture radar is used to improve angular resolution, then angular resolution is improved, but radar size increases making vehicle integration difficult
Solution Approach 1:
The patent combines multiple distributed small-aperture radars into a single large-aperture radar system through coherent signal processing. The multiple radars transmit orthogonal signals and their received signals are coherently combined to form a virtual large aperture, achieving high angular resolution without requiring a physically large radar aperture.
Solution Approach 2:
The patent introduces a coherent combining mechanism as an intermediary that processes signals from multiple distributed radars. This intermediary performs phase alignment and coherent integration of the signals, enabling the system to achieve the performance of a large aperture radar while using multiple small physical apertures.
2Measurement precision
If distributed radars are combined to form virtual aperture, then angular resolution is improved, but system complexity increases due to common reference LO and cross-correlation requirements
Solution Approach 1:
The patent segments the signal processing tasks among the distributed radars, with each radar independently transmitting orthogonal signals and processing its own received signals. This segmentation eliminates the need for complex cross-correlation between radars and common reference LO distribution, reducing system complexity while maintaining the virtual aperture benefit.
Solution Approach 2:
The patent uses orthogonal signaling as a form of copying where each radar transmits a unique orthogonal version of the base signal. This allows the receiving radars to separately process each transmitted signal without requiring complex cross-correlation, simplifying the system architecture while still enabling coherent combining for virtual aperture formation.
3Measurement precision
If complex calculations are performed to construct virtual aperture, then angular resolution is improved, but computational overhead and processing time increase
Solution Approach 1:
The patent performs preliminary orthogonal signal transmission and independent received signal processing at each radar before coherent combining. By pre-processing the signals orthogonally and preparing them for coherent integration in advance, the system reduces the computational complexity and processing time required for virtual aperture construction compared to performing all calculations after signal collection.
Data Source
AI summary
A radar system, apparatus, architecture, and method are provided for generating a difference co-array virtual aperture by using a radar control processing unit to coherently combine virtual array apertures from multiple small aperture radar devices to construct a sparse MIMO virtual array aperture and to construct an extended difference co-array virtual array aperture that is larger than the MIMO virtual array aperture by using an FFT hardware accelerator to perform spectral-domain auto-correlation based processing of the sparse MIMO virtual array aperture to fill in holes in the sparse MIMO virtual array aperture and to suppress spurious sidelobes caused by holes in the sparse MIMO virtual array aperture.