Imaging Radar DOA Estimation With Complementary Virtual Subarrays
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Solution Overview
Problem
Conventional radar systems face high computational complexity and inflexibility in estimating two-dimensional fine angular direction of arrival, requiring strict antenna spacing and fixed fields of view, which limits their application in environments like autonomous vehicles and drones.
Innovation Solution
A MIMO radar system with a flexible arrangement of virtual receivers, using modulation and multiplexing to create a virtual array of receive channels, allowing for unambiguous two-dimensional direction of arrival estimation with reduced computational cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional beamforming or parametric methods are used for direction of arrival estimation, then measurement precision is improved, but device complexity increases significantly
Solution Approach 1:
The patent segments the virtual array into multiple subarrays (e.g., first subarray and second subarray) with different spatial configurations. Each subarray independently processes a portion of the signal space, dividing the computational burden of full 2D-FFT beamforming while maintaining directional estimation capabilities through complementary subarray coverage.
Solution Approach 2:
The patent employs partial action by using only a subset of virtual array elements (complementary subarrays) rather than processing all N×M virtual channels. This selective processing reduces computational complexity from O((N×M)²) to O(((N×M)/2)²) while maintaining adequate directional estimation through the complementary nature of the subarrays.
2Productivity
If FFT-based beamformers are used, then productivity is improved through efficient processing, but adaptability deteriorates due to fixed field of view and uniform grid requirements
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the radar system to selectively activate different subarrays based on the region of interest. The system can dynamically reconfigure which subarrays are active, enabling flexible field of view adjustment without requiring a complete redesign of the antenna geometry or processing pipeline.
Solution Approach 2:
The complementary subarrays are designed to serve multiple functions: they can independently cover different angular sectors, provide redundant measurement capabilities, and adapt to various scanning patterns. This multi-functionality allows a single hardware configuration to support diverse operational requirements including different field of view angles and resolution demands.
3Manufacturing precision
If uniform grid arrangement is used for receivers, then manufacturing precision is improved, but adaptability deteriorates due to fixed spacing requirements
Solution Approach 1:
The patent embraces asymmetry by designing subarrays with intentionally different spatial configurations and element distributions. Rather than requiring all receivers to be uniformly spaced, the system uses asymmetric subarray arrangements that are optimized for their respective functional roles, allowing flexibility in antenna placement while maintaining processing efficiency through the complementary subarray framework.
Data Source
AI summary
Technologies described herein relate to a multi-step direction of arrival estimation for imaging radars. A radar system includes X transmitter antennas that output radar signals into an environment and Y receiver antennas that generate detection signals based upon the receiving radar signals output by the transmitter antennas. The system separates the detection signals into N virtual receivers that generate a data cube. The system extracts first values from the data cube that correspond to a first set of virtual receivers and computes a first direction of arrival with respect to a target in the environment based on the first values. The system then computes a second direction of arrival with respect to the target in the environment, that is based upon the first direction of arrival and second values in the data cube that correspond to a second set of virtual receivers.