DoA Estimation Using Segmented Search and Non-Uniform Spacing
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Solution Overview
Problem
Current radar systems face challenges in accurately determining the directions of arrival angles for multiple targets using deterministic Maximum-Likelihood (DML) Direction-of-Arrival (DoA) estimation, particularly due to computational intensity and limitations in handling multiple targets in a two-dimensional antenna array.
Innovation Solution
The apparatus and method employ a processor to define beamsteering vectors and an objective function based on received radar signals, using a search space with non-uniform spacing to efficiently determine the DoA angles by evaluating the objective function over points corresponding to different combinations of elevation and azimuth angles, and utilizing look-up tables to reduce computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deterministic Maximum-Likelihood (DML) Direction-of-Arrival (DoA) estimation is used to determine directions of arrival angles for multiple targets, then measurement precision is improved, but device complexity increases due to computational intensity
Solution Approach 1:
The patent segments the DoA estimation process into two distinct stages: a coarse estimation stage that provides initial angle estimates, and a fine estimation stage that refines these estimates using DML. This segmentation reduces the computational burden on the complex DML algorithm by limiting it to refining only the most promising candidate angles rather than searching the entire angular space.
Solution Approach 2:
The patent performs preliminary coarse DoA estimation before applying the computationally intensive DML algorithm. This preliminary action provides initial estimates that serve as starting points for the fine estimation stage, thereby reducing the search space and computational requirements of the subsequent DML processing.
2Measurement precision
If deterministic Maximum-Likelihood (DML) Direction-of-Arrival (DoA) estimation is used to determine directions of arrival angles for multiple targets, then measurement precision is improved, but productivity decreases due to computational intensity
Solution Approach 1:
The patent segments the DoA estimation process into two distinct stages: a coarse estimation stage that provides initial angle estimates, and a fine estimation stage that refines these estimates using DML. This segmentation reduces the computational burden on the complex DML algorithm by limiting it to refining only the most promising candidate angles rather than searching the entire angular space.
Solution Approach 2:
The patent performs preliminary coarse DoA estimation before applying the computationally intensive DML algorithm. This preliminary action provides initial estimates that serve as starting points for the fine estimation stage, thereby reducing the search space and computational requirements of the subsequent DML processing.
3Device complexity
If uniform spacing search space is used for DoA angle evaluation, then device complexity is reduced, but measurement precision deteriorates for targets at different ranges and velocities
Solution Approach 1:
The patent applies non-uniform spacing to the search space, creating different evaluation densities for different angular regions. This local quality adjustment allows for finer angular resolution in regions where targets are more likely to occur or where higher precision is needed, while maintaining coarser spacing in other regions to reduce overall computational complexity.
Data Source
AI summary
An apparatus comprising a processor configured to receive an input dataset of radar signals received at a plurality of antenna elements that are arranged in a first plane; define a matrix of beamsteering vectors each representing an expected response at the antenna elements of the radar signals from the respective target and comprising a function of a first direction of arrival, DoA, angle θ, relative to the plurality of antenna elements, and a second DoA angle Φ, wherein the first DoA angle comprises a function of an elevation angle and the second DoA angle comprises an azimuth angle to the respective target, wherein the azimuth angle lies in a second plane that is arranged perpendicular to the first plane; define an objective function; search for a set of the first and second DoA angles for each of the plurality of targets by the repeated evaluation of the objective function.