Radar DoA Angle Search Using DML Branch Metric Screening
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Solution Overview
Problem
Existing radar systems face challenges in efficiently determining the directions of arrival angles for multiple targets due to unknown target numbers and system imperfections, leading to high computational complexity and limited accuracy in DoA estimation.
Innovation Solution
The use of Deterministic Maximum Likelihood (DML) techniques to evaluate an objective function for candidate direction-of-arrival angles, incorporating a branch metric function to optimize the search for additional targets, thereby reducing computational complexity and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Deterministic Maximum Likelihood techniques are used to evaluate objective function for candidate direction-of-arrival angles, then measurement precision of DoA estimation is improved, but device complexity increases due to high computational requirements
Solution Approach 1:
The patent segments the search space into multiple regions and processes targets in sequential stages. The branch metric function divides the computational task by evaluating candidate targets incrementally, allowing the system to handle complex multi-target scenarios by breaking down the overall DoA estimation problem into manageable sub-problems that can be solved sequentially rather than requiring exhaustive simultaneous evaluation of all candidates.
Solution Approach 2:
The patent performs preliminary evaluation using the branch metric function to assess candidate targets before committing to full objective function evaluation. By pre-screening candidates based on the branch metric and comparing against threshold λ, the system eliminates unpromising candidates early in the process, reducing the number of computationally intensive objective function evaluations needed and thereby lowering overall computational complexity while maintaining estimation accuracy.
2Measurement precision
If exhaustive search is performed to determine unknown number of targets and their DoA angles, then measurement precision is improved, but loss of time increases due to extensive computational evaluation
Solution Approach 1:
The patent performs preliminary evaluation using the branch metric function to assess candidate targets before committing to full objective function evaluation. By pre-screening candidates based on the branch metric and comparing against threshold λ, the system eliminates unpromising candidates early in the process, reducing the number of computationally intensive objective function evaluations needed and thereby lowering overall computational complexity while maintaining estimation accuracy.
Solution Approach 2:
The patent applies partial action by evaluating only the necessary subset of candidate targets rather than performing exhaustive search on all possible candidates. The branch metric function with threshold λ enables the system to stop evaluating candidates once a sufficient number of valid targets are identified, performing just enough computational work to achieve accurate DoA estimation without the overhead of complete exhaustive search.
3Productivity
If branch metric function is used to evaluate additional targets, then productivity of target detection is improved, but device complexity increases due to additional metric evaluation requirements
Solution Approach 1:
The patent segments the target detection process into distinct stages: initial target identification, branch metric evaluation for additional targets, and final objective function optimization. The branch metric function operates as an independent evaluation module that can be applied sequentially to detect additional targets beyond the first target, improving productivity by enabling efficient multi-target detection without requiring complete re-evaluation of all parameters for each new target.
Data Source
AI summary
An apparatus configured to:receive an input dataset indicative of radar signals, reflected from targets, received at an antenna;determine an objective function for evaluation over a plurality of points of a search space representing possible direction-of-arrival angles;evaluate the objective function for a first candidate number of targets;perform a first evaluation of a branch metric function based on a second candidate number of targets, wherein the branch metric function is indicative of a change in the objective function; andif the branch metric function is greater than a predetermined threshold, then evaluate the objective function for the second candidate number of targets;if the branch metric function is less than the predetermined threshold, then evaluate the objective function for the first candidate number of targets, wherein the evaluation is based on at least one of the first candidate number of targets having a different, second candidate direction-of-arrival angle.