Radar DoA Estimation With Antenna Imperfection Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing direction-of-arrival (DoA) estimation techniques in radar systems, particularly those using microstrip antennas, are limited by antenna imperfections, which complicate accurate determination of arrival angles and restrict the number of detectable targets, especially in complex radar scenes with multiple targets.
Innovation Solution
An apparatus and method that compensates for antenna imperfections by incorporating antenna-imperfection factors into the DoA estimation algorithm, using a processor to evaluate an objective function over a search space of discrete points, and employing look-up tables to efficiently determine direction-of-arrival angles for multiple targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional DML DoA estimation is used, then the estimation can be performed, but the accuracy is limited due to antenna imperfections and restricted to maximum two directions
Solution Approach 1:
The patent changes the mathematical parameters of the DoA estimation by incorporating antenna imperfection factors (gain and phase errors) into the steering vector model. This allows the system to accurately estimate DoA for multiple targets beyond the conventional limit of two directions by adjusting the estimation framework to account for real-world antenna deviations.
Solution Approach 2:
The patent employs an iterative optimization process where the objective function is repeatedly evaluated with updated steering vectors that incorporate measured antenna imperfection factors. This feedback mechanism allows the system to converge on accurate DoA estimates for multiple directions simultaneously, overcoming the conventional limitation.
2Manufacturing precision
If antenna imperfections are not accounted for, then the estimation process is simpler, but the resolution and power difference handling are limited
Solution Approach 1:
The patent performs preliminary characterization of antenna imperfections by measuring gain and phase error factors for each antenna element before the DoA estimation process. These pre-measured imperfection factors are then incorporated into the steering vectors, allowing the system to achieve high resolution and power difference handling without requiring complex real-time compensation during signal processing.
3Measurement precision
If the search space is continuous, then more precise angles can be found, but the computational evaluation becomes more intensive
Solution Approach 1:
The patent transforms the continuous search space into a discrete set of candidate directions by quantizing the angular range into finite steps. This discretization reduces the computational burden significantly while maintaining sufficient precision for practical DoA estimation, as the discrete candidate directions are evaluated using the optimized objective function that incorporates antenna imperfection factors.
Data Source
Figure 1~4
Figure 5
AI summary
An apparatus comprising a processor configured to: receive an input dataset indicative of radar signals received at a plurality of antenna elements from a plurality of targets; define a matrix, Ã, of direction-of-arrival-angle vectors representing an expected response of the radar signals from the target and comprising a function of a direction of arrival angle relative to the antenna elements and including antenna-imperfection-factors that represent the angle dependent effect of antenna imperfections; define an objective function based on the input dataset and the matrix; search for a set of the direction of arrival angles for each of the plurality of targets by the repeated evaluation of the objective function for a plurality of candidate matrices based on matrix Ã, wherein said set is derived from one of the candidate matrices of the plurality of candidate matrices that provides a maximum or minimum evaluation of the objective function.