Radar Sensor Angle Estimation via Azimuth-Elevation Segmentation
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Solution Overview
Problem
Radar sensors in motor vehicles face challenges in accurately estimating angles when reflections from elongated objects occur, leading to multi-dimensional search spaces that are calculation-intensive and prone to errors due to signal noise, and the inability to differentiate between real and apparent targets.
Innovation Solution
A method is introduced to model the occurrence of apparent targets caused by reflections, calculating the correlation between the real target's location angle and apparent targets', and limiting the search space to a sub-space defined by this correlation, reducing calculation complexity and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-target estimation is performed in a multi-dimensional search space to handle reflections from elongated objects, then the completeness of target detection is improved, but the computational complexity increases significantly
Solution Approach 1:
The patent segments the multi-dimensional search space into multiple one-dimensional search spaces by separating the angle estimation into azimuth angle estimation and elevation angle estimation. This allows the computational problem to be divided into independent sub-problems that can be solved sequentially, reducing overall computational complexity while maintaining detection completeness.
Solution Approach 2:
The patent transforms the multi-dimensional search space problem into a series of one-dimensional search problems by introducing a sequential estimation approach. First, the azimuth angle is estimated in one dimension, then the elevation angle is estimated in another dimension, effectively reducing the dimensionality of each search operation.
2Measurement precision
If multi-target estimation is performed in a multi-dimensional search space to differentiate real and apparent targets, then the measurement precision is improved, but the calculation time increases
Solution Approach 1:
The patent segments the angle estimation process into two separate one-dimensional estimation tasks: azimuth angle estimation followed by elevation angle estimation. This segmentation reduces calculation time by avoiding the need to search through the entire multi-dimensional space simultaneously, while still achieving accurate differentiation between real and apparent targets.
Solution Approach 2:
The patent performs preliminary azimuth angle estimation before conducting elevation angle estimation. This preliminary action allows the system to narrow down the search space and use the azimuth results to inform the subsequent elevation estimation, reducing overall calculation time while maintaining precision.
3Reliability
If multi-target estimation is performed to handle signal reflections, then the reliability of target identification is improved, but the system becomes more susceptible to errors from signal noise
Solution Approach 1:
The patent segments the estimation process into independent azimuth and elevation stages, where each stage operates in one dimension with its own antenna diagram. This segmentation reduces the impact of noise by allowing each dimension to be optimized independently, improving measurement precision while maintaining reliable target identification.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces computational load and enhances the accuracy of angle estimation by focusing the search on a defined sub-space, effectively distinguishing between real and apparent targets and improving the robustness against signal noise.
Implementation Method 1
Radar sensors are used in motor vehicles, for example, in order to measure the distances, relative speeds, and azimuth angles of vehicles or other objects located in the area in front of the own vehicle.
Implementation Method 2
Multiple antenna elements are then disposed, for example, at a distance from one another on a horizontal line, so that different azimuth angles of the located objects result in differences in the path lengths that the radar signals have traveled from the object to the respective antenna element. These path length differences result in corresponding differences in the amplitude and phase of the signals that are received by the antenna elements
Implementation Method 3
The angle of incidence of the radar signal, and thus the azimuth angle of the located object, can then be determined by comparing the (complex) amplitudes received in the various channels with corresponding amplitudes in an antenna diagram.
Data Source
AI summary
A method for a radar sensor for a motor vehicle, for angle estimation of radar targets based on an antenna diagram that indicates, for various configurations of radar targets, pertinent amplitudes and/or phase correlations between signals which are obtained for the relevant configuration in multiple evaluation channels of the radar sensor, wherein for a single real target, the occurrence of a number n of apparent targets, which are caused by reflection of the signal coming from the real target from elongated objects, is modeled mathematically; a correlation between the location angle of the real target and the location angles of the apparent targets is calculated; and to estimate the location angle of the real target, a multi-target estimate is performed in an n-dimensional search space and the search is limited to a sub-space that is determined by the calculated correlation.