Skewed L-Shaped MIMO Radar Angle Estimation Using Dual-Basis FFT
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Solution Overview
Problem
Existing radar systems face challenges in achieving fast angular resolution and efficient computation for obstacle detection due to the immense calculation effort required for determining the angles of detected obstacles, particularly in MIMO radar systems with non-perpendicular antenna arrays.
Innovation Solution
A method for transforming MIMO radar system data into the angular domain using a parameterization based on a dual basis constructed from the physical directions of the antenna array, allowing for reduced computational effort and improved angular resolution without compromising accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard azimuth/elevation parameterization is used for MIMO radar angle determination, then angular resolution is achieved, but computational effort becomes immense (approximately 10^9 operations)
Solution Approach 1:
The patent transforms the standard azimuth/elevation parameterization into a rotated coordinate system parameterization. This parameter transformation changes the mathematical representation of the angle determination problem, enabling the use of efficient Fast Fourier Transform algorithms instead of computationally intensive conventional methods, thereby reducing operations from approximately 10^9 to a manageable level while preserving angular resolution
Solution Approach 2:
The patent replaces the conventional mechanical/computational approach of angle determination with a signal processing-based approach using FFT algorithms. By substituting the direct computational method with a transform-domain method, the system achieves the same measurement precision with dramatically reduced computational effort
2Measurement precision
If high angular resolution is achieved with fine azimuth steps (M_az = 10^4), then measurement precision improves, but memory requirements increase to approximately 10^8 elements
Solution Approach 1:
By changing the parameterization from standard azimuth/elevation to a rotated coordinate system, the patent enables memory-efficient FFT-based processing. The transformed parameters allow the system to achieve fine angular resolution (M_az = 10^4) without requiring proportional memory increases, as the FFT algorithm processes the data in a transformed domain that reduces memory footprint
3Adaptability or versatility
If MIMO radar uses distributed Tx and Rx antennas in non-perpendicular arrangement, then adaptability to vehicle integration improves, but calculation effort for angle determination increases
Solution Approach 1:
The patent addresses the increased computation complexity from non-perpendicular antenna arrangements by transforming the parameterization to match the actual array geometry. This parameter transformation aligns the coordinate system with the physical antenna layout, enabling efficient FFT-based processing regardless of the specific non-perpendicular angles, thus maintaining adaptability while controlling computation complexity
Data Source
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AI summary
The invention relates to the determination of the angle of an obstacle with respect to a radar system. Especially the invention is concerned with the transformation of radar data into the angle domain. A method for transforming radar data of a coherent MIMO radar system to the angle domain is proposed. The coherent MIMO radar system comprises transmitter antennas (Tx) and receiver antennas (Rx) spanning a virtual 2D aperture wherein two lines defining two physical directions exist, which are not collinear and wherein a group of said antennas is associated with each of said two lines, and wherein the antennas of each of said two groups are spaced apart from each other mainly along the physical direction associated with the respective line of said two groups, where in the calculations to transform the received data from a delay/Doppler domain to an angle domain is carried out using a parameterization in a coordinate system that is a dual basis to a basis constructed from the two physical directions and a third direction being perpendicular to the first physical direction and said second physical direction, and wherein the origin is chosen to be the point of intersection of the lines defined by the two physical directions or the midpoint of the line segment connecting the points of closest contact of these two lines.