MIMO Radar Phase Compensation for Velocity Ambiguity
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Solution Overview
Problem
Automotive radar systems face issues with velocity ambiguity in detecting objects with high relative radial velocity and angle measurement errors due to distorted angle of arrival estimation in multiple input multiple output systems.
Innovation Solution
A method for detecting objects using a radar system with M transmit antennas and N receive antennas, involving phase compensation and decoding of range/relative velocity matrices, along with calculating the angle of arrival, employing frequency modulated continuous wave signals and multiple two-dimensional Fast Fourier transforms to improve accuracy and resolve ambiguities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MIMO radar system uses multiple transmit and receive antennas to improve detection capability, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the MIMO radar system into distinct functional modules: transmit antenna array, receive antenna array, signal processing unit with FFT processors, and control unit. Each module handles specific tasks independently, making the complex system manageable and maintainable while preserving detection accuracy
Solution Approach 2:
The radar system uses identical transmit and receive antenna elements that can function in multiple roles. The same antenna types are used for both transmission and reception, and the signal processing pipeline handles multiple functions (range measurement, velocity measurement, angle estimation) using standardized processing blocks
2Measurement precision
If radar system processes NxM digital signals through multiple 2D FFT operations to reduce velocity ambiguity, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary signal conditioning and organization before the main FFT processing. Received signals are pre-processed to organize them into proper matrix formats, and preliminary range estimation is performed to guide subsequent velocity and angle processing, reducing the overall computation time
Solution Approach 2:
The radar system uses periodic chirp signal transmission with structured time scheduling. The FMCW signals are transmitted in periodic sequences, and the processing follows a periodic pattern with FFT operations performed on regularly spaced signal blocks, enabling efficient batch processing and reducing total processing time
3Measurement precision
If phase compensation is applied to Nx(M-1) range/velocity matrices to correct range differences, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware-based phase compensation mechanisms with software-based digital signal processing. Phase correction is achieved through mathematical operations on the received signals rather than requiring additional physical phase shifters or complex hardware circuits, reducing overall system complexity
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
The method enhances the radar system's ability to unambiguously detect objects' distance, relative radial velocity, and angle of arrival, reducing velocity ambiguity and angle measurement errors, thereby improving road safety and radar system performance.
Implementation Method 1
A frequency modulated continuous wave (FMCW) signal including a sequence of frequency chirped waveforms is transmitted
Implementation Method 2
processing the NxM digital signals to produce NxM first range / relative velocity matrices
Implementation Method 3
downconverting NxM received signals to produce NxM downconverted signals wherein the received signals correspond to the M sequences of encoded transmitted signals
Data Source
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AI summary
Various exemplary embodiments relate to a method for detecting an object using radar system having M transmit antennas, N receive antennas, and a processor, including: receiving, by the processor, NxM digital signals, wherein the N receivers receive M received signals corresponding to M sequences of encoded transmitted signals resulting in NxM digital signals; processing the NxM digital signals to produce NxM first range / relative velocity matrices; applying a phase compensation to Nx(M-1) first range / relative velocity matrices to compensate for a difference in range between the Nx(M-1) first range / relative velocity matrices and the Mth range / velocity matrix; decoding the M phase compensated range / relative velocity matrices for the N receivers using an inverse of the transmit encoding to produce M decoded phase range / relative velocity matrices for the N receivers; detecting objects using the M range / relative velocity matrices for the N receivers to produce a detection vector.