MIMO Radar Doppler Ambiguity Resolution via Phase Shift Mitigation
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Solution Overview
Problem
Multiple input, multiple output (MIMO) radar systems face ambiguity in angle measurements due to phase differences exceeding π, which complicates direction of arrival (DOA) estimation and Doppler measurement accuracy.
Innovation Solution
The method involves mitigating phase shifts caused by target motion, estimating a fine DOA, and resolving Doppler ambiguity by comparing coarse DOA with speed hypotheses based on phase differences between receiver pairs, using multiple transmitters and receivers to output location, distance, and speed information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wide aperture radar with increased spacing between receivers is used to achieve high angular resolution, then the field of view and angular resolution are improved, but phase differences exceed π resulting in arrival angle ambiguity
Solution Approach 1:
The patent combines phase difference information from multiple receiver pairs with Doppler frequency measurements to resolve arrival angle ambiguity. By merging these two types of measurements, the system achieves both high angular resolution and unambiguous angle estimation, eliminating the trade-off between aperture size and measurement accuracy.
Solution Approach 2:
The patent introduces Doppler frequency as an intermediary parameter to resolve the ambiguity in arrival angle measurements. The Doppler frequency serves as a mediator that, when combined with phase difference data from receiver pairs, enables accurate determination of target angle without being constrained by the half-wavelength spacing limitation.
2Measurement precision
If Doppler measurements are used to resolve arrival angle ambiguity, then angle measurement accuracy is improved, but system complexity increases due to multiple transmitters and receivers
Solution Approach 1:
The patent makes the radar system multi-functional by having the same receiver array perform both DOA estimation and Doppler frequency measurement. This universal approach allows the system to resolve arrival angle ambiguity without requiring separate dedicated hardware for each function, thereby reducing overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The patent segments the measurement process into distinct phases: coarse DOA estimation using phase differences from receiver pairs, followed by fine DOA estimation using Doppler frequency information. This segmentation allows the system to tackle the complexity in manageable steps, processing different types of information at appropriate stages to achieve accurate angle measurement.
3Measurement precision
If phase shifts caused by target motion are not mitigated, then processing is simpler, but fine DOA estimation accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by mitigating phase shifts caused by target motion before performing fine DOA estimation. By removing the harmful phase shifts in advance, the system ensures that the subsequent DOA estimation process operates on clean, uncorrupted signal data, thereby maintaining high accuracy without requiring overly complex processing algorithms.
Solution Approach 2:
The patent converts the harmful effect of target motion-induced phase shifts into a beneficial measurement opportunity. By measuring the phase shifts caused by target motion across different receiver pairs, the system can calculate Doppler frequency information, which then becomes a useful parameter for resolving arrival angle ambiguity and improving fine DOA estimation accuracy.
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 enhances radar system performance by resolving DOA ambiguity and providing accurate speed and location information, improving discrimination between speed hypotheses and compensating for phase shifts caused by target motion.
Implementation Method 1
Doppler ambiguity resolution in MIMO radars using a SIMO evaluation
Implementation Method 2
mitigating phase shifts in the radar signals caused by a motion of the target
Data Source
AI summary
Embodiments include methods, systems and computer readable storage medium for a method for determining a fine direction of arrival (DOA) for a target is disclosed. The method includes receiving, by a plurality of receivers of a radar system, radar signals reflected by a target. The method further includes mitigating, by the radar system, phase shifts in the radar signals caused by a motion of the target. The method further includes determining, by the radar system, the fine DOA in response to the mitigation of phase shifts and based on the radar signals. The method further includes estimating and storing, by the radar system, a Doppler frequency based on the fine DOA.