MIMO Radar Velocity Ambiguity Resolution via Phase Shift Correction
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Solution Overview
Problem
Conventional TDM-MIMO radar systems face limitations in measuring maximum unambiguous velocity, leading to incorrect velocity estimation for objects moving beyond this limit, due to the reduction in velocity measurement range caused by the number of transmit antennas used.
Innovation Solution
A method that involves receiving chirps transmitted by multiple transmitters and reflected off objects, estimating the velocity-induced phase shift, correcting the virtual array vector, and performing Fourier transforms to detect signatures indicating velocities exceeding the maximum unambiguous velocity, allowing for accurate velocity determination beyond conventional limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TDM-MIMO radar uses multiple transmit antennas to improve angle estimation capability, then measurement precision is improved, but the maximum unambiguous velocity that can be measured is reduced
Solution Approach 1:
The patent extends the measurement capability from a single velocity dimension to multiple velocity dimensions by utilizing signals from multiple transmit antennas. By analyzing the velocity measurements from different antenna pairs, the system can resolve ambiguities and determine both the unambiguous velocity and the aliased velocity components, effectively adding dimensional information to the velocity measurement process.
Solution Approach 2:
The patent changes the interpretation parameters of the received signals by estimating phase shifts induced by different velocity components. By calculating phase shifts for both unambiguous and aliased velocity ranges and comparing them against measured phase shifts, the system can identify the true velocity even when it exceeds the maximum unambiguous velocity of individual antenna pairs.
2Reliability
If TDM-MIMO radar operates with multiple transmitters to improve angle estimation, then reliability is improved, but velocity measurement accuracy deteriorates for high velocity objects
Solution Approach 1:
The patent implements a feedback mechanism where the system first performs velocity measurements using individual antenna pairs, identifies velocity ambiguities, then uses the combined information from multiple antenna pairs to resolve these ambiguities. The process iteratively refines the velocity estimate by comparing phase shifts from different antenna configurations until the true velocity is determined, ensuring accurate velocity measurement while maintaining reliable angle estimation.
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
Enables accurate detection and correction of velocity aliasing, effectively determining the true velocity of objects moving beyond the maximum unambiguous velocity, improving the radar's velocity measurement capabilities.
Implementation Method 1
estimating the velocity induced phase shift (φd) in a virtual array vector S
Implementation Method 2
A first Fourier transform on the corrected virtual array vector Sc generates a corrected virtual array spectrum
Data Source
AI summary
In accordance with described examples, a method determines if a velocity of an object detected by a radar is greater than a maximum velocity by receiving on a plurality of receivers at least one frame of chirps transmitted by at least two transmitters and reflected off of the object. A velocity induced phase shift (φd) in a virtual array vector S of signals received by each receiver corresponding to a sequence of chirps (frame) transmitted by each transmitter is estimated. Phases of each element of virtual array vector S are corrected using φd to generate a corrected virtual array vector Sc. A first Fourier transform is performed on the corrected virtual array vector Sc to generate a corrected virtual array spectrum to detect a signature that indicates that the object has an absolute velocity greater than a maximum velocity.