TDM MIMO Radar Doppler Dealiasing for Phase Compensation

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Solution Overview

Problem

Time Division Multiplexing (TDM) MIMO radars face issues with Doppler ambiguity and phase compensation due to mismatched phase delays caused by target motion, leading to incorrect radial velocity measurements and distorted angle spectra.

Innovation Solution

A disambiguation algorithm is applied to estimate unambiguous radial velocity, de-alias the Doppler spectrum, and apply phase compensation using a least-spurious spectrum criterion to resolve Doppler ambiguity and correct MIMO array measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If Time Division Multiplexing is used to simplify MIMO transmission and receiving processing, then device complexity and cost are reduced, but Doppler ambiguity and phase compensation errors occur due to target motion

Engineering Contradiction:
ImproveMIMO transmission and receiving processing complexityVSAvoidradial velocity measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies feedback by using the measured radial velocity from the range-Doppler cell to calculate phase compensation values that are then applied back to correct the MIMO array measurements. This closed-loop approach compensates for the phase errors introduced by TDM while maintaining the simplified transmission structure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the phase parameter of the MIMO array measurements based on the measured radial velocity. By calculating and applying phase compensation values that depend on the target's radial velocity, the system corrects the phase errors introduced by TDM without altering the fundamental TDM operation.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If phase compensation is applied to correct MIMO array measurements, then measurement precision improves, but additional processing steps increase device complexity

Engineering Contradiction:
Improveangular resolution accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by estimating the radial velocity and calculating the required phase compensation values before applying them to the MIMO array measurements. This preparatory step ensures that the phase compensation is ready and optimized before the actual measurement correction, improving efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical or hardware-based phase compensation mechanisms with signal processing algorithms. By using digital signal processing to calculate and apply phase compensation based on radial velocity measurements, the system achieves precise angular resolution without requiring complex physical adjustments.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If Doppler spectrum de-aliasing is performed to resolve velocity ambiguity, then measurement precision improves, but processing time increases

Engineering Contradiction:
Improveradial velocity unambiguityVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by focusing the de-aliasing processing only on the specific range-Doppler cell being analyzed, rather than processing the entire spectrum. This targeted approach resolves the velocity ambiguity for the relevant target while minimizing the overall processing time and computational burden.

Inventive Principle:
Principle #16Partial or excessive action

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 allows for single-frame processing and accurate reconstruction of MIMO array measurements, improving angular resolution and reducing errors in radar systems, particularly in automotive applications like ADAS and autonomous driving.

Implementation Method 1

Radar systems are used to detect the range, velocity, and angle of targets

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4050365B1Method and system for time division multiplexing MIMO radar doppler compensation
Publication Date: 2026.04.15 NXP USA INC
  • EP4050365B1 patent drawingFigure 1
  • EP4050365B1 patent drawingFigure 2
  • EP4050365B1 patent drawingFigure 3

AI summary

A method and system are provided to resolve Doppler ambiguity and multiple-input, multiple-output array phase compensation issues present in Time Division Multiplexing MIMO radars (100) by estimating an unambiguous radial velocity measurement. Embodiments apply a disambiguation algorithm (180) that dealiases the Doppler spectrum to resolve the Doppler ambiguity of a range-Doppler detection. Phase compensation (180) is then applied for corrected reconstruction of the MIMO array measurements. The dealiasing processing first forms multiple hypotheses associated with the phase corrections for the radar transmitters based on a measured radial velocity of a range-Doppler cell being processed. A correct hypothesis, from the multiple hypotheses, is selected based on a least-spurious spectrum criterion. Using this approach, embodiments require only single-frame processing and can be applied to two or more transmitters (120) in a TDM MIMO radar system (100).