Staggered FMCW TDM MIMO Waveform for Doppler Velocity Estimation

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Solution Overview

Problem

Traditional MIMO radar systems face limitations in detecting fast-moving objects and slow-moving targets due to inefficient time and frequency resource usage, and they struggle to achieve high angular resolution and unambiguous Doppler velocity estimation, especially with a large number of transmit antennas.

Innovation Solution

The implementation of a staggered FMCW TDM MIMO waveform with non-uniform sampling and an iterative adaptive spectral estimation approach, which extends maximum unambiguous Doppler velocity estimation by N-fold while preserving orthogonality for high-resolution direction of arrival estimation, and mitigates global leakage in the spectral window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional uniform TDM-MIMO waveform is used, then orthogonality is maintained for direction of arrival estimation, but maximum unambiguous Doppler velocity estimation is limited by the Nyquist rate

Engineering Contradiction:

ImproveDoppler velocity estimation rangeVSAvoidwaveform design complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by transitioning from uniform time-division multiplexing to staggered TDM-MIMO waveform. The staggered approach uses non-uniform time offsets between transmit antennas, creating an asymmetric sampling pattern that extends the unambiguous Doppler velocity estimation range beyond the Nyquist limit while preserving orthogonality through careful design of the staggered timing structure

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent changes the temporal sampling parameters by introducing staggered time offsets between different transmit antennas. This parameter modification allows the system to achieve extended Doppler velocity estimation capability by altering the sampling instants from uniform to non-uniform distribution, thereby expanding the measurable velocity range

Inventive Principle:

Principle #35Parameter changes

2Speed

If uniform time sampling is used for MIMO radar signals, then simple processing is achieved, but fast-moving objects cannot be detected due to Doppler aliasing

Engineering Contradiction:

Improvedetectable velocity rangeVSAvoidvelocity estimation accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by implementing a staggered TDM-MIMO waveform where the time offsets between transmit antennas are specifically designed to adapt to higher velocity targets. This dynamic sampling approach allows the system to track and estimate velocities of fast-moving objects without Doppler aliasing, while the coordinated staggered structure maintains the necessary orthogonality for accurate estimation

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If staggered TDM-MIMO waveform with non-uniform sampling is implemented, then extended Doppler velocity estimation is achieved, but spectral leakage may occur

Engineering Contradiction:

ImproveDoppler velocity estimation rangeVSAvoidspectral leakage

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent converts the potential harm of spectral leakage into a benefit by designing a staggered TDM-MIMO waveform where the non-uniform sampling pattern, which could cause leakage, is carefully structured to extend the unambiguous Doppler velocity range. The specific staggered timing design transforms what would normally be a source of spectral leakage into a mechanism for achieving extended velocity estimation capability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution enables the detection of extended ranges of Doppler velocities beyond the Nyquist limit with improved root mean square error, specifically up to 26.6 m/sec with less than 0.01 m/s error for SNR values greater than 5 dB, compared to traditional TDM-MIMO waveforms.

Implementation Method 1

improve doppler velocity estimation

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS11592548B2Methods and apparatus to improve doppler velocity estimation

Publication Date: 2023.02.28 INTEL CORP

AI summary

Methods, apparatus, systems and articles of manufacture are disclosed to improve Doppler velocity estimation. An example apparatus is disclosed including a transmitter to transmit a first sweep signal at a first position in a first block of time during a transmit time sequence pattern, and transmit a second sweep signal at a second position in a second block of time during the transmit time sequence pattern, the second position different than the first position. The example apparatus also includes a velocity analyzer to determine a velocity and a direction of arrival of a target object identified during the transmit time sequence pattern.