Radar Device Local Oscillator Synchronization for Angle Resolution

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Solution Overview

Problem

Radar devices face challenges in enhancing angle resolution and maintaining detection accuracy due to phase noise issues, particularly when using different local oscillation signals for transmission and reception, which increases costs and degrades performance.

Innovation Solution

The radar device employs a configuration with a first module using the same local oscillation signal for transmission and reception, and a second module using a synchronized local oscillation signal for reception, with signal processing to calculate the target's angle through coherent integration of signals from both modules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If different local oscillation signals are used for transmission and reception in distributed sub-array units, then angle resolution is improved, but phase noise increases and detection accuracy deteriorates

Engineering Contradiction:

Improveangle resolutionVSAvoiddetection accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The radar device is divided into multiple independent sub-array units, each capable of transmission and reception operations. This segmentation allows distributed aperture synthesis for improved angle resolution while maintaining independent local oscillation signal generation in each unit, thereby managing phase noise through localized signal processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the frequency parameter of local oscillation signals used for transmission and reception. By operating at different frequencies (f_tx for transmission, f_rx for reception) and utilizing frequency conversion processes, the system achieves improved angle resolution through distributed sub-array processing while managing phase noise through frequency domain separation and synchronization techniques.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the same local oscillation signal is distributed to each module by wire, then phase noise is reduced, but system complexity and cost increase

Engineering Contradiction:

Improvephase noise suppressionVSAvoidsignal distribution system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system extracts and removes the need for complex wired distribution networks by generating local oscillation signals independently in each sub-array unit. This extraction of the signal distribution function eliminates the complexity and cost associated with high-frequency signal routing while maintaining phase coherence through synchronization of locally generated signals.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Each sub-array unit generates its own local oscillation signals autonomously without requiring external distribution. This self-service approach allows each unit to independently perform frequency conversion and signal processing, eliminating the need for complex wired signal distribution infrastructure while maintaining operational coherence across the distributed array.

Inventive Principle:

Principle #25Self-service

3Device complexity

If each module has its own local oscillation source with synchronized reference signals, then device complexity is reduced, but phase noise increases and detection accuracy deteriorates

Engineering Contradiction:

Improvesignal distribution systemVSAvoiddetection accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system dynamically adjusts the frequency parameters of locally generated oscillation signals in each sub-array unit. By implementing dynamic frequency conversion processes that adapt to transmission and reception requirements, the system maintains phase coherence and suppresses phase noise effects while keeping each unit independently configured, thus reducing overall system complexity.

Inventive Principle:

Principle #15Dynamics

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 angle resolution while maintaining detection accuracy and reducing the influence of phase noise, allowing for the detection of targets with small reflected power without increasing costs.

Implementation Method 1

obtains the distance to the target on the basis of a time from the emission of radio waves from the transmission antenna till the reception of the reflected waves by the reception antenna

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 2

each unit has a phased array antenna. Multiple phased array antennas distributed on a plane constitute a single equivalent large-aperture antenna

Methodology Applied

Scientific EffectPhased array:

Implementation Method 3

a local oscillation signal used for down-converting a reception signal

Methodology Applied

Scientific EffectFrequency conversion:

Data Source

PatentUS11921230B2Radar device and signal processing method

Publication Date: 2024.03.05 MITSUBISHI ELECTRIC CORP

AI summary

A first module generates a first reception signal from a reflection RF signal of a transmission RF signal using a first local oscillation signal, a second module generates a second reception signal from the reflection RF signal using a second local oscillation signal synchronized with the first local oscillation signal, and a first signal processor calculates the angle of a target using a signal obtained by coherent integration based on the first reception signal and second reception signal.