Radar Pulse Duration Jitter for Interference Suppression

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Solution Overview

Problem

Existing methods for determining parameters to correlate two objects, such as vehicles and their surroundings, are susceptible to interference from electromagnetic signals, leading to incorrect warnings and reduced driver acceptance.

Innovation Solution

A method that varies the transmission duration of electromagnetic pulses in consecutive sequences to introduce 'jitter', which blurs strong interference peaks, reducing the need for active filtering and improving evaluation accuracy by making interference signals less distinct.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electromagnetic signals are used to monitor adjacent lanes and detect vehicles, then the ability to detect objects is improved, but susceptibility to interference from jamming transmitters and power supply signals increases

Engineering Contradiction:
Improveobject detection accuracyVSAvoidinterference susceptibility
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention applies dynamics by continuously varying the transmission duration of radar pulses in a pseudo-random manner. This dynamic adjustment prevents stationary interference sources (such as power supply signals and jamming transmitters) from establishing consistent correlation peaks, while still allowing moving vehicles to be detected through their Doppler-shifted return signals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter of transmission duration dynamically. By varying the pulse width in a pseudo-random sequence, the system alters the temporal characteristics of transmitted signals, which disrupts the correlation between stationary interference sources and received signals, thereby reducing false detections from interference.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If transmission duration is varied to reduce interference susceptibility, then false alarms are reduced, but the complexity of the transmission control increases

Engineering Contradiction:
Improvefalse alarm reductionVSAvoidtransmission control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention uses a pseudo-random sequence generator to control transmission duration variations. This copying approach generates a reproducible yet unpredictable pattern that can be regenerated at both transmitter and receiver, simplifying the control mechanism while maintaining effective interference suppression through consistent pseudo-random variation.

Inventive Principle:
Principle #26Copying

3Object-affected harmful factors

If groups of eight long pulses and eight short pulses are alternately generated, then interference susceptibility is reduced, but the device complexity and structural complexity increase

Engineering Contradiction:
Improveinterference susceptibilityVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of using fixed alternating groups of long and short pulses, the invention dynamically varies transmission duration in a pseudo-random manner. This dynamic approach achieves interference suppression without requiring complex group structures, reducing both device and structural complexity while maintaining effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention simplifies the approach by continuously varying the transmission duration parameter in a pseudo-random sequence rather than using fixed alternating patterns. This reduces the structural complexity of pulse generation while maintaining the ability to suppress interference through parameter variation.

Inventive Principle:
Principle #35Parameter changes

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 effectively suppresses interference peaks, reducing false alarms and enhancing system acceptance by drivers, as the method does not require additional filtering and maintains accuracy in determining parameters like distance and relative speed.

Implementation Method 1

a plurality of successive transmission pulse sequences, each containing at least one transmission pulse of an electromagnetic signal, are emitted

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

In the receiving circuit, this high frequency is downconverted

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 3

the transmission duration of the individual transmission pulses is varied from transmission pulse sequence to transmission pulse sequence in order to reduce the susceptibility to interference

Methodology Applied
Scientific EffectJitter:

Data Source

PatentEP2783234B1Method for determining at least one parameter for correlating two objects
Publication Date: 2022.03.23 HELLA GMBH & CO KGAA
  • EP2783234B1 patent drawingFigure 1
  • EP2783234B1 patent drawingFigure 2

AI summary

The present invention relates to a method for determining at least one parameter for correlating two objects (10, 20), in particular the distance (r) therebetween, and/or the relative velocity (v) of said two objects (10, 20), wherein a plurality of successive transmission pulse sequences, each having at least one transmission pulse of an electromagnetic signal, forms a series of transmission pulse sequences, wherein the transmission duration of the individual transmission pulses varies from transmission pulse sequence to transmission pulse sequence, in order to reduce the interference as the at least one parameter is being determined.