Spread Spectrum Radar Signal Processing for Interference Suppression

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Solution Overview

Problem

Current radar systems face challenges in suppressing interference, particularly co-channel interference from other radar signal sources, when using narrow band electromagnetic waves without spread spectrum.

Innovation Solution

A signal processing system and method that employs spread spectrum techniques, including a transmission module to generate and transmit spread spectrum signals, and a reception module to despread and process signals, effectively separating interference from useful Doppler effect information using spread spectrum signals and digital filtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If narrow band electromagnetic waves are used for radar transmission, then the radar system can be simpler and energy consumption can be reduced, but interference suppression capability deteriorates

Engineering Contradiction:
Improveenergy consumptionVSAvoidinterference suppression capability
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the radar signal bandwidth variable rather than fixed. The system dynamically adjusts the bandwidth of the spread spectrum signal based on interference conditions and detection requirements, allowing the radar to operate with narrow bandwidth when interference is low (saving energy) and expand to wide bandwidth when interference suppression is needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the bandwidth parameter of the transmitted signal from a fixed narrow band to a variable spread spectrum bandwidth. By modulating the signal across a wide frequency range and controlling the spectral distribution, the system achieves superior interference suppression while maintaining flexible energy consumption characteristics

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If spread spectrum signals are used to suppress interference, then interference suppression capability is improved, but device complexity increases

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

Solution Approach 1:

The patent extracts and processes only the essential spectral characteristics of the received signal. Instead of implementing full spread spectrum processing complexity, the system extracts the spectral density information and uses this extracted feature for interference suppression and target detection, significantly reducing device complexity while maintaining effectiveness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the complex time-domain spread spectrum signal processing into simpler frequency-domain spectral analysis. By changing the processing domain from time to frequency, the system achieves interference suppression using relatively simple spectral density estimation and comparison operations

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If spectral density is spread from narrow band to wide band for interference suppression, then interference reduction is achieved, but signal processing complexity increases

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

Solution Approach 1:

The patent replaces complex mechanical or computational signal processing operations with simpler spectral analysis. Instead of performing complex time-domain filtering or adaptive processing, the system substitutes these with frequency-domain spectral density estimation, which is computationally more efficient and easier to implement

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

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

The system significantly reduces interference by spectrally spreading interference from a narrow band to a wider band while preserving the narrowband signal carrying Doppler effect information, thereby improving detection accuracy and interference suppression.

Implementation Method 1

a transmission module to generate and transmit spread spectrum signals

Methodology Applied
Scientific EffectSpread spectrum modulation: Phase Modulation

Implementation Method 2

a reception module to despread and process signals, effectively separating interference from useful Doppler effect information using spread spectrum signals

Methodology Applied
Scientific EffectDespreading: Homodyne Detection

Implementation Method 3

preserving the narrowband signal carrying Doppler effect information

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP3451014B1Signal processing system and signal processing method for object detection or data transmission
Publication Date: 2025.07.23 RICHWAVE TECH CORP
  • EP3451014B1 patent drawingFigure 1
  • EP3451014B1 patent drawingFigure 2
  • EP3451014B1 patent drawingFigure 3

AI summary

A signal processing system (100) includes a transmission module (Tm1) and a receiving module (Rm1). The transmission module (Tm1) generates and transmits a transmitted radio frequency signal (Stx1) according to a data signal (Sdata1) and a first spread vector (v11). The transmission module includes a spread spectrum unit (Usf1), a digital-to-analog converter (Udac1) and a mixer (Umx11). The spread spectrum unit (Usf1) generates a spread spectrum signal according to the data signal and the first spread vector. The digital-to-analog converter (Udac1) generates an analog signal according to the spread spectrum signal. The mixer (Umx11) mixes the analog signal and a carrier signal so as to generate the transmitted radio frequency signal. The receiving module (Rm1)receives a received radio frequency signal (Srx1) and a second spread vector (v12) so as to generate a spectrum despread signal (Sdf1) and generate object detection information data accordingly. The received radio frequency signal is generated by having the transmitted radio frequency signal reflected by a measured object (Od).