Side Lobe Canceller for Wideband Radar Interference

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Solution Overview

Problem

Existing side lobe cancellation solutions are limited to narrow band operation, which is inadequate for wideband radar systems, as they cannot effectively cancel jammer interference across the entire bandwidth of the radar antenna.

Innovation Solution

A Side Lobe Canceller (SLC) method that divides the output waveforms from both the main and auxiliary antennas into spectral components, applying frequency-dependent time delays and attenuations/amplifications to each component, allowing for accurate control of gain and phase across the bandwidth, thereby enabling effective side lobe cancellation over a wide bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If narrow band cancellation is used in existing solutions, then the control unit can produce error signals effectively, but the side lobe cancellation is only effective in a part of the operating bandwidth

Engineering Contradiction:

Improvecancellation effectivenessVSAvoidbandwidth coverage

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The wideband signal is divided into multiple narrowband spectral components using FFT. Each spectral component is processed independently through the side lobe cancellation mechanism, allowing precise cancellation control for each frequency band while covering the entire operating bandwidth through summation of all processed components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The problem is transformed from the time domain to the frequency domain using FFT. This dimensional transformation allows the control unit to operate effectively on narrowband spectral components while the overall system achieves wideband cancellation performance by processing multiple frequency components simultaneously

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If wideband processing is attempted directly, then the bandwidth coverage is improved, but the computational complexity increases significantly

Engineering Contradiction:

Improvebandwidth coverageVSAvoidcomputational complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The wideband processing task is segmented into multiple independent narrowband processing tasks in the frequency domain. Each spectral component requires minimal computational resources, and the overall computational load is distributed across parallel processing of frequency components rather than requiring complex wideband processing algorithms

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Complex time-domain wideband filtering and cancellation operations are replaced by simpler frequency-domain operations using FFT and IFFT. The mathematical transformation to frequency domain converts difficult computational problems into simpler algebraic operations on spectral components

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2088449B1Side lobe suppression

Publication Date: 2012.06.06 SAAB AB

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AI summary

The invention provides a method to suppress side lobes of a main antenna by creating cancellation directions using a Side Lobe Canceller (SLC). The invention also provides the Side Lobe Canceller (200).