Missile Boresight Error Compensation Using Kalman Filter

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Solution Overview

Problem

Conventional methods for compensating boresight error (BSE) in missiles, particularly those with composite radomes, are inadequate due to assumptions about noise characteristics and material differences, leading to degraded guidance performance and increased errors in estimating target position.

Innovation Solution

A guidance section with a BSE compensation element that includes a Kalman filter and high-pass filtering, adding controlled bias and generating revised error-compensated BSE correction tables using iterative processes and IIR filtering to tailor system bandwidth and noise characteristics, specifically addressing radome refraction-induced noise in composite radomes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional BSE correction tables are used with composite radomes, then manufacturing simplicity is maintained, but measurement precision of target position deteriorates due to non-Gaussian noise characteristics

Engineering Contradiction:
ImproveBSE correction table generationVSAvoidtarget position estimation
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transforms the non-Gaussian noise characteristics of composite radomes into Gaussian noise by applying spectral shaping filters. This parameter transformation allows the use of conventional correction tables while maintaining measurement precision, as the filtered noise conforms to the assumptions underlying traditional BSE correction methodologies.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces spectral shaping filters as an intermediary component between the composite radome and the BSE correction system. These filters act as a mediator that converts the problematic non-Gaussian noise into acceptable Gaussian noise, enabling the existing correction tables to function effectively without requiring complete redesign.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If adaptive filter bandwidth is reduced to attenuate refraction-induced noise, then reliability of noise attenuation improves, but measurement precision of target velocity deteriorates

Engineering Contradiction:
Improvenoise attenuationVSAvoidtarget velocity estimation
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the spectral characteristics of the refraction-induced noise through spectral shaping filters, transforming it into Gaussian noise with controlled bandwidth. This parameter transformation allows the guidance loop to maintain optimal filter bandwidth settings while achieving reliable noise attenuation, as the shaped noise no longer contains the problematic high-frequency components that previously forced bandwidth reduction.

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

Improves estimation of target velocity and position, maintaining optimal guidance loop bandwidth and probability of guidance by filtering out refraction-induced noise and ensuring Gaussian noise characteristics, thus enhancing missile trajectory accuracy.

Implementation Method 1

A guidance section with a BSE compensation element that includes a Kalman filter and high-pass filtering

Methodology Applied
Scientific EffectKalman filter:

Implementation Method 2

A guidance section with a BSE compensation element that includes a Kalman filter and high-pass filtering

Methodology Applied
Scientific EffectHigh-pass filtering: Filter (electronic)

Implementation Method 3

generating revised error-compensated BSE correction tables using iterative processes and IIR filtering

Methodology Applied
Scientific EffectIIR filtering: Filter (electronic)

Data Source

PatentEP2609393B1Method for compensating for boresight error in missiles with composite radomes and guidance section with boresight error compensation
Publication Date: 2018.08.29 RAYTHEON CO
  • EP2609393B1 patent drawingFigure 1~2
  • EP2609393B1 patent drawingFigure 3
  • EP2609393B1 patent drawingFigure 4

AI summary

Embodiments of a guidance section that compensates for boresight error (BSE) caused by effects of a composite radome. The guidance section includes a BSE compensation element to add high-pass filtered noise to compensated BSE data. The guidance section also includes and a Kalman filter to generate line-of-sight rate (LOSR) BSE noise from the compensated BSE data and the added high-pass filtered noise. In some embodiments, a method for generating a revised BSE correction matrix is provided. The revised BSE correction matrix may compensate for BSE caused by effects in the composite radome and may correct for relative target velocity error.