Laser Beam Riding Missile Alignment via Temporal Pulse Encoding

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Solution Overview

Problem

Laser beam riding missile guidance systems face alignment errors between the center of the laser information field and the target aimpoint, leading to guidance errors and potential misses, especially when engaging smaller targets like UAVs and RAMs.

Innovation Solution

The system generates a pulsed laser beam with varying inter-pulse intervals across a region, allowing the missile to determine its alignment point based on time intervals and spatial resolution, using an inertial navigation system to calculate distances and a guidance processor unit to adjust fins for realignment, ensuring accurate targeting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser beam riding guidance system is used to guide the missile, then the missile can be guided towards the target using light sensors to detect the beam, but an optical alignment error exists between the centre of the laser information field and the target aimpoint centre in the optical sight, leading to guidance errors

Engineering Contradiction:
Improvealignment accuracyVSAvoidguidance accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The missile determines its current alignment point in the laser information field by detecting the time interval between successive laser pulses. This feedback mechanism allows the missile to continuously monitor its position and make real-time corrections to maintain accurate alignment with the target, thereby resolving the optical alignment error between the laser information field center and the target aimpoint center.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system pre-establishes a relationship between time intervals and spatial positions in the laser information field. By encoding position information into the timing of laser pulses before the missile engages the target, the missile can directly translate detected time intervals into spatial alignment data, enabling accurate target acquisition without suffering from optical alignment errors.

Inventive Principle:
Principle #10Preliminary action

2Loss of information

If the laser beam is scanned to form a laser information field with modulated light signals, then the missile can determine its position within the field, but the system complexity increases due to pulse interval variation and spatial resolution calculations

Engineering Contradiction:
Improveposition information accuracyVSAvoidguidance system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or electronic position encoding mechanisms with a temporal encoding scheme. Instead of using complex modulation schemes or mechanical position markers in the laser beam, the system encodes position information into the time intervals between successive laser pulses. This substitution of temporal encoding for spatial or electronic encoding simplifies the overall system while maintaining high position information accuracy.

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

This approach significantly reduces guidance errors, enabling precise engagement of smaller targets by correcting misalignments and maintaining alignment with the laser information field, thereby improving the system's accuracy and effectiveness.

Implementation Method 1

The system comprises a laser operable to generate an intermittently projected laser beam 105

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

The missile is provided with aft mounted sensors that can detect the signal encoded in the laser beam

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3205973B1A missile for use in a laser beam riding missile guidance system
Publication Date: 2021.09.08 THALES HOLDINGS UK PLC
  • EP3205973B1 patent drawingFigure 1
  • EP3205973B1 patent drawingFigure 2
  • EP3205973B1 patent drawingFigure 3

AI summary

A method for aligning a missile with a target in a laser beam riding missile guidance system, the system including a laser transmitter for generating and projecting a laser information field towards the target and an optical sight for aiming the laser beam towards the target, the method comprising: determining a point in the laser information field with which the missile is currently aligned; determining a distance of the target from the missile; determining an angular displacement between the missile's current direction of travel and the direction in which the target lies from the missile; determining, based on said distance and angular displacement, a new point in the laser information field with which the missile should be aligned to reach the target; and controlling missile guidance systems on board the missile to bring the missile into alignment with the new point in the laser information field.