Projectile Muzzle Velocity Measurement via Onboard Magnetic Sensors

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Solution Overview

Problem

Existing methods for determining muzzle velocity in shoulder firearms are cumbersome, increasing the weight and length of the weapon, requiring additional power and logistical effort, and risking damage to the launch tube due to external magnetic field sensors.

Innovation Solution

Integrating a magnetic field transmitter, such as a permanent magnet, at the launch tube's end and placing two spaced-apart sensors on the projectile to measure the time difference between signal detection, allowing the projectile to calculate its muzzle velocity directly without weakening the launch tube.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an external magnetic field sensor is attached to the launch tube to measure muzzle velocity, then measurement precision is improved, but the weight and length of the weapon increase

Engineering Contradiction:
Improvemuzzle velocity measurement precisionVSAvoidweapon weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent merges the muzzle velocity measurement function with the projectile itself by integrating a magnetic field sensor and evaluation unit into the projectile. This combines the measurement task with an existing component, avoiding the need for separate external measuring devices that would increase weapon weight and length.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of placing the sensor in the launch tube as in conventional systems, the patent inverts the arrangement by placing the sensor on the projectile and the magnetic field transmitter on the launch tube. This inversion transfers the measurement burden from the weapon system to the projectile, resolving the weight and length constraints.

Inventive Principle:
Principle #13The other way round (Inversion)

2Measurement precision

If an external magnetic field sensor is attached to the launch tube to measure muzzle velocity, then measurement precision is improved, but the launch tube is weakened and may burst

Engineering Contradiction:
Improvemuzzle velocity measurement precisionVSAvoidlaunch tube strength
Core Design Contradiction:
Measurement precisionVSStrength

Solution Approach 1:

The patent inverts the conventional arrangement by placing the magnetic field transmitter on the launch tube and the sensor on the projectile. This eliminates the need to embed sensors in the launch tube wall, preserving its structural integrity and preventing burst risks while still enabling precise velocity measurement.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the launch tube and the sensor. The magnetic field transmitter on the launch tube generates a field that the sensor on the projectile detects, allowing velocity measurement without direct physical contact or embedding in the launch tube structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If an external measuring device is used to measure muzzle velocity, then measurement capability is improved, but additional power supply and maintenance effort are required

Engineering Contradiction:
Improvemuzzle velocity measurement capabilityVSAvoidpower supply requirement
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The projectile's evaluation unit processes the velocity measurement data autonomously without requiring external power supply or control. The system uses the projectile's own onboard electronics to evaluate the time difference measurement and control the fuze, making the measurement system self-sufficient and eliminating additional maintenance requirements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent merges the velocity measurement evaluation function with the projectile's existing fuze control electronics. By integrating the evaluation unit into the projectile's onboard system, the measurement capability is added without requiring separate power supplies or external control systems.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If an external measuring device is used to measure muzzle velocity, then measurement capability is improved, but logistical effort increases

Engineering Contradiction:
Improvemuzzle velocity measurement capabilityVSAvoidlogistical effort
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from the weapon system and places it entirely on the projectile. This separation eliminates the need for external measuring devices attached to the launch tube, simplifying the weapon system and reducing logistical complexity while maintaining measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The projectile independently performs the velocity measurement and evaluation without requiring external equipment or support systems. The onboard sensor and evaluation unit work autonomously, eliminating the need for external power supplies, control systems, or maintenance infrastructure.

Inventive Principle:
Principle #25Self-service

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 method accurately determines muzzle velocity without compromising the launch tube's integrity, reducing weight and logistical effort, and enabling precise fuze control without external power sources.

Implementation Method 1

a magnetic field transmitter and in particular a permanent magnet is used as the transmitter... Magnetic field sensors are preferably used as sensors

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

A current is induced in the magnetic field sensor by the movement of the projectile and thus the permanent magnet in the launch tube

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2411758B1Determination of the muzzle velocity of a projectile
Publication Date: 2017.08.30 DYNAMIT NOBEL DEFENCE
  • EP2411758B1 patent drawingFigure 1

AI summary

The invention relates to a method for determination of the muzzle velocity of a projectile (2) when it emerges from the firing barrel (1) of a shoulder-held weapon. In order not to weaken the firing barrel, it is proposed that a transmitter (3) for transmission of signals be arranged on the end face of the firing barrel (1) and that two sensors (9, 10), which are arranged at a distance d from one another, be arranged in or on the projectile (2) in order to detect the signals transmitted by the transmitter (3) and that these sensors (9, 10) detect a pulse on flying past the transmitter (3), and that the muzzle velocity for the projectile (2) be determined from the time difference between the pulses detected by the two sensors (9, 10).