Projectile Trigger Time Programming via In-Flight Velocity Correction
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Solution Overview
Problem
Small projectiles face deviations in muzzle velocity and environmental factors, leading to inaccurate impact positions due to the inability to account for variations in explosive charge, barrel conditions, and environmental factors, particularly for inexpensive projectiles without active tracking systems.
Innovation Solution
A method to update the trigger time of a projectile by determining its muzzle velocity and flight speed using signal strength, flow sensors, or MEM accelerometers, and applying Kalman filtering with reliability weighting, allowing for real-time adjustments to ensure accurate targeting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If permanently programmed trigger time is used in inexpensive projectiles, then device complexity is reduced and cost is lowered, but manufacturing precision of impact position deteriorates due to inability to account for muzzle velocity variations
Solution Approach 1:
The trigger time is changed from a static permanently programmed value to a dynamic value that can be updated during flight based on measured muzzle velocity and environmental conditions. The ballistic computer calculates adjusted trigger time values in real-time to compensate for variations in projectile performance.
Solution Approach 2:
The system implements feedback by measuring actual muzzle velocity using Doppler or laser tachometer, comparing it to expected values, and using this information to recalculate and update the trigger time setting. This closed-loop approach allows the projectile to self-correct for manufacturing variations and environmental factors.
2Manufacturing precision
If active tracking systems with booster and steering fins are employed, then impact position accuracy is improved, but device complexity and cost increase significantly
Solution Approach 1:
The invention extracts only the essential correction mechanism (trigger time adjustment) from the complex active tracking system. By removing unnecessary components like booster fins, steering fins, and continuous active control systems, the solution achieves acceptable accuracy with minimal added complexity.
Solution Approach 2:
Instead of implementing complex physical active tracking systems in each projectile, the invention uses a simplified approach where the ballistic computer calculates corrected trigger times based on measured parameters, effectively copying the intelligence of active tracking into a computational algorithm rather than physical hardware.
3Manufacturing precision
If trigger time is updated using Doppler or laser tachometer, then impact position accuracy is improved, but use of energy and device complexity increase
Solution Approach 1:
The invention uses an external intermediary system (ballistic computer with antenna) to perform the velocity measurement and calculation functions. The projectile itself only needs to emit signals and receive correction commands, offloading the energy-intensive computation and measurement functions to the external system.
Solution Approach 2:
The velocity measurement and trigger time update occurs periodically at specific points during flight rather than continuously. The projectile emits signals at predetermined times, and the ballistic computer processes these discrete measurements to determine the appropriate trigger time adjustment.
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 enables precise programming of the trigger time during flight, compensating for wind and environmental variations, thereby optimizing the projectile's effectiveness and accuracy.
Implementation Method 1
calculating the projectile's speed from signal strength-distance data stored in the ballistic computer
Implementation Method 2
The projectile's muzzle velocity and flight speed are obtained from a flow sensor
Implementation Method 3
The projectile's muzzle velocity and flight speeds may be obtained from a MEM accelerometer
Data Source
Figure 1~3
Figure 4
AI summary
The present invention describes methods for programming trigger time of a projectile (60) based on remaining flight time to a target (P) after the projectile (60) is airborne. The actual muzzle (Vo) and flight speeds (V1, V2, etc.) are independently determined and compared to those used by the ballistic computer (30), and a better estimate of trigger time is accordingly used to activate detonation of the projectile (60). In one embodiment, a Kalman algorithm is used to provide a better estimate of the projectile's flight speeds obtained by independent methods to provide the better estimate of the trigger time.