Resonant Sensor Reinitialization for Rocket Guidance Fault Tolerance
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Solution Overview
Problem
Rocket and missile guidance systems with resonant sensors often experience improper initialization due to vibrations during fuel burn, leading to inaccurate data and course deviations, as existing shock isolators and Built-in-Test fault detectors can be inadequate or fooled by vibrations.
Innovation Solution
A fault detection and reset system that compares guidance data with physical limits to determine proper initialization, initiating a reinitialization sequence if data is unphysical, and continues monitoring to prevent further errors, even if the Built-in-Test fault detector fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shock isolators are used to isolate resonant sensors from vibrations, then the sensor protection is improved, but the isolation effectiveness deteriorates under severe vibration environments during rocket motor burn
Solution Approach 1:
The system continuously monitors guidance data from resonant sensors and compares it against pre-established physical limits. When data exceeds these limits (indicating improper initialization), the system generates feedback signals to trigger sensor reinitialization, creating a closed-loop protection mechanism that adapts to vibration conditions in real-time
Solution Approach 2:
The guidance system performs self-diagnosis by evaluating its own sensor data against physical constraints. When improper initialization is detected, the system automatically reinitializes the resonant sensors without external intervention, enabling the system to service itself during critical vibration periods
2Reliability
If Built-in-Test fault detectors are used to detect sensor failures, then the fault detection capability is improved, but the detection accuracy deteriorates because the fault detector can be fooled by vibrations
Solution Approach 1:
The system introduces physical limits as an intermediary reference frame between the fault detector and sensor data. Instead of directly trusting or rejecting sensor readings, the system compares data against these intermediate physical constraints (maximum acceleration, rotation rates, etc.), which serve as a mediator to distinguish genuine faults from vibration-induced anomalies
Solution Approach 2:
Physical limits are pre-calculated and stored before flight based on the specific rocket or missile configuration. These preliminary established boundaries enable rapid comparison during flight without requiring complex real-time analysis, allowing the system to quickly determine if sensor readings are physically plausible
3Device complexity
If the guidance system operates without reinitialization capability, then the system simplicity is improved, but the fault tolerance deteriorates when improper initialization occurs during vibrations
Solution Approach 1:
The system implements periodic monitoring of guidance data against physical limits throughout flight. This periodic checking mechanism, combined with on-demand reinitialization when faults are detected, provides a simple yet effective approach to improving fault tolerance without requiring continuous complex control algorithms
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
Ensures reliable detection and correction of improper initialization, maintaining accurate guidance data and preventing course deviations by repeatedly resetting the resonant sensor until successful reinitialization is achieved, even after vibrations have diminished.
Implementation Method 1
Resonant sensors are devices which use mechanical vibrations, typically induced at a specific resonant frequency, to detect any of a variety of conditions.
Data Source
AI summary
An apparatus and method improves the fault tolerance of a rocket or missile guidance system which includes a resonant sensor. When improper initialization is detected, the resonant sensor is reinitialized, repeatedly if necessary, until normal operation is achieved. Improper initialization is detected by comparing data from the guidance system with pre-specified physical limits to roll, pitch, yaw, and/or other features of the flight scenario. Embodiments can also detect a fault condition due to an error signal from a “Built-in-Test” (BIT) module. The initialization sequence initiated by the invention can be identical to the power-on sequence, or it can be a separate, reinitiating sequence. Subsequent resets are initiated as needed, for example until the burn of the rocket fuel and the associated vibrations have ceased and the resonant sensor has been successfully initialized.