Ratiometric Sensor Characterization for Air Data Accuracy
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Solution Overview
Problem
Low-cost air data systems in vehicles like missiles, drones, and UAVs face challenges in achieving moderate accuracy due to the sensitivity of commercial sensors to temperature and pressure, leading to inaccuracies in altitude, velocity, and mach number measurements.
Innovation Solution
A method involving ratiometric characterization of static and total pressure sensors to adjust total pressure measurements based on static pressure sensor errors, using a processor to determine and correct errors, thereby improving the accuracy of air data parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low-cost commercial sensors are used in air data systems, then cost is reduced, but measurement precision deteriorates due to sensor sensitivity to temperature and pressure
Solution Approach 1:
The patent applies parameter changes by using ratiometric characterization that references total pressure measurements to static pressure sensor errors. This method changes the measurement approach from absolute pressure measurement to a ratio-based measurement, where the relationship between total pressure and static pressure is used to cancel out temperature and pressure sensitivity errors in low-cost sensors, thereby improving measurement precision while maintaining cost effectiveness
Solution Approach 2:
The patent implements feedback through the ratiometric characterization process where static pressure sensor errors are measured and used to correct total pressure measurements. The system continuously references total pressure to static pressure sensor errors, creating a feedback mechanism that compensates for sensor drift and environmental sensitivity, enabling low-cost sensors to achieve the required measurement precision
2Measurement precision
If sensor characterization is performed to reduce errors, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent uses static pressure sensor errors as an intermediary to correct total pressure measurements. Instead of directly characterizing each sensor independently, the system uses the static pressure sensor error characterization as a mediator that references and corrects the total pressure measurements, simplifying the overall characterization process while improving measurement precision
Solution Approach 2:
The patent merges the characterization of static and total pressure sensors by using ratiometric characterization that references one to the other. This combining approach allows the system to characterize the sensor system as a whole rather than as separate components, reducing device complexity while achieving improved measurement precision through the referenced error correction
Data Source
AI summary
A method for characterizing pressure sensors to improve accuracy in an air data system is described where the sensors include at least one static pressure sensor (40) and at least one total pressure sensor (50). The method includes characterizing the static pressure sensor and the total pressure sensor to determine a static pressure sensor error, Pse, and a total pressure sensor error, Pte, and performing a second ratiometric characterization to reference the total pressure sensor error, Pte, to the static pressure sensor error, Pse.