Altitude Estimation Using Humidity-Adjusted Gas Constant
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Solution Overview
Problem
Existing altitude estimation methods in urban environments, particularly in multi-story buildings, face inaccuracies due to obstructions from buildings, and fail to account for humidity's effect on pressure measurements, leading to significant errors in determining the correct floor level.
Innovation Solution
A system that uses pressure and temperature measurements from both local and remote sensors, along with humidity data, to compute an accurate altitude by adjusting the gas constant for humid air conditions, thereby minimizing errors caused by humidity and ensuring meter-level accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure and temperature measurements are used to estimate altitude, then accuracy is improved compared to positioning signals in dense urban settings, but measurement precision deteriorates when humidity is not compensated for
Solution Approach 1:
The patent modifies the gas constant parameter in the altitude calculation formula to account for humidity variations. By changing the gas constant from a fixed value to a humidity-adjusted value, the system compensates for the effect of water vapor on pressure measurements, thereby improving measurement precision while maintaining reliability in humid urban environments
2Measurement precision
If positioning signals from terrestrial beacons are used, then altitude estimation is possible, but reliability deteriorates due to building obstructions
Solution Approach 1:
The patent introduces environmental parameters (pressure, temperature, and humidity) as intermediaries to estimate altitude. Instead of relying directly on positioning signals that are blocked by buildings, the system uses these environmental measurements as a mediator to infer altitude, thereby maintaining reliability and precision in obstructed urban environments
3Device complexity
If fixed gas constant is used in altitude calculation, then calculation simplicity is maintained, but measurement precision deteriorates under humid conditions
Solution Approach 1:
The patent dynamically adjusts the gas constant parameter based on humidity measurements. The system calculates a corrected gas constant that incorporates humidity information, then uses this adjusted value in the altitude calculation. This parameter change approach improves measurement precision under humid conditions while adding only minimal calculation complexity
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
The system provides accurate altitude estimation by accounting for humidity, reducing errors to less than 1 meter, which is crucial for distinguishing between consecutive floors in high-rise buildings, thereby enhancing location determination and access control.
Implementation Method 1
a measurement of pressure from a local pressure sensor, a measurement of pressure from a remote pressure sensor
Implementation Method 2
compute an accurate altitude by adjusting the gas constant for humid air conditions
Implementation Method 3
a measurement of temperature from a temperature sensor at the second location or a third location
Implementation Method 4
a measurement of humidity from a humidity sensor
Implementation Method 5
compensating for the effect that humidity has on pressure
Data Source
AI summary
Described are methods, systems, means and machine-readable media embodying program instructions for considering water molecules and other mixtures in air when estimating an altitude of a pressure sensor. In at least one implementation, a measurement of humidity is used to compute a gas constant value, and the computed gas constant value is used to estimate an altitude of a pressure sensor. In another embodiment, the measurement of humidity is compared to a threshold condition related to humidity. Depending on the results of the comparison, the measurement of humidity is used to determine the altitude of the pressure sensor.