Barometric Height Determination Using Slope and Differential Analysis
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Solution Overview
Problem
Existing methods for determining the height of a device above ground, especially in emergency situations, face inaccuracies due to compounded errors in absolute pressure changes within buildings, and existing solutions do not effectively differentiate between elevator and automobile movements, leading to incorrect height calculations.
Innovation Solution
The use of a combination of barometric pressure rate of change and differential pressure methods, in conjunction with GPS checks, to accurately determine height changes, with specific approaches for elevator rides, automobile travel, and charger reset mechanisms to minimize errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If absolute pressure changes are used to determine height, then height can be calculated, but compounded errors occur in building environments
Solution Approach 1:
The patent segments the height determination process into two distinct methods: (1) absolute pressure change method for general height calculation, and (2) differential pressure method for error correction. By dividing the measurement approach, the system can use the appropriate method for different scenarios and combine results to reduce compounded errors in building environments.
Solution Approach 2:
The patent introduces GPS data as an intermediary reference point to verify and correct barometric pressure-based height calculations. When GPS is available, it serves as a mediator to validate the height determination, reducing reliance on potentially erroneous absolute pressure changes alone.
2Measurement precision
If barometric pressure sensing is used to detect elevation changes, then height can be determined, but elevator and automobile movements cannot be differentiated, leading to incorrect calculations
Solution Approach 1:
The patent merges multiple sensing modalities including barometric pressure sensors, accelerometers, and GPS receivers to create a comprehensive height determination system. By combining these different sensing approaches, the system can differentiate between elevator movements (vertical acceleration patterns) and automobile travel (horizontal movement with different acceleration characteristics), resolving the ambiguity in movement type classification.
Solution Approach 2:
The patent monitors changes in multiple parameters simultaneously (pressure rate of change, acceleration vectors, GPS position changes) to distinguish between different movement types. By analyzing the pattern and magnitude of parameter changes, the system can identify whether the device is in an elevator or automobile, and adjust height calculations accordingly.
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 solution provides accurate height determination by combining rate of change and differential pressure methods, reducing errors in both short and long elevation changes, and resets height to zero during automobile travel, thereby improving the precision of height calculations in emergency scenarios.
Implementation Method 1
a barometric pressure sensor, reads data produced from the sensor
Data Source
AI summary
A device updates a value representing its current height above ground when it detects a height change. The device uses the slope calculated from collected barometric pressure data samples to calculate height change during a period when the value of the slope exceeds a predetermined value. The device also analyzes a predetermined number of barometric pressure sensor data samples preceding and succeeding a height change indicated by the slope change. The device performs an evaluation, i.e., determining the difference between an average of the preceding and succeeding samples, to determine a height change. The device may select either the slope-of-the-curve-during-the-height-change-period method or the difference-between-the-averages method based on meeting a criterion. The processor de-energizes a GPS circuit, height determination method, and sets the height above ground to zero if it detects movement. Placing the device on a charger resets the device's height value to the charger height above ground.