Terminal Elevation Acquisition via GPS and Barometric Calibration
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Solution Overview
Problem
Existing methods for acquiring elevation values, such as those using GPS signals, become inaccurate when signals are unavailable, like inside buildings or tunnels, due to unreliable atmospheric pressure measurements.
Innovation Solution
A terminal device equipped with GPS, QZS satellite signal reception, atmospheric pressure, and temperature sensors, which calculates elevation values using GPS signals when available and atmospheric data when GPS is unavailable, ensuring high precision through calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS signal reception is used to calculate elevation value, then measurement precision is improved, but reliability deteriorates when GPS signal cannot be received
Solution Approach 1:
The patent combines GPS-based elevation calculation and atmospheric pressure-based elevation calculation into a unified system. The terminal device integrates both measurement methods and uses a control unit to select or combine results, ensuring high precision when GPS is available and maintaining reliability when GPS is unavailable by switching to atmospheric pressure measurement.
2Reliability
If atmospheric pressure measurement is used to calculate elevation value, then reliability is improved, but measurement precision deteriorates due to internal-external pressure differences
Solution Approach 1:
The patent introduces an atmospheric pressure difference correction unit that acts as an intermediary to correct the atmospheric pressure measurement. This unit calculates the pressure difference between the internal and external environments of buildings or tunnels and applies correction to the elevation calculation, thereby eliminating the precision deterioration caused by pressure differences.
3Reliability
If dual elevation calculation system is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a control unit with multi-functional capabilities that can perform GPS-based calculation, atmospheric pressure-based calculation, pressure difference correction, and automatic selection between methods. This universal control unit manages the dual system efficiently, maintaining reliability while minimizing the operational complexity through integrated control logic.
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
Enables accurate elevation value acquisition even in areas with no GPS signal, like buildings or tunnels, by combining GPS and atmospheric pressure data for precise calculations.
Implementation Method 1
an atmospheric pressure measurement unit to measure an atmospheric pressure
Implementation Method 2
a method using a barometer is known
Data Source
AI summary
A terminal receives a GPS signal and a GPS correction signal, and a first elevation value calculation unit calculates an elevation value from the GPS signal and the GPS correction signal. The terminal includes an atmospheric pressure information detection unit that detects ambient atmospheric pressure information, and a second elevation value calculation unit for calculating an elevation value from the atmospheric pressure information. If a GPS correction signal can be received, the elevation value calculated by the first elevation value calculation unit is used as the elevation value of the current position and the calculated elevation value is used to calibrate the second elevation value calculation unit. If a GPS correction signal cannot be received, the elevation value calculated by the calibrated second elevation value calculation unit is used as the elevation value of the current position to acquire an accurate elevation value even when inside a building or tunnel.