Hybrid GPS Visible Light Positioning for Shadow Areas
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Solution Overview
Problem
Position measurement technologies using GPS face challenges in shadow areas, such as urban environments with tall buildings that block satellite signals, and require significant power consumption, limiting the effectiveness of portable devices, while also needing separate communication modules for mobile communication or Wi-Fi.
Innovation Solution
A position measurement apparatus and method that utilizes visible light communication to calculate positions using GPS signals and visible light communication device position information, activating a visible light communication mode when GPS errors exceed a predetermined range, allowing for position determination even in shadow areas without mobile communication or wireless Internet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS is used to measure position in shadow areas, then position measurement is enabled, but power consumption increases excessively
Solution Approach 1:
The patent combines GPS positioning with visible light communication (VLC) technology to create a hybrid positioning system. The GPS receiver provides satellite-based positioning while the VLC receiver uses visible light from LEDs to determine position through triangulation. This merging allows the system to use GPS for general positioning and VLC for supplemental positioning in shadow areas, reducing the need for GPS to operate continuously at high power consumption levels.
Solution Approach 2:
The patent introduces visible light communication as an intermediary positioning method between the device and GPS satellites. When GPS signals are blocked in shadow areas, the VLC system acts as an intermediary that uses visible light sources (LEDs) and photodetectors to establish positioning capability without requiring continuous high-power GPS operation, thus reducing overall power consumption while maintaining positioning reliability.
2Reliability
If A-GPS is used to measure position in shadow areas, then position measurement is enabled, but device complexity increases due to separate communication modules
Solution Approach 1:
The patent makes the visible light communication system multi-functional by enabling it to serve both as a communication channel and a positioning system. The same LED-based VLC infrastructure that provides communication services also enables positioning through triangulation of light source positions. This eliminates the need for separate dedicated communication modules for positioning purposes, as the VLC system handles both communication and positioning functions.
Solution Approach 2:
The patent merges communication and positioning functions into a single integrated system using visible light communication technology. The communication module and positioning system share the same hardware infrastructure (LEDs, photodetectors, signal processing units), eliminating the need for separate communication modules that would be required if using traditional A-GPS methods with mobile networks or Wi-Fi.
3Measurement precision
If GPS receiver operates continuously to maintain position in shadow areas, then position measurement accuracy is maintained, but effective time is reduced due to power constraints
Solution Approach 1:
The patent implements dynamic switching between GPS and VLC positioning modes based on environmental conditions and power availability. The system can dynamically adjust which positioning method is active - using GPS when available and VLC when needed in shadow areas - allowing the device to adapt its operation to conserve battery life while maintaining positioning accuracy when possible.
Solution Approach 2:
Instead of requiring continuous full-power GPS operation, the patent uses partial action by employing VLC positioning as a supplementary method that activates only when needed (in shadow areas). This partial use of VLC positioning reduces the overall power consumption requirement compared to continuous GPS operation, extending the effective time of portable devices while maintaining sufficient positioning accuracy for most applications.
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 position measurement in shadow areas by using visible light communication to supplement GPS signals, reducing power consumption and eliminating the need for separate communication modules, thereby improving position measurement accuracy and device efficiency.
Implementation Method 1
A GPS receiver receives microwaves transmitted from twenty-four or more satellites rotating at a medium earth orbit, thereby allowing a position vector of the receiver to be determined
Implementation Method 2
Visible light communication uses light within a visible light wavelength area. The visible light communication, which mainly uses a Light Emitting Diode (LED) as a light source for communication
Implementation Method 3
a visible light receiver receives the visible light by using a Photo Detector (PD) and processes a received visible light signal
Data Source
AI summary
Methods and apparatus are provided for measuring a position of a mobile terminal. A first position is calculated by using a GPS signal. A visible light communication mode of the mobile terminal is activated, when the first position exceeds a predetermined error range. Visible light communication device position information is received. A third position is calculated by using a second position, which corresponds to a position prior to the first position, and the visible light communication device position information.