GPS Geofencing with Fewer Than Three Satellites
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Solution Overview
Problem
Existing GPS systems struggle to determine a user's location when fewer than three satellites are in view, as this results in an unbounded Solution Surface that is not useful for location determination.
Innovation Solution
A method to compute the minimum distance from a known reference location to the Solution Surface, allowing for geofence monitoring and route adherence testing by using the distance from a base location to the Solution Plane or Solution Line, even with only two satellites visible, through specific formulae and algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If GPS receiver operates with fewer than three satellites in view, then the receiver can maintain operation in blocked environments, but the Solution Surface becomes unbounded and location determination becomes impossible
Solution Approach 1:
The patent introduces a known reference location as an intermediary element between the GPS receiver and the Solution Surface. By computing the distance from this reference location to the Solution Surface, the system creates a bounded measurement that enables location determination even with only two satellites visible. This intermediary reference point transforms the unbounded Solution Surface problem into a solvable distance calculation.
2Measurement precision
If the system requires at least three satellites for location determination, then location accuracy is maintained, but the system fails to provide useful information in environments with only two satellites visible
Solution Approach 1:
The patent performs preliminary computation of the distance from a known reference location to the Solution Surface when only two satellites are visible. This preliminary action enables the system to provide useful location information (the computed distance) even though a full 3D fix cannot be obtained. The reference location is established in advance, allowing the system to extract meaningful data from the limited satellite geometry.
3Reliability
If geofence monitoring is implemented with unbounded Solution Surface, then the system can detect departures, but false alarms and missed detections increase due to lack of bounded area
Solution Approach 1:
The patent changes the parameter used for geofence monitoring from the unbounded Solution Surface to the bounded distance measurement from a known reference location. By computing this distance and comparing it to the geofence radius, the system achieves reliable geofence detection with reduced false alarms and missed detections. The parameter transformation from unbounded surface to bounded distance resolves the reliability issue.
Data Source
AI summary
Particular implementations are particularly useful in providing a system in which the hardware is more easily upgradable and new hardware functionality may be added without adding any new physical hardware. Through placement of an FPGA closely associated with the CPU of a personal computer, the FPGA may be reconfigured to act as new hardware. A system for installing new virtual hardware involves loading firmware into memory associated with the FPGA and reconfiguring the FPGA through a microcontroller. Particular implementations include universal ports associated with the FPGA into which adapter plugs can be placed to quickly adapt to any device that may be added through the virtual hardware use of the FPGA. Other implementations include high density connectors into which a plurality of ports of varying configurations may be plugged for connection of external electronic equipment through the FPGA.