Dynamic Reverse Geofencing for Mobile Object Location

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Solution Overview

Problem

Traditional geofencing techniques rely on accurate and stable GPS locations, which are not always available or reliable, especially in asset tracking applications where large estimation errors and instability in location reporting occur, making it difficult to determine if a mobile object is at its expected location.

Innovation Solution

A system and method that uses cellular network information to generate an estimated location for a mobile object, defines a reverse geofence boundary, and calculates the relative probability of the object's location from a database of known locations, providing a measure of estimation confidence and identifying the most probable location.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS-based location determination is used, then location precision is improved, but reliability deteriorates when GPS is unavailable or provides unstable readings

Engineering Contradiction:
Improvelocation precisionVSAvoidlocation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces cellular network location services as an intermediary when GPS is unavailable. The system uses cell tower triangulation and other cellular-based methods to determine location when satellite GPS signals are not available, providing a fallback mechanism that maintains location determination capability under degraded conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes the parameters of location determination by switching between GPS-based high-precision mode and cellular network-based mode with larger error margins. When GPS readings become unstable or unavailable, the system transitions to using cellular network information, accepting larger estimation errors in exchange for maintaining continuous location tracking capability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If cellular network location services are used, then reliability is improved by providing location data when GPS is unavailable, but measurement precision deteriorates due to larger estimation errors

Engineering Contradiction:
Improvelocation reliabilityVSAvoidlocation precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic location determination system that adjusts its methodology based on available resources and conditions. The system dynamically switches between GPS and cellular network-based location services, and even dynamically adjusts the geofence boundary size based on the estimated error margin of the current location method, optimizing the balance between reliability and precision in real-time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system segments the location determination process into multiple independent methods (GPS-based determination and cellular network-based determination). Each method operates independently with its own error characteristics, allowing the system to select or combine methods based on availability and required precision, rather than relying on a single monolithic location service.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If traditional geofencing with fixed boundaries is used, then ease of operation is improved, but adaptability deteriorates when dealing with unstable location data

Engineering Contradiction:
Improvegeofence management simplicityVSAvoidadaptability to location uncertainty
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent transforms static geofence boundaries into dynamic boundaries that adapt to the estimated error margin of the location determination method being used. When cellular network location services are used with larger error margins, the system automatically enlarges the geofence boundary to account for this uncertainty, preventing false positives and negatives while maintaining the simplicity of geofence-based tracking.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS9801015B2Dynamic reverse geofencing
Publication Date: 2017.10.24 SIERRA WIRELESS AMERICA
  • US9801015B2 patent drawing
  • US9801015B2 patent drawing
  • US9801015B2 patent drawing

AI summary

A system and method for determination the relative location of a mobile object is described that includes building a database of known/expected locations with the exact longitude and latitude for each location. Next, an estimated location for a mobile object is generated using information from the cellular network and an area boundary is defined around the mobile object that defines, with some probability, where the object is actually located. The known locations in the database that fall within the area boundary are then identified and a relative probability is calculated for each known location that indicates its relative likelihood of where the mobile object is actually located. From this information at least the most probable location of the mobile object is determined along with a measure of estimation confidence.