Dual-Antenna Mobile Positioning for Wire-Free Boundary Navigation

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Solution Overview

Problem

Current robotic lawnmowers face challenges in adhering to stringent safety regulations without the need for perimeter wires, particularly in complex or shadow areas, where satellite technologies may fail to provide reliable position detection.

Innovation Solution

A mobile device equipped with a control unit that utilizes a pair of antennas to estimate position uncertainty and orientation, combining GPS signals with odometer and sensor data to ensure accurate navigation and operation within defined areas without the need for perimeter wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If perimeter wire is laid to define working area contours, then safety compliance is improved, but installation complexity and time increase

Engineering Contradiction:
Improvesafety complianceVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the perimeter wire from the system by implementing virtual boundary definition through GPS coordinates and geometric algorithms. The mobile device autonomously determines whether to enter or exit the working area based on calculated position relative to defined contours, eliminating the need for physical wire installation while maintaining safety compliance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical perimeter wire system with an electronic/GPS-based virtual boundary system. Instead of using physical wires to define contours, the system uses satellite positioning, coordinate geometry, and algorithmic boundary calculation to create a digital representation of the working area, substituting mechanical infrastructure with computational methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If perimeter wire is used to define working area, then boundary detection reliability is improved, but maintenance requirements increase

Engineering Contradiction:
Improveboundary detection reliabilityVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces the mechanical perimeter wire that requires physical maintenance with a software-based virtual boundary system defined by GPS coordinates. The virtual contours stored in memory do not suffer from wear, damage, or environmental degradation, eliminating maintenance requirements while maintaining boundary detection reliability through continuous GPS positioning and geometric calculation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If satellite technologies are used for position detection, then perimeter wire requirement is reduced, but reliability in shadow areas deteriorates

Engineering Contradiction:
Improveperimeter wire requirementVSAvoidposition detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent prepares for potential GPS signal failures in shadow areas by implementing pre-defined virtual boundaries with tolerance thresholds and backup detection methods. When GPS position uncertainty exceeds acceptable thresholds, the system uses the pre-calculated virtual contours and tolerance values to determine safe operation, cushioning against the unreliability of satellite positioning in challenging environments.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent implements continuous feedback by monitoring GPS position accuracy and comparing it against virtual boundary contours. The system constantly updates position estimates and recalculates distance to virtual boundaries, using feedback loops to maintain reliable operation even when satellite signal quality varies, adjusting navigation decisions based on real-time position uncertainty assessment.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3761142B1Mobile device, method for estimating the uncertainty in the position of such a mobile device and method for estimating the orientation of such a mobile device
Publication Date: 2022.08.31 STIGA S P A IN BREVE ANCHE ST SPA
  • EP3761142B1 patent drawingFigure 1~2
  • EP3761142B1 patent drawingFigure 3
  • EP3761142B1 patent drawingFigure 4~6

AI summary

The invention relates to a mobile device (2) comprising a frame (3), moving means (4) carried by the frame (3) to determine the movement of the mobile device (2) and receiving means (10) configured to receive at least one position signal. A control unit (20) is operatively connected to the receiving means (10) so as to determine the position of the mobile device (2) starting from the position signal received from the receiving means (2), the control unit (10) being further operatively connected to the moving means (4) so as to drive the moving means (4) according to the position of the mobile device (2). According to the invention, the receiving means (10) comprise a first antenna (11) configured to receive a first position signal and a second antenna (12) configured to receive a second position signal. The first antenna (11) is arranged in a first region (3a) of the frame (3), whilst the second antenna (12) is arranged in a second region (3b) of the frame (3) distinct from the first region (11). The invention further relates to a method for estimating the uncertainty in the position of the mobile device (2) and to a method for estimating the orientation of the mobile device (2).