UAV Charging Pad Identification Using Fiducial Marker Constellations

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Solution Overview

Problem

Uncrewed aerial vehicles (UAVs) face challenges in precisely identifying and landing on designated charging pads within a cluster due to limited GPS accuracy, necessitating a method to augment navigational precision.

Innovation Solution

UAVs utilize a reference map of fiducial markers distributed across charging pads, capturing images to identify constellations and patterns, and apply pattern matching to disambiguate the correct charging pad using context-based navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS-based navigation is used for UAV landing, then the navigation system is simple and easy to implement, but the positioning precision is insufficient for identifying specific charging pads in a cluster

Engineering Contradiction:

Improvepositioning precisionVSAvoidnavigation system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces fiducial markers as intermediary objects placed on charging pads to serve as mediators between the UAV's GPS-based coarse navigation and the precise identification of specific charging pads. These markers act as visual intermediaries that the UAV's imaging system can detect and use to disambiguate which specific pad within the cluster is the target, thereby improving positioning precision without requiring the navigation system itself to be more complex

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces reliance on purely mechanical/GPS-based positioning with an optical recognition system. By substituting the mechanical navigation approach with image-based fiducial marker detection and pattern recognition, the system achieves higher positioning precision for identifying specific charging pads while maintaining the simplicity of the overall navigation architecture

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If multiple unique fiducial markers are placed on each charging pad for precise identification, then the identification accuracy is improved, but the manufacturing and deployment complexity increases

Engineering Contradiction:

Improvecharging pad identification accuracyVSAvoidmarker deployment ease

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies homogeneity by using identical or similar fiducial marker designs across all charging pads rather than requiring unique markers for each pad. This allows the same marker type to be manufactured and deployed uniformly across the entire cluster, significantly easing manufacturing and deployment while still enabling precise identification through the spatial constellation patterns formed by multiple markers

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent transitions from identifying charging pads through individual marker characteristics (zero-dimensional or one-dimensional identification) to identifying pads through the two-dimensional spatial constellation patterns formed by multiple markers. This dimensional shift allows simple, identical markers to provide complex identification capability through their arrangement rather than through marker uniqueness

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If strict precision requirements are imposed on fiducial marker placement and orientation, then the identification accuracy is improved, but the system becomes more sensitive to placement errors and harder to deploy

Engineering Contradiction:

Improvemarker identification accuracyVSAvoidsystem tolerance to placement errors

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing the expected constellation patterns of fiducial markers for each charging pad location in the environment. This allows the UAV to compare observed marker constellations against these pre-established reference patterns, enabling accurate identification even when actual marker placements have minor deviations from ideal positions, thereby increasing system tolerance to placement errors

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250363897A1Context-Based Navigation of Uncrewed Vehicles Using Relative Position Markers

Publication Date: 2025.11.27 WING AVIATION LLC

AI summary

In an example embodiment, a method carried out by an uncrewed aerial vehicle (UAV) may involve receiving a reference map of a cluster of charging pads from a server. The cluster may include a layout of charging pads and fiducial markers distributed across the layout, the reference map representing the layout and fiducial markers. The UAV may fly to the cluster and acquire an image of charging pads and observed fiducial markers near the charging pads. The image may capture an observed constellation of fiducial markers at apparent positions and orientations relative to the charging pads. A reference constellation of fiducial markers at reference positions and orientations relative to reference charging pads may be identified in the reference map. Identities of the reference charging pads and a match of the reference constellation to the observed constellation may be used to disambiguate a particular charging pad from among the charging pads.