RF Signal Location Refinement Using Map Anchors

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Solution Overview

Problem

Determining the absolute location of wireless access points, especially indoors, is challenging due to signal interference and multipath effects, leading to errors in mobile device positioning.

Innovation Solution

A system and method that utilize a centralized server to receive RF signals from access points, determine anchor locations using map data, and adjust access point positions based on signal strength and environmental context information to improve location accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional RF signal-based location determination is used, then the system can operate without map data, but the location accuracy deteriorates due to signal interference and multipath effects

Engineering Contradiction:

Improvelocation accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces map data as an intermediary reference system to mediate between RF signal measurements and actual location determination. The map provides known anchor points and path constraints that serve as a reference framework, allowing the system to correct RF-based location estimates by comparing them against map-based expectations, thereby improving accuracy without requiring complex additional hardware

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameter space by incorporating map-based parameters (known anchor locations, path geometries) alongside RF signal parameters (signal strength, time of flight). This multi-parameter approach allows the system to resolve ambiguities in RF measurements by cross-referencing against map data, improving location precision while maintaining reasonable system complexity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If access point locations are determined using only RF signals, then the implementation is simpler, but the reliability of location determination worsens due to signal attenuation and multipath effects

Engineering Contradiction:

Improvelocation determination reliabilityVSAvoidimplementation difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The system performs preliminary action by pre-establishing a map with known anchor points and path information before conducting location determination. This pre-prepared reference data allows the system to quickly correct RF measurements against known geographical constraints, improving reliability without requiring complex real-time processing or additional infrastructure

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously comparing RF-based location estimates against map-based expectations and using the discrepancies to adjust and refine location determinations. The map serves as a feedback reference that helps correct errors caused by signal attenuation and multipath effects, improving reliability while keeping the implementation approachable

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9194933B2Context and map aiding for self-learning

Publication Date: 2015.11.24 QUALCOMM TECH INT

AI summary

A system and method for determining locations of a plurality of radio frequency (RF) signal sources. The method includes receiving RF signals from the RF signal sources, and determining locations of the RF signal sources based on the received RF signals. The method also includes determining an anchor having an absolute location identified by map data, and then adjusting the determined locations of the RF signal sources based on the anchor.