Radio Map Segmentation for Indoor Round-Trip-Time Positioning

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Solution Overview

Problem

Satellite-based positioning technologies are inadequate for indoor navigation due to insufficient signal penetration through walls and roofs, leading to poor performance indoors.

Innovation Solution

A method and apparatus for determining round-trip-time positioning sections using a radio map that includes radio models of multiple devices, enabling accurate positioning by estimating positions based on round-trip-times of radio signals observed by mobile devices within defined sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If satellite signals are used for positioning, then positioning coverage is improved, but positioning accuracy deteriorates indoors due to insufficient signal penetration through walls and roofs

Engineering Contradiction:
Improvepositioning coverage areaVSAvoidindoor positioning accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The environment is segmented into multiple positioning sections based on radio map information, where each section is associated with specific radio devices that provide reliable positioning signals. This segmentation allows the system to maintain accurate positioning indoors by using local radio devices rather than relying on satellite signals that penetrate walls poorly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Radio devices and radio map information serve as intermediaries between the mobile device and the positioning system. Instead of directly using satellite signals indoors, the system uses radio devices transmitting radio signals as mediators to enable accurate indoor positioning through round-trip-time measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If radio map information is used to estimate position, then positioning works indoors, but positioning accuracy is insufficient without round-trip-time information

Engineering Contradiction:
Improveindoor positioning reliabilityVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system merges radio map information with round-trip-time measurements to achieve accurate indoor positioning. The radio map provides the foundation for identifying observable radio signals, while round-trip-time information adds precision to the position estimation, combining both approaches to resolve the contradiction between reliability and accuracy.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If round-trip-time positioning is enabled throughout the environment, then positioning accuracy is improved, but system complexity increases due to needing to determine positioning sections

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of applying round-trip-time positioning uniformly throughout the entire environment, the system determines specific positioning sections where this method is applicable. Each section has localized radio devices and radio map information tailored to that area, making the system more manageable and less complex while maintaining high accuracy where needed.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3739355B1Determining one or more round-trip-time positioning sections
Publication Date: 2026.02.25 HERE GLOBAL BV
  • EP3739355B1 patent drawingFigure 1
  • EP3739355B1 patent drawingFigure 2~4
  • EP3739355B1 patent drawingFigure 5

AI summary

It is inter-alia disclosed a method, comprising: obtaining or holding available (501) radio map information representing a radio map representing a plurality of radio models for a plurality of radio devices (300-1 to 300-5), wherein each of the plurality of radio models is indicative of an expected radio-signal-strength field of a radio signal transmitted by a respective radio device of the plurality of radio devices (300-1 to 300-5); determining (502), at least partially based on the radio map information, one or more round-trip-time positioning sections (616, 617) of an environment covered by the radio map; providing (503) round-trip-time positioning information causing estimating a position of a mobile device (400) at least partially based on round-trip-times associated with radio signals observed by the mobile device (400) within one of the one or more round-trip-time positioning sections (616, 617) of the environment covered by the radio map.