Indoor Positioning With Wi-Fi RTT and IMU Drift Correction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional indoor positioning techniques suffer from inaccuracy, impracticality, and the uncommonness of UWB transceivers, making Wi-Fi positioning a strong but imperfect contender, particularly due to issues like low precision, measurement rate reduction, and sensor drift in Wi-Fi RTT measurements.

Innovation Solution

A method and apparatus that utilize Wi-Fi ranging and inertial measurement units (IMUs) for indoor positioning, employing filtering techniques and sensor-driven motion models to enhance accuracy by fusing RTT ranging measurements with sensor data, using methods like Extended Kalman Filter (EKF) and particle filtering to improve positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Wi-Fi RTT ranging is used for indoor positioning, then positioning coverage is improved due to widespread Wi-Fi infrastructure, but measurement precision deteriorates compared to UWB

Engineering Contradiction:

Improvepositioning coverageVSAvoidranging accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent combines Wi-Fi RTT ranging measurements with IMU sensor data (accelerometer, gyroscope, magnetometer) to create a fused positioning solution. The sensor data compensates for Wi-Fi ranging errors through dead reckoning, while Wi-Fi provides periodic position corrections, achieving both wide coverage and improved precision

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The positioning system uses a composite approach by integrating multiple positioning technologies (Wi-Fi RTT and inertial sensing) into a unified system. This composite system leverages the strengths of each technology while mitigating their individual weaknesses, similar to how composite materials combine different materials to achieve superior properties

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If Wi-Fi RTT ranging is used, then positioning availability is improved, but measurement rate deteriorates due to protocol limitations

Engineering Contradiction:

Improvepositioning availabilityVSAvoidmeasurement rate

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The system maintains continuous positioning by running IMU-based dead reckoning continuously while periodically updating with Wi-Fi RTT measurements. The sensor data fills the gaps between Wi-Fi ranging updates, ensuring uninterrupted position estimation despite Wi-Fi's lower measurement rate

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The IMU sensors act as an intermediary that bridges the time gaps between Wi-Fi RTT measurements. The inertial data provides continuous position estimates during intervals when Wi-Fi ranging cannot be performed, maintaining measurement continuity

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If IMU sensor data is used for positioning, then short-term accuracy is improved, but drift accumulates over time deteriorating long-term accuracy

Engineering Contradiction:

Improveshort-term positioning accuracyVSAvoidlong-term positioning accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system uses Wi-Fi RTT measurements as feedback to correct accumulated drift in the IMU-based dead reckoning. Periodic Wi-Fi position updates reset the drift accumulation, while the sensor data continues to provide high-rate tracking between corrections

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The positioning system performs periodic Wi-Fi RTT measurements to reset drift accumulation, while maintaining continuous IMU-based tracking between periodic updates. This periodic correction approach prevents unbounded drift while preserving high measurement rates

Inventive Principle:

Principle #19Periodic action

4Measurement precision

If UWB transceivers are deployed for high-precision positioning, then measurement precision is improved, but device complexity and cost increase due to uncommon hardware

Engineering Contradiction:

Improveranging accuracyVSAvoidtransceiver availability

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses widely available, low-cost Wi-Fi transceivers and standard IMU sensors instead of expensive UWB hardware. By fusing these common components, the patent achieves UWB-like positioning accuracy without requiring uncommon or expensive transceivers

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS12607735B2Method and apparatus for indoor positioning using ranging and sensing information

Publication Date: 2026.04.21 SAMSUNG ELECTRONICS CO LTD

AI summary

An indoor positioning method includes scanning for registered Wi-Fi nodes with known coordinates to generate a list of the registered Wi-Fi nodes. The method also includes performing a ranging operation by (i) selecting nodes to range with from the list of the registered Wi-Fi nodes, and (ii) processing ranging responses from the selected nodes to generate a series of distance measurements. The method further includes obtaining a series of sensor readings generated by one or more inertial measurement units (IMUs) of a device. The method also includes estimating a position of the device based on the series of distance measurements and the series of sensor readings using first and second filtering operations that are performed in parallel.