Pseudo-Range Multipath Estimation Using TDCP for Urban Positioning

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Solution Overview

Problem

Existing satellite navigation systems face significant accuracy degradation due to multipath errors in urban environments, particularly in pseudo-range measurements, which are not effectively addressed by current methods.

Innovation Solution

A method utilizing time-differenced carrier phase measurement values to estimate and compensate for multipath errors in pseudo-range measurements, employing monitoring variables and filters to determine a usable time period and correct the errors, thereby improving positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pseudo-range measurement values are used for positioning in deep urban environments, then low-cost receivers can determine position, but measurement accuracy significantly decreases due to multipath errors from signal distortion

Engineering Contradiction:

Improvereceiver costVSAvoidpositioning accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary processing method that uses carrier phase measurement values as a mediator to estimate and compensate multipath errors in pseudo-range measurements. The carrier phase measurements serve as a reference to characterize multipath error patterns, which are then applied to correct the pseudo-range data, enabling low-cost receivers to achieve higher positioning accuracy in urban environments

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the approach by changing the parameter being measured from raw pseudo-range values to time-differenced pseudo-range values. This parameter transformation helps eliminate certain error components and enhances the effectiveness of multipath error compensation, allowing low-cost receivers to achieve millimeter-level positioning accuracy despite signal distortion in deep urban environments

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If carrier phase measurements are used for precise positioning, then measurement noise is reduced to mm level, but integer ambiguity terms make it difficult to determine absolute position and require complex calculations

Engineering Contradiction:

Improvemeasurement noise levelVSAvoidcalculation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary component from carrier phase measurements - the multipath error characteristics - and applies them to pseudo-range measurements. By separating the multipath error estimation function from the positioning function, the patent avoids the need for complex integer ambiguity resolution while still achieving mm-level noise performance in the final position solution

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using carrier phase measurements directly for positioning (which requires resolving integer ambiguities), the patent inverts the approach by using carrier phase measurements to characterize errors and then applying those error corrections to pseudo-range measurements. This reversal eliminates the need for complex ambiguity resolution while maintaining high precision

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If pseudo-range measurement values are used without correction information, then navigation can be performed independently, but error of measurement values increases significantly in deep urban environments

Engineering Contradiction:

Improveindependent navigation capabilityVSAvoidmeasurement error

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent enables the receiver to self-correct its measurements by using its own carrier phase measurements to estimate and compensate multipath errors in the pseudo-range data. This self-service approach allows independent navigation without external correction information while maintaining high positioning accuracy in challenging urban environments where signal distortion is severe

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12493123B2Method for estimating multipath error of pseudo-range measurement value, and positioning method using same

Publication Date: 2025.12.09 SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION

AI summary

A method for estimating a multipath error of a pseudo-range measurement value, comprising obtaining satellite navigation system information including a pseudo-range measurement value and a carrier phase measurement value; obtaining a time-differenced carrier phase (TDCP) measurement value by differentiating the carrier phase measurement value with respect to time; setting a monitoring variable for multipath error estimation by using the TDCP measurement value; detecting a change in multipath error using the monitoring variable, and determining a time period usable to estimate the multipath error; and estimating the multipath error at a specific time point using the change relative to a reference time. Accordingly, the location of a target can be precisely determined even in a downtown environment with severe signal distortion, by estimating the multipath error included in the pseudo-range measurement value, and compensating for or excluding the multipath error.