Satellite Radio Source Positioning Without Direction-Finding Arrays

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Solution Overview

Problem

Existing methods for positioning unknown target radio wave sources using satellite-based TDOA and FDOA require direction information, leading to ambiguity and increased hardware and cost due to array antennas.

Innovation Solution

A positioning device that calculates TDOA and FDOA using correlation processing, converts geolocation points to latitude and longitude, and estimates the target's position by extracting geolocation points from frequency distributions and error ellipses without relying on direction information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direction information is used to remove ambiguity in positioning, then positioning accuracy is improved, but hardware complexity and cost increase due to array antenna requirements

Engineering Contradiction:

Improvepositioning accuracyVSAvoidhardware complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts only the necessary TDOA and FDOA information from satellite signals through correlation processing, discarding the need for complex direction finding hardware. By focusing on time and frequency differences rather than full direction information, the system removes ambiguity through mathematical processing of extracted parameters rather than through hardware complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical/array antenna system required for direction estimation with a signal processing-based approach using correlation functions. Instead of using multiple antenna elements physically arranged to determine direction, the system uses temporal and spectral analysis of signals from simpler antenna configurations to achieve the same positioning objective.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If array antenna is mounted to acquire direction information, then ambiguity is removed, but cost increases

Engineering Contradiction:

Improveambiguity removalVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention uses simple, inexpensive antenna elements rather than costly array antenna systems. The correlation processing method allows the use of basic receiving hardware that can be easily manufactured and deployed, replacing expensive specialized direction-finding equipment with more economical signal processing techniques.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the parameters used for positioning from direction-based measurements to time-difference and frequency-difference measurements. By transforming the measurement space from angular domain to temporal-spectral domain, the system achieves reliable ambiguity removal using parameters that can be obtained from simpler, lower-cost hardware configurations.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate positioning of unknown target radio wave sources without the need for direction information, reducing hardware requirements and costs.

Implementation Method 1

calculating information of TDOA and FDOA by correlation processing between relevant complex signal vectors on a basis of the acquired complex signal vectors

Methodology Applied

Scientific EffectCorrelation processing:

Implementation Method 2

converting, on a basis of geolocation points calculated for a plurality of time periods, the geolocation points into information of latitude and longitude

Methodology Applied

Scientific EffectCoordinate transformation:

Implementation Method 3

calculating an error ellipse that is an area where there is a possibility that the geolocation point is present for each of sets of the satellites on a basis of the extracted geolocation point

Methodology Applied

Scientific EffectError ellipse calculation:

Data Source

PatentUS20260036667A1Positioning device and positioning method

Publication Date: 2026.02.05 MITSUBISHI ELECTRIC CORP

AI summary

There are included signal receiving units to acquire complex signal vectors of signals received by satellites, a correlation processing unit to calculate information of TDOA and FDOA by correlation processing between relevant complex signal vectors, a geolocation point calculating unit to calculate a geolocation point corresponding to the TDOA and the FDOA, a coordinate converting unit to convert the geolocation points into information of latitude and longitude, a frequency distribution calculating unit to calculate a frequency distribution of the geolocation point on a basis of the information of latitude and longitude, a geolocation point extracting unit to extract a geolocation point included in an area having a maximum frequency from the frequency distribution on a basis of the calculated frequency distribution, and a position estimating unit to estimate a position of a target radio wave source on a basis of the extracted geolocation point.