Hyperbolic Positioning Using TDOA and Lateration Without GNSS
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Solution Overview
Problem
Global Navigation Satellite Systems (GNSS) face vulnerabilities such as obstructions, signal interference, lack of coverage, and potential destruction, leading to situations where accurate positioning is denied or unavailable.
Innovation Solution
A hyperbolic positioning system utilizing signals of opportunity (SOOP) and reference systems with known locations to determine client system location through spherical lateration and time difference of arrival (TDOA) hyperbolic positioning, combined with Kalman filtering for enhanced accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS systems are used for positioning, then global location accuracy is achieved, but the system becomes vulnerable to obstructions, signal interference, and lack of coverage in certain environments
Solution Approach 1:
The system changes the fundamental parameter of positioning methodology from satellite-based spherical interpolation to terrestrial hyperbolic positioning using TDOA measurements. This parameter change enables operation in environments where GNSS signals are unavailable or unreliable, such as indoors, underground, or in urban canyons with heavy obstructions
Solution Approach 2:
The patent introduces terrestrial reference systems as intermediary elements between the client and the positioning calculation. These reference systems receive signals of opportunity, perform TDOA measurements, and provide processed positioning data to clients, thereby mediating the positioning function in environments where direct GNSS reception is compromised
2Reliability
If multiple reference systems are deployed for hyperbolic positioning, then positioning reliability in GNSS-denied environments is improved, but system complexity increases
Solution Approach 1:
The reference systems are designed to perform multiple functions: receiving signals of opportunity from various sources (GNSS satellites, terrestrial transmitters), performing TDOA measurements, calculating hyperbolic positions, and serving multiple client systems simultaneously. This multi-functionality reduces the need for dedicated infrastructure for each function
Solution Approach 2:
The positioning system is segmented into independent reference systems that can be distributed geographically and operate autonomously. Each reference system processes signals independently and can serve clients in its coverage area, allowing the system to scale modularly without requiring centralized control of all components
3Measurement precision
If spherical lateration and hyperbolic positioning are combined, then positioning accuracy is enhanced, but computational complexity increases
Solution Approach 1:
The patent merges spherical lateration (based on round-trip time measurements) and hyperbolic positioning (based on TDOA measurements) into a unified positioning framework. The client system receives and processes both types of measurements simultaneously, combining them to achieve enhanced positioning accuracy through data fusion
Solution Approach 2:
The system implements feedback mechanisms where the reference systems provide not only position estimates but also measurement quality indicators and confidence levels. This feedback enables the client system to weight and fuse measurements appropriately, reducing computational complexity by avoiding processing of low-quality data
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 in environments where GNSS is unavailable by leveraging SOOP and reference systems, providing robust navigation and timing solutions even in challenging conditions.
Implementation Method 1
determining the round trip times of bidirectional communications between the client system and first, second, and third reference systems
Implementation Method 2
determining the time difference of arrival of the bidirectional communications between client system and the first, second, and third reference systems with respect to a fourth reference system
Data Source
AI summary
A method of determining the location of client system, including: determining the round trip times of bidirectional communications between the client system and first, second, and third reference systems, wherein the locations of the first, second, and third reference systems are known at the time of reception from the client system and at the time of transmission to the client system; calculating a first location of the client system using spherical lateration based upon the determined round trip times; determining the time difference of arrival of the bidirectional communications between client system and the first, second, and third reference systems with respect to a fourth reference system wherein the location of the fourth reference system is known at the time of reception from the client system and at the time of transmission to the client system; calculating a second location of the client system using time difference of arrival hyperbolic positioning based upon the determined time difference of arrival between the client and the first, second, third systems with respect to the fourth reference system; and determining the position of the client system by combining the first location and the second location.