Radio Beacon Geolocation via Satellite TDOA and FDOA
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Solution Overview
Problem
Current geolocation methods using low-orbit satellites for radio beacons are inefficient due to long location times and insufficient precision, and embedding a GNSS receiver in the beacon increases complexity and battery consumption.
Innovation Solution
A method that uses medium-orbit satellites to determine the position of a radio beacon by calculating pseudo-distances and time lags between satellite receptions, eliminating the need for a GNSS receiver in the beacon by leveraging the SAR alert system and GNSS satellite positioning, allowing for precise positioning without complex processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler-Fizeau localization is used with low-Earth orbit satellites, then the radio beacon's position can be determined, but the localization time becomes long and accuracy is insufficient
Solution Approach 1:
The patent combines TDOA (Time Difference of Arrival) and FDOA (Frequency Difference of Arrival) measurement techniques into a joint geolocation method. By merging these two approaches, the system achieves both high positioning accuracy and reduced localization time, overcoming the limitations of using either method alone with low-Earth orbit satellites
Solution Approach 2:
The patent changes the orbital parameter of the satellites from low-Earth orbit to medium-Earth orbit. This parameter change allows satellites to remain visible longer and enables the use of TDOA measurements in addition to FDOA, significantly improving both positioning accuracy and reducing the time required for geolocation
2Measurement precision
If a GNSS receiver is embedded in the radio beacon, then positioning precision is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the geolocation function from the radio beacon itself and relocates it to external satellite-based processing systems. Instead of embedding a GNSS receiver in the beacon, the system uses satellite-based TDOA and FDOA measurements to determine position, thereby eliminating the need for complex onboard positioning hardware while maintaining high precision
Solution Approach 2:
The patent introduces satellite-based intermediaries (processing centers) that perform the geolocation calculations externally. The satellites act as intermediaries between the simple radio beacon and the ground-based processing systems, enabling precise positioning without requiring the beacon to contain complex GNSS receiving and processing equipment
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
This approach reduces processing complexity and battery consumption while achieving precise positioning, enabling faster location determination and optimizing resource use by utilizing the joint properties of SAR and GNSS systems.
Implementation Method 1
the determination of the reception times TRi of said message by said relay satellites, the determination of the pseudo-distances Di between said device and said relay satellites by solving the system of equations TRi = Di/c + Te
Data Source
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AI summary
The method involves determining times of reception of message by relay satellite (102) that is a part of constellation of a search and rescue (SAR) system. Pseudo-distances between a radio beacon (101) and the satellite are determined by solving an equation comprising parameters representing speed of propagation of transmitted signal, time of transmission of message by the device and number of visible satellites. Position of the beacon is determined from the pseudo-distances and from positioning coordinates of the satellite. An independent claim is also included for a system for geolocation of a device transmitting signal containing message to relay satellite.