Satellite Beacon Localization via Preliminary Timing Synchronization
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Solution Overview
Problem
Current satellite-based search and rescue systems face challenges in accurately localizing distress signals, particularly in situations like a person falling overboard at sea, due to limited satellite visibility and environmental conditions, which can degrade antenna orientation and signal strength.
Innovation Solution
A method for localizing a radio beacon using a first satellite payload broadcasting a signal at a known epoch, with the beacon transmitting a second signal after detecting this signal, and a second satellite payload relaying it to a remote receiver, allowing for coordinate determination based on time records and satellite positions, even with fewer satellites in view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple satellites are required for localization, then localization accuracy is improved, but the system fails under degraded conditions with fewer satellites in view
Solution Approach 1:
The beacon pre-synchronizes its transmission timing with the satellite's signal by detecting the satellite signal and setting its transmission time based on the detected timing information, rather than transmitting immediately. This preliminary synchronization action allows the single satellite to accurately determine the beacon's position by comparing the pre-synchronized transmission timing with its own timing, resolving the contradiction between requiring multiple satellites for accuracy and needing to work with fewer satellites in degraded conditions
Solution Approach 2:
The beacon uses its own received satellite signal as the timing reference for its transmission, eliminating the need for separate timing synchronization infrastructure. The beacon serves its own timing synchronization needs by autonomously detecting and using the satellite's signal timing, which enables accurate localization with fewer satellites while maintaining measurement precision
2Loss of time
If the beacon transmits immediately upon activation, then response time is reduced, but localization accuracy deteriorates due to lack of timing synchronization
Solution Approach 1:
The beacon performs preliminary timing synchronization by detecting the satellite signal and setting its transmission timing based on the detected timing information before actually transmitting the localization signal. This preliminary action ensures that when the beacon transmits, its transmission time is already synchronized with the satellite's reference timing, thereby maintaining localization accuracy without significant delay
Solution Approach 2:
The system uses periodic satellite signal transmissions with known timing patterns that the beacon can detect and synchronize to. The satellite transmits signals at regular intervals with embedded timing information, allowing the beacon to periodically update its synchronization and maintain accurate timing reference for its localization transmissions
3Measurement precision
If the beacon transmits continuously, then localization accuracy is improved through multiple measurements, but energy consumption increases
Solution Approach 1:
The beacon performs timing synchronization as a preliminary action upon activation or when satellite signal is detected, then enters a low-power state. Instead of continuously transmitting or continuously synchronizing, the beacon only performs the necessary preliminary synchronization and transmits localization signals at optimized intervals, significantly reducing energy consumption while maintaining localization accuracy through the pre-established timing reference
Solution Approach 2:
The system uses disposable timing synchronization information embedded in each satellite transmission. The beacon extracts timing reference from each satellite signal it receives and uses it for synchronization, rather than maintaining continuous synchronization. This approach treats timing synchronization as a discrete, replenishable resource rather than a continuous process, reducing energy consumption while preserving measurement precision
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 method enables more accurate and reliable localization of distress signals in challenging conditions, such as a single satellite view, improving the chances of timely rescue by reducing localization errors and increasing the effective range of satellite-based search and rescue operations.
Implementation Method 1
Determine the detection time of said first signal; Transmit a second signal a predefined delay after said detection time
Implementation Method 2
Configuring said second satellite payload to relay said second signal
Data Source
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AI summary
A method and devices are disclosed, for localization of a radio beacon at a remote receiver in the framework of a satellite system. Such satellite system could be Cospas-Sarsat, for Search and Rescue of people, ships and aircraft in distress, and particularly its MEOSAR (Medium Earth Orbit Search and Rescue) segments: DASS/GPS, SAR/Galileo and SAR/Glonass; said beacon is typically one of a PLB (Personal Locator Beacon) or EPIRB (Emergency Position Indicating Radio Beacon) or ELT (Emergency Locator Beacon); and said remote receiver is typically a MEOLUT (Medium Earth Orbit Local User Terminal) base station. Present art MEOSAR localization is based on Time measurements and Frequency measurements on signals emitted by radio beacons, relayed by satellites and detected at a MEOLUT; however since the exact time of transmission of the beacon is unknown at the MEOLUT, Time Difference of Arrival (TDOA) equations are applied. The present invention however, discloses that by carefully configuring the time of transmission at said beacon, even without directly communicating that specific time to the MEOLUT, Time of Arrival (TOA) equations could be applied at the MEOLUT enabling enhanced localization accuracy and/or fewer satellites in view required to localize the beacon. In particular, localization is enabled even upon a single burst emitted by the beacon and relayed to the MEOLUT by a single satellite.