Time of Flight Localization in GPS-Denied Environments
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Solution Overview
Problem
Current localization methods rely heavily on Global Positioning System (GPS) networks, which are not applicable underwater and can be unreliable in overcast conditions, and lack the capability to detect large motions and movements effectively.
Innovation Solution
A method for determining the location of a frequency receiver device relative to at least two frequency originator devices using clock synchronization, message reception, and time-of-flight calculations, allowing for localization without GPS, and enabling detection of large motions and movements through sensor integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS network is used for localization, then localization accuracy is improved, but the system cannot operate underwater or in GPS-denied environments
Solution Approach 1:
The patent introduces an intermediary localization system using acoustic signals and time-of-flight measurements between devices. Instead of relying on satellite-based GPS, the system uses local devices as intermediaries to determine position through signal transmission time, enabling operation in GPS-denied environments while maintaining localization capability
Solution Approach 2:
The patent replaces the electromagnetic satellite-based GPS system with an acoustic signal-based localization system. By substituting the mechanical/physical basis of localization from radio waves to acoustic waves, the system becomes operational in underwater and other GPS-denied environments where acoustic signals can propagate
2Difficulty of detecting and measuring
If vibration sensor is used to detect movement, then motion detection capability is improved, but the system cannot distinguish between significant movements and minor vibrations
Solution Approach 1:
The patent applies partial action by using vibration detection only for a specific purpose (detecting case removal or significant movement events) rather than continuous monitoring. The system triggers alerts only when vibration patterns exceed certain thresholds, filtering out minor vibrations while detecting significant movements
Solution Approach 2:
The patent implements feedback mechanisms where vibration sensor data is continuously monitored and compared against predefined thresholds. When significant movement is detected, the system provides feedback through alerts to the user, enabling distinction between significant movements and minor vibrations through adaptive response
3Reliability
If GPS infrastructure is deployed, then localization reliability is improved, but the system becomes dependent on external infrastructure
Solution Approach 1:
The patent implements self-service localization where devices autonomously determine their position using only local resources - transmitting and receiving acoustic signals between devices without requiring external GPS infrastructure. Each device serves as both a signal source and receiver, making the system independent of external infrastructure while maintaining reliability
Solution Approach 2:
The patent creates a universal localization method that works across multiple environments (terrestrial, underwater, GPS-denied) using the same basic principle of time-of-flight measurement. The system is not tied to any specific infrastructure, making it universally applicable while reducing device complexity and external dependencies
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 localization of devices underwater and in GPS-denied environments, while detecting significant movements, thus providing a robust and cost-effective solution for various applications, including aerial vehicle navigation.
Implementation Method 1
determining the location of a frequency receiver device with respect to at least two frequency originator devices
Implementation Method 2
an accelerometer capable of detecting motion of the mobile device case
Data Source
AI summary
A method for determining the location of a frequency receiver device with respect to at least two frequency originator devices, each of a current location, the method including synchronizing a clock of the frequency receiver device with a clock of one of the at least two frequency originator devices; receiving by the frequency receiver device, a message including an identification code configured for identifying one of the at least two frequency originator devices and obtaining a broadcast time and a current location of the one of the at least two frequency originator devices by looking up a table correlating the at least two frequency originator devices and their respective broadcast times and current locations; calculating a time of flight of the message by calculating the difference between a receive time at which the message is received by the frequency receiver device and the broadcast time.