Far-source Positioning via Time-Difference Arrival Metrics
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Solution Overview
Problem
Current positional determination systems rely on precise location and timing information of satellite signals, which is often unavailable or imprecise, making it difficult to implement navigation without multiple high-fidelity monitor stations observing signal sources from geographically dispersed locations.
Innovation Solution
A system and method for navigation using a Monitor Station (MS) with known location, where both MS and User Equipment (UE) make measurements on common signals, allowing for positional determination without precise ephemeris or signal timing information, using time-difference of arrivals and synchronized clocks to identify the relative position of the UE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional GPS navigation methods are used requiring precise satellite location and timing information, then positioning accuracy is improved, but system complexity and requirement for multiple high-fidelity monitor stations increases
Solution Approach 1:
The patent extracts and eliminates the requirement for precise satellite ephemeris and timing information from the traditional GPS navigation process. By using a different measurement approach (comparing signal arrival times at two receivers rather than calculating from satellite position data), the system achieves positioning without needing to know or access precise satellite location and timing data, thereby simplifying the system architecture.
Solution Approach 2:
The patent introduces an intermediary measurement approach using a second receiver (which could be a monitor station or another receiver with known position) to mediate the positioning process. Instead of directly calculating position from satellite signals, the system uses the time difference of signal arrival at two receivers as an intermediary measurement, which eliminates the need for precise satellite ephemeris and reduces system complexity.
2Measurement precision
If precise ephemeris and signal timing information are required for navigation, then positioning accuracy is improved, but availability of the system deteriorates when such information is unavailable
Solution Approach 1:
The patent removes the dependency on precise ephemeris and signal timing information from the navigation process. By formulating a positioning method that relies solely on measuring signal arrival time differences at two receivers, the system eliminates the need to access or process satellite ephemeris data, thereby maintaining availability even when such information is unavailable or imprecise.
Solution Approach 2:
The patent enables the receiver system to determine position using only local measurements of signal arrival times at two receivers, without needing to obtain or process satellite ephemeris information from external sources. The system serves itself by using the time difference measurements directly to calculate position, making the navigation process self-sufficient and available without external data support.
3Measurement precision
If multiple high-fidelity monitor stations are deployed to characterize signal sources, then measurement precision is improved, but device complexity and cost increases
Solution Approach 1:
The patent extracts the essential measurement function from multiple distributed monitor stations and consolidates it into a single receiver pair. By using the time difference of signal arrival at two receivers as the primary measurement, the system achieves signal characterization without needing multiple geographically dispersed monitor stations, thereby reducing device complexity and cost while maintaining measurement precision.
Solution Approach 2:
The patent makes the receiver system multi-functional by enabling it to perform both positioning and signal characterization using the same time difference measurements. The same measurement infrastructure (two receivers) that provides positioning also characterizes the signal sources, eliminating the need for separate monitor station networks and reducing overall system complexity.
4Measurement precision
If precise satellite location and timing data are embedded in signals, then navigation accuracy is improved, but loss of information occurs when such data is not publicly available or is protected
Solution Approach 1:
The patent extracts the navigation function from the satellite signal content itself and relocates it to the signal propagation characteristics (arrival time differences). By measuring when signals arrive at two receivers rather than decoding position and timing information from the signal content, the system achieves navigation without needing to access or process protected satellite data, eliminating information loss due to data availability restrictions.
Solution Approach 2:
The patent uses signal arrival time differences as an intermediary measurement that bridges the gap between satellite transmissions and user navigation needs without requiring access to protected satellite ephemeris data. This intermediary approach allows the system to derive navigation information from the physical propagation of signals rather than from encoded data, bypassing information access restrictions.
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 positional determination of the UE using signals from distant sources, such as satellites in various orbits, without requiring precise location or timing data, improving navigation accuracy and reducing the need for multiple high-fidelity MS units.
Implementation Method 1
measuring one or more time-difference of arrivals of one or more signals from one or more, respective, far sources, each time-difference of arrival being between difference of arrival of each of the one or more signals at a first receiver and arrival of each of the one or more signals at a second receiver
Data Source
AI summary
A method of dynamic position determination using a Kalman Filter to estimate a position of a moving aided node, including assigning a predicted value to each of twelve state variables for the aided node, weighting the accuracy of each prediction, determining a measurement for each state variable using a far source navigation algorithm, and then updating each state variable value using the measurement. A method for dynamic position determination that includes locating a moving aided node and one or multiple aiding nodes within a region of interest, and identifying one or multiple visible far sources. The aiding nodes and visible far sources are down selected using a set of metrics for evaluating the suitability of the aiding nodes and far sources, or pairs thereof, for use in developing a position of the aided node using a far source navigation algorithm.