Magnetic Anomaly Positioning Using Time-Series Measurements
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Solution Overview
Problem
GNSS signals are susceptible to jamming and spoofing, leading to inaccurate geographic position determination using magnetic anomaly measurements due to similar magnetic field strengths at multiple geographic locations, resulting in erroneous navigation filter outputs.
Innovation Solution
Utilize a series of magnetic anomaly measurements to generate a set of geographic locations within a threshold range, determine vector distances, and refine these locations to a single accurate position using inertial navigation data, compensating for magnetic effects from the body, space weather, and Earth's core field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single magnetic anomaly measurement is used to determine geographic location, then the navigation process is simple and fast, but the position determination accuracy deteriorates due to ambiguous magnetic field strengths at multiple locations
Solution Approach 1:
The system performs preliminary actions by collecting multiple magnetic anomaly measurements at different time instances before final position determination. This advance data collection creates a more distinctive magnetic signature that resolves the ambiguity of single measurements, allowing the navigation filter to accurately identify the vehicle's location even in areas where multiple positions have similar magnetic field strengths.
Solution Approach 2:
The system maintains continuous magnetic anomaly measurements over time rather than relying on isolated snapshots. This continuous data stream allows the navigation filter to track the vehicle's movement pattern and correlate it with the magnetic anomaly map, improving position accuracy while maintaining efficient processing through the continuous nature of the data flow.
2Measurement precision
If multiple magnetic anomaly measurements are collected to improve position accuracy, then position determination accuracy improves, but the device complexity and processing requirements increase
Solution Approach 1:
The navigation filter performs multiple functions simultaneously: it processes magnetic anomaly measurements, integrates inertial measurement unit data, compares results against the magnetic anomaly map, and determines geographic position. This multi-functionality allows the system to achieve high position accuracy through multiple measurements without requiring separate dedicated systems for each function, thereby managing complexity efficiently.
Solution Approach 2:
The system merges magnetic anomaly measurements with inertial measurement unit data in the navigation filter. By combining these different data sources, the system achieves improved position determination accuracy without requiring complex standalone systems for each measurement type, as the integrated approach leverages the strengths of both measurement methods.
3Area of stationary object
If multiple geographic locations are identified with similar magnetic field strengths, then the magnetic anomaly map coverage is comprehensive, but the reliability of position determination decreases due to ambiguity
Solution Approach 1:
The system transitions from spatial-only analysis to spatio-temporal analysis by incorporating the time dimension. Instead of relying solely on the spatial distribution of magnetic field strengths, the system uses measurements taken at different time instances to create a temporal signature of the vehicle's movement. This additional dimension allows the navigation filter to distinguish between multiple locations with similar magnetic characteristics, thereby improving position determination reliability while maintaining comprehensive map coverage.
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
Enhances the accuracy of geographic position determination by reducing ambiguity in magnetic anomaly maps, thereby improving navigation filter precision.
Implementation Method 1
receiving a first magnetic measurement and a first time when the first magnetic measurement was made
Data Source
AI summary
Techniques are provided for generating more accurate aiding data from magnetic anomaly measurements to aid in determining geographic position of a body. The following data is acquired: a series of more than one magnetic anomaly measurement (e.g., made with a magnetometer), a corresponding time of each magnetic anomaly measurement, and a vector distance between each successive magnetic anomaly measurement. With a single magnetic anomaly measurement, more than one geographic location on the magnetic anomaly map may be identified. As the number of magnetic anomaly measurements increases, a number of geographic locations diminishes eventually to a single geographic location on a magnetic anomaly map. Once determined, the single geographic location and a time is transmitted to a navigation filter.