Agile Electromagnetic Geolocation Using Power Ratios
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rapid and accurate geolocation of electromagnetic radiation sources is challenging due to complex signal propagation in environments with hills, mountains, vegetation, and urban structures, especially when the source is trying to avoid detection or has limited battery life.
Innovation Solution
A method using multiple electromagnetic sensors to estimate received power, generate propagation loss ratios, and compute a minimum mean squared value to determine the location of an electromagnetic transmitter by integrating sensor data and accounting for environmental factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional triangulation or locating techniques are used, then location accuracy can be achieved, but the time required for geolocation becomes excessive and the electromagnetic source may avoid detection or exhaust its battery
Solution Approach 1:
The system pre-establishes a grid of hypothesized radiator locations and pre-calculates propagation losses for all possible sensor-grid point combinations before actual measurement. This preliminary computation enables rapid comparison during real-time measurement, achieving both speed and accuracy without requiring time-consuming calculations during the geolocation process itself
Solution Approach 2:
The patent creates a virtual copy of the physical measurement process by computing expected power ratios for each hypothesized location using propagation loss models. These virtual measurements are then compared with actual sensor readings, allowing rapid identification of the most likely radiator location without requiring additional physical measurements at each hypothesized point
2Measurement precision
If multiple sensors are deployed to improve location accuracy, then measurement precision increases, but device complexity and cost increase
Solution Approach 1:
The patent divides the measurement system into independent sensor nodes, each performing simple power ratio measurements locally. The complexity is segmented and distributed across multiple simple sensors rather than concentrated in a single complex system, with each sensor contributing one data point to the overall location determination
Solution Approach 2:
The patent transforms the location determination problem from a spatial optimization problem to a mathematical ratio-matching problem. By working with power ratios rather than absolute power values and using grid-based hypothesized locations, the system reduces the dimensional complexity of the search space while maintaining measurement precision
3Measurement precision
If propagation loss models are used to handle complex environments, then location accuracy in challenging terrain improves, but computational requirements and system complexity increase
Solution Approach 1:
The system pre-computes propagation loss values for all possible sensor-to-grid-point paths before actual measurement. By establishing these computational models in advance, the system avoids the need for complex real-time calculations during geolocation, reducing operational computational complexity while maintaining environmental accuracy
Solution Approach 2:
The patent extracts the complex propagation loss calculations from the real-time measurement process and separates them into a preliminary computational phase. This extraction allows simple sensors to perform straightforward ratio measurements while the computational complexity is handled separately during the analysis phase
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 enables timely and accurate geolocation of electromagnetic radiation sources even in complex environments, minimizing errors and effectively handling signal fading and propagation complexities.
Implementation Method 1
generating received electromagnetic signals from the radiator. The power received from the radiator is estimated or measured for each of the sensors
Data Source
AI summary
The unknown location of an electromagnetic transmitter is determined by receiving the radiation at plural sensors distributed over an area. Received power is determined at each sensor, and normalized by taking ratios of powers from the various sensors. A plurality of transmitter locations are hypothesized, and losses from each hypothesized location to each sensor are estimated or measured. The losses are normalized. The differences between the normalized powers and normalized losses are integrated, and the mean-square values determined. The location at which the mean-square value is minimum is deemed to be the location of the transmitter.