Distributed Sensor Localization Using Phase and Power Difference
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Solution Overview
Problem
Existing electromagnetic source localization techniques face challenges such as high communication bandwidth requirements, complex antenna array integration, ambiguity in fixed position measurements, uncertain localization performance in urban environments, and inability to systematically locate all communications using blind localization systems.
Innovation Solution
A method using a distributed architecture of sensors with at least two antennas, estimating signal powers and phase differences to determine potential directions of arrival, merging data to calculate geographical coordinates, and selecting the densest intersection points for accurate source localization, employing a propagation model to define elementary and potential location zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TDOA localization technique is used to estimate transmitter position, then localization accuracy is improved, but communication bandwidth requirement increases significantly
Solution Approach 1:
The patent extracts only the essential localization information (phase difference and power ratio) from the received signals, rather than transmitting all raw signal data. This extraction approach maintains localization accuracy while dramatically reducing the communication bandwidth required between sensors and the localization system.
Solution Approach 2:
The patent introduces an intermediary processing step where sensors perform local signal processing to compute phase differences and power ratios before transmission. This intermediary computation acts as a data compression mechanism, reducing the volume of data that needs to be communicated while preserving the information necessary for accurate localization.
2Measurement precision
If MAOA localization technique with unambiguous antenna arrays is used, then localization accuracy is improved, but device complexity increases due to large array sizes
Solution Approach 1:
The patent changes the measurement parameters from requiring large spatial baselines (unambiguous arrays) to using phase difference measurements that can be obtained with compact antenna arrays. By operating in the phase domain rather than requiring large geometric baselines, the system achieves comparable localization accuracy with much simpler, smaller antenna structures.
3Measurement precision
If PhDOA goniometry is used to resolve localization ambiguities, then measurement precision is improved, but it requires moving sensors or long observation durations
Solution Approach 1:
The patent merges phase difference measurements from multiple sensors with power ratio measurements to simultaneously resolve localization ambiguities without requiring temporal motion or extended observation periods. The combination of these two measurement types provides sufficient geometric constraints to eliminate ambiguities in a single snapshot, avoiding the time loss associated with moving sensors.
4Ease of operation
If PwDOA technique is used for blind localization, then ease of operation is improved, but localization performance becomes uncertain in urban environments
Solution Approach 1:
The patent substitutes the power-based measurement approach with a phase-based measurement approach for determining direction of arrival. Phase measurements are less sensitive to propagation channel variations and environmental effects compared to power measurements, thereby improving reliability in urban environments while maintaining the simplicity of blind localization operation.
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 and efficient localization of electromagnetic sources with reduced data exchange and ambiguity resolution, facilitating simultaneous sensing and communication services without assuming stationary positions or complex antenna arrays.
Implementation Method 1
estimate a differential phase, from which are determined a set of potential directions of arrival
Implementation Method 2
merge the values of the powers estimated by the two sensors, the values of the potential directions of arrival and the geographical coordinates of the antenna arrays of the two sensors to calculate the coordinates of the emitting source
Data Source
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AI summary
The invention relates to a method for performing distributed localization of an electromagnetic source using several sensors disseminated over the geographical area of interest. These sensors, using two receiving channels, perform: • an estimation of the received power, • an estimation of the phase difference between the two receiving channels. The estimated data from each sensor are then used to estimate the power difference at arrival (PwDOA) and subsequently the position of the various intercepted emissions. The first part of the localization algorithm uses the PwDOA technique and an uncertainty margin related to propagation models to reduce the potential localization areas of the source and thus eliminate many ambiguities.The second part of the localization algorithm selects, within the potential localization zones, the zone where the intersections of the lines of sight are the densest, and the centroid of the points of the intersections of the lines of sight in this zone provides an estimate of the position of the source to be located.