Signal Source Localization via Accumulated Phase Differential
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Solution Overview
Problem
Existing techniques for locating a signal source with high pulse repetition frequency (PRF) or constant pulse repetition interval (PRI) face challenges in accurately determining the source location, especially when receivers are far apart, leading to ambiguity in modulation patterns and time of arrival measurements.
Innovation Solution
The proposed solution involves calculating the accumulated phases of signals received at each receiver, which reduces data communication bandwidth and processing time. This method also employs differential phase differences and time of arrival measurements to resolve ambiguities, without requiring monitoring of receiver trajectories and velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If receivers are located far apart to improve location estimation accuracy, then measurement precision is improved, but ambiguity in modulation patterns increases due to multiple PRI multiples
Solution Approach 1:
The patent performs preliminary actions by calculating accumulated phases over multiple pulses before resolving ambiguities. The system accumulates phase information from multiple pulses at each receiver, then uses these preliminary accumulated values as the basis for subsequent ambiguity resolution through differential phase calculations and multiple hypothesis testing.
Solution Approach 2:
The patent introduces differential phase differences as an intermediary quantity to resolve the ambiguity between direct phase measurements and source location. By calculating the difference between accumulated phases at different receivers, the system creates an intermediate measurement that eliminates the ambiguous integer multiples of PRI while preserving the relative phase information needed for accurate localization.
2Loss of substance
If accumulated phases are calculated at each receiver to reduce data communication bandwidth, then loss of substance is reduced, but device complexity increases due to phase accumulation and differential calculations
Solution Approach 1:
The patent extracts only the essential phase information from the received signals and transmits only these accumulated phase values to the central processor. By taking out only the necessary phase data rather than transmitting complete signal waveforms or raw data, the system significantly reduces communication bandwidth requirements while maintaining the capability to perform accurate source localization through differential phase calculations.
3Measurement precision
If DTOA method is used to determine source location, then location estimation is obtained, but ambiguity multiples of PRI reduce reliability
Solution Approach 1:
The patent applies partial action by using only a subset of the available phase information - specifically, it uses differential phase differences between receivers rather than absolute phase values. This partial use of information allows the system to resolve ambiguities by focusing on relative phase changes that are insensitive to the ambiguous integer multiples of PRI, while still obtaining accurate source location estimates.
Data Source
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AI summary
A method of estimating the location of a signal source comprises, by a processing unit: determining ΔΔϕm,n which represents a difference between accumulated phases of signals, Sm and Sn, received by at least one pair of the receivers, determining a first estimate of the location of said signal source based on position data and ΔΔϕm,n of said at least one pair of receivers, said first estimate being associated with an accuracy area, determining data representative of difference in times of arrival of modulation patterns of the signals Sm, Sn, wherein said data comprise an ambiguity, and for said at least one pair of receivers, using at least said data representative of difference in times of arrival of the modulation patterns of the signals, ΔΔϕm,n, and said accuracy area, to obtain second estimates e^Srck of the source location, at least some of them being located within the accuracy area