Signal Source Location Using Start-Time-Aligned Sample Streams
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Solution Overview
Problem
Existing systems for passively locating electromagnetic signal sources face challenges in accurately processing sampled data streams due to unsynchronized sampling clocks and staggered start times among receivers, leading to degraded position estimation accuracy and operational inefficiencies.
Innovation Solution
A method for synchronizing sampled data streams by aligning timestamps and compensating for frequency and phase differences among receivers, using techniques such as start-time alignment and reshaping sample streams to improve data alignment and reduce data loss, enabling efficient and accurate location estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sampled data streams from multiple vehicles are processed using existing synchronization methods, then position estimation can be performed, but position estimation accuracy is degraded due to unsynchronized sampling clocks and staggered start times
Solution Approach 1:
The patent applies preliminary action by performing start-time alignment on sampled data streams before processing them for position estimation. The system identifies the start time of each vehicle's sampled data stream and adjusts them to a common reference time, ensuring all streams are synchronized before being used in multilateration calculations. This preliminary synchronization step eliminates accuracy degradation caused by staggered start times and unsynchronized clocks.
2Measurement precision
If strict time alignment is enforced among all sample streams, then position estimation accuracy improves, but data loss increases due to disregarding data values from streams that cannot be aligned
Solution Approach 1:
The patent applies parameter changes by introducing a maximum time difference threshold parameter that controls the alignment tolerance. Instead of requiring perfect time alignment, the system allows data streams with time differences within the threshold to be included in position estimation. This parameter-based approach maintains position accuracy while minimizing data loss by flexibly accommodating slight timing variations across different vehicles.
3Measurement precision
If complex synchronization algorithms are used to achieve perfect time alignment, then position estimation accuracy improves, but computational power requirements and processing complexity increase
Solution Approach 1:
The patent extracts and processes only the critical timing information (start times and timestamps) from each data stream, rather than attempting to synchronize the entire data sets. By identifying and aligning only the temporal reference points, the system achieves sufficient synchronization for accurate position estimation without the computational burden of complex full-stream alignment algorithms.
4Productivity
If existing synchronization methods are used, then processing can proceed, but operational efficiency is reduced due to computational overhead and processing delays
Solution Approach 1:
The patent performs start-time alignment as a preliminary step that establishes a common temporal reference for all data streams. By synchronizing the timing structure beforehand, subsequent position estimation processing can proceed efficiently without requiring complex real-time synchronization calculations, thereby reducing overall processing time and improving operational efficiency.
Data Source
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AI summary
The application relates to a method of processing data for estimating a location of a source of an electromagnetic signal, a system comprising apparatus for carrying out the method, and a computer-readable medium storing a computer program for carrying out the method, wherein the method comprises: obtaining a plurality of sample streams, each sample stream comprising a plurality of data values representative of successive samples of a property of the signal as received at a respective one of a plurality of vehicles, each sample stream further comprising timestamp information comprising one or more timestamps, each timestamp indicating the time at which a corresponding one of the data values was sampled; obtaining start-time-aligned sample streams by (i) comparing pairs of timestamps, each pair comprising a timestamp from a first sample stream of the plurality of sample streams and a timestamp from a second sample stream of the plurality of sample streams, the comparing further comprising determining a respective time difference between at least one pair of timestamps, (ii) selecting a pair of timestamps which have a time difference that does not exceed a first predetermined maximum time difference, said selected pair comprising a first selected timestamp from the first sample stream and a second selected timestamp from the second sample stream, and (iii) time-aligning the starts of the first and second sample streams based on the selected pair of timestamps, by disregarding data values in the first sample stream which are earlier than the first selected timestamp, and disregarding data values in the second sample stream which are earlier than the second selected timestamp; and estimating a location of the source of the signal, based upon the start-time-aligned sample streams.