Nyquist-Folding Receivers Using Spatial Diversity for RF Ambiguity Resolution
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Solution Overview
Problem
Existing Nyquist-folding receivers face ambiguity in RF frequency measurement due to folding, requiring multiple samplers at the same location, which increases storage and downlink requirements and complicates signal resolution in dense RF environments.
Innovation Solution
Distribute samplers across multiple collectors/receivers at diverse locations, combining geo-observable measurements with RF-ambiguous data to resolve frequency ambiguities and enhance signal reconstruction using spatial information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple samplers operate at the same location to resolve RF ambiguity, then measurement precision improves, but device complexity and storage requirements increase
Solution Approach 1:
The patent divides the sampling function across multiple geographically distributed collectors rather than concentrating multiple samplers at a single location. Each collector performs sub-Nyquist sampling independently, and the processing center combines results from these segmented measurements to resolve RF ambiguity through spatial diversity.
Solution Approach 2:
The patent introduces a spatial dimension to the sampling system by distributing collectors across different geographic locations. This spatial distribution provides additional independent measurements that enable RF ambiguity resolution without requiring multiple samplers at each individual collector, thus reducing device complexity while maintaining measurement precision.
2Measurement precision
If multiple Nyquist-folded data streams are collected to resolve ambiguity, then measurement precision improves, but loss of substance increases due to higher storage and transmission requirements
Solution Approach 1:
The patent segments the data collection function across multiple remote collectors, each performing sub-Nyquist sampling independently. This segmentation allows the system to achieve accurate signal reconstruction through distributed measurements without requiring any single collector to store or transmit multiple high-rate data streams, thereby reducing overall storage and transmission resource consumption.
Solution Approach 2:
The patent uses multiple geographically distributed collectors to create redundant copies of the sampling function rather than requiring multiple data streams from a single collector. Each collector produces a simplified sub-Nyquist data stream, and the processing center combines these copies to reconstruct the original signal accurately, reducing the total data volume that must be stored and transmitted compared to traditional approaches.
3Loss of substance
If sub-Nyquist sampling is used to reduce data volume, then loss of substance decreases, but measurement precision deteriorates due to RF frequency ambiguity
Solution Approach 1:
The patent merges measurements from multiple geographically distributed collectors that each perform sub-Nyquist sampling. The processing center combines these distributed sub-Nyquist measurements to resolve RF frequency ambiguity through spatial diversity and number-theoretic techniques, thereby maintaining measurement precision while preserving the data volume reduction benefits of sub-Nyquist sampling.
Solution Approach 2:
The patent introduces a processing center as an intermediary that receives sub-Nyquist data streams from multiple distributed collectors and performs advanced signal processing. This intermediary combines the ambiguous measurements from different spatial locations using number-theoretic techniques and spatial information to resolve RF frequency ambiguity, enabling accurate signal reconstruction without requiring any single collector to perform high-rate Nyquist sampling.
Data Source
AI summary
A geolocation system for efficiently reconstructing and geolocating signals collected in multiple spatially-distributed sensors using a plurality of different Nyquist-folding samplers operating at sub-Nyquist rates. The sensors use Nyquist-folding with a plurality of sampling rates and patterns to reduce the volume of data transmitted off the sensor while retaining the ability to detect weak signals, and produce high-quality signal reconstructions and geolocations. The ambiguities in signal reconstruction introduced by sub-Nyquist sampling are addressed by using spatial consistency computed from sub-Nyquist geo-observables to assist in RF ambiguity resolution.