Neural Network Calibration for Watson-Watt Direction Finding

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Solution Overview

Problem

Direction finding systems, particularly those using the Watson-Watt method, face challenges with biasing errors and require large lookup-tables for calibration, which are cumbersome and inefficient in terms of storage and computational resources.

Innovation Solution

A lightweight calibration method utilizing a neural network configured to mimic the two-argument arctangent function, allowing for rapid calibration through transfer learning, reducing the need for lookup-tables and enabling efficient operation across various environments with minimal storage requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a lookup-table is used for calibration in Watson-Watt direction finding systems, then calibration accuracy is improved, but storage space requirements and computational overhead increase

Engineering Contradiction:
Improvecalibration accuracyVSAvoidstorage space
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent transforms the calibration approach from using a comprehensive lookup-table with extensive calibration data to a neural network model with significantly fewer parameters. The neural network learns the essential calibration relationships through training, achieving accurate direction finding with reduced storage requirements while maintaining calibration precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a simplified computational model (neural network) that copies the essential functionality of the lookup-table approach but with reduced complexity. The neural network is trained to replicate the calibration behavior of traditional methods while requiring far less storage space, effectively creating a lightweight version of the calibration system.

Inventive Principle:
Principle #26Copying

2Measurement precision

If a lookup-table is used for calibration, then calibration accuracy is improved, but computational complexity and processing time increase

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the computational parameters from extensive lookup-table queries to a compact neural network with fewer parameters. The neural network processes calibration data through learned weight matrices and activation functions, reducing computational complexity while maintaining accuracy. This parameter transformation enables faster processing with lower computational overhead.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs the complex calibration computations in advance during the neural network training phase. Once trained, the neural network contains pre-learned calibration knowledge that can be applied rapidly during operation without requiring complex real-time computations. This preliminary action shifts computational burden from runtime to training time.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If traditional calibration methods are used, then system accuracy is improved, but the calibration process becomes cumbersome and time-consuming

Engineering Contradiction:
Improvesystem accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs comprehensive calibration computations during the neural network training phase before deployment. The trained model encapsulates calibration knowledge that can be rapidly applied during operation. This preliminary action eliminates the need for time-consuming calibration procedures during field operations, reducing calibration time while maintaining system accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the calibration process from iterative adjustments and extensive measurements to a streamlined neural network training process. The neural network learns calibration parameters efficiently through supervised learning, reducing the time required to achieve accurate calibration while maintaining system performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20240302475A1Lightweight calibration method for direction finding
Publication Date: 2024.09.12 THE REGENTS OF THE UNIVERSITY OF COLORADO
  • US20240302475A1 patent drawing
  • US20240302475A1 patent drawing
  • US20240302475A1 patent drawing

AI summary

A direction finding system can be configurable to: (i) access a baseline neural network initially configured to imitate behavior of a two-argument arctangent function; (ii) apply transfer learning to the baseline neural network to generate a calibrated neural network, wherein the transfer learning calibrates the baseline neural network to perform Watson-Watt direction finding without utilizing a lookup table for error correction; (iii) access measurement data acquired via the direction finding sensor array; (iv) generate preprocessed data by applying one or more preprocessing operations to the measurement data; (v) utilize the preprocessed data as input to the calibrated neural network; and (vi) output angle of arrival data, the angle of arrival data comprising output of the calibrated neural network.