Monopulse Signal Extraction Using Polynomial Models

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Solution Overview

Problem

Existing monopulse systems face challenges in accurately detecting and resolving closely spaced targets due to merged angle of arrival data, which is affected by phase differences and radar/sonar cross section ratios, leading to biased trajectory measurements and increased system complexity and cost.

Innovation Solution

A method and system that extract relative signals from monopulse scan data using cubic and linear polynomial models to fit merged azimuth angle values, determining relative signals through polynomial coefficients and exponential parameters, thereby isolating the azimuth angles and radar cross section ratios of closely spaced targets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If standard monopulse data processing is used, then the system is simple and cost-effective, but the measurement precision of target angles deteriorates due to merged angle of arrival data

Engineering Contradiction:
Improvetarget angle measurement precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the merged monopulse data into multiple polynomial models (linear, quadratic, cubic) corresponding to different target scenarios. By selecting appropriate polynomial orders based on target characteristics, the system achieves high measurement precision without requiring complex additional hardware, thus resolving the contradiction between precision and complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the mathematical parameter representation by fitting monopulse data to polynomial functions of different orders. This transformation allows extraction of precise target parameters (angles, velocities, accelerations) from merged data through coefficient analysis, improving measurement precision while maintaining system simplicity

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If additional hardware is added to resolve closely spaced targets, then the measurement precision improves, but the device complexity and cost increase

Engineering Contradiction:
Improvetarget resolution capabilityVSAvoidhardware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces physical hardware modifications with mathematical signal processing techniques. By applying polynomial fitting and coefficient analysis to the existing monopulse data, the system achieves enhanced target resolution capability without adding any physical components, thus resolving the contradiction between resolution and hardware complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If polynomial fitting is applied to extract relative signals, then the measurement precision of target parameters improves, but the computational complexity increases

Engineering Contradiction:
Improvetarget parameter extraction accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial polynomial fitting by selecting specific polynomial orders (linear, quadratic, or cubic) based on the actual target scenario. This selective approach extracts only the necessary target parameters with appropriate precision while avoiding unnecessary computational overhead from higher-order fitting, thus resolving the contradiction between accuracy and computational complexity

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS7911371B2Extraction of relative signals from closely spaced targets in a monopulse system
Publication Date: 2011.03.22 NORTHROP GRUMMAN GUIDANCE AND ELECTRONICS CO INC
  • US7911371B2 patent drawing
  • US7911371B2 patent drawing
  • US7911371B2 patent drawing

AI summary

Systems and methods are provided for extracting relative signal parameters representing two closely spaced targets from monopulse scan data. A maximum quadrature angle value from the scan data is compared with a threshold quadrature value representing a noise level. A linear polynomial model is utilized if the maximum quadrature angle exceeds the threshold value. The linear polynomial model fits a function of the azimuth angle values and quadrature angle values to a linear function of an exponential parameter derived from the boresight angles to produce polynomial coefficients and determines the relative signal parameters from the polynomial coefficients. A cubic polynomial model is utilized if the maximum quadrature angle fails to exceed the threshold value. The cubic polynomial model fits azimuth angle values to a cubic function of corresponding boresight angles to produce a set of polynomial coefficients and determines the relative signal parameters from the set of polynomial coefficients.