Radar Antenna Beam Segmentation for Projectile Impact Prediction

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Solution Overview

Problem

Existing methods for determining the impact point of a projectile fired at a target above the sea surface are unreliable due to multipath effects and require separate antenna beams, which can lose sight of the target and are ineffective at short ranges and low elevations.

Innovation Solution

A radar system using a single antenna beam for tracking both the target and projectile, employing Doppler filtering and Kalman filters to predict the impact point without elevation measurements, allowing simultaneous detection of the projectile and target through a Range-Doppler plane analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate antenna beam is used to monitor projectile trajectory in the multipath-free zone, then measurement reliability is improved, but the radar system cannot detect the surface target in the centre of the beam anymore

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidtarget detection capability
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The radar system divides the antenna beam into multiple functional zones: a main beam for target tracking and separate sidelobes for projectile detection. This spatial segmentation allows simultaneous target monitoring and projectile trajectory measurement without mutual interference, resolving the contradiction between reliable measurement and target detection capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from using a single centralized beam to utilizing the three-dimensional radiation pattern of the antenna, specifically employing sidelobes for projectile detection while the main lobe tracks the target. This dimensional approach allows both functions to operate concurrently in different spatial regions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If a separate antenna beam is used for projectile trajectory monitoring, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvetrajectory measurement precisionVSAvoidradar system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The radar system achieves multi-functionality by using the existing antenna beam structure for dual purposes: the main beam tracks the surface target while the sidelobes simultaneously monitor projectile trajectories. This eliminates the need for separate dedicated beams, maintaining measurement precision while avoiding increased device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If elevation measurements are used for projectile trajectory monitoring, then impact point determination is improved, but reliability deteriorates in low elevation situations

Engineering Contradiction:
Improveimpact point determinationVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The invention extracts and eliminates the problematic elevation measurement component from the trajectory monitoring process. By relying solely on azimuth measurements from the radar system, it removes the source of unreliability in low elevation situations while maintaining sufficient precision for impact point determination through mathematical modeling of the projectile trajectory.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate prediction of projectile impact without losing sight of the target, suitable for short-range and low-altitude trajectories, and improves measurement accuracy by using Doppler filtering and interpolation techniques, reducing false alarms and applicable to various ammunition types.

Implementation Method 1

a radar antenna (11) through a dedicated antenna beam, typically used for tracking targets

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

employing Doppler filtering and Kalman filters to predict the impact point

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 3

due to the electromagnetic waves reflecting on the sea surface

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2788789B1Method for determining the impact point of a projectile fired at a target above sea surface, and radar system implementing such method
Publication Date: 2023.04.19 THALES NEDERLAND BV
  • EP2788789B1 patent drawingFigure 1A~1B
  • EP2788789B1 patent drawingFigure 2

AI summary

There is disclosed a method for determining the impact point of a projectile fired at a target (15) tracked by use of a radar antenna (11) through a dedicated antenna beam, the method being characterized in that it comprises at least a step of measuring the range and bearing of the projectile based upon the use of said radar antenna (11) and said dedicated antenna beam, a step of Doppler filtering distinguishing the projectile measurements from the tracked target (15) and sea clutter measurements, and a step of determining the projectile trajectory (131) from a plurality of range and bearing measurements performed at successive instants of time (ti), and a step of determining the impact point of the determined projectile based upon the projectile trajectory (131). The current invention can be applied to splash spot location prediction and miss distance indication.