Multimode Radar Pulse Sequencing With Random Phases for Range Fidelity

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Solution Overview

Problem

Radar systems struggle to perform multiple tasks simultaneously without degrading performance, particularly in terms of range, due to limitations in antenna architecture and emission techniques like sub-arraying and colored emission.

Innovation Solution

A method for operating a radar system that involves alternating between different modes, such as synthetic aperture radar imaging and Doppler modes, by generating sequences of pulses with random phases, frequencies, and polarizations, allowing for simultaneous task execution within a common time window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sub-arraying and colored emission are used to perform multiple tasks simultaneously, then task execution capability is improved, but range performance deteriorates

Engineering Contradiction:
Improvetask execution capabilityVSAvoidrange performance
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent applies periodic action by alternating between different radar operating modes (SAR imaging mode and Doppler surveillance mode) in a time-division multiplexed manner. The radar performs SAR imaging during specific time intervals and Doppler surveillance during other intervals, allowing multiple tasks to be executed without simultaneously degrading range performance. This periodic switching enables the radar to maintain optimal performance for each mode during its active period.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent utilizes parameter changes by dynamically adjusting radar operating parameters (frequency, pulse repetition rate, waveform) depending on the current operating mode. During SAR imaging, parameters are optimized for high-resolution imaging, while during Doppler surveillance, parameters are adjusted for velocity detection. This parameter adaptation allows the radar to maintain optimal performance for each specific task without the continuous performance degradation associated with sub-arraying.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If time budget is allocated to multiple tasks, then task diversity is improved, but detection effectiveness for individual tasks deteriorates

Engineering Contradiction:
Improvetask diversityVSAvoiddetection effectiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements periodic action through time-division multiplexing, where the radar alternates between SAR imaging tasks and Doppler surveillance tasks in regular intervals. Each task receives dedicated time slots with optimized parameters, ensuring that detection effectiveness for individual tasks is maintained while still achieving task diversity. The periodic structure allows the radar to fully dedicate resources to each task during its active period.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If single-task mode is used, then system performance is maintained, but adaptability to multiple missions deteriorates

Engineering Contradiction:
Improvesystem performanceVSAvoidadaptability to multiple missions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent resolves this contradiction by implementing periodic switching between different operating modes (SAR imaging and Doppler surveillance). The radar maintains optimal system performance for each specific mode during its active period while achieving adaptability to multiple missions through time-division multiplexing. This approach allows the radar to be reconfigured for different missions without continuously compromising performance.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the radar operating mode changeable and adaptive over time. The system dynamically switches between SAR imaging mode and Doppler surveillance mode based on mission requirements, allowing the radar to adapt to different missions while maintaining optimal performance characteristics for each mode during its active period.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4671824A1Method for operating a radar according to an aperture synthesis imaging mode and a second operating mode using random phases and associated radar
Publication Date: 2025.12.31 THALES SA
  • EP4671824A1 patent drawingFigure 1
  • EP4671824A1 patent drawingFigure 2
  • EP4671824A1 patent drawingFigure 3

AI summary

The present invention relates to a method for operating a target detection radar according to a first operating mode and at least one second operating mode, the first operating mode being a synthetic aperture radar imaging mode and each second operating mode being different from the first operating mode, the method comprising the implementation of several recurrences of a signal transmission/reception step, each recurrence of said step comprising the following sub-steps: - generation of a sequence of consecutive pulses, each pulse of the sequence being associated with a respective operating mode, - transmission of the pulses in different frequency bands, and - reception in a common time window of the echoes of the pulses, during the transmission sub-step of each recurrence, at least one of the pulses, called the phase-shifted pulse,being emitted with a random phase associated with the number N.,