Multi-Static SAR Synchronization Using GNSS Clock Signals

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Solution Overview

Problem

Synchronizing multi-static synthetic aperture radar (SAR) platforms is complex and prone to interference due to the need for inter-satellite communication, which is difficult to scale and maintain accuracy in phase and time alignment.

Innovation Solution

Utilize Global Navigation Satellite System (GNSS) clock signals and ultra-stable oscillators on-board SAR platforms to synchronize timing and phase, eliminating the need for inter-satellite communication by deriving timing signals from a common source, such as a GNSS satellite network, and using ultra-stable oscillators for phase synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inter-satellite communication is used to synchronize multi-static SAR platforms, then time and phase alignment can be achieved, but the system complexity increases and scalability deteriorates

Engineering Contradiction:

Improvetime and phase alignment accuracyVSAvoidinter-satellite communication system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces GNSS satellites as intermediary devices that provide timing signals to multiple SAR platforms. Instead of direct inter-satellite communication between SAR platforms, each platform independently receives timing signals from GNSS satellites, simplifying the synchronization architecture while maintaining precision

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Each SAR platform autonomously generates its own timing signals using ultra-stable oscillators that are synchronized to GNSS satellite signals. This self-service approach eliminates the need for complex inter-satellite communication infrastructure while maintaining synchronization accuracy

Inventive Principle:

Principle #25Self-service

2Measurement precision

If multiple SAR platforms operate multi-statically with different observation angles, then image resolution and target discrimination improve, but synchronization difficulty increases

Engineering Contradiction:

Improveimage resolution and target discriminationVSAvoidsynchronization system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The synchronization function is segmented into independent components: GNSS signal reception, ultra-stable oscillator generation, and phase alignment. Each SAR platform implements these segmented functions independently, allowing multiple platforms to operate with different observation angles without increasing overall system complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

GNSS satellites serve as intermediary timing sources that provide a common reference for all SAR platforms. This intermediary approach enables multiple platforms to maintain precise synchronization despite spatial separation and different operational configurations

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If ultra-stable oscillators are used for phase synchronization, then signal-to-noise ratio improves, but the system requires more sophisticated timing components

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidtiming component sophistication

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or electronic phase synchronization systems with a simpler approach based on ultra-stable oscillators synchronized to GNSS timing signals. This substitution maintains high signal-to-noise ratio while reducing overall system complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This method simplifies satellite operations, enhances scalability, and maintains precise time and phase synchronization, improving signal-to-noise ratio and image quality in multi-static SAR systems.

Implementation Method 1

SAR images are a type of image created by transmitting radar pulses, receiving the reflected and scattered return echoes

Methodology Applied

Scientific EffectRadar: Radar

Implementation Method 2

This is achieved by exploiting the Doppler effect created by the moving SAR platform

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Implementation Method 3

receiving, by a first SAR platform, a first Global Navigation Satellite System (GNSS) clock signal transmitted from a GNSS satellite

Methodology Applied

Scientific EffectElectromagnetic signal reception: Electromagnetic Induction

Data Source

PatentEP4641255A1Synchronizing multi-static operation of synthetic aperture radar platforms

Publication Date: 2025.10.29 ICEYE OY

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AI summary

A method of synchronizing multi-static operation of synthetic aperture radar (SAR) platforms includes receiving, by a first SAR platform, a first Global Navigation Satellite System (GNSS) clock signal transmitted from a GNSS satellite of a GNSS satellite network, and receiving, by a second SAR platform, a second GNSS clock signal transmitted from a GNSS satellite of the GNSS satellite network. The method further includes generating, by the first SAR platform, a first timing signal, generating, by the second SAR platform, a second timing signal; adjusting the first and second timing signals based on the respective first and second GNSS clock signals, and generating SAR image data. The generating includes using the first SAR platform to transmit a first SAR signal according to the adjusted first timing signal, and using the second SAR platform to record echoes of the first SAR signal according to the adjusted second timing signal.