Satellite Oscillator Syntonisation via Inter-vehicle Signal Summing

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Solution Overview

Problem

Existing technologies face challenges in achieving precise syntonisation between satellites or other moving vehicles due to Doppler shifts and frequency deviations caused by aging or component tolerances, which are insufficient for demanding space applications.

Innovation Solution

The solution involves a mechanism where satellites 'swap' their oscillator signals, allowing each satellite to generate a sum frequency from its local oscillator signal and the received version of another satellite's oscillator signal, effectively balancing out Doppler shifts and eliminating frequency differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inter-satellite links are used for syntonisation, then frequency similarity can be improved, but Doppler shifts caused by relative movement hinder the precision

Engineering Contradiction:

Improvefrequency similarityVSAvoidDoppler shifts

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful Doppler shift effect into a beneficial mechanism for syntonisation. By having satellites transmit their oscillator signals to each other and using these signals to adjust local oscillators, the Doppler-induced frequency variations are exploited to achieve precise frequency matching, turning the previously harmful relative motion into a useful synchronisation tool

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback mechanism where satellites continuously monitor the frequency of received signals from other satellites and adjust their local oscillators accordingly. This closed-loop feedback process enables dynamic compensation for Doppler shifts and frequency deviations, achieving high-precision syntonisation despite relative movements

Inventive Principle:

Principle #23Feedback

2Measurement precision

If atomic clocks with extreme frequency stability are provided, then syntonisation can be improved, but the level of syntonisation is still insufficient for demanding applications

Engineering Contradiction:

Improvefrequency stabilityVSAvoidsyntonisation sufficiency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent merges the oscillator signals from multiple satellites in a collaborative manner. Instead of relying on a single atomic clock, the system combines signals from several satellites to achieve a collective syntonisation that exceeds the capability of individual clocks, enabling precision sufficient for demanding applications like event horizon imaging

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal syntonisation mechanism that can be applied across multiple satellites and various space applications. The same inter-satellite signal swapping and frequency adjustment process works for different mission types, from navigation to scientific observations, providing reliable syntonisation regardless of the specific application requirements

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If Doppler shift correction is applied, then syntonisation precision can be improved, but the correction becomes complex and ultimately insufficiently accurate

Engineering Contradiction:

Improvesyntonisation accuracyVSAvoidcorrection complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of attempting to correct for Doppler shifts through complex calculations and adjustments, the patent inverts the approach by directly using the Doppler-affected signals to achieve syntonisation. The frequency variations introduced by relative motion are embraced and utilized as the basis for frequency matching, eliminating the need for complex correction algorithms

Inventive Principle:

Principle #13The other way round (Inversion)

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 approach enables precise syntonisation with improved frequency stability, allowing for longer integration times and increased sensitivity in cooperative space applications, such as radio astronomy, without requiring highly stable master oscillators.

Implementation Method 1

satellites normally exhibit relative movement with respect to each other, which means that inter-satellite signals are subject to Doppler shifts

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentUS20250142501A1Syntonisation of signals between satellites

Publication Date: 2025.05.01 EUROPEAN SPACE AGENCY (ESA)

AI summary

A space or aerial vehicle may be configured to generate an internal signal having a frequency which is syntonised with the frequency of the internal signal generated by a second vehicle. The vehicle may comprise a master oscillator configured to oscillate at a nominal frequency and to generate an oscillator signal (F1) at the nominal frequency, a receiver (Rx-1) configured to receive an inter-vehicle signal, wherein the inter-vehicle signal is generated by the second vehicle by modulating a carrier (C2) with a second oscillator signal (F2), wherein the second oscillator signal is generated by a second master oscillator of the second vehicle configured to oscillate at the nominal frequency. Signal processing circuitry may be provided to demodulate the received inter-vehicle signal to obtain a demodulated signal comprising a received version of the second oscillator signal (F′2), and to generate the internal signal based on a sum frequency comprising the first oscillator signal (F1) and the received version of the second oscillator signal (F′2) as summands.