Distributed Satellite Phased-Array Antenna Doppler Compensation

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Solution Overview

Problem

Current satellite communication systems face challenges in deploying large antenna structures in space due to high costs and weight, which increase with the size of the antenna, and require significant power and payload capacity to maintain signal connectivity with low-power end-user devices.

Innovation Solution

A distributed aperture system comprising an array of small or very small satellites that can form a large aperture in space, eliminating the need for pre-fabricated structures and reducing weight and power requirements, while utilizing commercial-off-the-shelf components for efficient signal processing and beam forming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple beams are frequency multiplexed in a single 30 MHz carrier, then spectral efficiency is improved, but inter-beam interference increases causing blockage of good blocks

Engineering Contradiction:
Improvespectral efficiencyVSAvoidinter-beam interference
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the frequency spectrum by allocating different frequency ranges to different beams within the same carrier. Specifically, it divides the 30 MHz carrier into multiple frequency bands, with each beam assigned to a specific frequency range, thereby separating the frequency resources of different beams and eliminating inter-beam interference while maintaining spectral efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different frequency allocations to different beams based on their specific requirements and interference characteristics. Each beam receives a tailored frequency allocation within the carrier, optimizing performance for local beam conditions while maintaining overall system efficiency

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If frequency assignments are changed dynamically, then interference management is improved, but processing complexity increases

Engineering Contradiction:
Improveinterference managementVSAvoidprocessing complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by pre-configuring frequency assignment tables that define frequency allocations for different beams and time slots. These tables are prepared in advance based on predicted interference patterns and system requirements, allowing the system to manage interference effectively without requiring complex real-time processing decisions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs periodic action by updating frequency assignments in a periodic manner using predefined tables that are applied at regular intervals. This periodic updating strategy manages interference effectively while keeping processing complexity manageable through systematic, rhythm-based reconfiguration rather than continuous complex optimization

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If discrete satellite modules form a distributed phased-array, then system flexibility and scalability are improved, but maintaining phase and frequency synchronization becomes more difficult

Engineering Contradiction:
Improvesystem flexibilityVSAvoidphase and frequency synchronization
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where each satellite module continuously monitors and reports its phase and frequency status to a central coordinator. The coordinator processes this feedback information and generates correction instructions that are sent back to the modules, enabling automatic adjustment and maintenance of synchronization across the distributed array while preserving system flexibility

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent manages synchronization by dynamically adjusting operational parameters such as frequency offsets and phase corrections for each satellite module. By changing these parameters in response to measured conditions and using predictive algorithms, the system maintains precise synchronization across distributed modules without compromising adaptability

Inventive Principle:
Principle #35Parameter changes

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 drastically reduces the weight and cost of satellite systems, enables high throughput capabilities, and allows for direct connectivity with end-user devices using low-frequency spectrum, reducing interference and the need for additional tracking systems.

Implementation Method 1

perform, based on the stored information, Doppler compensation to a center or substantially center of each beam that provides communication between the set of end user devices and the distributed phased-array antenna operating in LEO

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

perform, according to the stored information, delay compensation to the center or substantially center of each beam in the given cell so that a delay as seen by the respective end user device of the set of end user devices is below 0.5 ms

Methodology Applied
Scientific EffectSignal propagation delay:

Data Source

PatentEP4236085A2High throughput fractionated satellites
Publication Date: 2023.08.30 AST & SCIENCE LLC
  • EP4236085A2 patent drawingFigure 1(a)~10
  • EP4236085A2 patent drawingFigure 1(b)
  • EP4236085A2 patent drawingFigure 2(a)~3

AI summary

A station configured to support direct communication between a set of discrete satellite modules operating in low Earth orbit (LEO) and forming a distributed phased-array antenna with a single aperture and a set of end user devices, the station comprising: memory configured to store information including at least one of communication link frequency assignments, beam mapping, or satellite constellation ephemeris information; and one or more processors operatively coupled to the memory, the one or more processors being configured to: perform, based on the stored information, Doppler compensation to a center or substantially center of each beam that provides communication between the set of end user devices and the distributed phased-array antenna operating in LEO, wherein each beam is associated with a corresponding cell of a set of cells according to the single aperture, so that a Doppler shift for each beam as seen by a respective end user device of the set of end user devices that is in a given one of the set of cells falls below 1200 Hz; and perform, according to the stored information, delay compensation to the center or substantially center of each beam in the given cell so that a delay as seen by the respective end user device of the set of end user devices is below 0.5 ms. There is further provided a corresponding system.