Autonomous Nanosatellite Message Scheduling with Energy Constraints

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Solution Overview

Problem

Existing satellite communication systems, particularly low earth orbiting nanosatellites, face challenges in efficiently scheduling message delivery due to energy management constraints and limited contact time windows, which are not adequately addressed by current centralized scheduling methods.

Innovation Solution

An autonomous, decentralized message delivery scheduling scheme for nanosatellites that estimates delivery time and energy availability for each message, allowing each nanosat to determine its own scheduling policy based on message size, energy capacity, and contact time windows to minimize total delivery time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If centralized ground control scheduling is used, then scheduling coverage and control capability are improved, but transmission delay and system overhead increase

Engineering Contradiction:

Improvescheduling control capabilityVSAvoidtransmission delay

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The centralized scheduling system is segmented into distributed autonomous scheduling units at each nanosatellite. Each satellite independently performs scheduling decisions based on local conditions, eliminating the need for continuous ground control intervention and reducing transmission delays while maintaining comprehensive scheduling coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The scheduling system transitions from static ground-controlled schedules to dynamic autonomous scheduling that adapts in real-time to changing conditions such as energy availability, contact time windows, and message priorities, reducing delays while maintaining operational control.

Inventive Principle:

Principle #15Dynamics

2Productivity

If more messages are delivered during contact time windows, then message delivery throughput is improved, but energy consumption increases

Engineering Contradiction:

Improvemessage delivery throughputVSAvoidsatellite energy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The scheduling system dynamically adjusts message delivery decisions based on real-time energy availability assessments. It optimizes the balance between delivering maximum messages during contact windows and preserving sufficient energy for future operations, adapting to varying energy states and charging conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters such as transmission power levels and message prioritization based on energy availability. When energy is abundant, higher throughput is achieved; when energy is limited, the system adjusts to maintain sustainable operations while still delivering critical messages.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If contact time windows are extended to deliver more messages, then message delivery capacity is improved, but satellite orbital constraints and charging opportunities are violated

Engineering Contradiction:

Improvemessage delivery capacityVSAvoidorbital constraint satisfaction

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary assessment of contact time windows and energy availability before making delivery decisions. By pre-evaluating orbital constraints and charging opportunities, it schedules message deliveries that maximize capacity while ensuring all orbital and energy constraints are satisfied, avoiding infeasible scheduling decisions.

Inventive Principle:

Principle #10Preliminary action

4Adaptability or versatility

If autonomous decentralized scheduling is implemented, then flexibility and adaptability are improved, but scheduling complexity increases

Engineering Contradiction:

Improvescheduling flexibilityVSAvoidscheduling algorithm complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The complex scheduling problem is segmented into smaller sub-problems handled by autonomous units at each satellite. Each unit manages its own message queue and energy state, making localized decisions that collectively achieve system-wide optimization without requiring complex inter-satellite coordination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each nanosatellite performs self-scheduling based on its own energy state, message priorities, and predicted contact windows. This autonomous self-service approach provides high flexibility and adaptability to local conditions while the modular nature of individual satellite decision-making keeps implementation complexity manageable.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20180294872A1Energy-Cognizant Scheduling of Store-and-Forward Communications with Multiple Priority Levels in Satellite Systems

Publication Date: 2018.10.11 THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY OF THE NAVY

AI summary

Delivery of a plurality of messages by a satellite is scheduled taking energy into account. An amount of time needed to deliver each of the plurality of messages received from a plurality of ground sources and intended for a plurality of ground recipients at respective different destinations is estimated based on the size of each of the messages. Each different destination has an associated contact time window during which the satellite will be in range of the ground recipients at that destination. An amount of energy that will be available from a power source for delivering the messages during each contact window is determined. Delivery of the plurality of messages to the ground recipients is scheduled such that a total time for delivery of the messages is minimized.