[DRAFT]OTA Update System Proposal

[yudataguy]

CubeSat Over-The-Air Update System Proposal

Executive Summary

This proposal outlines a robust and efficient Over-The-Air (OTA) update system designed specifically for CubeSat applications. The system addresses key challenges in satellite firmware updates, including limited transmission windows, bandwidth constraints, and the need for reliable file verification and recovery mechanisms.

System Overview

Core Features

1. Differential Updates
2. Priority-based Transmission
3. Chunked File Transfer
4. Compression Support
5. Progress Monitoring
6. Rollback Capability

Detailed System Architecture

1. Differential Update System

Purpose

• Minimize transmission overhead by sending only changed files
• Reduce update time and power consumption
• Optimize limited transmission windows

Implementation

• File state tracking using SHA-256 checksums
• Comparison between current and previous versions
• Status tracking: UNCHANGED, MODIFIED, ADDED, DELETED
• JSON-based state persistence for reliability

2. Priority Management

Priority Levels

1. CRITICAL

   • Bootloader
   • Core system files
   • Security-related components

2. HIGH

   • Main application code
   • Essential system modules

3. MEDIUM

   • Regular feature updates
   • Configuration files

4. LOW

   • Documentation
   • Non-essential resources

Bandwidth Planning

• Available transmission window calculation
• Priority-based file ordering
• Adaptive transmission scheduling
• Real-time bandwidth monitoring

3. Chunked File Transfer

Features

• Configurable chunk size (default: 1024 bytes)
• Individual chunk verification
• Resume capability after interruption
• Progress tracking per chunk

Chunk Management

• Unique chunk identification
• Independent checksum verification
• Offset tracking for precise file reconstruction
• Sequential and non-sequential reception support

4. Compression System

Capabilities

• ZLIB compression with configurable levels
• Adaptive compression based on file type
• Per-chunk compression analysis
• Compression efficiency monitoring

Optimization

• Compression ratio tracking
• Space savings calculation
• Adaptive compression level selection
• Bandwidth usage optimization

5. Progress Monitoring

Metrics

• Real-time transfer progress
• Average speed calculation
• Estimated completion time
• Bandwidth utilization

Reporting

• Per-file progress tracking
• System-wide status monitoring
• Compression efficiency statistics
• Error rate monitoring

6. Rollback Mechanism

Safety Features

• Automatic backup creation
• File integrity verification
• Staged rollback process
• Recovery point management

Process

1. Pre-update backup creation
2. Update application
3. Integrity verification
4. Automatic rollback on failure

Technical Implementation

File Processing

# Example chunk processing
def process_chunk(chunk_data: bytes) -> Tuple[bytes, str]:
    # Compress chunk
    compressed = zlib.compress(chunk_data, level=6)
    
    # Calculate checksum
    checksum = hashlib.sha256(compressed).hexdigest()
    
    return compressed, checksum

Transmission Protocol

1. Initial metadata exchange
2. Chunk-by-chunk transfer
3. Real-time verification
4. Progress monitoring
5. Completion confirmation

Error Handling

• Chunk verification failure
• Transmission interruption
• Corruption detection
• Recovery procedures

Bandwidth Considerations

Optimization Strategies

1. Prioritized transmission ordering
2. Adaptive compression
3. Chunk size optimization
4. Bandwidth monitoring

Resource Management

• Memory usage optimization
• CPU utilization balancing
• Power consumption monitoring
• Storage efficiency

Security Considerations

Integrity Protection

• SHA-256 checksums for all files
• Per-chunk verification
• Complete file validation
• Secure backup management

Update Verification

1. Individual chunk verification
2. Complete file integrity check
3. System state validation
4. Rollback capability

Implementation Timeline

Phase 1: Core Infrastructure

• Basic file handling
• Checksum implementation
• State management

Phase 2: Advanced Features

• Compression system
• Progress monitoring
• Rollback mechanism

Phase 3: Testing and Optimization

• System testing
• Performance optimization
• Documentation

Resource Requirements

Software Dependencies

• Python 3.8+
• Required libraries:
  • hashlib
  • zlib
  • json
  • logging

Hardware Considerations

• Minimum memory requirements
• Storage space for backups
• Processing power for compression
• Communication bandwidth

Testing Strategy

Unit Testing

• Individual component testing
• Error handling verification
• Edge case validation

Integration Testing

• Complete system testing
• Performance benchmarking
• Stress testing

Validation Criteria

1. Successful file transfer
2. Corruption recovery
3. Interrupt handling
4. Resource utilization

Conclusion

This OTA update system provides a robust, efficient, and secure method for updating CubeSat firmware. The system's modular design allows for future enhancements while maintaining reliability and performance.

Future Enhancements

Potential Improvements

1. Advanced compression algorithms
2. Machine learning-based optimization
3. Enhanced security features
4. Improved monitoring capabilities

Scalability Considerations

• Multiple satellite support
• Increased file sizes
• Enhanced bandwidth management
• Extended feature set