java

CCSDS 124.0-B-1 Java Implementation

Java implementation of the CCSDS 124.0-B-1 lossless compression algorithm for satellite housekeeping telemetry.

Citation

If CCSDS 124.0-B-1 contributes to your research, please cite:

D. Evans, G. Labrèche, D. Marszk, S. Bammens, M. Hernandez-Cabronero, V. Zelenevskiy, V. Shiradhonkar, M. Starcik, and M. Henkel. 2022. "Implementing the New CCSDS Housekeeping Data Compression Standard 124.0-B-1 (based on POCKET+) on OPS-SAT-1," Proceedings of the Small Satellite Conference, Communications, SSC22-XII-03. https://digitalcommons.usu.edu/smallsat/2022/all2022/133/

BibTeX

@inproceedings{evans2022ccsds124,
  author    = {Evans, David and Labrèche, Georges and Marszk, Dominik and Bammens, Samuel and Hernandez-Cabronero, Miguel and Zelenevskiy, Vladimir and Shiradhonkar, Vasundhara and Starcik, Mario and Henkel, Maximilian},
  title     = {Implementing the New CCSDS Housekeeping Data Compression Standard 124.0-B-1 (based on POCKET+) on OPS-SAT-1},
  booktitle = {Proceedings of the Small Satellite Conference},
  year      = {2022},
  note      = {SSC22-XII-03},
  url       = {https://digitalcommons.usu.edu/smallsat/2022/all2022/133/}
}

Requirements

• Java 11 or later
• Maven 3.6 or later

Building

# Build JAR
make build

# Run tests
make test

# Run all quality checks (format, checkstyle, spotbugs, tests)
make check

# Generate coverage report
make coverage

# Generate API documentation
make docs

Docker

# Build and run tests in container
docker build -t ccsds124-java .
docker run --rm ccsds124-java

# Or use docker-compose from repository root
docker-compose run --rm java

Usage

Command Line

# Compress
java -jar target/ccsds124-1.0.0.jar input.bin 90 20 50 100 2

# Decompress
java -jar target/ccsds124-1.0.0.jar -d input.bin.pkt 90 2

# Show version
java -jar target/ccsds124-1.0.0.jar --version

Library API

import space.tanagra.ccsds124.Ccsds124;

// Compress data
byte[] compressed = Ccsds124.compress(
    inputData,    // byte array of concatenated packets
    90,           // packet size in bytes
    2,            // robustness (0-7)
    20,           // pt limit
    50,           // ft limit
    100           // rt limit
);

// Decompress data
byte[] decompressed = Ccsds124.decompress(
    compressed,   // compressed data
    90,           // packet size in bytes
    2             // robustness (0-7)
);

// Check version
String version = Ccsds124.version();

Parameters

Parameter	Description	Range
packet_size	Size of each packet in bytes	1-8191
robustness	Robustness parameter R	0-7
pt	New mask period limit	> 0
ft	Full transmit period limit	> 0
rt	Reset period limit	> 0

Design

• Zero runtime dependencies - Only requires Java 11+
• Clean OOP design - Proper interfaces, classes, and encapsulation
• Comprehensive Javadoc - All public APIs documented
• High test coverage - Unit tests and reference vector validation
• CLI tool - Command-line interface for compress/decompress operations

Project Structure

implementations/java/
├── src/main/java/space/tanagra/ccsds124/
│   ├── BitVector.java       # Fixed-length bit vectors
│   ├── BitBuffer.java       # Variable-length output buffer
│   ├── BitReader.java       # Sequential bit reading
│   ├── Encoder.java         # COUNT, RLE, BE encoding
│   ├── Decoder.java         # COUNT, RLE decoding
│   ├── MaskOperations.java  # Mask/build vector operations
│   ├── Compressor.java      # Compression algorithm
│   ├── Decompressor.java    # Decompression algorithm
│   ├── Ccsds124.java      # High-level API
│   ├── Ccsds124Exception.java # Custom exception
│   └── cli/Main.java        # CLI tool
├── src/test/java/           # Unit tests
├── pom.xml                  # Maven build
├── checkstyle.xml           # Code style rules
├── Makefile                 # Build targets
└── Dockerfile               # Container build

API

High-Level

• Ccsds124.compress() / Ccsds124.decompress() - Compress/decompress entire buffer
• Ccsds124.version() - Library version

Low-Level

• Compressor.compressPacket() / Decompressor.decompressPacket() - Single packet
• Encoder / Decoder - COUNT, RLE, BE encoding/decoding (Eq. 9-11)
• BitVector / BitBuffer / BitReader - Bit-level primitives
• MaskOperations - Mask/build vector updates

Test Vectors

The implementation is validated against reference test vectors:

Vector	Packets	Robustness	Expected Ratio
simple	100	R=1	14.04x
housekeeping	10,000	R=2	4.03x
edge-cases	500	R=1	4.44x
venus-express	151,200	R=2	2.31x
hiro	100	R=7	5.87x

References

• CCSDS 124.0-B-1 Standard
• POCKET+ on OPS-SAT-1