canvod-auxiliary 0.2.1

Ephemeris and auxiliary data handling for GNSS-Transmissometry

canvod-auxiliary

Auxiliary data augmentation for GNSS VOD analysis

Part of the canVODpy ecosystem.

Overview

canvod-auxiliary provides tools for downloading, parsing, and interpolating auxiliary GNSS data files including:

• SP3 ephemerides - Satellite orbit positions and velocities
• CLK corrections - Satellite clock corrections
• Interpolation strategies - Hermite and linear interpolation for temporal alignment
• Augmentation framework - Pluggable system for enriching RINEX datasets

Features

SP3 File Handling

• Download from ESA or NASA CDDIS servers
• Parse SP3 format (positions + velocities)
• Cubic Hermite interpolation using velocities
• Fallback to linear interpolation

Clock Corrections

• CLK file download and parsing
• Jump-aware interpolation
• Segment-based processing

Flexible Pipeline

• Automatic file discovery and caching
• Thread-safe downloading
• Configurable FTP servers and agencies

Augmentation System

• Spherical coordinate calculation (φ, θ, r)
• Clock correction application
• Extensible via ABC pattern

Installation

# From PyPI (when published)
pip install canvod-auxiliary

# Development install
cd canvodpy/packages/canvod-auxiliary
uv pip install -e .

Quick Start

Basic SP3 Usage

from pathlib import Path
from canvod.auxiliary import Sp3File

# Load SP3 ephemeris file
sp3 = Sp3File.from_file(Path("COD0MGXFIN_20240150000_01D_05M_ORB.SP3"))

# Access data as xarray Dataset
data = sp3.data
print(data)  # Coordinates: epoch, sid | Variables: X, Y, Z, Vx, Vy, Vz

# Get interpolation strategy
strategy = sp3.get_interpolation_strategy()
print(strategy.config)  # Sp3Config(use_velocities=True)

Pipeline Usage

from canvod.auxiliary import AuxDataPipeline
from pathlib import Path

# Create pipeline
pipeline = AuxDataPipeline(
    agency="COD",
    product_type="final",
    ftp_server="ftp://gssc.esa.int/gnss",
    aux_file_path=Path("aux_data")
)

# Get augmented data for specific date
augmented_ds = pipeline.get_or_create_aux_data(
    yyyydoy="2024015",
    target_epochs=my_rinex_epochs
)

Custom Interpolation

from canvod.auxiliary import Sp3Config, Sp3InterpolationStrategy
import numpy as np

# Configure interpolation
config = Sp3Config(use_velocities=True, fallback_method='cubic')
strategy = Sp3InterpolationStrategy(config=config)

# Interpolate to new epochs
target_epochs = np.array([...])  # Your target timestamps
interpolated = strategy.interpolate(sp3_dataset, target_epochs)

Documentation

Centralized documentation

Package Structure

canvod-auxiliary/
├── src/canvod/aux/
│   ├── __init__.py              # Public API
│   ├── _internal/               # Internal utilities
│   │   ├── units.py             # UREG unit registry
│   │   ├── date_utils.py        # YYYYDOY, GPS week utils
│   │   └── logger.py            # Logging utilities
│   ├── reader.py                # AuxFile ABC
│   ├── container.py             # FTP downloader
│   ├── interpolation.py         # Interpolation strategies
│   ├── sp3.py                   # SP3 handler
│   ├── clk.py                   # CLK handler
│   ├── pipeline.py              # AuxDataPipeline
│   └── augmentation.py          # Augmentation framework
├── tests/                       # 65 tests, 100% core coverage
├── docs/                        # MyST documentation
└── pyproject.toml

Development

Setup

# Clone repository
git clone https://github.com/nfb2021/canvodpy.git
cd canvodpy/packages/canvod-auxiliary

# Install dependencies
uv sync

# Install pre-commit hooks
pre-commit install

Commands

# Run tests
pytest

# With coverage
pytest --cov=canvod.auxiliary --cov-report=html

# Lint and format
ruff check .
ruff format .

# Type check
ty check src/

Project Tasks (Just)

If you have Just installed:

just test          # Run tests
just check         # Lint + format check
just fix           # Auto-fix linting issues
just docs          # Build documentation

Dependencies

Core:

• scipy ≥1.15.0
• numpy ≥1.24.0
• xarray ≥2023.12.0
• pydantic ≥2.5.0
• pint ≥0.23

Network:

• requests ≥2.31.0

• retrying ≥1.3.4

• beautifulsoup4 ≥4.12.0

• lxml ≥5.3.0

Development:

• pytest ≥8.0
• pytest-cov ≥5.0
• ruff ≥0.14
• ty ≥0.0.9

Contributing

Contributions welcome! Please see the main repository for contribution guidelines.

License

Apache License 2.0 - See LICENSE file

Related Packages

Part of the canVODpy ecosystem:

• canvod-readers - RINEX data readers
• canvod-grids - Hemisphere grids
• canvod-vod - VOD calculations
• canvod-store - Icechunk storage
• canvod-viz - Visualization
• canvodpy - Umbrella package

Citation

If you use canvod-auxiliary in your research, please cite:

@software{canvodpy2026,
  author = {Bader, Nicolas F.},
  title = {canVODpy: GNSS Transmissometry Analysis},
  year = {2026},
  publisher = {TU Wien},
  url = {https://github.com/nfb2021/canvodpy}
}

Author & Affiliation

Nicolas François Bader Climate and Environmental Remote Sensing Research Unit (CLIMERS) Department of Geodesy and Geoinformation TU Wien (Vienna University of Technology) Email: [e-mail] https://www.tuwien.at/en/mg/geo/climers