Radio Interferometric Calibration with the Exponential Map
Abstract
The antenna-elements that make up a radio interferometer form a spatial filter that samples components of the Fourier transform of a target radio astronomical source brightness. Along the signal path, there are multiplicative and additive perturbation effects that alter the signal and that should be corrected. The process of mitigating these perturbation effects is called calibration. In this work, we develop a new and fast Maximum Likelihood based estimator of these perturbation effects using the Exponential Map and Lie groups. To evaluate its performance, we compare it to the Cramér-Rao Lower Bound and, to test the estimation time, we compare it with the Expectation Maximization algorithm, another fast Maximum Likelihood estimator. Finally, we apply our estimator to a real observation of the protoplanetary disk AS 209 made with the Submillimeter Array. We found that our proposed estimator meets the Cramér-Rao Lower Bound and it was approximately 40 times faster than the Expectation Maximization algorithm.
Related
- SIFARI: Self-Supervised Interferometric Fitting for Astronomical Radio Imaging
- Spectral stacking of radio-interferometric data
- Flux Density Calibration of Radio Bursts Detected in the Sidelobes of the Canadian Hydrogen Intensity Mapping Experiment
- Interferometric Survey of Stellar Parameters: Limb darkening study with the Pipeline for Interferometric Measurements of Stars
- IViS: Interferometric Visibility-domain inversion Software. A GPU-accelerated Python framework for joint deconvolution with ASKAP
BibTeX
@misc{cabral2026radio,
title = {{Radio Interferometric Calibration with the Exponential Map}},
author = {L. Cabral and M. Fernandez-Corazza and G. Gancio and P. Benaglia},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.01895},
eprint = {2610.01895},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.01895},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Radio Interferometric Calibration with the Exponential Map
AU - L. Cabral
AU - M. Fernandez-Corazza
AU - G. Gancio
AU - P. Benaglia
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2610.01895
UR - https://arxiv.org/abs/2610.01895
AB - The antenna-elements that make up a radio interferometer form a spatial filter that samples components of the Fourier transform of a target radio astronomical source brightness. Along the signal path, there are multiplicative and additive perturbation effects that alter the signal and that should be corrected. The process of mitigating these perturbation effects is called calibration. In this work, we develop a new and fast Maximum Likelihood based estimator of these perturbation effects using the Exponential Map and Lie groups. To evaluate its performance, we compare it to the Cramér-Rao Lower Bound and, to test the estimation time, we compare it with the Expectation Maximization algorithm, another fast Maximum Likelihood estimator. Finally, we apply our estimator to a real observation of the protoplanetary disk AS 209 made with the Submillimeter Array. We found that our proposed estimator meets the Cramér-Rao Lower Bound and it was approximately 40 times faster than the Expectation Maximization algorithm.
ER -