A Robust Test for Detecting Non-Stationarity in Data from Gravitational Wave Detectors

TL;DR

This paper introduces a robust, threshold-independent time-frequency test for detecting non-stationarity in gravitational wave data, improving burst detection capabilities without prior noise distribution knowledge.

Contribution

A new robust non-stationarity test that is nearly independent of noise models and enhances burst detection compared to ideal methods with prior information.

Findings

Test detects bursts 3 times larger in amplitude than ideal methods.

Threshold remains stable regardless of ambient noise distribution.

Suitable for real-time monitoring of stationarity.

Abstract

It is difficult to choose detection thresholds for tests of non-stationarity that assume {\em a priori} a noise model if the data is statistically uncharacterized to begin with. This is a potentially serious problem when an automated analysis is required, as would be the case for the huge data sets that large interferometric gravitational wave detectors will produce. A solution is proposed in the form of a {\em robust} time-frequency test for detecting non-stationarity whose threshold for a specified false alarm rate is almost independent of the statistical nature of the ambient stationary noise. The efficiency of this test in detecting bursts is compared with that of an ideal test that requires prior information about both the statistical distribution of the noise and also the frequency band of the burst. When supplemented with an approximate knowledge of the burst duration, this test can detect, at the same false alarm rate and detection probability, bursts that are about 3 times larger in amplitude than those that the ideal test can detect. Apart from being robust, this test has properties which make it suitable as an online monitor of stationarity.