
## TimeRadar: A Domain-Rotatable Foundation Model for Time Series Anomaly Detection
[](https://arxiv.org/abs/2602.19068)
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[](LICENSE)
[](https://opensource.org/licenses/Apache-2.0)
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## Overview
We introduce **TimeRadar**, an innovative time series foundation model (TSFM) built in a **fractional time–frequency domain** to support generalist time series anomaly detection (TSAD) across diverse unseen datasets. Our key insight is that rotating a time series into a **data-dependent fractional time–frequency representation** can adaptively differentiate normal and abnormal signals across different datasets. To this end, we propose a novel component, **Fractionally modulated Time-Frequency Reconstruction (FTFRecon)**, which leverages a **learnable fractional order** to rotate the time series to the most pronounced angle between the continuous time and frequency domains for accurate data reconstruction. This design enables **adaptive reconstruction in an optimal time–frequency domain** for each input, effectively distinguishing **unbounded abnormal patterns** from regular ones across datasets, including previously unseen datasets. To further capture **local abnormalities** that may not be reflected by global reconstruction, we introduce a **Contextual Deviation Learning (CDL)** component, which models the local deviation of the input relative to its contextual time series data in the rotatable domain.