Self-learning signal classifier for decameter coherent scatter radars

TL;DR

This paper introduces an automatic classifier for decameter coherent scatter radar data, trained on multi-year data from 12 radars, utilizing radio wave propagation models and measured parameters.

Contribution

It presents a novel self-learning classification method based solely on radar data and propagation modeling, with detailed analysis of class dynamics and physical interpretation.

Findings

Optimal number of classes is 37, with 25 frequently observed.

14 classes are confidently separable in model training.

Key parameters include signal trajectory shape, scattering height, and Doppler velocity.

Abstract

The paper presents a method for automatic constructing a classifier for processed data obtained by decameter coherent scatter radars. Method is based only on the radar data obtained, the results of automatic modeling of radio wave propagation in the ionosphere, and mathematical criteria for estimating the quality of the models. The final classifier is the model trained at data obtained by 12 radars of the SuperDARN and SECIRA networks over two years for each radar. The number of the model coefficients is 2669. For the classification, the model uses both the calculated parameters of radio wave propagation in the model ionosphere and the parameters directly measured by the radar. Calibration of radiowave elevation measurements at each radar was made using meteor trail scattered signals. The analysis showed that the optimal number of classes in the data is 37, of which 25 are frequently observed. The analysis made it possible to choose 14 classes from them, which are confidently separated in other variants of model training. A preliminary interpretation of 10 of them was carried out. The dynamics of observation of various classes and their dependence on the geographical latitude of radars at different levels of solar and geomagnetic activity were presented, it was shown that it does not contradict with known physical mechanisms. The analysis showed that the most important parameters to identify the classes are the shape of the signal ray-tracing trajectory in its second half, the ray-traced scattering height and the Doppler velocity measured by the radar.