# Multi-Domain Feature Analysis and Application Research of GPR Aliased Signals

## TL;DR

This paper studies how overlapping radar signals from rebar in concrete structures can be analyzed and interpreted to improve detection accuracy.

## Contribution

A novel aliasing peak point extraction algorithm with less than 10% relative error is proposed for analyzing GPR signals.

## Key findings

- Amplitude increases were observed in the time domain of aliased GPR signals.
- The Hilbert transform effectively captures instantaneous phase inversions in the signals.
- STFT provides a clear time–frequency distribution for feature extraction.

## Abstract

In radar detection of concrete structures, the significant differences in electromagnetic properties between rebar and concrete result in strong reflections at rebar interfaces. The electromagnetic waves reflected by the dual-layer rebar interfere with and superimpose, severely obscuring their characteristic signals, making accurate identification challenging. This study investigates the aliasing effect in ground-penetrating radar (GPR) signals through simulation analysis of aliased signals at different rebar spacings and examines their characteristics across the time, frequency, and time–frequency domains. Experimental results indicate amplitude increases in the time domain. The Hilbert transform effectively extracts instantaneous phase inversions, and STFT provides an intuitive time–frequency distribution, facilitating the extraction and analysis of signal features. Additionally, this study includes the design and implementation of an aliasing peak point extraction algorithm with a relative error of less than 10% in practical applications.