# Radar Interferometry Using gNB Base Stations: Estimation and Compensation of Mast Motion and Atmospheric Effects

## TL;DR

This paper shows that 5G base stations can be used as radar systems to monitor structural movements, with a new method to improve accuracy by removing motion and atmospheric effects.

## Contribution

A regression-based method is introduced to estimate and compensate for mast motion and atmospheric effects in radar interferometry using 5G base stations.

## Key findings

- 5G gNB base stations can effectively monitor structural displacements as ground-based radar interferometers.
- The proposed regression method outperforms auxiliary sensor-based approaches in compensating for mast motion and atmospheric disturbances.
- The technique was validated on a bridge and a gNB mast, showing its effectiveness for structural health monitoring.

## Abstract

What are the main findings?
A gNB 5G base station can be effectively used as a ground-based radar interferometer for monitoring structural displacements.A regression-based compensation method is proposed to estimate and remove antenna mast motion and atmospheric disturbances directly from radar data, achieving better performance than approaches relying on auxiliary sensors.

A gNB 5G base station can be effectively used as a ground-based radar interferometer for monitoring structural displacements.

A regression-based compensation method is proposed to estimate and remove antenna mast motion and atmospheric disturbances directly from radar data, achieving better performance than approaches relying on auxiliary sensors.

What are the implications of the main findings?
Using existing 5G infrastructures for radar sensing significantly reduces deployment and maintenance costs for large-scale Structural Health Monitoring.Radar interferometry can be used even for health monitoring of a gNB telecommunication mast itself.

Using existing 5G infrastructures for radar sensing significantly reduces deployment and maintenance costs for large-scale Structural Health Monitoring.

Radar interferometry can be used even for health monitoring of a gNB telecommunication mast itself.

Radar interferometry can provide important information for Structural Health Monitoring (SHM) of bridges and other transportation structures. In this article, joint communication and sensing (JCAS) telecommunication infrastructure is tested as a ground-based radar, offering advantages in terms of long-term costs, deployment and maintenance. This work specifically addresses the estimation of the radar support movement (i.e., pylon or mast), which represents a major challenge in this kind of measurements. Movements of the radar system combine with the true target motion and, if not correctly compensated, can compromise the accuracy of the results. A technique for estimating radar movements based on the displacement tracking of multiple permanent scatterers (PSs) in the scenario is presented. True target displacements can then be retrieved by applying linear regression methods to fixed PSs located at different viewing angles, accounting for both radar movements and atmospheric displacement components. The technique was validated using real data acquired during an experimental campaign on a bridge test site. First, results obtained for a target subject to known displacements are shown. A second measurement session was aimed at testing the method for bridge dynamic monitoring. Finally, the same technique was applied antenna mast monitoring in terms of modal analysis and vibration characterization.