title: SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell.
abstract: This paper presents an experimental Synthetic Aperture Radar (SAR) system that is under development in the Universidad Politécnica de Madrid. The system uses Linear Frequency Modulated Continuous Wave (LFM-CW) radar with a two antenna configuration for transmission and reception. The radar operates in the millimeter-wave band with a maximum transmitted bandwidth of 2 GHz. The proposed system is being developed for Unmanned Aerial Vehicle (UAV) operation. Motion errors in UAV operation can be critical. Therefore, this paper proposes a method for focusing SAR images with movement errors larger than the resolution cell. Typically, this problem is solved using two processing steps: first, coarse motion compensation based on the information provided by an Inertial Measuring Unit (IMU); and second, fine motion compensation for the residual errors within the resolution cell based on the received raw data. The proposed technique tries to focus the image without using data of an IMU. The method is based on a combination of the well known Phase Gradient Autofocus (PGA) for SAR imagery and typical algorithms for translational motion compensation on Inverse SAR (ISAR). This paper shows the first real experiments for obtaining high resolution SAR images using a car as a mobile platform for our radar.
authors.affiliation: Universidad Politécnica de Madrid. Departamento de Señales, Sistemas y Radiocomunicaciones, Av. Complutense s/n, 28040 Madrid, Spain. joseto@gmr.ssr.upm.es.
authors.forename: José-Tomás
authors.initials: JT
authors.lastname: González-Partida
authors.affiliation: Universidad Politécnica de Madrid. Departamento de Señales, Sistemas y Radiocomunicaciones, Av. Complutense s/n, 28040 Madrid, Spain. almorox@gmr.ssr.upm.es.
authors.forename: Pablo
authors.initials: P
authors.lastname: Almorox-González
authors.affiliation: Universidad Politécnica de Madrid. Departamento de Señales, Sistemas y Radiocomunicaciones, Av. Complutense s/n, 28040 Madrid, Spain. mateo@gmr.ssr.upm.es.
authors.forename: Mateo
authors.initials: M
authors.lastname: Burgos-Garcia
authors.affiliation: Universidad de Las Palmas de Gran Canaria. Departamento de Señales y Comunicaciones. Edificio de Electrónica y Telecomunicaciones, 35017 Campus Universitario de Tafira, Las Palmas de Gran Canaria, Spain. pdorta@dsc.ulpgc.es.
authors.forename: Blas-Pablo
authors.initials: BP
authors.lastname: Dorta-Naranjo
keywords: Phase Gradient Autofocus (PGA).; Synthetic Aperture Radar (SAR); Unmanned Aerial Vehicle (UAV); motion compensation; range alignment