A new parametric autofocus technique with a high accuracy of flight-parameter estimation dedicated to strip-mode synthetic aperture radar (SAR) systems is presented. Most of the known autofocus techniques require high-reflectivity targets (man-made targets) to obtain a properly focused SAR image. The technique proposed in this paper allows flight parameters to be estimated effectively, even for a low-contrast scene (e.g., forests, fields, small paths, etc.). The autofocus technique is based on well-known MapDrift (MD) principles. The presented technique is a coherent one, which allows flight parameters to be estimated more precisely than in the other well-known parametric technique referred to as classical MD. The presented technique allows flight parameters to be estimated with accuracy that is independent of the initial velocity error. It can be used for real-time processing for both Earth imaging and moving-target indication.

This paper presents the pioneering results of successful target detection using a fully operational and cooperative 5G cellular network as a source of illumination in a passive radar system. The electromagnetic wave generated by the real-life base station allowed for remote sensing of a moving car in bistatic geometry, which shows the feasibility of passive radar in which new generation radio networks serve as an illuminator of opportunity. The paper describes passive radar principles, the theoretical fundamentals of the 5G signal structure, and proposed processing for 5G network-based passive radar. Also, the 5G passive radar demonstrator is described, and the trial results showing the possibilities and limitations of using new radio standards in the context of passive radars.

This paper presents an experimental system dedicated for the detection and tracking of small aerial targets such as Unmanned Aerial Vehicles (UAVs) in particular small drones (multirotors). The system was proposed in response to increasing drone popularity and the related threats. The hardware and software parts of the system are covered, including the analogue front-end, FPGA based pre-processing and PC based processing, detection and tracking. Real life trials are described with promising results provided. Further research on the subject is proposed.

This study presents an analysis of the detection range of a passive bistatic radar (PBR) by using FM radio transmitters as the illuminators of opportunity and the analysis of a required analogue‐front‐end dynamic range. Firstly, the theoretical considerations are presented in which the power budget is analysed, by taking into account the specific features of the PBR such as instantaneous reception of the direct illumination signal and weak target echoes and direct path interference removal. In the second part of this study, measurements performed by using an FM‐based PBR demonstrator PaRaDe (passive radar demonstrator) are presented. The PaRaDe is a deployable system operating in real time, developed at the Warsaw University of Technology, Poland. The measurements include a scan of a typical spectrum in the range of 88–108 MHz, and the analysis of the long range detection of the air targets.

In this letter, pioneering experimental results of passive synthetic aperture radar (SAR) imaging are presented. The classical active SAR radar operates in monostatic geometry. The SAR sensor presented in this letter is a passive radar utilizing commercial Digital Video Broadcasting-Terrestrial transmitters as illuminators of opportunity. It works in a bistatic configuration, where the receiver is placed on a moving platform and the transmitter is placed on the ground and is stationary. The imaged scenes are stationary surfaces on Earth such as agriculture or urban areas, buildings, etc. In this letter, pioneering results of signal processing verified by a measurement campaign are presented. In the experiment, two synchronized passive radar receivers were mounted on a small airborne platform. The main goal of the presented experiment was to verify the possibility of ground imaging using passive SAR technology and validate previously presented theoretical results.

A new approach to the passive coherent location (PCL) signal processing technique dedicated for use on mobile radar platforms is presented. The main goal of the research conducted was to present different aspects of an efficient space-time ground moving target indication (GMTI) algorithm for PCL radar mounted to airborne platforms. The algorithm described, based on displacement phase center antenna (DPCA), has been successfully tested with simulated and real-life data collected with an airborne passive radar demonstrator (PaRaDe).