Development of a cooperative multistatic radar network based on the Aveillant holographic radar

Abstract

Staring radars use a transmitting static wide-beam antenna and a directive digital array to form multiple simultaneous beams on receive. Because beams are static, the radar can employ long integration times that facilitate the detection of slow low-RCS targets, such as drones, which present a challenge to traditional air surveillance radar. Typical low-altitude trajectories employed by drones often result in low-grazing angle multipath effects, which are difficult to mitigate with a monostatic radar alone. Using multiple spatially separated receivers cooperating with the staring transmitters in a multistatic network allows multi-perspective target acquisitions that can help mitigate interference from the environment and improve the detection and localisation of drones. The term drone refers to small unmanned aerial systems (UASs) with a radar cross-section (RCS) of approximately 0.01 m2,such as the DJI Phantom/Inspire series. This thesis presents the development of a cooperative radar network. The radar network consists of a staring transmitter and multiple bistatic passive receivers. The advantage of a staring transmitter is that the network can use long integration times to detect slow and low RCS targets such as drones. The staring transmitter ensures a constant signal at the receiver nodes within the radar’s coverage and, therefore, can be simplified as they do not need to employ pulse-chasing techniques. Target position and velocity estimation algorithms have been developed for the cooperative radar network. The theoretical lower bound on the error of estimation algorithms is used to determine the estimation performance of the radar network and is further used to optimise the network’s geometry by minimising estimation error. As part of the thesis, a passive bistatic dual-channel receiver has been developed and employed in a bistatic configuration with a staring transmitter of opportunity to test the theoretical algorithms and measure a drone in flight. The receivers are designed along passive radar principles and consist of two receive channels: a surveillance channel aligned with the transmitter and a reference channel aligned with the target. The receiver employs horn antennas with a wide 90◦ degree beamwidth and has been used to perform laboratory measurements of a rotating fan, the micro-Doppler signature of a remote-control helicopter, a moving car and a drone in flight.