Automatic target recognition using passive bistatic radar signals

Doctoral thesis (2013)

We present the design, development, and test of three novel, distinct automatic target recognition (ATR) systems for the recognition of airplanes and, more specifically, non- cooperative airplanes, i.e ... [more ▼]

We present the design, development, and test of three novel, distinct automatic target recognition (ATR) systems for the recognition of airplanes and, more specifically, non- cooperative airplanes, i.e. airplanes that do not provide information when interrogated, in the framework of passive bistatic radar systems. Passive bistatic radar systems use one or more illuminators of opportunity (already present in the field), with frequencies up to 1 GHz for the transmitter part of the systems considered here, and one or more receivers, deployed by the persons managing the system, and not co-located with the transmitters. The sole source of information are the signal scattered on the airplane and the direct-path signal that are collected by the receiver, some basic knowledge about the transmitter, and the geometrical bistatic radar configuration. The three distinct ATR systems that we built respectively use the radar images, the bistatic complex radar cross-section (BS-RCS), and the bistatic radar cross-section (BS- RCS) of the targets. We use data acquired either on scale models of airplanes placed in an anechoic, electromagnetic chamber or on real-size airplanes using a bistatic testbed consisting of a VOR transmitter and a software-defined radio (SDR) receiver, located near Orly airport, France. We describe the radar phenomenology pertinent for the problem at hand, as well as the mathematical underpinnings of the derivation of the bistatic RCS values and of the construction of the radar images. For the classification of the observed targets into pre-defined classes, we use either extremely randomized trees or subspace methods. A key feature of our approach is that we break the recognition problem into a set of sub-problems by decomposing the parameter space, which consists of the frequency, the polarization, the aspect angle, and the bistatic angle, into regions. We build one recognizer for each region. We first validate the extra-trees method on the radar images of the MSTAR dataset, featuring ground vehicles. We then test the method on the images of the airplanes constructed from data acquired in the anechoic chamber, achieving a probability of correct recognition up to 0.99. We test the subspace methods on the BS-CRCS and on the BS-RCS of the airplanes extracted from the data acquired in the anechoic chamber, achieving a probability of correct recognition up to 0.98, with variations according to the frequency band, the polarization, the sector of aspect angle, the sector of bistatic angle, and the number of (Tx,Rx) pairs used. The ATR system deployed in the field gives a probability of correct recognition of 0.82, with variations according to the sector of aspect angle and the sector of bistatic angle. [less ▲]

Passive radar testbed and preliminary experiments in recognition of non-cooperative aircraft intruding into controlled airspace

Conference (2012, September 14)

We consider the automatic classification of aircraft observed with a passive radar, thus using illuminators of opportunity. We deployed a testbed and developed classification algorithms. Preliminary tests ... [more ▼]

We consider the automatic classification of aircraft observed with a passive radar, thus using illuminators of opportunity. We deployed a testbed and developed classification algorithms. Preliminary tests show a correct recognition rate of 72%. [less ▲]

Status of on-board radiocommunication system of OUFTI-1 nanosatellite as of mid-2012: design, implementation, and tests

Conference (2012, September 14)

We describe the space-segment component of the radiocommunication system of the OUFTI-1 nanosatellite system, providing D-STAR digital voice & data communication, AX.25 telecommand & telemetry, and OOK ... [more ▼]

We describe the space-segment component of the radiocommunication system of the OUFTI-1 nanosatellite system, providing D-STAR digital voice & data communication, AX.25 telecommand & telemetry, and OOK beacon transmissions. [less ▲]

Automatic real-time collection of RCS of airplanes in a real bistatic low-frequency configuration using a software defined passive radar based on illuminators of opportunity

in Proceedings of the 2012 IEEE Radar Conference (2012, May)

Status of ground radiocommunication system of OUFTI-1 nanosatellite as of mid-2012: design, implementation, and tests

Conference (2012)

We describe the ground-segment component of the radiocommunication system of the OUFTI-1 nanosatellite system, comprising a ground station and a suitably modified D-STAR repeater.

Target classification system based on the characterization of targets by subspaces

in Proceedings of 2011 IEEE CIE International Conference on Radar (2011, October)

CubeSat Activities at the University of Liège

Conference (2011)

Radar Classification based on Extra-Trees

(2010, May 24)

In this paper, we describe a new automatic target recognition algorithm for classifying SAR images based on the PiXiT im- age classifier. It uses randomized sub-windows extraction and extremely randomized ... [more ▼]

In this paper, we describe a new automatic target recognition algorithm for classifying SAR images based on the PiXiT im- age classifier. It uses randomized sub-windows extraction and extremely randomized trees (extra-trees). This approach re- quires very little pre-processing of the images, thereby lim- iting the computational load. It was successfully tested on an extended version of the public standard MSTAR database, that includes targets of interest, false targets, and background clutter. A misclassification rate of about three percent has been achieved. [less ▲]

Le système de télécommunication du nanosatellite OUFTI-1

Scientific conference (2010, March 25)

Design, construction, and test of a reliable, redundant on-board computer (OBC) for the OUFTI-1 CubeSat of the University of Li`ege

Scientific conference (2010)