title: A fully photonics-based coherent radar system.
abstract: The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution. Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies, so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up- and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth, allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves, and the detection of such signals and their precise direct digitization without downconversion. Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up- and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system.
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ghelfi
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Laghezza
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Scotti
authors.affiliation: TeCIP Institute, Scuola Superiore Sant'Anna, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Serafino
authors.affiliation: National Laboratory of Radars and Surveillance Systems, Inter-university National Consortium for Telecommunications (CNIT), Galleria Gerace 18, 56126 Pisa, Italy.
authors.forename: Amerigo
authors.initials: A
authors.lastname: Capria
authors.affiliation: TeCIP Institute, Scuola Superiore Sant'Anna, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Pinna
authors.affiliation: TeCIP Institute, Scuola Superiore Sant'Anna, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Daniel
authors.initials: D
authors.lastname: Onori
authors.affiliation: TeCIP Institute, Scuola Superiore Sant'Anna, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Porzi
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Mirco
authors.initials: M
authors.lastname: Scaffardi
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Malacarne
authors.affiliation: TeCIP Institute, Scuola Superiore Sant'Anna, Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Vercesi
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Emma
authors.initials: E
authors.lastname: Lazzeri
authors.affiliation: 1] National Laboratory of Radars and Surveillance Systems, Inter-university National Consortium for Telecommunications (CNIT), Galleria Gerace 18, 56126 Pisa, Italy [2] Department of Information Engineering, University of Pisa, Via Caruso 16, 56122 Pisa, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Berizzi
authors.affiliation: National Laboratory of Photonic Networks, Inter-university National Consortium for Telecommunications (CNIT), Via Moruzzi 1, 56124 Pisa, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Bogoni