A fully photonics-based coherent radar system is presented, which uses a single mode-locked laser to generate and detect radar signals, avoiding traditional radio-frequency (RF) up- and downconversion. This system offers unprecedented frequency flexibility, signal quality, and receiver resolution at high carrier frequencies. The system's performance exceeds that of state-of-the-art electronic radar systems, particularly at carrier frequencies above two gigahertz. The radar system was tested in a real environment and demonstrated the ability to detect non-cooperating aeroplanes with high precision. The system uses photonic techniques for both RF signal generation and detection, enabling the generation of extremely stable RF signals with arbitrary waveforms up to millimetre waves. The photonic-based RF generator uses a mode-locked laser to generate tunable radar signals, while the photonic-based ADC uses optical sampling to digitize the received signals without downconversion. The system's performance is characterized by high signal-to-noise ratio, low phase noise, and high timing jitter, with the photonic ADC achieving a spurious-free dynamic range of >50 dB. The system's architecture is based on a single mode-locked laser, which is used for both generating and sampling the radar signal. To avoid the problem of the sampling frequency being a multiple of the carrier frequency, one of the laser modes is shifted before heterodyning. The system's performance is further enhanced by using photonic integration techniques, which allow for the generation of arbitrary amplitude- and phase-modulated signals. The system was tested in a field-trial demonstrator, where it successfully detected non-cooperating aeroplanes with high precision. The system's ability to detect targets with a range resolution of 150 m and a velocity resolution of 2 km/h was demonstrated. The system's performance was compared with state-of-the-art electronic radar systems, and it was found to offer significant advantages in terms of frequency flexibility, signal quality, and precision. The PHODIR project has pioneered a fully photonics-based radar system, enabling the software-defined radio approach with performance exceeding that of state-of-the-art radar systems. The system's use of photonics allows for additional functionalities, such as tunable time delay for beamforming and the use of optical fibres for signal transport. The system's architecture is expected to enable future smart multifunction surveillance systems.A fully photonics-based coherent radar system is presented, which uses a single mode-locked laser to generate and detect radar signals, avoiding traditional radio-frequency (RF) up- and downconversion. This system offers unprecedented frequency flexibility, signal quality, and receiver resolution at high carrier frequencies. The system's performance exceeds that of state-of-the-art electronic radar systems, particularly at carrier frequencies above two gigahertz. The radar system was tested in a real environment and demonstrated the ability to detect non-cooperating aeroplanes with high precision. The system uses photonic techniques for both RF signal generation and detection, enabling the generation of extremely stable RF signals with arbitrary waveforms up to millimetre waves. The photonic-based RF generator uses a mode-locked laser to generate tunable radar signals, while the photonic-based ADC uses optical sampling to digitize the received signals without downconversion. The system's performance is characterized by high signal-to-noise ratio, low phase noise, and high timing jitter, with the photonic ADC achieving a spurious-free dynamic range of >50 dB. The system's architecture is based on a single mode-locked laser, which is used for both generating and sampling the radar signal. To avoid the problem of the sampling frequency being a multiple of the carrier frequency, one of the laser modes is shifted before heterodyning. The system's performance is further enhanced by using photonic integration techniques, which allow for the generation of arbitrary amplitude- and phase-modulated signals. The system was tested in a field-trial demonstrator, where it successfully detected non-cooperating aeroplanes with high precision. The system's ability to detect targets with a range resolution of 150 m and a velocity resolution of 2 km/h was demonstrated. The system's performance was compared with state-of-the-art electronic radar systems, and it was found to offer significant advantages in terms of frequency flexibility, signal quality, and precision. The PHODIR project has pioneered a fully photonics-based radar system, enabling the software-defined radio approach with performance exceeding that of state-of-the-art radar systems. The system's use of photonics allows for additional functionalities, such as tunable time delay for beamforming and the use of optical fibres for signal transport. The system's architecture is expected to enable future smart multifunction surveillance systems.