Abstract: A transmitter device of a bi-static or multi-static radar system is disclosed and implemented for aerial surveillance. The transmitter device is intended to be on board a satellite orbiting the Earth. Once in orbit, the transmitter device is configured to obtain information relating to a region of interest monitored by at least one receiver device of the radar system, and to transmit a signal in a radio beam illuminating at least one portion of the region of interest.

Abstract: A transmitter device of a bi-static or multi-static radar system is disclosed and implemented for aerial surveillance. The transmitter device is intended to be on board a satellite orbiting the Earth. Once in orbit, the transmitter device is configured to obtain information relating to a region of interest monitored by at least one receiver device of the radar system, and to transmit a signal in a radio beam illuminating at least one portion of the region of interest.

Abstract: A payload of a satellite to measure a positioning system of an earth-based transmitter of a target signal received by a main satellite. A direct receiver of the payload is configured to measure the target signal directly received from the earth-based transmitter. An indirect receiver of the payload is configured to measure the target signal retransmitted by the main satellite. A transmitter of the payload is configured to transmit, to an earth-based station of the positioning system, (i) a group of signals, referred to as homologous signals, measured by the direct receiver and the indirect receiver, and/or (ii) data determined based on the homologous signals. The homologous signals correspond to the target signal received from the earth-based transmitter and the main satellite, respectively. A positioning system and method are also provided herein.

Abstract: A method and system for estimating a direction of arrival of a target signal relative to a measuring antenna array of an earth-orbiting satellite. The direction of arrival of the target signal being estimated on the basis of measurement signals corresponding to the target signal received respectively by at least a first measuring antenna and a second measuring antenna of the measuring antenna array. Each of the measurement signals are combined with a reference signal corresponding to the target signal received by a receiving antenna of the satellite. The receiving antenna has a maximum gain greater than the respective maximum gains of the first measuring antenna and of the second measuring antenna. The direction of arrival of the target signal is estimated from the signals obtained by combining the measurement signals with the reference signal.

Abstract: A method and system for estimating a path-length difference between two paths followed by a target signal transmitted by a spacecraft or aircraft to a first receiving antenna and a second receiving antenna of a receiving base, respectively. A useful-phase difference is measured between signals that correspond to the target signal received by the first receiving antenna and second receiving antenna. The path-length difference is estimated in accordance with the useful-phase difference measurements. The measurement of the useful-phase difference comprises either correlating the signals received by the first receiving antenna and second receiving antenna, respectively, with a reference target signal, or analyzing the signals received by the first receiving antenna and second receiving antenna, respectively, using an FFT or a PLL.

Abstract: A method and system for estimating a direction of arrival of a target signal relative to a measuring antenna array of an earth-orbiting satellite. The direction of arrival of the target signal being estimated on the basis of measurement signals corresponding to the target signal received respectively by at least a first measuring antenna and a second measuring antenna of the measuring antenna array. Each of the measurement signals are combined with a reference signal corresponding to the target signal received by a receiving antenna of the satellite. The receiving antenna has a maximum gain greater than the respective maximum gains of the first measuring antenna and of the second measuring antenna. The direction of arrival of the target signal is estimated from the signals obtained by combining the measurement signals with the reference signal.

Abstract: A method and system for estimating a path difference between two paths followed by a target signal transmitted by a spacecraft or aircraft to a first receiving antenna and a second receiving antenna of a receiving base, respectively. A useful-phase difference is measured between signals corresponding to the target signal received on the first receiving antenna and second receiving antenna. The path difference is estimated on the basis of the measurements of the useful-phase difference. A calibration signal is transmitted to the receiving base and a calibration phase difference between signals corresponding to the calibration signal received on the first receiving antenna and second receiving antenna is measured. Variations are compensated in the measurements of the calibration-phase difference relative to the measurements of the useful-phase difference.

Abstract: A method and system for estimating a path-length difference between two paths followed by a target signal transmitted by a spacecraft or aircraft to a first receiving antenna and a second receiving antenna of a receiving base, respectively. A useful-phase difference is measured between signals that correspond to the target signal received by the first receiving antenna and second receiving antenna. The path-length difference is estimated in accordance with the useful-phase difference measurements. The measurement of the useful-phase difference comprises either correlating the signals received by the first receiving antenna and second receiving antenna, respectively, with a reference target signal, or analyzing the signals received by the first receiving antenna and second receiving antenna, respectively, using an FFT or a PLL.

Abstract: A method and system for estimating a path difference between two paths followed by a target signal transmitted by a spacecraft or aircraft to a first receiving antenna and a second receiving antenna of a receiving base, respectively. A useful-phase difference is measured between signals corresponding to the target signal received on the first receiving antenna and second receiving antenna. The path difference is estimated on the basis of the measurements of the useful-phase difference. A calibration signal is transmitted to the receiving base and a calibration phase difference between signals corresponding to the calibration signal received on the first receiving antenna and second receiving antenna is measured. Variations are compensated in the measurements of the calibration-phase difference relative to the measurements of the useful-phase difference.