Airbus Defence and Space Sas

Centre National Detudes Spatiales

Jean-Marc Aymes

Frederic Voulouzan

Raphael Sanchez

Sébastien Mazuel

Antoine Poulet

Frédéric Voulouzan

Raphaël Sanchez

A method for estimating a direction of a satellite in the transfer phase. The direction of the satellite is estimated relative to a measurement antenna by executing steps for measuring the reception power, by the measurement antenna, of a target signal emitted by the satellite, for different pointing directions of the measurement antenna. The target signal has a substantially sinusoidal component referred to as a single-frequency component. Each power measurement step includes a transposition in the frequency domain of a digital signal, obtained from a signal supplied by the measurement antenna, to obtain a frequency spectrum of the digital signal over a predetermined frequency band having the single-frequency component. The power measurement for the pointing direction being considered is determined based on a maximum value of the frequency spectrum.

Method and system for estimating the direction of a satellite in the transfer phase from an initial orbit to a mission orbit

Disclosed is a method () for monitoring a phase for transferring a satellite () from one earth orbit, called 'initial orbit', to another earth orbit, called 'mission orbit', in particular a transfer using electric propulsion unit. The monitoring method includes a step for estimating the direction of the satellite during the transfer phase by way of an earth array antenna () including a plurality of elementary antennas (), each elementary antenna having a primary radiation lobe with a width greater than or equal to 20&#xb0;, the elementary antennas () being oriented such that their respective fields of vision overlap, the direction of the satellite being estimated based on at least one useful phase difference measurement between signals corresponding to a target signal, transmitted by the satellite and received on a pair of elementary antennas ().

Method and system for monitoring a phase for transferring a satellite from an initial orbit to a mission orbit

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.

Method and system for estimating the direction of arrival of a target signal relative to a satellite

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.

Method and system for estimating a path-length difference of a target signal transmitted by a spacecraft or aircraft

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.

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Saint Orens de Gameville, France

Jean-Marc Aymes