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

A method for estimating a path-length difference between two paths followed by a target signal transmitted by a spacecraft or aircraft respectively to a first receiving antenna and a second receiving antenna of a receiving base, the method comprising the steps of:

• measuring a useful phase difference between signals corresponding to the target signal received respectively on the first receiving antenna and the second receiving antenna;
• estimating the path-length difference as a function of useful phase difference measurements;
• measuring the useful phase difference comprising either a correlation of the signals received respectively on the first receiving antenna and the second receiving antenna with a reference target signal, or the analysis of the signals received respectively on the first receiving antenna and the second receiving antenna using a Fast Fourier Transform (FFT) or Phase-Locked Loop (PLL);
• transmitting a calibration signal to the receiving base via a transmitting antenna;
• measuring a calibration phase difference between signals corresponding to the calibration signal received respectively on the first receiving antenna and the second receiving antenna;
• and
• compensating variations of the calibration phase difference measurements on the useful phase difference measurements.

A non-transitory computer readable medium comprising computer executable code for estimating a path-length difference between two paths followed by a target signal transmitted by a spacecraft or aircraft respectively to a first receiving antenna and a second receiving antenna of a receiving base, the code comprising instructions for a processing device to:

• measure a useful phase difference between signals corresponding to the target signal received respectively on the first receiving antenna and the second receiving antenna;
• estimate the path-length difference as a function of useful phase difference measurements;
• measure the useful phase difference comprising either a correlation of the signals received respectively on the first receiving antenna and the second receiving antenna with a reference target signal, or the analysis of the signals received respectively on the first receiving antenna and the second receiving antenna using a Fast Fourier Transform (FFT) or Phase-Locked Loop (PLL);
• transmit a calibration signal to the receiving base via a transmitting antenna;
• measuring a calibration phase difference between signals corresponding to the calibration signal received respectively on the first receiving antenna and the second receiving antenna;
• and
• compensate variations of the calibration phase difference measurements on the useful phase difference measurements.

A system for estimating a path-length difference between two paths followed by a target signal transmitted by a spacecraft or aircraft respectively to a first receiving antenna and a second receiving antenna of a receiving base of the system, comprising

• a transmitter for transmitting a calibration signal to the receiving base via a transmitting antenna,
• a processing device operable to:
• measure a useful phase difference between signals corresponding to the target signal received respectively on the first receiving antenna and the second receiving antenna by performing either a correlation of the signals received respectively on the first receiving antenna and the second receiving antenna with a reference target signal, or an analysis of the signals received respectively on the first receiving antenna and the second receiving antenna using a Fast Fourier Transform (FFT) or Phase-Locked Loop (PLL);
• estimate the path-length difference as a function of useful phase difference measurements;
• measure a calibration phase difference between signals corresponding to the calibration signal received respectively on the first receiving antenna and the second receiving antenna;
• and
• compensate variations of the calibration phase difference measurements on the useful phase difference measurements.