Abstract: The present invention relates to a method of eliminating ground echoes for a meteorological radar. The ground echoes being received from a predetermined area by a radar, the radar illuminating, for a predetermined number R of transmission recurrences, the area over a number P of distance cells, the method includes a step for calculating a spatial statistical parameter of the cluttered echoes received by the radar in response to the recurrences over an analysis path for distance cells, and a step to compare the spatial variation level of the spatial statistical parameter along the analysis path, the echoes being considered to be ground echoes when the level of said variation is greater than a predetermined threshold.

Abstract: The present invention relates to a method of eliminating ground echoes for a meteorological radar. The ground echoes being received from a predetermined area by a radar, the radar illuminating, for a predetermined number R of transmission recurrences, the area over a number P of distance cells, the method includes a step for calculating a spatial statistical parameter of the cluttered echoes received by the radar in response to the recurrences over an analysis path for distance cells, and a step to compare the spatial variation level of the spatial statistical parameter along the analysis path, the echoes being considered to be ground echoes when the level of said variation is greater than a predetermined threshold.

Abstract: A high resolution Doppler analysis of a radiofrequency signal is exemplified by the analysis of air mass movement using meteorological radar. A high resolution spectral analysis method for a remotely sampled periodic radiofrequency signal, based on the application of a trellis autoregressive filtering Burg algorithm, is used to determine the natural frequencies of the received signal for each distance cell based on the determination of an optimum set of reflection coefficients of the signal. Reflection coefficients are the object of a regularization operation aiming to limit the numerical instabilities of the calculations. These regularized reflection coefficients are used to estimate the effective order of the identification model of the trellis filter, and to determine the natural frequencies of the signal by determining the arguments of the complex roots of the polynomial representing the transfer function of the trellis filter.

Abstract: The invention relates to the general field of high resolution doppler analysis of a radiofrequency signal. It deals more particularly with the analysis of the movement of air masses by means of a meteorological radar. The subject of the invention is a high resolution spectral analysis method for a remotely sampled periodic radiofrequency signal, based on the application of a trellis autoregressive filtering Burg algorithm, which can be used to determine the natural frequencies of the received signal for each distance cell based on the determination of an optimum set of reflection coefficients N of the signal. According to the invention, the reflection coefficients are the object of a regularization operation aiming mainly to limit the numerical instabilities of the calculations.

Abstract: A coding process for the adaptive prediction differential PCM type. An error signal e.sub.t is formed between a sample of signal y.sub.t to be coded and a prediction signal p.sub.t of said signal. The prediction signal p.sub.t is formed from restored signals y.sub.t and e.sub.t by two linear filtering operations, the first relating to N successive samples of y.sub.t and using coefficients A1.sub.t, A2.sub.t, . . . , AN.sub.t and the second relating to P successive samples of e.sub.t and using coefficients B1.sub.t, B2.sub.t, . . . , BP.sub.t, the coefficients A1.sub.t, A2.sub.t, . . . , AN.sub.t and B1.sub.t, B2.sub.t, . . . , BP.sub.t being sequentially adjusted at each time t so that the mean power of error signal e.sub.t is minimal. Instead of carrying out the prediction on the basis of signals y.sub.t and e.sub.t only according to the invention, use is also made of the real signal y.sub.t and the real error e.sub.t. A linear filtering of y.sub.t using the coefficients A1.sub.t, A2.sub.t, . . . , AN.sub.