Abstract: This interference reduction method in a receiver (2) comprising at least two antennas (4, 6), each receiving a signal transmitted through a radio propagation channel, comprises the following steps: —weighting (20) of each of the signals received with a weighting vector associated respectively with a respective antenna of the receiver; —combination (22) of the weighted signals received to obtain a combined received signal; —weighting (24) of a reference signal with another weighting vector; —comparison (26) of the combined received signal and the weighted reference signal to obtain an error; and —determination (28) of the weighting vectors with the help of the maximum a posteriori criterion by maximizing the probability of realization of the said weighting vectors conditionally with the error obtained.

Abstract: This method for the estimation of a channel between an emitter and a receiver, where the said emitter emits a signal comprising symbol frames distributed in time and frequency, among which pilot symbols known to the receiver, is characterized in that it comprises the following steps: •—computation (30) of a covariance matrix MF and MT of the channel in the frequency and time domains respectively; •—decomposition (32) of the covariance matrices MF and MT into eigenvectors according to the relations MF?WFHNFWF and MT?WTHNTWT; •—computation (34) of the Kronecker product of the matrices NVF and WT to obtain an eigenvector matrix W; •—computation (34) of a diagonal eigenvalue matrix N equal to the Kronecker product of the eigenvalue matrices NF and NT; and •—estimation of the channel with the help of pilot symbols and matrices W and N using the maximum a posteriori or quadratic error minimisation criterion.

Abstract: This method for the estimation of a channel between an emitter and a receiver, where the said emitter emits a signal comprising symbol frames distributed in time and frequency, among which pilot symbols known to the receiver, is characterised in that it comprises the following steps: •—computation (30) of a covariance matrix MF and MT of the channel in the frequency and time domains respectively; •—decomposition (32) of the covariance matrices MF and MT into eigenvectors according to the relations MF?WFHNFWF and MT?WTHNTWT; •—computation (34) of the Kronecker product of the matrices NVF and WT to obtain an eigenvector matrix W; •—computation (34) of a diagonal eigenvalue matrix N equal to the Kronecker product of the eigenvalue matrices NF and NT; and •—estimation of the channel with the help of pilot symbols and matrices W and N using the maximum a posteriori or quadratic error minimisation criterion.

Abstract: This interference reduction method in a receiver (2) comprising at least two antennas (4, 6), each receiving a signal transmitted through a radio propagation channel, comprises the following steps:—weighting (20) of each of the signals received with a weighting vector associated respectively with a respective antenna of the receiver;—combination (22) of the weighted signals received to obtain a combined received signal;—weighting (24) of a reference signal with another weighting vector;—comparison (26) of the combined received signal and the weighted reference signal to obtain an error; and—determination (28) of the weighting vectors with the help of the maximum a posteriori criterion by maximising the probability of realisation of the said weighting vectors conditionally with the error obtained.

Abstract: To reduce interferences in signals received by a receiver through a propagation channel, each including symbols distributed according to frequency and time dimensions and corresponding to a common emitted signal, the receiver weights an estimate of the emitted signal and the received signals by weighting vectors evolving in vector subspaces representing time variations and frequency variations of the channels for propagating the signals between an emitter and the receiver. These vector subspaces are defined by matrices, some columns of which are suppressed as a function of frequency and time constraints of the channel. The receiver minimizes a function of the difference between the sum of weighted received signals and the weighted estimate of the emitted signal in order to estimate the emitted signal as a function of the weighting vectors and the received signals.

Abstract: The invention proposes a data transmission process, from a first unit (1) situated at a predetermined depth of an oil well to a second unit (2) situated at the surface of this well, the process comprising a digital-analog conversion stage (8) of the data to obtain an analog signal forming support of the data, and an amplification stage (9) of this signal prior to its emission in a cable (11) connecting the two units, characterized in that at least two distinct scramblings (20, 21) of the data are completed, such that there is a first and a second set of scrambled data. After passage in a single complex inverse Fourier transform, that intended for emission is selected (26), whereof the dynamic in amplitude is the lowest. If the probability of saturating with a single set is 10?q, then due to this process the probability will be 10?2q.

Abstract: To reduce interferences in signals received by a receiver through a propagation channel, each including symbols distributed according to frequency and time dimensions and corresponding to a common emitted signal, the receiver weights an estimate of the emitted signal and the received signals by weighting vectors evolving in vector subspaces representing time variations and frequency variations of the channels for propagating the signals between an emitter and the receiver. These vector subspaces are defined by matrices, some columns of which are suppressed as a function of frequency and time constraints of the channel. The receiver minimizes a function of the difference between the sum of weighted received signals and the weighted estimate of the emitted signal in order to estimate the emitted signal as a function of the weighting vectors and the received signals.

Abstract: The invention proposes a data transmission process, from a first unit (1) situated at a predetermined depth of an oil well to a second unit (2) situated at the surface of this well, the process comprising a digital-analog conversion stage (8) of the data to obtain an analog signal forming support of the data, and an amplification stage (9) of this signal prior to its emission in a cable (11) connecting the two units, characterised in that at least two distinct scramblings (20, 21) of the data are completed, such that there is a first and a second set of scrambled data. After passage in a single complex inverse Fourier transform, that intended for emission is selected (26), whereof the dynamic in amplitude is the lowest. If the probability of saturating with a single set is 10?q, then due to this process the probability will be 10?2q.

Abstract: According to this method for transmitting a digital signal by a base station equipped with a multi-element antenna to a mobile, in the presence of interference sources and background noise, at least one frequency transposition operator is calculated which approximately transforms one reception calibration table into one transmission or reception calibration table; statistical data are calculated on the basis of the signals received by the various elements, originating from the mobile and the interference sources; for this mobile, an optimum set of spatial weightings is calculated on the basis of the statistical data, the frequency transposition operator, and a criterion for reinforcing the useful signal and reducing the interference sources; the digital signal is weighted on the basis of the optimum set of weightings, then it is transmitted.

Abstract: The analysis of an image of the field of observation from a heat camera by bands of n lines prompts the appearance of streaks or "striping" in certain zones of the image, all these zones constituting a "striping space". The device for the implementation of the method includes means to determine a base of orthonormal functions H and V, generating a vector space of functions for which the values taken, at each point of the image, represent the luminance values of all the types of striping, means to modelize the striping exhibited by the image in determining the coefficients of distribution of this striping on the basic functions, means to synthesize the striping, in determining the luminance values of the striping from the coefficients of correlation and from the values of he basic functions, and, finally, means to substract the luminance values of the synthesized striping from the luminance values of the initial image.

Abstract: According to the method, after a step for the digital processing of the video signal of the image analyzed by rows, there is determined, for each row, on the basis of the distribution of the mean light energy values below and above each position of the row, a step modelling function, the jump position of which gives the position of the horizon in this row. The device used to implement this method includes a sampler of the video signal coupled with a flip flop memory through an accumulator which adds up the luminance values row by row, and a processor which, on the basis of the distribution of the mean light energy levels, computes the signal to be subtracted from the digital video signal by means of a subtractor. The disclosed method and device can be applied to the detection of the horizon from an image analyzed by columns or by lines.