Abstract: Ground surveillance airborne radar device, characterized in that it reproduces a mapping of STRIPMAP type of an area of interest divided into bands (101), the images of these bands being captured successively, each according to a technique of scan SAR type, the operations for processing the image of a band (101) being produced successively to the capture of the image of this band (101) and in a manner concomitant with the realization of at least one additional radar mode, before the capture of the image of the following band (101).

Abstract: Ground surveillance airborne radar device, characterized in that it reproduces a mapping of STRIPMAP type of an area of interest divided into bands (101), the images of these bands being captured successively, each according to a technique of scan SAR type, the operations for processing the image of a band (101) being produced successively to the capture of the image of this band (101) and in a manner concomitant with the realization of at least one additional radar mode, before the capture of the image of the following band (101).

Abstract: In a method for the management of the memory of a processing machine comprising several elementary computers each having a local memory, an initial quantity of memory is allocated in each computer; then a dynamic allocation and a dynamic release of objects are carried out such that the first released object is the last allocated object; an attachment/detachment of at least one remote computer is made with respect to a declared object shared by the computer that is the proprietor of the object, with a list of attachments managed by the elementary computer that is the proprietor of the shared object; a transfer is made from an object of a computer to a shared object of a remote computer; and a release of the local memory is made for each computer. A memory manager is an opaque object providing services through which the management method carries out requests to make dynamic allocations on the one hand and attachments to remote memories on the other hand.

Abstract: The present invention relates to radars and sonars, and more particularly to a synthetic-band technique of pulse compression making it possible to reach a very high distance resolution. Synthetic band consists in transmitting a waveform pattern consisting of a string of N coherent elementary pulses, linearly frequency-modulated, following one another at a recurrence frequency F.sub.r, of rectangular frequency spectra of elementary band B and of stepped carrier frequencies such that their frequency spectra will link up exactly one ahead of another to form a global spectrum of width N.times.B. On reception, the frequency spectra of the signals received in return for the N elementary pulses of a pattern are extracted by calculation, translated and juxtaposed so as to reconstruct a global frequency spectrum of width N.times.B and then compressed. Pulse compression is thus obtained which is equivalent to that which would result from the transmission of a waveform having a single pulse of frequency band N.times.

Abstract: A Deramp type radar used in synthetic aperture radar for radar imaging transmits coherently repeated linear frequency-modulated pulses and carries out a sort of pulse compression in reception by demodulation of the echo signals received by means of a frequency ramp that reproduces all or part of a transmitted pulse, and by a Fourier transform performed in range. The application to a Deramp type radar signal of a standard SAR processing is disturbed by the fact that, in this signal, the effectively demodulated part of an echo signal due to a target has a position with respect to this echo signal and a duration that are variable as a function of the distance from the target to the radar. The proposed method makes it possible to eliminate this disturbance by means of a particular choice of a common temporal support used for the demodulation of the signals of all the targets of the useful swath and a phase correction applied to the level of the pulse response of the image focusing filter of the SAR processing.

Abstract: A Deramp type radar used in synthetic aperture radar for radar imaging transmits coherently repeated linear frequency-modulated pulses and carries out a sort of pulse compression in reception by demodulation of the echo signals received by means of a frequency ramp that reproduces all or part of a transmitted pulse, and by a Fourier transform performed in range. With this type of pulse compression, a parasitic phase modulation appears on the signal delivered by a Deramp type radar. This parasitic phase modulation disturbs the standard SAR procession operations for the construction of radar images. The proposed method is used to eliminate the detrimental effects of this parasitic phase modulation on the construction of a radar image.