Abstract: This radar system comprises an emitter (3, 4, 5) for the transmission of coherent non-equidistant pulses forming a periodic pattern and being distinguished from each other by a phase modulation according to different quasi-orthogonal laws, the average interval between pulses being of the order of magnitude of the minimum duration of the flashes. For reception, the system comprises a single receiver (7) and a device (8) for coherent elimination of the clutter and echoes of the target bodies, followed by N processing channels for pulse compression (9.1 to 9.N) by correlation with the particular phase modulation laws. The outputs from the processing channels are sent to a device (11) for elimination of secondary peaks due to partial ambiguities.The invention applies to radar surveillance systems for helicopter detection.

Abstract: A device providing summarized information from the digital spectrum analyzer output within a Doppler radar. Four memories, each of 256 word capacity, are included. Each of said memories is addressed by a group of eight bits among the sixteen bits provided by the spectrum analyzer and a logic circuit reconstitutes an elementary summary plot from the contents of said four memories. For a sixteen-line spectrum analyzer it is thus possible to replace a read-only memory for 64K, seven-bit words by the aforementioned four such read-only memories each of 256, seven-bit words.

Abstract: A device for suppressing autocorrelation sidelobes in a pseudo-random coded radar system employing a phase-coded CW signal in which the phase code is preselected to have a predetermined symmetry. Autocorrelation is affected in the standard manner and also in respect to the transmitted code shifted by one bit in time. Summation of the two autocorrelation functions provides a new autocorrelation function in which the sidelobes between main correlation peaks are suppressed.