"JOURNAL OF RADIO ELECTRONICS" (Zhurnal Radioelektroniki ISSN 1684-1719, N 9, 2016

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Compression algorithm for coherent additional signals


R. N. Ipanov

FFederal Governmental Institution «Research and Production Association «Special equipment and communication»

The paper is received on September 12, 2016

Abstract. A compression algorithm for radar signals that has an area of zero sidelobes in the vicinity of the central peak of the autocorrelation function has been considered. These signals, which are called coherent additional signals, are a burst of two coherent phase-code-manipulated pulses coded by a pair of complementary sequences. The zero sidelobe area of the aucorrelation function of the coherent additional signals permits to reduce the threshold of detection of radar targets to the noise level, thus increasing the detection probability. Also, by virtue of the relatively large base these signals have high compression coefficients, which makes it possible to solve the problem of discerning targets that are closely located in space to each other and have close radial velocities as well as measuring their coordinates with high precision.

The device for compression of the coherent additional signals consists of the input register with N cells, a discrete transform processor with N inputs and two outputs, a shift register with Q·N cells and an adder, where N is the number of the elements in the complementary sequence and Q is the parameter inverse to the duty ratio. It has been shown that the block diagram of the coherent additional signal compression device is an equivalent block diagram of a matched filter, the discrete transform processor being the main element of it. The algorithm of the processor’s operation is an algorithm of fast Walsh–Hadamard transform (Haramard ordered), the signal graph of which contains complementary real weighing coefficients «‑1» from the first to the penultimate iteration. The reports of the discrete transform spectrum for computing one autocorrelation function are taken from one of the N/2 pairs of its outputs. Therefore, N/2 various autocorrelation functions can be obtained — according to the number of the different pairs of the complementary sequences N long.

The considered compression algorithm for the coherent additional signals makes it possible to achieve effective real-time solutions of the problems of discerning and measuring the coordinates of grouped targets of the radar that have close radial velocities.

Key words: burst of pulses, complementary sequences, autocorrelation function, sidelobe, signal detection threshold, radial velocity, matched filter, Walsh-Hadamard transform, signal graph, weighting coefficient.


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