Influence of Probing Pulse Duration on the Operation of Interference-Proof Range Discriminator

Introduction. The operation of a radar system of automatic range tracking (ATR), equipped with a moving target selector (MTS) for the purpose of increasing assessment accuracy, under conditions of intensive passive interference in the form of reflections from the Earth's surface is considered. The level of such passive interference can significantly exceed useful signals. Range tracking by the ATR system is carried out by a pair of tracking half-strobes, which receive weakly correlated signals from different parts of the Earth's surface during each probing of the space. This reduces the efficiency of the MTS system and increases the error of range measurement.
Aim. To study the correlation properties of passive interference in the modes of search and automatic tracking of moving targets by the ATR system depending on probing pulse duration and target velocity. To determine the efficiency of the MTS system as part of the ATR system when exposed to correlated interference. To evaluate the effect of probing pulse duration and target velocity on the passive interference suppression coefficient and range discriminator operation when the ATR system operates in the search and automatic tracking modes.
Materials and methods. The method of correlation analysis of statistical properties of signals and devices for their processing was used.
Results. We derived an expression for the correlation function of signal fluctuations reflected by a homogeneous Earth's surface, taking into account probing pulse duration and target velocity as applied to pulse Doppler radars. The results of calculating the passive interference suppression coefficient by means of the MTS as part of an interference-proof range discriminator for various values of probing pulse duration and target velocity are presented. It is shown that a decrease in probing pulse duration, as well as an increase in target velocity, leads to a significant decrease in the passive interference suppression coefficient and an increase in the dispersion of the interference signal at the output of the range discriminator of the ATR system. Thus, when the target velocity interval is τ = 0.2 s, the target velocity is νp = 500 km/h, and the probing pulse duration varies from 1 to 0.1 μs, the correlation coefficient of the inter-period fluctuations of the passive interference r_м (nT ) decreases from 0.83 to 0.67, resulting in a decrease in the suppression coefficient of the passive interference by the MTS system.

Conclusion. The results obtained can be used when designing pulse Doppler radars using interference-proof systems for measuring the parameters of moving targets.

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