RU-1841395-C - Method for creating relay interference for semi-active SAM systems

Abstract

FIELD: technique of creating interference. SUBSTANCE: invention relates to the technique of creating interference and, in particular, to methods of disrupting the target selection by speed by the homing head (HH) of semi-active anti-aircraft guided missiles (SAMs). The claimed method of creating a relay interference for a semi-active SAM complex using speed selection is based on the removal of the speed gate of the homing head. The retransmitted signal is split into two channels at a high frequency, one of which is used to generate a narrow-band noise interference and a grid of Doppler frequencies, while the other is used to periodically shift the frequencies of the received signal and sum them before emission. EFFECT: technical result is to ensure that the tracking system of the HH by speed is removed from the search range and that the tracking system of the HH by speed is transferred to search after the interference is turned off. 1 cl, 4 dwg

Inventors

• Yudin Leonid Mikhajlovich
• VOLKOV LEV VASILEVICH
• Ishkarin Anatolij Borisovich
• Altman Iosif Yakovlevich

Assignees

• Акционерное общество "Центральный научно-исследовательский радиотехнический институт имени академика А.И. Берга"

Dates

Publication Date

20260506

Application Date

19710604

Claims (1)

1. A method for creating retransmission interference for semi-active SAM systems using speed selection based on the drift of the homing head speed strobe, characterized in that, in order to overcome the channel for compensating for the drift of the homing head speed strobe in the radar circuit illumination, the retransmitted signal is split at high frequency into two channels, in one of which a narrow-band noise drift and a Doppler frequency grid are alternately formed, and in the other a periodic frequency shift of the received signal is carried out and summed before emission.

Description

The invention relates to jamming technology and, in particular, to methods for disrupting target selection based on the speed of the homing head of semi-active SAM guidance systems. Several methods are known for disrupting the target selection by speed of the seeker of semi-active SAM systems. The most widely used is velocity-based jamming, which involves smoothly increasing or decreasing the frequency of the re-emitted signal from the target illumination radar (TIR) according to a specific pattern relative to the frequency of the signal reflected from the target. When the frequency mismatch reaches a certain value, the jamming frequency very quickly matches the frequency of the signal reflected from the target. When the jamming signal's energy exceeds that of the target's signal, the speed tracking system switches to tracking the jamming signal. This results in a speed mismatch between the tracking system and the target signal. Furthermore, a narrowband masking noise jammer, whose spectrum is symmetrical to the target signal, is used to disrupt the seeker's speed selection. The drawback of these jamming methods is that currently, semi-active missile guidance systems employ methods to protect the velocity channel from the effects of such jamming, rendering them ineffective. For example, the compensatory protection method renders the effect of diverting velocity jamming ineffective (USTENKO I.M., PhD thesis, 1968). Another well-known protection method allows the seeker to track the maximum spectrum of narrowband noise interference. Since both of these methods are used for protection, the effectiveness of diverting and narrowband masking noise jamming is very low. This is because such jamming cannot cause interruptions in the flow of information into the angular-measuring channel long enough to reduce the probability of defeating the jammer. The presence of such protection also renders ineffective a number of combined and redirecting jamming techniques, which require prior disruption of the selection process. The purpose of the present invention was to develop a method for creating interference on the seeker speed channel which, despite the above-described measures to protect the seeker from interference, would allow the seeker speed tracking system to be moved outside the search range and would cause the seeker speed tracking system to switch to search after the interference is turned off. According to the invention, this objective is achieved by smoothly shifting the peak of the narrowband noise interference spectrum relative to the target's Doppler frequency by a certain amount, after which the interference signal is turned off, and after a certain period of time, a new interference cycle begins. If the interference duration was sufficient to ensure the required misalignment of the velocity tracking strobe with the target signal (greater than the search range), then turning off the interference for a sufficient period of time will cause a loss of guidance. When the interference is turned off, the tracking system switches to a velocity search to improve the jamming efficiency. After the narrowband noise interference has been applied, a Doppler frequency grid is formed in the region of the noise interference spectrum peak, shifting in the same direction as the peak of the noise interference spectrum. If frequency hopping is enabled in the seeker during the transition to search, the velocity tracking filter will alternately re-acquire one of the spectral components of the Doppler frequency grid with each hop. Therefore, when switching to the search mode, the mismatch increases each time by the frequency spacing between the components of the Doppler frequency grid. The distance between the spectral components of the Doppler frequency grid must be less than the velocity bounce of the seeker tracking system. To increase the frequency mismatch between the seeker's tracking system and the target signal or to reduce the time required to achieve a specified mismatch, a small-range velocity-deviating interference can be simultaneously enabled at the target's Doppler frequency while simultaneously activating the Doppler frequency grid (shifting in the same direction as the noise interference spectrum peak). In this case, compensation will account for these short-term deviations and cause the seeker's tracking system to switch to search mode, leading to the tracking system's successive acquisition of increasingly distant frequency components of the Doppler frequency grid spectrum. Subsequently, disabling the interference triggers the tracking system to switch to search mode. The proposed method of creating interference is shown schematically in the figures, where: Fig. 1 shows graphs illustrating the behavior of the speed tracking systems (homing head and target tracking system) when exposed to diverting, narrowband noise, and diverting noise interference: F per is the carrier frequency of the RPD transmitter; F c is t