RU2807614C1 - Method for forming weighting coefficient in conditions of non-stationary interference conditions - Google Patents

Abstract

FIELD: radar.

SUBSTANCE: invention can be used in radar receiving devices for processing radar radio signals for protection against continuous active noise interference (CAI) coming from directions other than the directions of arrival of useful signals against the background of rapid changes in the interference environment. The specified technical result is achieved by the fact that in the method of compensation for CAI of radars, based on the reception of radio signals by the main and additional channels, during setting the parameters of the automatic interference compensator (AIC), which ensures the subtraction of signals received from the direction to the source of interference, the settings of the parameters of the automatic compensator are changed through the use of an algorithm of linear interpolation of the adjustment of weighting coefficients (WC), which takes into account the scanning of the radar antenna pattern or the spatial movement of the interference source over the viewing period.

EFFECT: compensation for active noise interference when the auto-compensator operates in conditions of a non-stationary interference environment associated with scanning the radiation pattern of the radar antenna, or the movement of the jammer in space during the review period.

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Description

Active noise interference creates great problems in the operation of radars for detecting air targets [1]. Let us consider the situation when the side lobes of the radiation pattern of the main channels are acted upon by one ANC director fixed in space, whose signals have stationary Gaussian distributions. In the all-round viewing mode, due to the rotation of the phased array radar, the angular positions of the ACP sources change over time. The jammer can also move during the review period.

The movement in space of the jammer, as well as radar surveillance objects, associated with the dynamics of their movement or the movement of the locator on a moving object can be characterized as one of the main factors in the non-stationary nature of the signal-interference situation. Non-stationarity can also be caused by the radar review mode, since during the review process the angular relationships between the antenna beam and the jammer, and, consequently, the angular position of the zeros of the radiation pattern relative to the maximum of the main lobe change. This means that nonstationarity is associated with the effect of mismatch between the parameters of the ACP weighting coefficients and the spatial position of the antenna radiation pattern and the interference source. This leads to a gradual deterioration of the ACP compensation procedure due to the inconsistency (obsolescence) of the VC, so they must be periodically updated (recalculated). Regular, frequent recalculation of weight coefficients is not always acceptable from the point of view of practical implementation, and entails the loss of useful information, which leads to losses in detection and deterioration in the quality of inter-period processing.

The closest method to the proposed one is known for compensating for active noise interference [2]. The ACP signals (Fig. 1), received by the digital antenna array 1, are supplied to the DOS of the main receiving channel 2 and the DOS of the compensation receiving channels 3. ACP compensation is carried out in the main channel and is a procedure for subtracting 6 weighted signals of the compensation channels from the main channel. In this case, the weighting sum is an estimate of the value of active interference in a given channel, the process of obtaining which is carried out in three stages. At the first stage, the ACP correlation matrix is estimated. At the second stage, the method of direct matrix inversion is applied. The estimate of the matrix VK 4 is calculated in accordance with the Wiener-Hopf solution [2]. At the third stage, the resulting vector of active interference 5 in the main channel is estimated and subtracted from the process in this channel.

The disadvantage of the known method is that when the angular movements of the interference source change with respect to the radar during the review period, the ANC compensation deteriorates and the remainder of the uncompensated interference increases.

The device closest to the proposed one is known [SU 1809401 A1], containing (Fig. 2) a reference signal generator 1, a subtraction unit 2, a noise analysis unit 3 including a quadrator 14, a division unit 15, an M-clock delay unit 16, a second subtraction unit 18, threshold device 19, multi-bit key 20, matrix adder 21, accumulating adder 17, read-only memory 22. The device also includes a unit for generating matrix transfer coefficients of the Kalmon filter 4, a scalar product generation unit 5, a summation unit 6, a delay unit 7 , block for generating extrapolation assessment 8.

However, the known device increases the stability of the adaptive formation of weighting coefficients when operating in a non-stationary interference environment associated with the inclusion of additional sources of interference or a change in their intensity. At the same time, this device does not take into account the nonstationarity associated with the spatial movement of the interference source during the review period.

For long-range radars, setting the autocompensator parameters during the review period is usually carried out either at the end of the working distance or at the beginning of the working distance before radiation. In this case, the VCs are calculated and stored in the memory device. This adjustment procedure ensures minimal fluctuations in the VC estimate, but has poor stability in the event of a discrepancy between the real and calculated VC estimates over time.

For short-range radars, the autocompensator parameters are adjusted in special service azimuthal zones within the general azimuthal pack, where no radiation occurs, and work is carried out only for reception. The duration of such a service zone is several probing cycles. In this way, setting the parameters of the auto-compensator, the ANC cannot be compensated to the level of its own noise of the main receiving channel due to the rapid scanning of the radar antenna pattern or the movement of the jammer in space during the working area.

The reason for the ineffective operation of the autocompensator in long- and short-range radars is the failure to update the VC (non-compliance with the VC) taking into account the change in the interference environment and, as a consequence, the low suppression coefficient of the automatic transmission.

Thus, the technical problem being solved (technical result) is the compensation of ANC due to scanning of the radiation pattern of the radar antenna or movement of the jammer in space during the review period.

The technical result is achieved by the fact that in the known ACP auto-compensation device with direct inversion of the interference correlation matrix, an algorithm for linear interpolation of weight coefficients is used, which makes it possible to reduce the influence of the VC aging effect and increase the operating efficiency of such an ACP.

The invention is illustrated in Fig. 3. To implement the claimed method of forming a weight coefficient in conditions of non-stationary interference conditions, the radar must contain a phased antenna array 1, a beamforming system (DOS) of the main receiving channel 2, a DOS of compensating receiving channels 3, an automatic transmission unit, which includes a block for calculating weight coefficients 4, delay line 5, linear interpolation block of weighting coefficients 6, multiplier 7, subtraction block 8.

Let us consider the feasibility of the claimed method. The ACP signals received by the phased antenna array 1 are supplied to the DOS of the main receiving channel 2 and the DOS of the compensating receiving channels 3. The amplified ACP signals are supplied to the first input of the ACP (directly to the input of the weighting coefficient calculation unit 4), implemented in software and operating according to the matrix inversion algorithm and direct calculation of the vector of weighting coefficients. The implementation of this algorithm requires only knowledge of the correlation matrix of interference in the compensation receiving channels and the cross-correlation matrix of interference in the main and compensation channels. They are, as a rule, unknown a priori, but from the available time sample of noise it is possible to obtain their maximum likelihood estimates. The estimate of the vector of weighting coefficients is calculated in block 6.

In the block of linear interpolation of weight coefficients 6, the influence of the effect of VC aging is reduced and the efficiency of the automatic transmission is increased due to the algorithm for linear interpolation of tuning coefficients [4-6], which works as follows:

1. For long-range radars, in the first period of operation of the radar, the VCs are configured and memorized. Then the useful signal is emitted and received, and subsequently all range readings are stored. Then, in the second period of radar operation, the next adjustment and memorization of the VK occurs. To compensate for ACP in the first period of radar operation, it is necessary to subtract the VC calculated in the first period from the VC calculated in the second period. To do this, a delay line VK 5 is introduced. Divide the resulting difference VK by the total number of range readings and obtain the so-called weight addition. To form new weight coefficients, it is necessary to add the product of the weight additive and the current range reference number to the VC calculated in the first period.

2. For short-range radars in the first service zone, the VCs are configured and stored. In the service zone, the radar does not transmit, but only receives; the duration of the service zone is several periods of pulse probing. The useful signal is emitted and received in the first working zone. In the working area of the radar, probing pulses are emitted, the VC is not adjusted, the duration of the working area is tens of pulse probing periods. Next, in the second service area, the next configuration and memorization of the VC takes place. To do this, delay line 5 is introduced. The difference in VC is calculated. The resulting VC difference must be multiplied by the number of adjustment readings for the first half working zone and added to the VC until the middle of the working area, and after the middle of the working area, multiply by the next adjustment readings for the second half working area in the reverse order and add to the weight coefficient of the second service zone. Thus, in order to compensate for interference in the first working zone, it is necessary to adjust the VC in the second working zone.

Multiplier 7 calculates the interference impact estimate. In the subtraction block 8, the estimate is subtracted from the interference in the main channel, which is formed as a function of the interference values in the compensation channels.

Thus, the problem of ANC compensation is solved when the auto-compensator operates in a non-stationary interference environment associated with scanning the radiation pattern of the radar antenna or moving the jammer in space during the review period.

BIBLIOGRAPHY

[1] Radio interference protection, ed. M.V. Maksimova, M. Sov. Radio, 1976, p. 496.

[2] Monzingo R.A., Miller T.W. Adaptive antenna arrays: Introduction to theory. M.: Radio and communication, 1986. 448 p.

[3] A.s. SU 1809401 A1 USSR, MKI G01S 7/36 / Device for forming weight coefficients in non-stationary noise conditions / A.A. Adamenko, V.A. Doroshchuk, V.I. Shandrik, Yu.M. Nail (USSR). - No. 4902005/09; application 01/11/91; published 04/15/93, Bulletin. No. 14 - 6 p.

[4] Fitasov E.S., Nasonov V.V., Guseva Yu.S., Kozlov S.A. On the issue of assessing the efficiency of the auto-compensator for active noise interference during spatial movement of the jammer // Radio engineering and telecommunication systems. 2019 No. 2 (34). P.21-29.

[5] Kozlov S.A., Fitasov E.S., Vasilenko E.V., Nasonov V.V. Increasing the efficiency of automatic compensation of noise active interference in short-range radar stations // Bulletin of the Almaz-Antey Air Defense Concern No. 1(9), JSC Almaz-Antey Air Defense Concern, 2013. pp. 45-48.

[6] Nasonov V.V., Zhuravlev I.V., Fitasov E.S. Increasing the efficiency of the autocompensator with direct inversion of the correlation matrix of interference during spatial movement of the jammer // Bulletin of the Yaroslavl Anti-Aircraft Missile Institute of Air Defense: collection. scientific works / YAZRI Air Defense - Yaroslavl, 2003. - Issue. 5. - p. 90-101.

Claims (2)

1. A method for forming a weighting coefficient in conditions of non-stationary interference conditions, based on adjusting the parameters of the auto-compensator with direct inversion of the interference correlation matrix, implementing the subtraction of signals received from the direction of the interference source, characterized in that before the next period of review of a long-range radar station, the auto-compensator implements the procedure for linear interpolation of weight coefficients, which consists in setting and storing weight coefficients in the first review period, the useful signal is emitted and received in the first review period, then in the second review period the next adjustment and storage of weight coefficients occurs, the difference in weight coefficients is calculated from the obtained values and divided the total number of range readings calculated is multiplied by the value of the current range reading number, the resulting product is added to the weighting coefficients of the first review period, after which interference in the first review period is compensated. 2. A method for forming a weighting coefficient in conditions of non-stationary interference conditions, based on adjusting the parameters of the auto-compensator with direct inversion of the interference correlation matrix, ensuring the subtraction of signals received from the direction of the interference source, characterized in that before the next period of review of a short-range radar station, a procedure is implemented in the auto-compensator linear interpolation of weight coefficients, which consists in setting and storing weight coefficients in the first service zone, the useful signal is emitted and received in the first working zone, then in the second service zone the next setting and storing of weight coefficients occurs, the difference in weight coefficients is calculated from the obtained values and multiplied by the number of adjustment readings for the first half of the working area is added to the weight coefficients of the first service area until the middle of the working area, and after the middle of the working area, multiplied by the following adjustment counts for the second half of the working area in the reverse order and added to the weighting coefficients of the second service area.

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