JPS63165784A - Apparatus for suppressing generation of unnecessary wave - Google Patents

Abstract

PURPOSE:To stably continue the tracking of a target, by estimating the position of the target and unnecessary wave arriving direction at the time of the next tracking of the target from the memory data of a history data memory part and controlling an adaptation control loop on the basis of the estimation result. CONSTITUTION:The signal received by each antenna element 1 is detected through a receiving and amplifying part 2 and subsequently converted to a digital signal by an A/D converter 4 to be distributed to each of a plurality of beam forming operation parts 6 by a distributor 5. The signal operated by each of the operation parts 6 having beam formed thereto is guided to a signal processing part 7 to perform the measurement of a mono-pulse. When an unnecessary wave is present, adaptation control is performed by the adaptation control loop of an adaptation control part 8 so as to minimize the unnecessary wave component of the output signal of the operation part 6. From the present and past data of a target and data of an unnecessary wave arriving direction stored in a memory 9, the position of the target at the time of the next tracking of the target is estimated by an estimation operation part 10 and the estimation result is given to the control part 8. Therefore, when the next tracking of the target is started, a beam shape almost becomes the optimum shape and the stable tracking of the target can be continued.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an unnecessary wave suppression device in a target tracking radar device using a digital beam forming method.

(Prior art) In an electronic warfare environment, it is extremely important for radar equipment that tracks aerial targets to suppress or eliminate unnecessary waves such as jamming waves and clutter, and to continue stable target tracking. It is. Conventionally, methods for controlling the beam shape, that is, the side lobe pattern and the pointing direction of the null, have been devised for such purposes. However, in the so-called phased array system, which performs signal synthesis and beam formation in the high frequency section or intermediate frequency section, it is difficult to sufficiently suppress unnecessary waves due to the following limitations.

(1) The number of control bits of the phase shifter for controlling the phase is small, and only rough control is possible.

(2) Since signal synthesis is performed by a power combiner, the amplitude weighting coefficient cannot be changed.

On the other hand, there is a digital beam forming method which is a more superior method, and with the rapid progress of digital technology in recent years, the feasibility of using hardware is increasing. In this digital beam forming method, an A/D converter with high precision and high speed operation has been realized, and by using this, the received signal is not only converted into a digital signal with high precision, but also processed by digital calculation. Since arbitrary weighting coefficients can be given to both the phase and amplitude components of the received signal, the beam shape can be controlled arbitrarily, and it is possible to obtain a sufficient suppression effect on unnecessary waves. . Therefore, in order to suppress unnecessary waves and continue target tracking, the output signal of each antenna and the combined output signal are monitored, and the phase and amplitude weighting coefficients are optimized to minimize the influence of unnecessary waves. Adaptive control has been devised to control the beam shape. However, in such adaptive control, depending on the correlation between the beam shape at the initial stage of target tracking and the direction of arrival of unwanted waves, the S/N ratio of the target signal deteriorates, and the convergence time of the adaptive control loop decreases. As a result, there is a problem that target tracking cannot be continued in the worst case.

(Problems to be Solved by the Invention) As described above, when suppressing unnecessary waves by adaptive control in a conventional digital beam forming type target tracking radar device, the correlation between the initial beam shape and the direction of arrival of the unnecessary waves is Depending on the relationship, target tracking may not continue.

This invention was made to improve the above problem.
Excellent suppression effect on unnecessary waves such as interference waves and clutter,
It is an object of the present invention to provide an unnecessary wave suppression device that can stably continue target tracking.

[Structure of the Invention] (Means for Solving the Problems) That is, the unnecessary wave suppression device according to the present invention separately detects each received signal of a plurality of antenna elements constituting an array antenna and converts it into a digital signal. It is used in a target tracking radar device that converts and processes each digital signal in parallel to form a plurality of simultaneous and independent reception beams, and generates target position data at the time of target tracking from the pattern of each reception beam. The parallel 'a'! based on the pattern of each receive beam! In the apparatus for suppressing unnecessary waves in each of the received signals by forming an adaptive control loop that controls J processing, the plurality of received beams have an optimal beam shape, and the present and past target tracking points are a history data storage unit that stores the target position data, a prediction calculation unit that predicts and calculates the target position and direction of arrival of unwanted waves at the time of next target tracking from the data stored in the history data storage unit; and this prediction calculation unit and an adjusting means for controlling the adaptive control loop based on the calculation result to adjust the initial beam shape during target tracking.

(Function) The unnecessary wave suppression device having the above configuration stores target position data and unnecessary wave arrival direction data during current and past target tracking in the history data storage unit, and uses the stored data to determine the target position during the next target tracking. and predict the arrival direction of unwanted waves,
By controlling the adaptive control loop based on this prediction result, the receiving beam is adjusted to an optimal shape at the time of target tracking.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

The drawing shows its configuration, in which the part surrounded by a dashed line shows the part added according to the present invention, and the other parts show parts related to digital beam forming and adaptive control.

That is, 1 is a large number of antenna elements constituting an array antenna, and the signal received by each antenna element 1 passes through a reception amplification section 2 installed separately for each antenna element 1, and then is sent to a detector 3. After being detected by A/
It is converted into a digital signal by the D converter 4 (usually!
A/D conversion is performed on each of the signal and the Q signal, but it is shown here in a simplified manner). The A/D converter 4 is one that operates with high precision and high speed, and converts each amplitude and phase component of the received signal into a digital signal with high precision. Digital signals from each A/D converter 4 are distributed to a plurality of beam forming calculation units 6 by a signal distribution circuit 5, respectively. These beam forming calculation units 6 perform the following calculations to form a beam.

n=1 SO; Output signal N: Number of antenna elements Sn: Received signal for each antenna element (digital coded signal) An: Amplitude weighting coefficient φn: Phase weighting coefficient Here, 5n of the right side of equation (1) -An -ejφ
0 is An and φ using a digital multiplication circuit (not shown).
It can be calculated by specifying n, and Σ can be calculated by a digital adder (not shown). In other words, different An,
By specifying φn, separate beams can be formed simultaneously. For example, by forming a sum signal Σ and difference signals ΔAZ and ΔEL by each of the three beam forming calculation units 6 and guiding them to the corresponding signal processing unit 7, monopulse measurement or the like can be performed.

Therefore, the adaptive control unit 8 determines the optimum An.

An adaptive control loop that specifies φn is constructed, and the received signal of each antenna probe 1, that is, the output digital signal of each A/D converter 4 and the output signal of each beam forming calculation unit 6, and the output signal of each signal processing unit 7 is configured. The output signal is monitored, and if unnecessary waves are present, adaptive control is performed using an adaptive control loop so that the unnecessary wave component of the output signal of each beam forming calculation section 6 is minimized.

Here, if only the above portion is used, the above-mentioned problem may occur depending on the correlation between the beam shape and the direction of arrival of unwanted waves.

Therefore, by applying the present invention, a configuration surrounded by a dashed line in the figure is added to eliminate this problem.

In the figure, reference numeral 9 denotes a history data storage unit that stores and stores data on the direction of arrival of unwanted waves obtained from the target position data obtained from each signal processing unit 7 and the convergence value of the adaptive control loop by the adaptive control unit 8. It is something to do. Reference numeral 10 denotes a prediction calculation unit which requests and introduces the current and past data stored in the history data storage unit 9, and predicts the target position and direction of arrival of unwanted waves at the time of next target tracking.

This prediction is performed, for example, by predicting the target position after the next sample time based on the target trajectory derived from past data. The prediction results obtained here are given to each adaptive control section 8.

That is, from the current and past target position data and unnecessary wave arrival direction data stored in the historical data storage section 9,
The prediction calculation unit 10 predicts the target position and unwanted wave arrival direction at the time of the next target tracking, and provides the results to each adaptive control unit 8, so that the beam shape is close to the optimal shape at the start of the next target tracking. Become.

Therefore, by using the unnecessary wave suppression device configured as described above, it is possible to continue stable target tracking without reducing the S/N ratio of the target signal and shortening the convergence time of the adaptive control loop for unnecessary waves. I can do it.

Note that the storage capacity of the history data storage section 9 is sufficient to store data from the current and several past target tracking times.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide an unnecessary wave suppression device that has an excellent suppressing effect on unnecessary waves such as interference waves and clutter, and is capable of stably continuing target tracking. .

[Brief explanation of the drawing]

The drawing is a block circuit diagram showing an embodiment of an unnecessary wave suppression device according to the present invention. ■...Antenna element, 2...Reception amplification section, 3...
Detector, 4... A/D converter, 5... Signal distribution circuit, 6... Beam forming calculation section, 7... Signal processing section, 8
...adaptive control unit, 9...history data storage unit, ■0.
...Prediction calculation section.

Claims (1)

[Claims] Each received signal from the antenna elements that make up the array antenna is detected separately and converted into a digital signal, and each digital signal is processed in parallel to form multiple simultaneous and independent receive beams. The plurality of reception beams is used in a target tracking device that generates target position data at the time of target tracking from a pattern, and forms an adaptive control loop that controls the parallel processing based on the pattern of each of the reception beams. In the unnecessary wave suppression device that suppresses unnecessary waves in each of the received signals by making the beam shape optimal, the target position data is stored for current and past target tracking times, and the adaptive control loop converges. a history data storage unit that stores arrival direction data of unwanted waves obtained from the data; and a prediction calculation unit that predicts and calculates the target position and arrival direction of unnecessary waves at the time of next target tracking from the data stored in the history data storage unit. and an adjustment means for controlling the adaptive control loop based on the calculation result of the prediction calculation unit to adjust the initial beam shape during target tracking.