KR101007892B1 - Missile warning radar system - Google Patents

Abstract

PURPOSE: A missile warning radar system is provided to rapidly respond to threatened situations by previously generating warning. CONSTITUTION: A first mixer(105) adds the frequency of a pulse through a transmitter and the radio frequency(RF) generated from a first oscillator. A second mixer(110) subtracts the RF participated to the upward conversion of a transmission signal from the frequency of a signal through a low noise amplifier. A third miser(112) subtracts the second intermediate frequency participated in the upward conversion of the transmission signal from the frequency of a signal through an intermediate frequency amplifier. A signal converter(113) converts the intermediate frequency signal through the third mixer into a digital intermediate frequency signal. The digital signal is inputted to a digital signal processor(114) and verifies whether target is threatened based on a signal processing algorithm.

Description

Missile warning radar system

The present invention relates to a radar system, and more particularly, to a missile warning radar system capable of determining whether a target is directed to a radar based on radar detection information and generating a threat alarm.

The penetration of antitank missiles, rockets, artillery and other antitank weapons has increased significantly. In particular, anti-tank missiles have a high power generation speed, which greatly increases the penetration force, and in the case of the guidance method, is developed into a forgetful method after firing with a unique searcher installation from the conventional line of sight guidance method.

Common missile-detection radars detect missiles that attack traps or aircraft, and radars that detect missiles that attack ground weapon systems are rare.

In the detection of the target by the ground weapon system radar as described above, the target signal is very small and the ground clutter is very large so that the azimuth change is severe, thus determining whether the target is coming to me or heading to the adjacent weapon system. Algorithm implementation is very difficult. In addition, since the target signal is 20-30 dB lower than the noise level, various methods are needed to overcome this.

The present invention has been made in consideration of the above matters, and an object of the present invention is to provide a missile warning radar system capable of determining whether a target is directed to a radar based on radar detection information and generating a threat alarm.

Missile warning radar system according to the present invention for achieving the above object,

A first oscillator for generating an RF frequency f ₃ for up-conversion of the transmitted signal and down-conversion of the received signal;

A second oscillator for generating a second intermediate frequency f ₂ for upconverting the transmitted signal and downconverting the received signal;

A first intermediate frequency of the second intermediate frequency (f ₂₎ the first intermediate frequency (f ₁₎ and the synthesized frequencies generated by the second oscillator generating a pulse, and in (f ₁₎ of the transmission signal (f ₁ a waveform generator for outputting a pulse of + f ₂ );

A transmitter which receives the pulse output from the waveform generator and preprocesses the shape and frequency of the pulse for upconversion;

Frequency of the pulses passed through the transmitter (f ₁ + f ₂₎ and in addition the RF frequency (f ₃₎ produced by the first oscillator, the high frequency _{(f 1 + f 2 + f} 3) of claim 1, which up-conversion to the signal of the mixer;

A high frequency power amplifier for amplifying the high frequency pulse signal passing through the first mixer to a high output and transmitting the same through a transmitting antenna;

A low noise amplifier for low noise amplifying a high frequency f ₁ + f ₂ + f ₃ + f _d mixed signal received through a receiving antenna;

A second mixer subtracting an RF frequency f ₃ involved in upconversion of the transmission signal at a frequency f ₁ + f ₂ + f ₃ + f _{d of the} signal passing through the low noise amplifier;

An intermediate frequency amplifier for amplifying an intermediate frequency (f ₁ + f ₂ + f _d ) signal passed through the second mixer;

A third mixer subtracting and subconverting the second intermediate frequency f ₂ involved in the upconversion of the transmission signal at the frequency f ₁ + f ₂ + f _{d of the} signal passing through the intermediate frequency amplifier;

A signal converter for converting the intermediate frequency signal (analog signal) passed through the third mixer into a digital intermediate frequency signal; And

It is characterized in that it comprises a digital signal processor for receiving a digital signal converted by the signal converter to perform a predetermined signal processing algorithm to determine whether the target threat.

Here, the signal converter includes an analog-to-digital (A / D) converter for converting an analog intermediate frequency signal into a digital intermediate frequency signal, and a digital intermediate frequency signal converted by the A / D converter down to a digital baseband signal. It may include a digital down converter (DDC) to convert.

In addition, the signal processing algorithm performed by the digital signal processor,

When the digital baseband signal is input through the DDC, windowing is performed by multiplying the baseband signal by weight to reduce the influence of a signal such as clutter, thereby making five bursts of data. module;

A doppler filter bank (DFB) processing module performing fast fourier transformation (FFT) on five bursts generated by the windowing module to calculate power values for five distance cells and Doppler (speed) cells;

A constant false alarm rate (CFAR) module for detecting a signal passing through a threshold value determined to be a constant false alarm rate from a noise level among the signals input through the DFB processing module;

A post-detection module for receiving a signal passing through the CFAR module and recognizing a case where three or more bursts passing the CFAR level are targeted among the five bursts generated by the windowing module;

An azimuth estimation module for calculating azimuth angles using values of a plurality of channels (I, Q) for signals passing through a CFAR level of the CFAR module; And

TTI (time to impact) calculated by azimuth calculated by the azimuth estimation module with respect to a target passing through the post-detection module, velocity and distance in Doppler and distance cells of the DFB processing module, velocity and distance It includes a threat determination module for determining whether the threat to the target using.

Preferably, the transmitting antenna and the receiving antenna have a structure in which a transmitting antenna is disposed at a central portion thereof, and receiving antennas are arranged at right and left sides of the transmitting antenna so as to form an angle of 45 ° with the transmitting antenna, respectively.

According to the present invention, a threat alert can be generated early by determining whether the target is aimed at the radar based on the detection information of the radar, thereby determining the threat, and thus the radar system operator can quickly respond to the threat situation. There is an advantage to this.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing the configuration of a missile warning radar system according to the present invention.

Referring to FIG. 1, the missile warning radar system according to the present invention includes a first oscillator 101, a second oscillator 102, a waveform generator 103, a transmitter 104, a first mixer 105, and a high frequency power amplifier. 106, transmit antenna 107, receive antenna 108, low noise amplifier 109, second mixer 110, intermediate frequency amplifier 111, third mixer 112, signal converter 113, digital A signal processor 114.

The first oscillator 101 generates an RF frequency f ₃ for upconverting the transmitted signal and downconverting the received signal.

The second oscillator 102 generates a second intermediate frequency f ₂ for upconverting the transmitted signal and downconverting the received signal.

The waveform generator 103 generates a pulse of a first intermediate frequency f ₁ for the transmission signal, and converts the second intermediate frequency f ₂ generated by the second oscillator 102 into the first intermediate frequency F ₂ . f ₁ ) and the pulse of the combined frequency (f ₁ + f ₂ ) are output.

The transmitter 104 receives the pulse output from the waveform generator 103 and preprocesses the shape and frequency of the pulse for upconversion.

The first mixer 105 adds the frequency f ₁ + f ₂ of the pulse passed through the transmitter 104 and the RF frequency f ₃ generated by the first oscillator 101 to add a high frequency f ₁ +. up-converts to the signal f ₂ + f ₃ ).

The high frequency power amplifier 106 amplifies the high frequency pulse signal passed through the first mixer 105 to a high output and transmits the same through the transmitting antenna 107. As such a high frequency power amplifier 106, a solid state power amplifier (SSPA) may be used.

The low noise amplifier 109 low noise amplifies the high frequency (f ₁ + f ₂ + f ₃ + f _d ) mixed signal received through the receiving antenna 108. Here, the frequency f _d means the frequency of the signal reflected back from the target.

The second mixer 110 subtracts the RF frequency f ₃ involved in upconversion of the transmission signal at the frequency f ₁ + f ₂ + f ₃ + f _{d of the} signal passing through the low noise amplifier 109. Down-convert

The intermediate frequency amplifier 111 amplifies the intermediate frequency (f ₁ + f ₂ + f _d ) signal passed through the second mixer.

The third mixer 112 subtracts the second intermediate frequency f ₂ involved in the upconversion of the transmission signal at the frequency f ₁ + f ₂ + f _{d of the} signal passing through the intermediate frequency amplifier 111. Down-convert

The signal converter 113 converts the intermediate frequency signal (analog signal) passed through the third mixer 112 into a digital intermediate frequency signal.

The digital signal processor 114 receives the digital signal converted by the signal converter 113 and performs a predetermined signal processing algorithm to determine whether the target is threatened.

Here, the signal converter 113 is an analog-to-digital (A / D) converter 113a for converting an analog intermediate frequency signal into a digital intermediate frequency signal, and the digital intermediate converted by the A / D converter 113a. And a digital down converter (DDC) 113b for downconverting the frequency signal into a digital baseband signal.

In addition, the signal processing algorithm executed by the digital signal processor 114 is composed of modules 114a to 114f as a plurality of unit programs that perform respective specific functions as one software program.

When the windowing module 114a receives a digital baseband signal via the DDC 113b, the windowing module 114a multiplies the baseband signal by a weight to reduce the influence of a signal such as a clutter. FIGS. 2 and 3 As shown in Fig. 5, the data is made up of five bursts of data (1024 data).

The doppler filter bank (DFB) processing module 114b performs fast fourier transformation (FFT) on the five bursts produced by the windowing module 114a to generate power values for each of the five distance cells and the Doppler (speed) cells. Calculate

The constant false alarm rate (CFAR) module 114c detects a signal that passes a threshold determined from the noise level to be a constant false alarm rate among the signals input through the DFB processing module 114b.

The post-detection module 114d receives a signal passing through the CFAR module 114c and has three or more bursts that have passed the CFAR level among the five bursts produced by the windowing module 114a. Recognize as a target.

The azimuth estimation module 114e calculates an azimuth using values of a plurality of channels (channels 1 and 2; see FIG. 6) for signals passing through the CFAR level of the CFAR module 114c.

The threat determination module 114f is configured to calculate the azimuth angle calculated by the azimuth estimation module 114e with respect to the target passing through the post-detection module 114d, the Doppler cell and the distance cell of the DFB processing module 114b. Speed and distance, time to impact (TTI) calculated by speed and distance are used to determine if a target is threatened.

In addition, preferably, as shown in FIG. 4, the transmitting antenna 107 and the receiving antenna 108 have a transmitting antenna 107 disposed at the center thereof, and a transmitting antenna 107 disposed at the left and right sides of the transmitting antenna 107. ) And the receiving antennas 108 are respectively arranged to form an angle of 45 °.

On the other hand, Figure 5 is a view showing a state composed of four units the missile warning radar system of the present invention having the configuration as described above.

Referring to Figure 5, the missile warning radar system of the present invention is configured with four LRU (Line Replacement Unit) to increase the utilization of the mounting space and easy troubleshooting. That is, it is composed of two antenna units 510 and 520, a transceiver / signal processor 530, and a power supply 540.

The antenna units 510 and 520 include an antenna assembly and receiving front ends 511 and 521. The length of the cable between the reception front ends 511 and 521 and the reception rear end 535 may be considerably increased by a cable loss of about 3 m. Accordingly, the reception front ends 511 and 521 are preferably located in the antenna parts 510 and 520 to minimize the noise figure of the receiver.

As described above (refer to FIG. 4), the antenna units 510 and 520 are each composed of one transmitting antenna 107 and two receiving antennas 108, and the receiving antennas 108 are formed around the transmitting antennas 107. The left and right are disposed at 45 degrees, and the receiving antennas 108 are arranged to form 90 degrees. Accordingly, when the single pole double throw (SPDT) 532 is connected to the left antenna unit 510, the left pole 90 ° is covered with respect to the front side. ° can be detected.

The transceiver unit of the transceiver / signal processing unit 530 performs high power amplification of the radar transmission signal of the L-band frequency band generated by up-conversion and transmits it through the transmission antenna 107, and the signal received through the reception antenna 108. After the two-stage super heterodyne method of down-conversion and demodulation is applied, the signal is transmitted to the signal processor 536. The transmitter / receiver includes a transmitter 104, a frequency synthesizer 534 (corresponding to the first oscillator 101, the second oscillator 102, and the waveform generator 103 in FIG. 1), the reception front ends 511, 521, and reception. The rear end 535 is configured for each of the detailed modules of the high frequency power amplifier 106. The SPDT 532 is a switch having one input terminal and two output terminals. The SPDT 532 is a switch for connecting signals to the left and right antenna units.

The signal received by the receiving antenna 108 passes through the limiters of the receiving front end portions 511 and 521, and is then amplified by the low noise amplifier 109 (see FIG. 1) and transmitted to the receiving rear end 535. The low noise amplifier 109 The low noise amplified signal is transformed down into an intermediate frequency signal, and this signal (analog signal) is converted into a digital signal by the A / D converter 113a again. The converted signal is demodulated to an I / Q signal by the DDC (Digital Down Converter) 113b.

The frequency synthesizer 534 multiplies and divides using a frequency generated from an Oven-Controlled Crystal Oscillator (OCXO) as a reference frequency. The frequency for synchronizing the entire radar system is 40 MHz, the reference clock is 10 MHz, and the second oscillator 102 uses 5 MHz.

The signal processing unit 536 (corresponding to the signal converter 113 and the digital signal processor 114 in FIG. 1) transmits a 5 MHz intermediate frequency signal from the receiving side at a sampling rate of 20 MHz by the A / D converter 113a. The signal is converted into a digital signal, and the digital signal is down-converted from the DDC 113b to the baseband signal. This will be described in more detail with reference to FIG. 6.

6 is a view showing a signal processing procedure in the signal processor of the missile warning radar system of the present invention.

Referring to FIG. 6, the A / D converter 113a of the signal converter 113 converts an analog intermediate frequency signal into a digital intermediate frequency signal, and the DDC 113b converts the digital intermediate frequency signal back into a digital baseband signal. Convert and demodulate into I / Q signals.

The windowing module 114a then multiplies the received baseband signal by its weight to reduce the effects of very large signals, such as clutter, into five bursts of 1024 data, as shown in FIGS.

The DFB processing module 114b then performs fast fourier transformation (FFT) on these five bursts to calculate power values for each of the five distance cells and the Doppler (speed) cells. That is, the complex FFT 601 of the DFB processing module 114b calculates the baseband signal as the power values of the distance cell and the Doppler (speed) cell, and the magnitude calculator 602 receives the signal. Calculate the size of for all cells.

The CFAR module 114c receives the output signal from the DFB processing module 114b and passes the threshold value V _th according to the threshold value V _th determined to be a constant false alarm rate from the noise level. Detect. That is, the CFAR module 114c determines the threshold value, calculates the threshold value V _th multiplied by the determined threshold value k and compares the threshold value V _th with the value V of the current cell, thereby A signal whose value V is greater than the threshold value V _th is detected and transmitted to the post-detection module 114d.

The post-detection module 114d recognizes as a target when there are three or more bursts that pass the CFAR level among the five bursts. That is, the post-detection module 114d uses the 3/5 interconnection unit 603 therein for velocity data for signals passing three or more CFAR levels out of five bursts to determine whether it is a threat. In the interpolation unit, the distance data is transmitted to the threat detection module 114f after performing interpolation (finding the optimal distance value) in the interpolation unit.

Meanwhile, the azimuth estimation module 114e calculates an azimuth using the values of channels 1 and 2 with respect to the signals passing through the CFAR level. That is, the azimuth estimation module 114e calculates a power ratio from the signals of channels 1 and 2 calculated by the DFB processing module 114b to obtain an azimuth, and uses the azimuth angle from the first detected data to the currently detected azimuth. Poly fitting, and averages the three recent azimuth angles and transmits the data to the threat determination module 114f.

The threat determination module 114f calculates the TTI (time calculated by the azimuth of the azimuth estimation module 114e, the speed in the Doppler cell, the distance in the distance cell, the speed and distance with respect to the target passing through the post-detection module 114d. to impact) to track and determine the threat against the target. At this time, the threat determination module 114f calculates the TTI using the speed and the distance, calculates the threat using the azimuth, and determines whether the threat is using the TTI calculation and the threat calculation data.

Then, the target information (distance, speed, azimuth, TTI, threat presence) obtained by the above process is transmitted to a control system (not shown) and displayed on the display.

As described above, the missile warning radar system according to the present invention may generate a threat warning early by determining whether the target is directed to the radar based on the detection information of the radar, thereby determining the threat. It has the advantage of being able to respond quickly to threat situations.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Accordingly, the true scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of the same should be construed as being included in the scope of the present invention.

1 is a view showing the configuration of a missile warning radar system according to the present invention.

2 is a view showing a frame configuration window of the DFB processing module in the missile warning radar system according to the present invention;

3 is a view showing a frame structure of a post-detection module in the missile warning radar system according to the present invention.

Figure 4 is a view showing the arrangement of the transmitting antenna and the receiving antenna of the missile warning radar system according to the present invention.

5 is a view showing a state in which the missile warning radar system according to the present invention is composed of four units.

6 is a view showing a signal processing in the signal processing unit of the missile warning radar system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

101: first oscillator 102: second oscillator

103: waveform generator 104: transmitter

105: first mixer 106: high frequency power amplifier

107: transmit antenna 108: receive antenna

109: low noise amplifier 110: second mixer

111: intermediate frequency amplifier 112: third mixer

113: signal converter 114: digital signal processor

113a: A / D converter 113b: digital down converter (DDC)

114a: windowing module 114b: Doppler filter bank (DFB) processing module

114c: constant false alarm rate (CFAR) module 114d: post-detection module

114e: Azimuth estimation module 114f: Threat determination module

Claims (7)

A first oscillator for generating an RF frequency f ₃ for up-conversion of the transmitted signal and down-conversion of the received signal; A second oscillator for generating a second intermediate frequency f ₂ for upconverting the transmitted signal and downconverting the received signal; A first intermediate frequency of the second intermediate frequency (f ₂₎ the first intermediate frequency (f ₁₎ and the synthesized frequencies generated by the second oscillator generating a pulse, and in (f ₁₎ of the transmission signal (f ₁ a waveform generator for outputting a pulse of + f ₂ ); A transmitter which receives the pulse output from the waveform generator and preprocesses the shape and frequency of the pulse for upconversion; Frequency of the pulses passed through the transmitter (f ₁ + f ₂₎ and in addition the RF frequency (f ₃₎ produced by the first oscillator, the high frequency _{(f 1 + f 2 + f} 3) of claim 1, which up-conversion to the signal of the mixer; A high frequency power amplifier for amplifying a high frequency pulse signal passing through the first mixer and transmitting the same through a transmitting antenna; A low noise amplifier for low noise amplifying a high frequency f ₁ + f ₂ + f ₃ + f _d mixed signal received through a receiving antenna; A second mixer subtracting an RF frequency f ₃ involved in upconversion of the transmission signal at a frequency f ₁ + f ₂ + f ₃ + f _{d of the} signal passing through the low noise amplifier; An intermediate frequency amplifier for amplifying an intermediate frequency (f ₁ + f ₂ + f _d ) signal passed through the second mixer; A third mixer subtracting and subconverting the second intermediate frequency f ₂ involved in the upconversion of the transmission signal at the frequency f ₁ + f ₂ + f _{d of the} signal passing through the intermediate frequency amplifier; A signal converter for converting the intermediate frequency signal (analog signal) passed through the third mixer into a digital intermediate frequency signal; And And a digital signal processor that receives the digital signal converted by the signal converter and performs a predetermined signal processing algorithm to determine whether or not the target is threatened. The method of claim 1, The signal converter includes an analog-to-digital (A / D) converter for converting an analog intermediate frequency signal into a digital intermediate frequency signal, and a down converter for converting the digital intermediate frequency signal converted by the A / D converter into a digital baseband signal. A missile warning radar system comprising a digital down converter (DDC). The method of claim 2, The signal processing algorithm performed by the digital signal processor, When the digital baseband signal is input through the DDC, windowing is performed by multiplying the baseband signal by weight to reduce the influence of a signal such as clutter, thereby making five bursts of data. module; A doppler filter bank (DFB) processing module performing fast fourier transformation (FFT) on five bursts generated by the windowing module to calculate power values for five distance cells and Doppler (speed) cells; A constant false alarm rate (CFAR) module for detecting a signal passing through a threshold value determined to be a constant false alarm rate from a noise level among the signals input through the DFB processing module; A post-detection module for receiving a signal passing through the CFAR module and recognizing a case where three or more bursts passing the CFAR level are targeted among the five bursts generated by the windowing module; An azimuth estimation module for calculating azimuth angles using values of a plurality of channels (I, Q) for signals passing through a CFAR level of the CFAR module; And TTI (time to impact) calculated by azimuth calculated by the azimuth estimation module with respect to a target passing through the post-detection module, velocity and distance in Doppler and distance cells of the DFB processing module, velocity and distance The missile warning radar system, characterized in that it comprises a threat whether to determine whether the threat to the target using a module. The method of claim 3, The post-detection module transmits velocity data for signals passing more than three CFAR levels out of five bursts by an internal 3/5 correlation to the threat determination module, and distance data is interpolated. Missile warning radar system, characterized in that for performing the interpolation (finding the optimal distance value) in the interpolation unit, and then transmits to the threat determination module. The method of claim 3, The azimuth estimation module obtains an azimuth angle by calculating a power ratio from the signals of channels 1 and 2 calculated by the DFB processing module, and converts the azimuth angle using the first detected data from the currently detected azimuth angle, Missile warning radar system, characterized in that for transmitting the average of the three azimuth angle to the threat determination module. The method of claim 3, The threat detection module is a missile warning radar system, characterized in that for calculating the TTI using the speed and distance, calculate the threat using the azimuth, using the TTI calculation and threat calculation data. The method of claim 1, The transmitting antenna and the receiving antenna is a missile warning radar system, characterized in that the transmission antenna is disposed in the center, and the receiving antenna is arranged so as to form an angle of 45 ° with each of the transmission antenna on the left and right sides of the transmission antenna, respectively.

Images