KR100949951B1 - Radar for being equipped to weapon system on the ground and method for suppressing frequency interference between adjacent radars using the same radar - Google Patents

Abstract

PURPOSE: A radar for being equipped to weapon system on the ground and a method for suppressing frequency interference between adjacent radars using the same radar are provided to prevent fundamentally the frequency Interference between radars by processing a signal by receiving the coded signal in the pulse phase coding scheme and decoding the received signal. CONSTITUTION: A pseudo noise code generator(301) codes a transmitted signal, and generates a code corresponding to the specific phase of the transmission signal. A frequency synthesizer(302) generates an RF frequency for the up-converting of the transmission signal and an intermediate frequency for the down-conversion of the received signal. A transmitter(303) changes the transmission signal into the radio frequency signal. A phase shifter(304) is inputted with the PN code and the radio frequency signal. The phase of the radio frequency signal is varied according to the PN code. A digital signal processor(309) implements the signal processing algorithm through the restored signal. A target is detected.

Description

Radar for ground weapon system mounting and method for suppressing frequency interference between radars {Radar for being equipped to weapon system on the ground and method for suppressing frequency interference between adjacent radars using the same radar}

The present invention relates to a radar for mounting a terrestrial weapon system, and more particularly, by introducing a method of encrypting and transmitting a transmission signal from a radar mounted on the terrestrial weapon system and decoding a received signal. The present invention relates to a radar for mounting a ground weapon system that can be excluded, and a method for suppressing frequency interference between radars using the same.

In general, no interference between adjacent radars occurs because the radar operation is not performed at a short distance. However, radars mounted on ground weapon systems operate within a few tens of meters, resulting in frequency interference and thermal noise interference.

In order to suppress the frequency interference of adjacent channels that occur when terrestrial weapon systems equipped with the same radar are operated at a short distance, the interference is conventionally performed by a shaping filter to attenuate the signal level of the adjacent channels in hardware. Was suppressed. However, this method uses the saturation region of the high output amplifier, which causes a problem that the signal levels of adjacent channels rise again. Therefore, this method using the shaping filter is not suitable as a way to suppress the frequency interference of the adjacent channel.

In addition, the radar initially designed 13 channels, 5MHz frequency channel, and 500kHz channel bandwidth in order to exclude frequency interference of the channel. In order to avoid interference, the power at the position 5MHz away from the center frequency satisfies -110dBc or less than the channel power as shown in FIG. shall.

However, due to the characteristics of high-power amplifiers, the power in adjacent channels 5MHz apart is -50dBc. This characteristic causes channel interference to other adjacent radars, and such interference causes deterioration of detection performance and false alarms.

As an experimental example, if the interfering radar is transmitted 50m away on channel n + 1 and the radar is received on channel n, as shown in FIG. 2, multiple false targets are received even when there is no target signal. Interference occurred.

The present invention was created to solve the problems of the inter-radar frequency interference suppression method in the conventional terrestrial weapon system as described above, by introducing a method of encrypting and transmitting the transmission signal, and decoding the received signal, the inter-radar frequency interference The purpose of the present invention is to provide a ground weapon system mounting radar capable of excluding the source of the radar and a method for suppressing frequency interference between radars using the same.

In order to achieve the above object, the ground weapon system mounting radar according to the first embodiment of the present invention,

A pseudo random (PN) code generator for generating a code corresponding to a specific phase of the transmission signal to encode and transmit a signal transmitted through the transmission antenna;

A frequency synthesizer for generating a radio frequency (RF) frequency for up-converting the transmitted signal and an intermediate frequency for down-converting a signal received through a receiving antenna;

A transmitter which receives the RF frequency generated by the frequency synthesizer and upconverts the frequency of the transmission signal to convert the transmission signal into an RF signal;

A phase shifter which receives a PN code generated by the PN code generator and an RF signal converted by the transmitter, and changes a phase of the RF signal according to the PN code;

A solid state power amplifier (SSPA) for amplifying the phase-changed RF signal to a high output via the phase shifter;

A low noise amplifier (LNA) for low noise amplifying a signal received through a receive antenna;

A receiver which receives the intermediate frequency generated by the frequency synthesizer and down-converts the frequency of the low noise amplified signal to the intermediate frequency by the LNA;

An analog-to-digital (A / D) converter for converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of an intermediate frequency; And

The digital signal of the intermediate frequency converted by the A / D converter is input, and the frequency of the signal is down-converted to baseband, and the phase of the input signal is synchronized with a phase corresponding to the code generated by the PN code generator. It is characterized in that it comprises a digital signal processor for decoding an input signal and performing a predetermined signal processing algorithm using the recovered signal to detect a target.

Here, the PN code generator generates a code at 0 for zero phase and 1 for 180 ° of the transmission signal.

In addition, the phase shifter changes the phase of the RF signal to 0 ° if the PN code is 0 and 180 ° to 1.

In addition, the radar for mounting a ground weapon system according to a second embodiment of the present invention to achieve the above object,

A pseudo random (PN) code generator for generating a code corresponding to a specific phase of the transmission signal in order to encode and transmit a signal transmitted through the transmission antenna;

A frequency synthesizer for generating an intermediate frequency f ₂ for transmit and receive signals in the radar and an RF frequency f ₃ for the transmit signal;

A direct digital synthesizer (DDS) for receiving a PN code from the PN code generator and an intermediate frequency f ₂ from the frequency synthesizer and generating a fundamental frequency f ₁ for a transmission signal;

Final RF signal f ₁ + f ₂ for transmission in the radar using the fundamental frequency f ₁ generated by the DDS, the intermediate frequency f ₂ and the RF frequency f ₃ generated by the frequency synthesizer a transmitter for generating + f ₃ );

A solid state power amplifier (SSPA) that amplifies the final RF signal f ₁ + f ₂ + f ₃ generated by the transmitter to a high output;

A low noise amplifier (LNA) for low noise amplifying a signal received through a receive antenna;

A receiver which receives an intermediate frequency f ₂ generated by the frequency synthesizer and down-converts the frequency of the signal low-amplified by the LNA to an intermediate frequency;

An analog-to-digital (A / D) converter for converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of an intermediate frequency; And

The digital signal of the intermediate frequency converted by the A / D converter is input, and the frequency of the signal is down-converted to baseband, and the phase of the input signal is synchronized with a phase corresponding to the code generated by the PN code generator. It is characterized in that it comprises a digital signal processor for decoding an input signal and performing a predetermined signal processing algorithm using the recovered signal to detect a target.

In addition, the radar frequency interference suppression method using the ground weapon system mounting radar according to the first embodiment of the present invention to achieve the above object,

a) generating a code corresponding to a specific phase of a corresponding transmission signal by a pseudo random (PN) code generator to encode and transmit a signal transmitted through a transmission antenna;

b) generating, by a frequency synthesizer, an RF frequency for up-converting the transmitted signal and an intermediate frequency for down-converting the signal received through a receiving antenna;

c) receiving an RF frequency generated by the frequency synthesizer by a transmitter and upconverting the frequency of the transmission signal to convert the transmission signal into an RF signal;

d) receiving a PN code generated by the PN code generator and an RF signal converted by the transmitter by a phase shifter and changing a phase of the RF signal according to the PN code;

e) receiving a phase shifted RF signal by a solid state power amplifier (SSPA) through the phase shifter and amplifying the RF signal to a high output and transmitting the same through a transmitting antenna;

f) low noise amplifying a signal received through the receiving antenna by a low noise amplifier (LNA);

g) receiving an intermediate frequency generated by the frequency synthesizer by a receiver and down converting a frequency of a signal low amplified by the LNA into an intermediate frequency;

h) converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of intermediate frequency by an A / D converter; And

i) A digital signal of the intermediate frequency converted by the A / D converter is input by a digital signal processor, and the frequency of the signal is down-converted to the base band, and the phase of the input signal is generated by the PN code generator. And decoding the input signal in synchronization with a phase corresponding to the step of detecting the target by performing a predetermined signal processing algorithm using the restored signal.

Here, the signal processing algorithm of step i),

Windowing module as unit software program, doppler filter bank (DFB) processing module, constant false alarm rate (CFAR) module, azimuth estimation module, 3/5 detection module, threat detection and tracking module,

III-1) by the windowing module, multiplying the baseband signals inputted through a plurality of channels (channels A and B) by weight to produce five burst data;

III-2) calculating a power value for each of five distance cells and Doppler (speed) cells by performing a fast fourier transformation (FFT) on the five bursts produced by the windowing module by the DFB processing module;

III-3) receiving a signal processed by the DFB processing module by the CFAR module and detecting a signal passing the threshold value among the signals according to a threshold value determined to be a constant false alarm rate from a noise level;

III-4) calculating azimuth angles using signals of a plurality of channels (channels A and B) by the azimuth estimation module with respect to the signals passing through the CFAR level of the CFAR module;

III-5) Recognizing, by the 3/5 detection module, a case where there are three or more bursts passing the CFAR level among the five bursts created by the windowing module; And

III-6) the azimuth calculated by the azimuth estimation module by the threat status and tracking module for the target passing through the 3/5 detection module, the velocity and distance in the Doppler and distance cells of the DFB processing module, Determining the threat and tracking the target using a time to impact (TTI) calculated by speed and distance.

Here, after the above step III-6),

III-7) The method may further include transferring the acquired target information (distance, speed, azimuth, TTI, threat status, etc.) to the controller of the radar system by the target information module and displaying it on the display.

In addition, the radar frequency interference suppression method using a ground weapon system mounting radar according to a second embodiment of the present invention to achieve the above object,

a) generating a code corresponding to a specific phase of a corresponding transmission signal by a pseudo random (PN) code generator to encode and transmit a signal transmitted through a transmission antenna;

b) generating by the frequency synthesizer an intermediate frequency f ₂ for transmit and receive signals in the radar and an RF frequency f ₃ for the transmit signal;

c) receiving a PN code from the PN code generator and an intermediate frequency f ₂ from the frequency synthesizer by a direct digital synthesizer (DDS) to generate a fundamental frequency f ₁ for a transmission signal;

d) a final RF signal for transmission in the radar by the transmitter using the fundamental frequency f ₁ generated by the DDS and the intermediate frequency f ₂ and RF frequency f ₃ generated by the frequency synthesizer ( f ₁ + f ₂ + f ₃ );

e) receiving the final RF signal (f ₁ + f ₂ + f ₃ ) generated by the transmitter by a solid state power amplifier (SSPA) and amplifying the signal to a high output and transmitting the same through a transmitting antenna;

f) low noise amplifying a signal received through the receive antenna by a low noise amplifier (LNA);

g) receiving an intermediate frequency f ₂ generated by the frequency synthesizer by a receiver and down converting the frequency of the signal low amplified by the LNA into an intermediate frequency;

h) converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of intermediate frequency by an A / D converter; And

i) A digital signal of the intermediate frequency converted by the A / D converter is input by a digital signal processor, and the frequency of the signal is down-converted to the base band, and the phase of the input signal is generated by the PN code generator. And decoding the input signal in synchronization with a phase corresponding to the step of detecting the target by performing a predetermined signal processing algorithm using the restored signal.

According to the present invention, in the transmission and reception of signals in a radar, a pulse phase coding method is applied to encrypt and transmit a transmitted signal, and a signal is processed by a method of decoding a received signal, thereby causing frequency (channel) interference between radars. Can be prevented.

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

3 is a view schematically showing the system configuration of the radar for mounting the ground weapon system according to the first embodiment of the present invention.

Referring to FIG. 3, a radar for mounting a terrestrial weapon system according to a first embodiment of the present invention includes a pseudo random (PN) code generator 301, a frequency synthesizer 302, a transmitter 303, and a phase shifter. 304, solid state power amplifier (SSPA) 305, low noise amplifier (LNA) 306, receiver 307, analog-to-digital (A / D) converter 308, digital signal processor digital signal processor) 309.

The PN code generator 301 generates a code corresponding to a specific phase (eg, 0 °, 180 °) of a transmission signal in order to encode and transmit a signal transmitted through the transmission antenna 310. . The PN code generator 301 generates a code at 0 for zero phase and 1 for 180 ° of the transmission signal.

The frequency synthesizer 302 generates an RF frequency for upconverting the transmitted signal and an intermediate frequency for downconverting the signal received through the receiving antenna 311.

The transmitter 303 receives the RF frequency generated by the frequency synthesizer 302 and up-converts the frequency of the transmission signal to convert the transmission signal into an RF signal.

The phase shifter 304 receives the PN code generated by the PN code generator 301 and the RF signal converted by the transmitter 303 and changes the phase of the RF signal according to the PN code. This phase shifter 304 changes the phase of the RF signal to 0 ° if the PN code is 0 and 180 ° to 1.

The SSPA 305 amplifies the phase-changed RF signal to a high output via the phase shifter 304.

The LNA 306 low noise amplifies the signal received through the receive antenna 311.

The receiver 307 receives the intermediate frequency generated by the frequency synthesizer 302 and down-converts the frequency of the low noise amplified signal by the LNA 306 to the intermediate frequency.

The A / D converter 308 converts the signal (analog signal) converted to the intermediate frequency by the receiver 307 into a digital signal of the intermediate frequency.

The digital signal processor 309 receives the digital signal of the intermediate frequency converted by the A / D converter 308 and down-converts the frequency of the signal to baseband, and converts the phase of the received signal into the PN code generator ( A signal is decoded in synchronization with a phase corresponding to a code generated by 301, and a target is detected by performing a predetermined signal processing algorithm using the reconstructed signal. The digital signal processor 309 receives a digital signal of an intermediate frequency converted by the A / D converter 308 and converts the frequency into baseband through a digital down conversion (DDC) function. Down-convert

In the above configuration, the phase shifter 304 should be installed at the final stage of the transmitter 303 if possible to maximize the suppression performance for all signals except for the transmitted and received signals. That is, the leakage signal generated inside the radar system may also be treated as an interference signal and converted into noise. A control signal for arbitrarily controlling the phase of the phase shifter 304 is generated using the PN code generator 301.

PN code generator 301 is composed of a total of 16 taps, as shown in FIG. Therefore, the code repetition period is 2 ¹⁶ = 65536. The coefficient of each tap is set by software (signal processing algorithm) of the digital signal processor 309, and codes are generated differently according to this value. As shown in Fig. 5, at the start of the scan, the tap coefficients are loaded into the D-flip-flop to generate a constant code for each scan.

In addition, the signal processing algorithm performed by the digital signal processor 309 will be described in more detail.

6 is a view showing the module configuration of the signal processing algorithm employed in the digital signal processor of the ground weapon system mounting radar according to the present invention.

Referring to FIG. 6, the signal processing algorithm executed by the digital signal processor 309 is a kind of software program and includes a plurality of modules (unit software programs) 401a to 406 as follows.

The windowing module 401a, 401b, when the baseband signal is input through a plurality of channels (channels A, B), the baseband signal to reduce the effect of a very large signal, such as clutter Is multiplied by the weight, resulting in five bursts of 1024 data, as shown in FIG.

Doppler filter bank (DFB) processing modules 402a and 402b perform fast fourier transformation (FFT) on the five bursts produced by the windowing modules 401a and 401b, thereby providing five distance cells and Doppler (speed) cells. Calculate the power value.

The constant false alarm rate (CFAR) module 403 detects a signal that passes a threshold determined from the noise level to a constant false alarm rate among the signals input through the DFB processing modules 402a and 402b.

The azimuth estimation module 404 calculates an azimuth using the values of a plurality of channels (channels A and B) for signals passing through the CFAR level of the CFAR module 403.

The three-fifth detection module 405 recognizes as a target a case where there are three or more bursts passing the CFAR level among the five bursts created by the windowing modules 401a and 401b.

The threat status and tracking module 406 includes the azimuth calculated by the azimuth estimation module 404 with respect to the target passing through the 3/5 detection module 405, the Doppler cells of the DFB processing modules 402a, 402b and Tracking and threats to targets are determined using time and impact (TTI), which is calculated from speed and distance, speed and distance in the distance cell.

Preferably, the apparatus further includes a target information module 407 which transmits the acquired target information (distance, speed, azimuth, TTI, threat status, etc.) to a controller (not shown) of the radar system and displays it in the display.

FIG. 8 is a diagram schematically illustrating a system configuration of a radar for mounting a ground weapon system according to a second embodiment of the present invention.

Referring to FIG. 8, a radar for mounting a terrestrial weapon system according to a second embodiment of the present invention may include a PN code generator 601, a frequency synthesizer 602, a direct digital synthesizer (DDS) 603, a transmitter 604, SSPA 605, LNA 606, receiver 607, A / D converter 608, digital signal processor 609.

The PN code generator 601 generates a code corresponding to a specific phase of the transmission signal in order to encrypt and transmit a signal transmitted through the transmission antenna 610. In this case, the PN code generator 601 uses a code of 0 (zero) for phase 0 ° and 1 for 180 °, similarly to the PN code generator 301 of the first embodiment of FIG. Create

The frequency synthesizer 602 generates an intermediate frequency f ₂ for transmit and receive signals in the radar and an RF frequency f ₃ for the transmit signal.

The DDS 603 receives a PN code from the PN code generator 601 and an intermediate frequency f ₂ from the frequency synthesizer 602 to generate a fundamental frequency f ₁ for a transmission signal.

The transmitter 604 uses a fundamental frequency f ₁ generated by the DDS 603 and an intermediate frequency f ₂ and an RF frequency f ₃ generated by the frequency synthesizer 602 in the radar. Generate the final RF signal f ₁ + f ₂ + f ₃ for transmission.

The SSPA 605 amplifies the final RF signal f ₁ + f ₂ + f ₃ generated by the transmitter 604 to a high output.

The LNA 606 low noise amplifies the signal received via the receive antenna 611.

The receiver 607 receives the intermediate frequency f ₂ generated by the frequency synthesizer 602 and down-converts the frequency of the low noise amplified signal to the intermediate frequency by the LNA 606.

The A / D converter 608 converts a signal (analog signal) converted to an intermediate frequency by the receiver 607 into a digital signal.

The digital signal processor 609 receives a digital signal of an intermediate frequency converted by the A / D converter 608 and downconverts the frequency of the signal to a base band, and converts the phase of the received signal into the PN code generator ( The input signal is restored in synchronization with the phase corresponding to the code generated by 601, and the target is detected by performing a predetermined signal processing algorithm using the restored signal.

Here, the signal processing algorithm performed by the digital signal processor 609 as described above is the same as the signal processing algorithm (see FIG. 6) performed by the digital signal processor 309 of the first embodiment of FIG. 3. Therefore, the description of the signal processing algorithm performed by the digital signal processor 609 of this second embodiment will be omitted.

Then, the radar frequency interference suppression method using the ground weapon system mounting radar according to an embodiment of the present invention having the above configuration will be described.

FIG. 9 is a flowchart illustrating an execution process of an inter-radar frequency interference suppression method using a ground radar mounting radar system according to the first embodiment of the present invention.

3 and 9, in accordance with the radar frequency interference suppression method using the ground weapon system mounting radar according to the first embodiment of the present invention, by first encrypting a signal transmitted through the transmitting antenna 310) In order to transmit, a pseudo random (PN) code generator 301 generates a code corresponding to a specific phase (eg, 0 °, 180 °) of the corresponding transmission signal (step S701). That is, the PN code generator 301 generates a code at 0 (zero) for phase 0 ° of the transmission signal and 1 for 180 °, respectively.

In addition, the frequency synthesizer 302 generates a radio frequency (RF) frequency for up-converting the transmission signal and an intermediate frequency for down-conversion for a signal received through the reception antenna 311 (step S702). . Then, the RF frequency generated by the frequency synthesizer 302 is input by the transmitter 303 to up-convert the frequency of the transmission signal to convert the transmission signal into an RF signal (step S703).

Then, the PN code generated by the PN code generator 301 and the RF signal converted by the transmitter 303 are input by the phase shifter 304 to adjust the phase of the RF signal according to the PN code. (Step S704). That is, the phase shifter 304 changes the phase of the RF signal to 0 ° if the PN code is 0 and 180 ° to 1. Then, the RF signal whose phase is changed through the phase shifter 304 is inputted by the solid state power amplifier (SSPA) 305 and amplified to a high output and transmitted through the transmitting antenna 310 (step S705).

Thereafter, the signal received through the reception antenna 311 is low noise amplified by a low noise amplifier (LNA) 306 (step S706). Then, the intermediate frequency generated by the frequency synthesizer 302 is input by the receiver 307 and down-converts the frequency of the signal low-amplified by the LNA 306 to the intermediate frequency (step S707). Then, the signal (analog signal) converted into the intermediate frequency by the receiver 307 is converted into the digital signal of the intermediate frequency by the A / D converter 308 (step S708).

Thereafter, the digital signal of the intermediate frequency converted by the A / D converter 308 is input by the digital signal processor 309 and down-converts the frequency of the signal to baseband, and the phase of the received signal is converted into the PN code. The input signal is decoded in synchronization with the phase corresponding to the code generated by the generator 301, and a target is detected by performing a predetermined signal processing algorithm using the reconstructed signal (step S709).

Here, the signal processing algorithm performed by the digital signal processor 309 in step S709 will be described in more detail.

10 is a flowchart showing a process of executing a signal processing algorithm employed in the method for suppressing inter-radar frequency interference using the radar for mounting the ground weapon system according to the present invention.

As described above, the signal processing algorithm includes the windowing modules 401a and 401b as the unit software program, the filter filter bank (DFB) processing modules 402a and 402b, and the constant false alarm rate (CFAR) module 403. ), Azimuth estimation module 404, 3/5 detection module 405, threat detection and tracking module 406. The target information module 407 may be further included as necessary.

6 and 10, first, the windowing modules 401a and 401b multiply a baseband signal input through a plurality of channels (channels A and B) into weights to generate five burst data. (Step S801). Thereafter, FFT (fast fourier transformation) is performed by the DFB processing modules 402a and 402b on the five bursts generated by the windowing modules 401a and 401b, so that the five distance cells and the Doppler (speed) cells are performed. The power value is calculated for each step (step S802).

Next, the CFAR module 403 receives a signal processed by the DFB processing modules 402a and 402b and passes the threshold value among the signals according to a threshold value determined to be a constant false alarm rate from a noise level. A signal to be detected is detected (step S803). Then, the azimuth angle is calculated by the azimuth estimation module 404 using the values of the plurality of channels (channels A and B) with respect to the signals passing through the CFAR level of the CFAR module 403 (step S804). The 3/5 detection module 405 recognizes as a target a case where there are three or more bursts passing the CFAR level among the five bursts created by the windowing modules 401a and 401b (step S805). .

Thereafter, the azimuth calculated by the azimuth estimation module 404 by the threat status and tracking module 406 with respect to the target passing through the 3/5 detection module 405, the DFB processing modules 402a, 402b. The tracking and the threat for the target are determined using the time to impact (TTI) calculated by the speed and the distance, the speed and the distance in the Doppler cell and the distance cell (step S806).

After the step S806, preferably, the acquired target information (distance, speed, azimuth, TTI, threat status, etc.) is transmitted to the controller (not shown) of the radar system by the target information module 407 and displayed on the display. It further includes a step (step S807).

FIG. 11 is a flowchart illustrating an execution process of a radar frequency interference suppression method using a radar for mounting a terrestrial weapon system according to a second embodiment of the present invention.

8 and 11, according to a method of suppressing inter-radar frequency interference using a ground weapon system mounting radar according to a second embodiment of the present invention, a signal transmitted through a transmitting antenna is first encoded and transmitted. In order to do this, a pseudo random (PN) code generator 601 generates a code corresponding to a specific phase (eg, 0 °, 180 °) of the corresponding transmission signal (step S901). At this time, the PN code generator 601 generates a code at 0 (zero) for phase 0 ° of the transmission signal and 1 for 180 °, respectively. Then, the frequency synthesizer 602 generates an intermediate frequency f ₂ for the transmission and reception signals in the radar and an RF frequency f ₃ for the transmission signal (step S902).

Thereafter, the PN code from the PN code generator 601 and the intermediate frequency f ₂ from the frequency synthesizer 602 are inputted by a direct digital synthesizer (DDS) 603 to obtain a fundamental frequency (for transmission signal). f ₁ ) is generated (step S903). Then, the transmitter 604 uses the fundamental frequency f ₁ generated by the DDS 603 and the intermediate frequency f ₂ and the RF frequency f ₃ generated by the frequency synthesizer 602. A final RF signal f ₁ + f ₂ + f ₃ is generated for transmission in the radar (step S904). Thereafter, the final RF signal f ₁ + f ₂ + f ₃ generated by the transmitter 604 is input by the solid state power amplifier (SSPA) 605 and amplified to a high output to transmit the transmit antenna 610. Transmit through (step S905).

Thereafter, the signal received through the receiving antenna 611 is low noise amplified by a low noise amplifier (LNA) 606 (step S906). Then, the intermediate frequency f ₂ generated by the frequency synthesizer 602 is input by the receiver 607 and down-converts the frequency of the signal low-amplified by the LNA 606 to the intermediate frequency (step S907). ). Then, the signal (analog signal) converted into the intermediate frequency by the receiver 607 is converted into the digital signal of the intermediate frequency by the A / D converter 608 (step S908).

Thereafter, the digital signal of the intermediate frequency converted by the A / D converter 608 is input by the digital signal processor 609, and the frequency of the signal is down-converted to the baseband, and the phase of the received signal is converted into the above-mentioned signal. Decode the input signal in synchronization with the phase corresponding to the code generated by the PN code generator 601, and perform a predetermined signal processing algorithm (a kind of software program) using the reconstructed signal to detect a target. (Step S909).

On the other hand, as described above, the method of the present invention changes the phase in order to encode and transmit the transmission signal. As described above, the phase of the transmission signal is 0 (zero) for phase 0 ° and 1 for 180 °. Generate code for each. Here, such a phase coding scheme will be described further.

In the present invention, in order to exclude the possibility of false alarm due to channel (frequency) interference, a phase coding scheme is applied between transmit and receive pulses. The inter-pulse phase coding applied to the radar is a method of transmitting an encrypted signal, deciphering the encryption at the receiving side, and then performing signal processing to spread false signals by noise to suppress false alarms.

It takes 0.2 seconds to transmit and receive pulses, signal processing, and data processing (scanning) on the radar, and the radar transmits and receives 6144 pulses to obtain a signal of one scan. In the conventional method, the phases of 6144 pulses remain the same and are transmitted and received. However, in the phase coding method, as shown in FIG. 12, a relative phase is randomly selected from 0 ° (code 0) and 180 ° (code 1) every pulse. Select and send and receive

13 is a view showing an example of a phase coding scheme applied to the method of the present invention.

Referring to FIG. 13, in the case of (A), when a signal is received, all signals are normally received as "1" after decoding, and the final signal has a magnitude of 8. However, in the case of (B), when an interference source is received, The magnitude of the signal for the interfering source is " 0 " and the magnitude of the final signal is four. Therefore, the phase coding scheme is very robust against interfering signals.

Suppression Factor (SF) for an interference signal to which such a phase coding scheme is applied is expressed as a formula below.

SF = 10log ₁₀ N _p

Here, N _p represents the number of pulses.

The suppression effect (SF) depends on the number of transmit / receive pulses. For radar using 6144 pulses, the SF has 37dB, but the burst in SF is 33dB because 2048 pulses are bundled and processed in burst units.

This concept is verified through simulation. The pulse repetition period of 25.6 ms and the number of pulses 2048 were used as parameters of the simulation, when the target signal (2 kHz) and the interference signal (2.9 kHz) existed, and the signal to noise ratio (SNR) of the interference signal was 30 dB. At 40 dB, we tested how much the interfering signal was suppressed and how much the noise increased.

14 and 15 are diagrams illustrating interference suppression and noise synergistic effects in the conventional scheme and the phase coding scheme when the SNRs of the interference signals are 30 dB and 40 dB, respectively. The interference signal is present in the scheme, but the interference signal does not exist in the phase coding scheme of (b). Since the suppression effect (SF) is 33dB, if the SNR of the interference signal before the phase coding is 33dB or more, the noise increases after the phase coding. That is, in FIG. 14, there is almost no noise rise, but in FIG. 15, the noise (about 10 dB) increases a lot, and the SNR of the target signal decreases due to the noise rise.

As described above, in the radar frequency interference suppression method using the ground weapon system mounting radar according to the present invention, the transmission signal is encrypted and transmitted by applying a method of coding a phase of a pulse in transmitting and receiving a signal in the radar, By processing the signal by a method of decoding the received signal, it is possible to fundamentally prevent inter-radar frequency (channel) interference.

As mentioned above, although the present invention has been described in detail with reference to the preferred embodiment, the present invention is not limited thereto, and it will be apparent to those skilled in the art that various changes and applications can be made without departing from the technical spirit of the present invention. 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 shows the relationship between design spectrum, fabrication spectrum and power of a channel in relation to channel interference in a radar;

2 is a view showing channel interference results in a conventional radar signal transmission and reception scheme.

Figure 3 is a schematic diagram showing the system configuration of the radar for mounting the ground weapon system according to the first embodiment of the present invention.

4 is a view schematically showing the structure of a PN code generator of a ground weapon system mounting radar according to a first embodiment of the present invention.

5 is a view showing a coefficient reset timing relationship in the PN code generator of the ground weapon system mounting radar according to the first embodiment of the present invention.

6 is a view showing the module configuration of the signal processing algorithm employed in the digital signal processor of the ground weapon system mounting radar according to the present invention.

7 shows a state in which a baseband signal input through two channels by a windowing module is made into five burst data;

8 is a view schematically showing a system configuration of a radar for mounting a ground weapon system according to a second embodiment of the present invention.

9 is a flowchart illustrating an execution process of a method for suppressing inter-radar frequency interference using a radar for mounting a ground weapon system according to the first embodiment of the present invention.

10 is a flowchart showing a process of executing a signal processing algorithm employed in the method for suppressing inter-radar frequency interference using the radar for mounting the ground weapon system according to the present invention.

FIG. 11 is a flowchart illustrating an execution process of an inter-radar frequency interference suppression method using a radar for mounting a terrestrial weapon system according to a second embodiment of the present invention. FIG.

12 is a conceptual diagram of a phase coding scheme applied to the method of the present invention.

13 illustrates an example of a phase coding scheme applied to a method of the present invention.

14 is a diagram showing interference suppression and noise synergistic effects in the conventional scheme and the phase coding scheme when the SNR of the interference signal is 30 dB.

15 is a diagram showing interference suppression and noise synergy in the conventional scheme and the phase coding scheme when the SNR of the interference signal is 40 dB.

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

301,601: pseudo random (PN) code generator 302,602: frequency synthesizer

303,604 transmitter 304: phase shifter

603: direct digital synthesizer (DDS)

305,605: solid state power amplifier (SSPA)

306,606: low noise amplifier (LNA) 307,607: receiver

308,608: A / D converter 309,609: digital signal processor

401a, 401b: windowing module

402a, 402b: Doppler Filter Bank (DFB) module

403: constant false alarm rate (CFAR) module

404: azimuth estimation module 405: 3/5 detection module

406: threat detection and tracking module 407: target information module

Claims (10)

A pseudo random (PN) code generator for generating a code corresponding to a specific phase of a transmission signal to encrypt and transmit a signal transmitted through the transmission antenna; A frequency synthesizer for generating an RF frequency for upconversion of the transmission signal and an intermediate frequency for downconversion of a signal received through a receiving antenna; A transmitter which receives the RF frequency generated by the frequency synthesizer and upconverts the frequency of the transmission signal to convert the transmission signal into an RF signal; A phase shifter which receives a PN code generated by the PN code generator and an RF signal converted by the transmitter, and changes a phase of the RF signal according to the PN code; A solid state power amplifier (SSPA) for amplifying the phase-changed RF signal via the phase shifter; A low noise amplifier (LNA) for low noise amplifying a signal received through a receive antenna; A receiver which receives the intermediate frequency generated by the frequency synthesizer and down-converts the frequency of the low noise amplified signal to the intermediate frequency by the LNA; An A / D converter for converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of an intermediate frequency; And The digital signal of the intermediate frequency converted by the A / D converter is input, and the frequency of the signal is down-converted to baseband, and the phase of the input signal is synchronized with a phase corresponding to the code generated by the PN code generator. A digital signal processor for recovering an input signal and detecting a target by performing a predetermined signal processing algorithm using the restored signal; And the PN code generator generates codes of 0 (zero) for phase 0 of the transmission signal and 1 for 180 °, respectively. delete The method of claim 1, And the phase shifter changes the phase of the RF signal to 0 ° if the PN code is 0 and 180 ° to 1. The method of claim 1, The signal processing algorithm performed by the digital signal processor, When a baseband signal is input through a plurality of channels (channels A and B), the baseband signal is multiplied by a weight to reduce the influence of a signal such as a clutter, resulting in five bursts of data. A windowing module for making; 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; An azimuth estimation module for calculating azimuth angles using values of a plurality of channels (channels A and B) with respect to signals passing through the CFAR level of the CFAR module; A 3/5 detection module that recognizes as a target a case where three or more bursts passing the CFAR level are among the five bursts created by the windowing module; And TTI (time to impact) calculated by azimuth calculated by the azimuth estimation module with respect to a target that has passed through the 3/5 detection module, velocity and distance, velocity and distance in the Doppler and distance cells of the DFB processing module Radar for mounting the ground weapon system, characterized in that it comprises a threat tracking and tracking module to determine the target and the threat using the). The method of claim 4, wherein And a target information module for transmitting the acquired target information (distance, speed, azimuth, TTI, threat or not) to the control unit of the radar system and displaying it in an exhibitor. A PN code generator for generating a code corresponding to a specific phase of the transmission signal in order to encrypt and transmit a signal transmitted through the transmission antenna; A frequency synthesizer for generating an intermediate frequency f ₂ for transmit and receive signals in the radar and an RF frequency f ₃ for the transmit signal; A direct digital synthesizer (DDS) for receiving a PN code from the PN code generator and an intermediate frequency f ₂ from the frequency synthesizer and generating a fundamental frequency f ₁ for a transmission signal; Final RF signal f ₁ + f ₂ for transmission in the radar using the fundamental frequency f ₁ generated by the DDS, the intermediate frequency f ₂ and the RF frequency f ₃ generated by the frequency synthesizer a transmitter for generating + f ₃ ); SSPA to amplify the final RF signal f ₁ + f ₂ + f ₃ generated by the transmitter; An LNA for low noise amplifying a signal received through the receiving antenna; A receiver which receives an intermediate frequency f ₂ generated by the frequency synthesizer and down-converts the frequency of the signal low-amplified by the LNA to an intermediate frequency; An A / D converter for converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of an intermediate frequency; And The digital signal of the intermediate frequency converted by the A / D converter is input, and the frequency of the signal is down-converted to baseband, and the phase of the input signal is synchronized with a phase corresponding to the code generated by the PN code generator. And a digital signal processor for recovering an input signal and detecting a target by performing a predetermined signal processing algorithm using the restored signal. a) generating a code corresponding to a specific phase of the transmission signal by the PN code generator to encrypt and transmit a signal transmitted through the transmission antenna; b) generating, by a frequency synthesizer, an RF frequency for upconversion of the transmitted signal and an intermediate frequency for downconversion of a signal received through a receive antenna; c) receiving an RF frequency generated by the frequency synthesizer by a transmitter and upconverting the frequency of the transmission signal to convert the transmission signal into an RF signal; d) receiving a PN code generated by the PN code generator and an RF signal converted by the transmitter by a phase shifter and changing a phase of the RF signal according to the PN code; e) receiving and amplifying the RF signal whose phase is changed by the SSPA through the phase shifter and transmitting through the transmitting antenna; f) low noise amplifying the signal received via the receive antenna by the LNA; g) receiving an intermediate frequency generated by the frequency synthesizer by a receiver and down converting a frequency of a signal low amplified by the LNA into an intermediate frequency; h) converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of intermediate frequency by an A / D converter; And i) A digital signal of the intermediate frequency converted by the A / D converter is input by a digital signal processor, and the frequency of the signal is down-converted to the base band, and the phase of the input signal is generated by the PN code generator. Restoring an input signal in synchronization with a phase corresponding to the step of detecting a target by performing a predetermined signal processing algorithm using the restored signal; The signal processing algorithm of step i), Windowing module as unit software program, doppler filter bank (DFB) processing module, constant false alarm rate (CFAR) module, azimuth estimation module, 3/5 detection module, threat detection and tracking module, III-1) by the windowing module, multiplying the baseband signals inputted through a plurality of channels (channels A and B) by weight to produce five burst data; III-2) calculating a power value for each of five distance cells and Doppler (speed) cells by performing a fast fourier transformation (FFT) on the five bursts produced by the windowing module by the DFB processing module; III-3) receiving a signal processed by the DFB processing module by the CFAR module and detecting a signal passing the threshold value among the signals according to a threshold value determined to be a constant false alarm rate from a noise level; III-4) calculating azimuth angles using signals of a plurality of channels (channels A and B) by the azimuth estimation module with respect to the signals passing through the CFAR level of the CFAR module; III-5) Recognizing, by the 3/5 detection module, a case where there are three or more bursts passing the CFAR level among the five bursts created by the windowing module; And III-6) the azimuth calculated by the azimuth estimation module by the threat status and tracking module for the target passing through the 3/5 detection module, the velocity and distance in the Doppler and distance cells of the DFB processing module, A method for suppressing inter-radar frequency interference using a ground weapon system-mounted radar, the method comprising: tracking and threatening a target using a time to impact (TTI) calculated by speed and distance. delete The method of claim 7, wherein After the above step III-6), III-7) The ground weapon system further comprising the step of transmitting the acquired target information (distance, speed, azimuth, TTI, threat or not) to the control unit of the radar system by the target information module and to display it in the exhibitor. Radar frequency interference suppression method using mounting radar. a) generating a code corresponding to a specific phase of the transmission signal by the PN code generator to encrypt and transmit a signal transmitted through the transmission antenna; b) generating by the frequency synthesizer an intermediate frequency f ₂ for transmit and receive signals in the radar and an RF frequency f ₃ for the transmit signal; c) receiving a PN code from the PN code generator and an intermediate frequency f ₂ from the frequency synthesizer by a direct digital synthesizer (DDS) to generate a fundamental frequency f ₁ for a transmission signal; d) a final RF signal for transmission in the radar by the transmitter using the fundamental frequency f ₁ generated by the DDS and the intermediate frequency f ₂ and RF frequency f ₃ generated by the frequency synthesizer ( f ₁ + f ₂ + f ₃ ); e) receiving and amplifying a final RF signal (f ₁ + f ₂ + f ₃ ) generated by the transmitter by a solid state power amplifier (SSPA) and transmitting it through a transmitting antenna; f) low noise amplifying a signal received through the receive antenna by a low noise amplifier (LNA); g) receiving an intermediate frequency f ₂ generated by the frequency synthesizer by a receiver and down converting the frequency of the signal low amplified by the LNA into an intermediate frequency; h) converting a signal (analog signal) converted to an intermediate frequency by the receiver into a digital signal of intermediate frequency by an A / D converter; And i) A digital signal of the intermediate frequency converted by the A / D converter is input by a digital signal processor, and the frequency of the signal is down-converted to the base band, and the phase of the input signal is generated by the PN code generator. Restoring the input signal in synchronization with the phase corresponding to the step of detecting the target by performing a predetermined signal processing algorithm using the restored signal, the radar inter-frequency using the radar for mounting a ground weapon system, characterized in that Interference Suppression Method.

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