CN115801144B

CN115801144B - Passive reconnaissance system

Info

Publication number: CN115801144B
Application number: CN202211716114.7A
Authority: CN
Inventors: 李振川; 黄一平; 黄超
Original assignee: Chengdu Fuyuanchen Technology Co ltd
Current assignee: Chengdu Fuyuanchen Technology Co ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-04-28
Anticipated expiration: 2042-12-30
Also published as: CN115801144A

Abstract

The invention relates to the technical field of electronic reconnaissance, in particular to a passive reconnaissance system which comprises an antenna subsystem, a receiving subsystem and a signal processing subsystem, wherein a centimetre wave frequency band and a millimeter wave frequency band are adopted as reconnaissance frequency bands of the passive reconnaissance system, the instantaneous bandwidth of the two frequency bands during joint reconnaissance processing is 2GHz, the instantaneous bandwidth of the passive reconnaissance system is greatly widened by adopting a reconnaissance processing mode of detection at once, the functions of pulse signal detection, parameter measurement and the like are realized by using a first channel, the rest channels are used for phase measurement, pulse detection results are output, meanwhile, the whole working frequency band is scanned according to the frequency band in sequence or according to a preset frequency band table, a reconnaissance task is implemented in a reciprocating mode, and when a suspicious target is found, an alarm prompt is output, and the working efficiency of the passive reconnaissance system is improved.

Description

Passive reconnaissance system

Technical Field

The invention relates to the technical field of electronic reconnaissance, in particular to a passive reconnaissance system.

Background

In the electronic warfare reconnaissance work, the reconnaissance system can be used for finding out interference electromagnetic radiation signals, finding out relevant parameters of enemy radars such as frequency, azimuth and the like, and providing reliable basis for strategic deployment of the electronic warfare. Meanwhile, the passive reconnaissance system also finds out the specific conditions of the configuration of the enemy electronic equipment, including the type, the number and other information of the electronic equipment, confirms the threat program according to the acquired information and gives an alarm.

The existing passive reconnaissance system does not have larger instantaneous broadband processing capability and higher sensitivity, so that signals which are captured simultaneously in a larger instantaneous bandwidth range can not be detected during electronic warfare reconnaissance, the reconnaissance range is smaller, and radiant energy beyond the fatal striking range of the weapon can not be detected in time.

Disclosure of Invention

Aiming at the problem that the existing passive reconnaissance system does not have larger instantaneous broadband processing capacity and higher sensitivity, the invention provides the passive reconnaissance system.

The invention is realized by the following technical scheme:

a passive reconnaissance system comprises an antenna subsystem, a receiving subsystem and a signal processing subsystem;

the receiving subsystem includes:

the system comprises a centimeter wave front end module and a millimeter wave front end module, which are used for receiving a first radio frequency signal of an antenna subsystem, and outputting a second radio frequency signal after amplitude limiting, filtering and amplifying treatment;

the switch matrix module is used for receiving the multipath second radio frequency signals sent by the centimeter wave front end module and the millimeter wave front end module, completing signal distribution and power compensation, and enabling the passive reconnaissance system to work independently in various frequency bands;

the frequency conversion and synthesis module is used for downwards converting the second radio frequency signal output by the switch matrix module into an intermediate frequency signal for output;

the signal processing subsystem includes:

the acquisition processing module is used for acquiring, detecting, measuring phase and extracting full pulse parameters of the intermediate frequency signals;

the fusion control module is used for cutting side lobes and splicing bandwidths;

and the computer module is used for sorting, identifying, displaying control and storing.

Further, the remote control terminal and the power module are also included;

the remote control terminal is an upper computer and is used for sending control instructions to the receiving subsystem and the signal processing subsystem;

the power module is used for converting 220V alternating current into 12V direct current and 3.3V direct current required by each module.

Further, the antenna subsystem comprises a centimeter wave frequency band antenna array and a millimeter wave frequency band antenna array, wherein the two sections of antenna arrays are four-channel three-baseline interferometer two-dimensional direction finding antenna arrays, and each antenna array comprises 7 direction finding antennas and 4 sidelobe cutting antennas.

Further, the centimeter wavefront module and the millimeter wavefront module each comprise an amplitude limiter, an attenuator and a first amplifier which are sequentially connected, the millimeter wavefront module further comprises a mixer and a second amplifier which are sequentially connected behind the first amplifier, the second amplifier is connected with a 22-channel switch matrix module, and 22-channel switch matrices realize 22-channel second radio frequency signal gating through built-in signal switches after receiving an upper computer instruction.

Further, the frequency conversion and frequency synthesis module comprises a seven-channel frequency conversion and frequency synthesis module and a four-channel frequency conversion and frequency synthesis module, wherein the seven-channel frequency conversion and frequency synthesis module comprises a down-conversion module, a local oscillation module, a control module and a power supply module, the down-conversion module down-converts an input second radio frequency signal into an intermediate frequency signal to be output, the local oscillation module outputs 2 paths of local oscillation signals for the frequency conversion of the down-conversion module, 1 path of clock signals are output for sampling of the acquisition processing module, the control module is communicated with an upper computer to form an internal control time sequence to control the down-conversion module and the local oscillation module, and the four-channel frequency conversion and frequency synthesis module is less than the seven-channel frequency conversion and frequency synthesis module to be assembled with three down-conversion modules.

Further, the seven-channel frequency conversion and frequency synthesis module is provided with 2 groups and is respectively connected with the signal output ends of the 22-channel switch matrix, and the four-channel frequency conversion and frequency synthesis module is provided with 2 groups and is respectively connected with the signal output ends of the 22-channel switch matrix.

Furthermore, the acquisition processing module comprises a seven-channel acquisition processing module and a four-channel acquisition processing module, wherein the seven-channel acquisition processing module comprises an ADC circuit and an FPGA circuit, the FPGA drives an ADC chip to sample a broadband intermediate frequency signal, so that the signal channelizing processing and parameter measurement are realized, the FPGA outputs processed data to the fusion module through interface communication, and the four-channel acquisition processing module is less than the seven-channel acquisition processing module in assembling of 3 ADC chips.

Further, the fusion control module comprises an FPGA chip XC7VX690T, FPGA chip XC7K325T, wherein the FPGA chip XC7K325T is connected with an upper computer and used for system control, state reporting and synchronous acquisition control, and the FPGA chip XC7VX690T is connected with a computer module and used for collecting, fusing and sending PDW processing results.

Further, the seven-channel acquisition and processing module is provided with 2 groups, the signal input ends of the 2 groups of seven-channel acquisition and processing modules are connected with the signal output ends of the 2 groups of seven-channel frequency conversion and frequency synthesis modules, and the signal output ends of the 2 groups of seven-channel acquisition and processing modules are connected with the signal input end of the fusion control module;

the four-channel acquisition processing module is provided with 2 groups, the signal input end of the 2 groups of four-channel acquisition processing module is connected with the signal output end of the 2 groups of four-channel frequency conversion and frequency synthesis module, and the signal output end of the 2 groups of four-channel acquisition processing module is connected with the signal input end of the fusion control module.

The invention has the beneficial effects that:

according to the invention, the centimetre wave frequency band and the millimeter wave frequency band are adopted as the reconnaissance frequency band of the passive reconnaissance system, the instantaneous bandwidth of the two frequency bands during the joint reconnaissance processing is 2GHz, the instantaneous bandwidth of the centimetre wave frequency band or the millimeter wave frequency band during the independent reconnaissance processing is 4GHz, the instantaneous bandwidth of the passive reconnaissance system is greatly widened, the first channel is adopted to realize the functions of pulse signal detection, parameter measurement and the like in a detection-in-detection mode, the other channels are used for phase measurement, the pulse detection result is output, meanwhile, the steering result is given, the whole working frequency band is scanned according to the frequency band in turn or according to a preset frequency band table, the reconnaissance task is implemented in a reciprocating mode, and when a suspicious target is found, an alarm prompt is output, and the working efficiency of the passive reconnaissance system is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it will be apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a block diagram of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a contrast direction finding method of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a phase interferometer of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a four-channel three-baseline interferometer arrangement of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 5 is a block diagram of a front end module and a switch matrix module of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 6 is a block diagram of a seven-channel frequency conversion and synthesis module of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 7 is a functional block diagram of a down conversion module of a passive reconnaissance system according to an embodiment of the present invention;

fig. 8 is a schematic block diagram of a local oscillation module of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 9 is a functional block diagram of a seventh channel acquisition processing module of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 10 is a block diagram of an ADC sampling clock of a passive reconnaissance system according to an embodiment of the present invention;

FIG. 11 is a functional block diagram of a fusion control module of a passive reconnaissance system according to an embodiment of the present invention;

fig. 12 is a schematic diagram of a normal operation mode of a fusion control module of a passive reconnaissance system according to an embodiment of the present invention;

fig. 13 is a schematic diagram of a self-checking working mode of a fusion control module of a passive reconnaissance system according to an embodiment of the present invention.

Detailed Description

For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention.

Example 1

Referring to fig. 1, the present embodiment proposes a passive reconnaissance system, including a front end module:

the centimeter wavefront module receives the radio frequency signals of the antenna unit group, and outputs the radio frequency signals after the processes of amplitude limiting, filtering, amplifying and the like are carried out;

the millimeter wave front end module receives the radio frequency signals of the antenna unit group, and outputs the radio frequency signals after carrying out the processes of amplitude limiting, filtering, amplifying, frequency conversion and the like;

and responding to the control instruction, and completing channel gain control and switching between a working channel and a BIT channel.

A switch matrix module:

and receiving 11+11 paths of radio frequency signals sent by the centimeter wave or millimeter wave front end module, and responding to the control instruction of the upper computer to complete signal distribution and power compensation, so that the reconnaissance system has three independent working states of centimeter wave 2 GHz+millimeter wave 2GHz, centimeter wave 4GHz and millimeter wave 4 GHz.

Frequency conversion and frequency synthesis module:

responding to the control signal of the upper computer, and changing the 8-18GHz radio frequency signal sent by the switch matrix down to 3.75+/-1 GHz intermediate frequency signal for output;

outputting local oscillation clocks required by the work of all functional modules of the system;

outputting a self-checking source required by the BIT of the system.

A receiving unit:

the system has the functions of multichannel signal detection and parameter measurement, samples and signal references the 3.75+/-1 GHz intermediate frequency signals sent by a microwave unit, adopts a phase contrast algorithm to finish azimuth measurement, and outputs parameters such as Radio Frequency (RF), azimuth angle (DOA), pulse Width (PW), pulse Amplitude (PA), arrival Time (TOA) and the like of the signals;

the method has the function of measuring parameter data fusion. Performing pressure side lobe judgment and data fusion on the reference information of 2GHz cm+2 GHz cm, 2GHz cm+2 GHz mm and 2GHz mm+2 GHz mm of the two frequency bands, and outputting PDW descriptive words;

the control function of the microwave unit is provided, and the control of commands such as self-checking, channel switching and the like is carried out on the microwave unit;

the system has the functions of unit self-checking and subsystem joint inspection, and the receiver judges the hardware state to finish the extension self-checking, and the fault is positioned to the field replaceable unit; under the control of the main control, the cooperative receiving subsystem completes subsystem joint inspection, forms a receiving channel amplitude comparison table and stores the receiving channel amplitude comparison table;

the system has an information analysis function and responds to a hidden shadow signal and a reset signal sent by an upper computer;

the method has the information resolving function: acquiring information such as system working parameters, system time, navigation attitude and the like sent by an upper computer, and resolving comprehensive parameter information to form PDW (power distribution) to be sent to a rear end for processing;

the digital filter has the functions of: the binding information of the upper computer is received, PDW specified in the PDW data stream is filtered, and the filtered PDW data is output to the display control end;

the system has the function of receiving and forwarding control information issued by the display control extension. According to control information and the like issued by the display extension, issuing a working parameter command to hardware through a designated interface, and issuing a control parameter command to the front end;

has a data distribution function. The method for distributing and controlling the PDW data and the original signal data information to complete the appointed function mainly comprises the following steps: pulse sorting, intra-pulse analysis, data storage management, etc.;

the system has the function of interacting control commands and state data with an external system of the equipment. Receiving an external system control command or a cooperative command according to an external interface of the equipment, and sending equipment state data, cooperative task output, target identification results and the like;

the data recording and playback functions are provided. And recording and playing back medium-frequency original data and processed full pulse data in the equipment according to actual combat demands so as to be ready for data transmission and data analysis.

Example 2

The embodiment provides a direction finding system selection of a passive reconnaissance system.

Radar signal direction finding generally comprises two systems of amplitude comparison direction finding and phase interferometer direction finding;

(1) And (3) comparing and measuring the direction: referring to FIG. 2, wherein

For the amplitude characteristic of the antenna pattern, +.>

For the amplitude characteristic of the antenna pattern, +.>

For a beam width of 3db>

Signals are received for the antenna. Multiple independent adjacent beams are generated by utilizing multiple independent antennas, and the radiation source position is determined by receiving the relative amplitude of the same signal by the adjacent beams, which is called a single pulse direction finding method. According to the method, an antenna array is arranged in an annular mode within the range of 360 degrees in azimuth, the front end of the radio frequency which follows each antenna is independent or combined according to different installation positions, the intermediate frequency which follows the front end of the radio frequency is received by a crystal detection system to obtain a pulse envelope signal, and then the envelope signal is quantized and logarithmically amplified and sent to pretreatment to conduct amplitude comparison direction finding, and the amplitude of the wave beam with the largest amplitude and the amplitude of the adjacent wave beam are selected to conduct logarithm subtraction operation during direction finding. The more the number of antennas is, the higher the angle measurement precision is, but the more complex the system structure is, so that the direction measurement of 360 degrees is common in a 4-antenna and 6-antenna structure, the beam width change, the antenna shaft clamping angle change and the inter-channel signal amplitude ratio change all cause direction measurement errors, wherein the amplitude change caused by the channel unbalance and the change of the antenna parameters caused by the frequency change are particularly prominent. The specific amplitude direction finding accuracy rms is generally in the range of 5-12 deg..

(2) Phase interferometer: the method for detecting the direction of the incoming wave by utilizing the phase difference in the wave path is called a phase interferometer direction finding method by receiving information of different wave paths from the same signal through a plurality of antenna channels, and has the greatest advantage of high direction finding precision.

With reference to figure 3 of the drawings,

，/>

；

receiving a signal for a first antenna; />

Receiving a signal for a second antenna;/>

is an amplitude modulation parameter;

for amplitude modulation parameter->

Taking the base line length between the antenna centers

Let the target signal arrive at azimuth angle +.>

Due to the distance between antennas->

The signals received by the two channels have wave path difference, and the output signals after front-end conversion have phase difference:

wherein the method comprises the steps of

For the speed of light->

For frequency +.>

For the phase difference between the two antennas, ">

For the phase of the antenna 1 branch, < >>

For the phase of the antenna 2 branch, < >>

To reach azimuth +.>

For the base line length, the phase difference can obtain the arrival azimuth after phase discrimination and angle conversion: />

。

From the above, it is known that the detection of frequency must be introduced simultaneously by using the interferometer method to measure the direction; the phase ambiguity problem arises when the difference in the wave path exceeds the half-wave wavelength of the signal. Because the azimuth angle of arrival detection results are inversely proportional to both the baseline length and the signal frequency, a baseline that is as short as possible is needed to ensure wider frequency adaptability of the interferometer direction finding method. But this also brings another problem of a decrease in direction-finding accuracy. In the practical application process, a mode of resolving a plurality of groups of baselines is adopted to realize wide frequency band and high direction finding precision.

According to the specific application environment requirements, the direction-finding precision of about 1-4 degrees is considered, the requirements of the scheme are met by adopting the direction-finding system of the phase interferometer, and the horizontal and pitching coverage airspace is achieved by matching with the mechanical turntable.

According to the requirements of the direction-finding range and the direction-finding precision, the direction-finding antenna array is divided into two sections according to 8GHz-8GHz and 33GHz-3GHz, the design of the space between the antenna arrays is referred to as figure 4,

for the baseline length between the first antenna and the second antenna, < >>

For the baseline length between the second antenna and the third antenna, +.>

Is the baseline length between the third antenna and the fourth antenna.

Example 3

The embodiment provides a front-end receiving module and a switch matrix module of a passive reconnaissance system.

Referring to fig. 5, after the 8GHz-18GHz and 33GHz-37GHz input signals are filtered, the signals pass through a limiter, pass through a 30dB dynamic expansion attenuator, and then enter a switch matrix module after being amplified by low noise, and the 33GHz-37GHz signals need to be shifted to a frequency band of 12GHz-16GHz by frequency down-conversion through a mixer.

Because the passive reconnaissance system has the requirement of splicing 4GHz instantaneous bandwidth, a switch matrix is required to be adopted for signal distribution, the insertion loss of the switch matrix is less than 2dB, and the isolation is more than 60dB.

Example 4

The embodiment provides a seven-channel frequency conversion and frequency synthesis module of a passive reconnaissance system.

Referring to fig. 6, the seven-channel frequency conversion and integration module is composed of a down-conversion module, a local oscillation module, a control module, a power supply module and the like, and the down-conversion module mainly has the function of down-converting an input 8GHz-18GHz high-frequency signal into an intermediate frequency signal of 3.75GHz + -1 GHz and outputting the intermediate frequency signal.

The local oscillation module mainly completes the output of 2 paths of local oscillation signals, each path of local oscillation signals comprises LO1 and LO2, provides local oscillation signals required by frequency conversion for the down-conversion module, and simultaneously outputs 1 path of 100MHz reference clock signals to the acquisition processing module for sampling.

The control unit is communicated with the upper computer through the SPI bus to form an internal control time sequence, controls the down-conversion and local oscillation module and uploads internal state information.

The power module can receive DC12V power, and generates secondary power through power conversion to supply power to other modules.

Referring to fig. 7, the 8-18GHz down-conversion module adopts a millimeter wave frequency conversion mode, and mainly realizes the receiving, filtering, amplifying and down-converting of signals to an intermediate frequency, and sends the signals to the multi-channel acquisition processing module. The down-conversion module consists of a front end amplifying and switching filter module, a primary frequency conversion module, an intermediate frequency module and the like

Combining with the requirements of the actual system operation of the scheme on spurious signals, spurious signals and image frequency suppression, a single-channel frequency conversion scheme is adopted to divide the frequency into 2 frequency bands: 7.3GHz-11.6GHz, 10.8GHz-12GHz, and the like, and the frequency conversion is adopted twice, and finally the frequency is reduced to 3.75 GHz.

The 8-18GHz input signal is amplified by low noise amplifier after passing through limiter, then mixed with a mixer to generate intermediate frequency signal 22GHz, filtered by a switch filter, mixed with a second local oscillator to generate 3.75GHz + -1 GHz, and output after filtering amplification and signal conditioning.

The whole link small signal gain is:

g= -1+15-3-9+15-3-9+15-3-14-3-3+24-3-10-5-3+18-5+18-5+15= +38dB, when a large signal is received, the input signal can be attenuated to a maximum attenuation of 31dB, so that the signal amplitude is maintained in a linear range.

Referring to fig. 8, the local oscillation module is composed of a clock reference circuit, a frequency synthesizer, a frequency multiplier and a point frequency source, and has the main function of providing local oscillation signals and clock signals for the up-down conversion component.

Example 5

The embodiment provides a seven-channel acquisition processing module of a passive reconnaissance system.

Referring to fig. 9, the seven-channel acquisition processing module mainly includes:

the high-speed ADC circuit adopts 7 ADC12DJ3200 chips, the sampling rate is set to 5000MSPS, and 7-channel synchronous intermediate-frequency data acquisition is completed;

the FPGA circuit is characterized in that 1 piece of XC7VX690TFFG1927PKG chip is adopted as a main processing FPGA chip, a GTH high-speed interface of the FPGA chip is adopted, high-speed serial sampling data output of an ADC chip is received, and an 8 pieces of DDR3 cache is hung on the FPGA chip for caching various processing data. The FPGA chip is externally provided with a 4xSRIO high-speed transmission channel;

the signal matching circuit realizes the conversion of intermediate frequency input between single end and differential and adapts to the signal input requirement of an ADC chip;

the bus interface circuit comprises a high-speed serial standard protocol SRIO, a low-speed control bus I2C and the like;

the optical transmitting and receiving circuit adopts HTG8518 modules of middle-navigation photoelectric company, and the number of the optical transmitting and receiving modules is 2. The single module is provided with 24 paths of optical channels 12 for receiving and transmitting, and the single channel speed can reach 10.3125Gbps at the highest;

the VPX interface circuit adopts a VPX series modularized connector, the model adopts VPX-61T8aAA8AAGD8-A, and the matched motherboard socket adopts VPX-61Z8elJ lJGD8-A;

the debugging test circuit is provided with an on-line debugging port of software and a board status indicator lamp on the front panel of the board, wherein the on-line debugging port adopts a rectangular electric connector J30JA-25ZKW-J and is matched with a debugging interface board;

and the power supply circuit has a power supply input voltage of DC+12V, and a DC/DC and linear power supply are selected to obtain a power supply required by the board.

The seven-channel acquisition processing module has the digital signal processing capability of intermediate frequency signals, and an FPGA processing chip XC7VX690TFFG1927PKG is selected;

the system has the capability of carrying out high-capacity high-speed data communication through SRIO, GTX high-speed data transmission channels and other devices;

the system has the capability of reporting commands, faults and status data with other devices through gigabit Ethernet and SRIO, GPIO, I C buses;

the high-speed ADC circuit can directly sample the input frequency from direct current to more than 10GHz, under the double channels, the maximum sampling rate of the ADC12DJ3200 is 3200Msps, the maximum sampling rate under the single channel mode is 6400Msps, the programmable switching function of the channel number and the Nyquist bandwidth single channel mode can be used for developing flexible hardware so as to meet the requirement of high-channel number or wide instantaneous signal bandwidth application, 8-bit effective bits can be achieved within the range 2750-4750 MHz of analog bandwidth, and when the band-pass sampling theorem allows the signal bandwidth to be far smaller than the center frequency, the ADC can sample by the sampling rate far lower than the low-pass sampling frequency, and the requirement on the ADC can be reduced. Bandpass sampling can reduce the actual sampling rate and the amount of data acquired to ease the burden of back-end digital signal processing.

The FPGA chip configuration adopts MASTER SPI mode.

The ADC12DJ3200 of the signal matching circuit is internally provided with a buffer, so that the input impedance under a broadband signal is constant, an interface between an input network and a high-impedance buffer is easier to design, the buffer provides isolation between a sampling capacitor and the input network due to a fixed input terminating resistor, the instantaneous change of charge injection is small, great convenience is brought to the design of the signal matching circuit, the ADC12DJ3200 requires that an input analog signal is in a differential form, single-end-to-differential conditioning is further required before acquisition, a radio frequency transformer JFFTB-1-1T-B with the impedance ratio of 1:1 is selected to realize single-end-to-differential of the signal, the JFFTB-1-1T-C supports the signal frequency band to be 10 MHz-6000 MHz, the insertion loss of the signal is not more than 1.5dB within the bandwidth range of 2750-47 MHz, the amplitude imbalance is not more than 0.8 dB, and the phase imbalance is not more than 10 degrees.

The seven-channel acquisition processing module also comprises a clock distribution circuit

The ultra-low jitter clock chip GMD7043 is selected to realize clock distribution. The clock tree multi-chip synchronization is realized by transferring the synchronization information from the clock source to the clock of the AD through the system synchronization frame pulse SYSREF. Each channel integrates a digital delay and analog delay adjusting circuit, so that the output phase of each channel can be flexibly and independently adjusted, nondeterministic delay deflection caused by external environment is compensated, and referring to fig. 10, a sampling clock is distributed by a 2.5G sampling clock externally supplied by a system, a GMD7043 generates a synchronous clock by an internal frequency divider, and the phase delay between the sampling clock and SYSREF can be configured by an FPGA.

Example 6

The embodiment provides a fusion control module of a passive reconnaissance system.

The fusion control module is an interaction center and a control center of the main control system and the extension, and has the main functions of: and the method completes the broadband splicing, the information fusion, the forwarding of system control information, the clock generation and synchronous management of the extension, the collection and reporting of the extension state information, and the interconnection of the signal processing result sent by the acquisition processing module and the computer module is convenient for debugging and testing. The fusion control module adopts a VPX architecture.

Referring to fig. 11, the fusion control module comprises 1 piece of FPGA chip XC7VX690TFFG1927-2 and 1 piece of FPGA chip XC7K325TFFG900-2, XC7K325t completing system control, status report and synchronous acquisition control; XC7VX690T completes the collection of PDW processing results, completes the fusion of PDW and the transmission of PDW, and is interconnected with a computer module by SRIO.

Referring to fig. 12, the parameter issuing of the master control system, that is, the upper computer, is to issue the parameter to be issued to the computer module through the UDP protocol of the gigabit ethernet, and the computer module transmits the parameter to the fusion control module through PCIE, and the fusion control module distributes the parameter to the modules of the other three acquisition processing modules. The main parameters include: working mode parameters, working frequency band parameters, amplitude and phase calibration coefficients and the like.

The passive reconnaissance system comprises a self-checking mode and a normal working mode, and referring to fig. 13, in the self-checking mode, the fusion control module collects self-checking information of each module, reports the self-checking information to the computer module through the high-speed interface and transmits the self-checking information to the main control system so as to monitor the states of each module of the extension at any time.

Example 7

The embodiment provides a computer module of a passive reconnaissance system.

The computer module has the main function of finishing the display of accurate analysis results and finishing the control of each module according to the system workflow. The computer module also needs to complete visual display of the results of the intra-pulse feature analysis. And according to the sorting result, corresponding original data are read from the four-channel acquisition processing module, the memory of the multi-channel acquisition processing module is controlled to carry out ping-pong switching, and the pulse characteristic analysis result is updated into the full pulse description word parameters by utilizing the read original data information. In the full pulse descriptor parameter acquisition mode or the original data acquisition mode, the computer module also needs to store full pulse descriptor parameters or intermediate frequency original data into an external SATA hard disk of the computer module.

The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The passive reconnaissance system is characterized by comprising an antenna subsystem, a receiving subsystem and a signal processing subsystem;

the receiving subsystem includes:

the frequency conversion and synthesis module is used for converting the second radio frequency signal output by the switch matrix module down to an intermediate frequency signal for output, the frequency conversion and synthesis module comprises a seven-channel frequency conversion and synthesis module and a four-channel frequency conversion and synthesis module, wherein the seven-channel frequency conversion and synthesis module comprises a down-conversion module, a local oscillation module, a control module and a power supply module, the down-conversion module is used for converting the input second radio frequency signal down to the intermediate frequency signal for output, the local oscillation module is used for converting the down-conversion module to output 2 local oscillation signals, and outputting 1 clock signal for sampling of the acquisition processing module, the control module is communicated with an upper computer to form an internal control time sequence for controlling the down-conversion module and the local oscillation module, and the four-channel frequency conversion and synthesis module is less provided with three down-conversion modules than the seven-channel frequency conversion and synthesis module;

the seven-channel frequency conversion and synthesis module is provided with 2 groups and is respectively connected with the signal output ends of the 22-channel switch matrix, and the four-channel frequency conversion and synthesis module is provided with 2 groups and is respectively connected with the signal output ends of the 22-channel switch matrix;

the signal processing subsystem includes:

the acquisition processing module is used for acquiring, detecting, measuring phase and extracting full pulse parameters of intermediate frequency signals, and comprises a seven-channel acquisition processing module and a four-channel acquisition processing module, wherein the seven-channel acquisition processing module comprises an ADC circuit and an FPGA circuit, the FPGA drives an ADC chip to sample the broadband intermediate frequency signals so as to realize channelized processing and parameter measurement of the signals, the FPGA simultaneously outputs processed data to the fusion module through interface communication, and the four-channel acquisition processing module is provided with 3 ADC chips less than the seven-channel acquisition processing module;

the fusion control module is used for cutting side lobes and splicing bandwidths, and comprises an FPGA chip XC7VX690T, FPGA chip XC7K325T, wherein the FPGA chip XC7K325T is connected with an upper computer and used for system control, state reporting and synchronous acquisition control, the FPGA chip XC7VX690T is connected with a computer module and used for collecting, fusing and sending PDW processing results, and the fusion control module is an interaction center and a control center of a main control system and an extension machine and has the main functions of: completing broadband splicing, information fusion, forwarding of system control information, clock generation and synchronous management of the extension, collecting and reporting of extension state information, receiving a signal processing result sent by the acquisition processing module, and interconnecting the signal processing result with the computer module, so that debugging and testing are convenient, and the fusion control module adopts a VPX architecture;

the computer module is used for sorting, identifying, displaying, controlling and storing, and has the main functions of finishing the display of accurate analysis results, finishing the control of each module according to the working flow of the system, further finishing the visual display of the intra-pulse feature analysis results, reading corresponding original data from the four-channel acquisition processing module according to the sorting results, controlling the memory of the multi-channel acquisition processing module to perform ping-pong switching, updating the intra-pulse feature analysis results into full-pulse description word parameters by using the read original data information, and storing the full-pulse description word parameters or intermediate frequency original data into a SATA hard disk of the computer module under the full-pulse description word parameter acquisition mode or the original data acquisition mode.

2. The passive reconnaissance system of claim 1, further comprising a remote control terminal and a power module;

3. The passive reconnaissance system of claim 1, wherein the antenna subsystem comprises a centimeter band antenna array and a millimeter wave band antenna array, the two antenna arrays are four-channel three-baseline interferometer two-dimensional direction finding antenna arrays, wherein each antenna array comprises 7 direction finding antennas and 4 sidelobe cutting antennas.

4. The passive reconnaissance system of claim 1, wherein the centimeter wavefront module and the millimeter wavefront module each comprise a limiter, an attenuator and a first amplifier connected in sequence, the millimeter wavefront module further comprises a mixer and a second amplifier connected in sequence after the first amplifier, the second amplifier is connected with a 22-way switch matrix module, and the 22-way switch matrix receives the upper computer instruction and realizes 22-way second radio frequency signal gating through a built-in signal switch.

5. The passive reconnaissance system of claim 1, wherein the seven-channel acquisition and processing module has 2 groups, the signal input ends of the 2 groups of seven-channel acquisition and processing modules are connected with the signal output ends of the 2 groups of seven-channel frequency conversion and synthesis modules, and the signal output ends of the 2 groups of seven-channel acquisition and processing modules are connected with the signal input ends of the fusion control module;