CN111866620B

CN111866620B - Multi-target measurement and control ground station system

Info

Publication number: CN111866620B
Application number: CN202010658701.XA
Authority: CN
Inventors: 吕春
Original assignee: CHENGDU FOURIER ELECTRONIC TECHNOLOGY CO LTD; Shenzhen SDG Information Co Ltd
Current assignee: CHENGDU FOURIER ELECTRONIC TECHNOLOGY CO LTD; Shenzhen SDG Information Co Ltd
Priority date: 2020-07-09
Filing date: 2020-07-09
Publication date: 2022-03-29
Anticipated expiration: 2040-07-09
Also published as: CN111866620A

Abstract

The multi-target measurement and control ground station system comprises a phased array antenna subsystem, a receiving demodulation subsystem and a data processing and monitoring subsystem. A phased array antenna subsystem comprising: the antenna feed module comprises a planar array antenna and a blind patch linear array antenna; the digital acquisition module is used for carrying out power division, filtering, amplification, down-conversion and AD acquisition digitization on the multi-channel radio frequency signals; the digital beam synthesis module is used for receiving a plurality of paths of digitized target signals and carrying out digital beam forming, and each target correspondingly forms 1 digital beam signal; the receiving and demodulating subsystem comprises a plurality of receiving and demodulating modules for receiving and demodulating a plurality of digital beam signals; and the data processing and monitoring subsystem is used for carrying out unified network time service and real-time monitoring on other equipment in the system. The measurement and control requirements of a plurality of large-airspace aircraft and long-distance space flight targets are met, the problems of intermodulation interference and ENOB compression when the targets are located at different distances are solved, the time service precision is improved, and the system integration is improved.

Description

Multi-target measurement and control ground station system

Technical Field

The invention belongs to the field of communication, relates to multi-target remote measurement/measurement and control, and particularly relates to a multi-target measurement and control ground station system.

Background

The rapid development of weaponry and the improvement of the actual combat requirements of test tasks, the traditional single-machine single-shot target practice test is changed into a multi-machine cooperative formation and multiple confrontation test task, and increasingly urgent needs are provided for the simultaneous multi-target tracking capability of a remote measuring system. The telemetering system used in the flight test is a large airspace and broadband wireless transmission system, has higher requirements on link gain, and meanwhile, the airborne and missile-borne transmitting systems are limited by transmitting power and the aperture of an antenna, and the equivalent radiation power of the airborne and missile-borne transmitting systems is limited in a smaller range, so that the improvement of the link gain mainly depends on the improvement of the equivalent aperture of a receiving antenna of a ground station.

The traditional telemetry ground station antenna servo feed subsystem adopts a parabolic antenna for mechanical tracking, improves receiving gain by increasing the area of the parabolic antenna and meets the requirement of remote sensing and receiving with high bandwidth, but is limited by a mechanical tracking system, and only one telemetry ground station can track and receive the telemetry information of one target. The omnidirectional array antenna needs to improve the gain, the antenna area and the number of feed elements are multiplied, the high-gain antenna is difficult to realize in engineering, and the application range is greatly limited.

CN104459687A discloses a multi-target vehicle-mounted measurement and control system based on a panel self-tracking antenna, which adopts a panel antenna, and uses a panel antenna to correspond to a target, and belongs to a mechanical tracking mode, and multi-target tracking can be realized only by correspondingly arranging a plurality of panels, and essentially, a plurality of traditional mechanical tracking antennas are integrated on a chassis to realize multi-target tracking, and the requirements of simultaneously tracking and receiving a plurality of target telemetering signals by a single antenna are not met. Under such conditions, limited by physical size and weight, the size of the antenna necessarily decreases as the number of antennas mounted on the same chassis increases, with the result that the antenna gain decreases by a power of 2 as the number of antennas increases.

In order to realize multi-target remote measurement and tracking, the measurement and control ground station antenna servo feed subsystem can only select a phased array system. However, the pure digital phased array or the pure analog phased array cannot solve the problems of intermodulation interference and ENOB compression when a plurality of targets are located at different distances, and the cost, the power consumption and the volume are greatly improved along with the increase of the number of the targets, so that the practical engineering application requirements cannot be met. Meanwhile, as a single ground station needs to track multiple targets simultaneously and maintain reliable data transmission, other subsystems in the system need to be optimized and modified aiming at multi-target application. And because the existing telemetering mode adopts IRIG-B code time service, the problems that the cable connection quantity is greatly increased along with the increase of the equipment quantity and the network high-precision time service is caused exist.

Disclosure of Invention

Aiming at the defects and shortcomings of the related prior art, the invention provides a multi-target measurement and control ground station system, which simultaneously meets the measurement and control requirements of a plurality of aviation aircrafts in a large airspace and long-distance space flight targets, solves the problems of intermodulation interference and ENOB compression when the targets are positioned at different distances, improves the time service precision, improves the system integration, and improves the convenience of erection, withdrawal, working mode switching, transportation and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

the multi-target measurement and control ground station system comprises a phased array antenna subsystem, a receiving demodulation subsystem, a data processing and monitoring subsystem and is characterized in that:

a phased array antenna subsystem comprising:

the antenna feed module comprises a plurality of digital-analog mixed planar array antennas and a blind-patch linear array antenna matched with the planar array antennas for use, and is used for receiving spatial signals pitching within the airspace range of 0-90 degrees and outputting multi-path radio frequency signals;

the digital acquisition module is used for performing power division, filtering and amplification on the multi-channel radio frequency signals to obtain a plurality of target frequency band channels, each channel is provided with different signal amplification gains according to the size of a target signal, and then AD acquisition and digitization are performed and then the signals are output through optical fibers; and

the digital beam synthesis module is used for receiving a plurality of paths of digitized target signals and performing digital beam forming, and each target correspondingly forms 1 digital beam signal and then outputs the digital beam signals;

the receiving and demodulating subsystem comprises a plurality of receiving and demodulating modules, is used for receiving and demodulating a plurality of digital beam signals to form PCM code streams, is matched with network time service time and is transmitted to a later stage;

data processing and monitoring subsystem, including:

the network time service module comprises an Ethernet switch which is connected with a plurality of receiving and demodulating modules and supports IEEE1588 protocol exchange and a time frequency controller connected to the switch, so that the time service network integrates a communication network and is used for carrying out unified network time service on other equipment in the system by combining satellite positioning signals and external time system signals to complete time synchronization; and

and the real-time monitoring module is used for monitoring and controlling the state of the whole system, realizing control instruction and state information transmission through an SNMP (simple network management protocol) to monitor the state of network data in real time, and uniformly managing the equipment state of the system and interfaces among subsystems.

Further, the antenna feeder module is configured to sweep the multi-target mode and the long-distance mode in a wide space domain, where a specific long-distance range is related to the transmission power and the transmission bandwidth, and may be a distance range not less than 1000km, where:

under the multi-target mode, a plurality of shaped beams are formed on a pitching surface by adopting a planar array antenna, and a digital multi-beam is formed on a horizontal plane; covering an airspace with the azimuth of +/-45 degrees and the pitching angle of 0-90 degrees together by combining the blind-patch linear array antenna;

further, in a low elevation angle high gain area, the planar array antenna is utilized to realize 0-9-degree airspace shaped beam coverage; in the middle elevation angle area, the shaped beam covering of a 9.0-66.0-degree airspace is realized by utilizing a planar array antenna; in the high elevation angle area, the shaped beam covering of a 66-90-degree airspace is realized by using the blind-filling linear array antenna.

In the long-range mode, the planar array antenna forms a two-dimensional phased array to form a high-gain beam.

Further, the digital acquisition module includes:

the receiving amplification unit is connected with the antenna feeder module and is used for respectively carrying out low-noise amplification on each path of the multi-path radio frequency signals;

the power divider is used for dividing each path of amplified signals into multiple paths of sub-signals;

the band-pass filtering unit is connected with the rear end of the one-to-many power divider and is used for carrying out band-pass filtering processing on each path of sub-signals to form a plurality of sub-bands;

the AGC control unit is connected with the band-pass filtering unit and is used for independently carrying out AGC control on each sub-band according to the strength of the target signal in each different sub-band so as to adjust the size of the target signal;

and the AD acquisition unit is connected with the AGC control unit and used for carrying out down-conversion and AD acquisition on the signals after the AGC is adjusted and converting the signals into digital signals for output.

Further, the digital acquisition module still includes:

the FPGA is matched with the one-in-multiple power divider in quantity, is correspondingly connected with the AD acquisition unit, is used for preprocessing the digital signals and is used for transmitting the preprocessed data to the digital beam forming module through the optical fiber transmission interface;

wherein, the conveying rule is as follows: target signals of the same sub-band are transmitted to the same digital beam synthesis module;

wherein, the pretreatment comprises the following steps:

a standard interface is realized in the FPGA to carry out AD sampling synchronization, an AD data frame is synchronized according to an external synchronization signal, and the sampling data synchronization of each channel is ensured;

realizing a digital local oscillator in the FPGA, realizing preset stepped adjustable frequency shift through the digital local oscillator, and shifting the target signal frequency in the sub-band to zero intermediate frequency to achieve digital shifting of any frequency point;

a variable bandwidth filter is realized in the FPGA to filter out interference signals in a sub-band;

realizing a group delay equalizer of a digital channel in the FPGA, and correcting the inconsistency of in-band group delay;

and realizing an amplitude phase compensation unit in the FPGA, and calculating a compensation value through a calibration algorithm to realize amplitude phase compensation in a configuration mode.

Further, a digital beam forming module comprising: the device comprises an amplitude measuring unit, a capturing unit and a tracking unit, wherein the amplitude measuring unit, the capturing unit and the tracking unit are connected with an FPGA (field programmable gate array), the amplitude measuring unit is connected with an AGC (automatic gain control) unit, the capturing unit is connected with the tracking unit, and the tracking unit is connected with a receiving and demodulating subsystem; wherein:

the amplitude measuring unit is used for measuring the target signal intensity and informing the AGC control unit to reduce the amplification gain when the target signal intensity is greater than a preset signal intensity upper threshold; when the target signal intensity is smaller than a preset signal intensity lower threshold, informing an AGC control unit to improve amplification gain;

the acquisition unit is used for detecting a space domain signal of the target signal, obtaining space signal characteristics by analyzing the space domain signal, and outputting target power information and azimuth information after acquisition;

and the tracking unit is used for tracking the power information and the azimuth information of the target and outputting the digital beam synthesis data for receiving and demodulating when the tracking is normal.

Further, the digital beam forming module further comprises a calibration algorithm unit for performing startup system calibration or off-line calibration, calculating phase consistency and channel consistency difference between each channel through an external input signal, calculating phase compensation and amplitude compensation parameters, and sending the phase compensation and amplitude compensation parameters to an amplitude phase compensation unit of the FPGA of the digital acquisition module, wherein the amplitude phase compensation unit performs calibration through the obtained parameter adjustment signal characteristics.

Further, the network time service module comprises:

the time frequency controller is used for acquiring time code signals from the satellite positioning receiver, generating an IEEE1588 master clock by combining external time system signals and carrying out network unified time service;

the Ethernet switch supporting IEEE1588 protocol exchange internally realizes the IEEE1588 boundary clock function and is connected with a time-frequency controller; and

the Ethernet switch synchronizes an IEEE1588 master clock to the slave clock units of each port of the switch;

each receiving demodulation module is connected with the Ethernet switch through a slave clock unit;

the antenna feeder module, the digital acquisition module and the real-time monitoring module are respectively connected with the Ethernet switch through a slave clock unit.

Through the cooperation of the time frequency controller, the Ethernet switch and the slave clock unit, the time service network integrates the communication network, and combines an external time system signal to perform network time service on other equipment in the system to complete time synchronization, wherein the time synchronization comprises the following steps: frequency and phase synchronization.

A time-frequency controller, comprising: the system comprises a 1588 time server PTP, a clock source, a second pulse unit and a PHY chip, wherein the clock source, the second pulse unit and the PHY chip are connected with the 1588 time server PTP; 1588 the time server PTP is configured to acquire reference time according to the GPS/beidou satellite positioning receiver, acquire an external time system signal through serial port connection, complete clock operation according to a clock source to generate a time service master clock, transmit 1pps through a second pulse unit, and output PTP packet time to a slave clock unit through an ethernet by a PHY chip;

the slave clock unit comprises a PHY chip and an FPGA connected with the PHY chip; the FPGA is used for capturing and processing the Ethernet packet, acquiring the PTP packet time received and output from the PHY chip, calculating delay and offset deviation so as to adjust clock deviation, and acting on the antenna feeder module, the digital acquisition module and the real-time monitoring module to carry out unified network time service.

The system comprises a vehicle body, a phased array antenna subsystem, a receiving demodulation subsystem and a data processing and monitoring subsystem, wherein the vehicle body is movable, and the phased array antenna subsystem, the receiving demodulation subsystem and the data processing and monitoring subsystem are integrated on the vehicle body.

Further, a receive demodulation subsystem comprising: a VPX motherboard; and the plurality of VPX receiving and demodulating modules, the at least one VPX computer main board and the at least one VPX power supply main board are connected with the VPX main board.

The invention has the beneficial effects that:

1. the digital-analog hybrid phased array scheme is adopted to meet the simultaneous remote measurement requirement that a plurality of aerial targets are located at different distances; in the antenna feeder module, a planar array antenna is arranged to be combined with a blind patch linear array antenna, the coverage in the azimuth is +/-45 degrees, and the coverage in the elevation is 0-90 degrees;

2. the problem that small signals are annihilated by large signals due to signal strength difference at different distances when a system receives multi-target telemetry signals is solved, a radio frequency channelization scheme is adopted to divide a working frequency band into a plurality of sub-bands, each sub-band is provided with an independent AGC control unit and can be adapted to receiving signals with different strengths, and the channels have higher isolation; the multi-target signal receiving with the maximum gain not lower than 31.5dB can be realized;

3. the data processing and monitoring subsystem adopts network time service, greatly reduces the number of cables connected with the system, and adopts a network management protocol based on SNMP, so that the whole equipment unifies a network management protocol, simplifies the system design and has comprehensive information; the time service scheme based on IEEE1588 solves the problems that the number of devices in the multi-target remote measurement system is increased and the connected cables need to be greatly increased due to the IRIG-B code time service mode, and the stability and reliability of the system time service are ensured due to the poor anti-interference capability of the IRIG-DC protocol and the high cost; the slave clock scheme adopts the FPGA to capture the Ethernet packet for processing, the PTP packet time output by the PHY chip can be accurately obtained, the clock deviation can be adjusted to the level of 1 clock cycle by calculating the delay and the offset deviation, and the actually achieved time synchronization precision can reach about 10ns when a 100MHz system clock is adopted in the FPGA;

5. the in-band arbitrary frequency point target demodulation is realized by adopting first-stage simulation and first-stage digital frequency spectrum shifting, wherein the first stage adopts AD internal DDC, the second stage adopts FPGA to carry out digital frequency spectrum shifting, the complexity of hardware design is greatly reduced, and the digital frequency shifting index and the applicability are superior to the frequency shifting of a hardware frequency comprehensive circuit;

6. the system is easy to maintain, and the mean time to failure (MTTR) is reduced;

7. the performance index of the system can reach: continuously tracking at least 10 targets in an airspace range; the normal gain of the long-distance mode is not lower than 38dB, and the maximum gain of the multi-target mode is not lower than 31.5 dB; the tracking mode comprises automatic, program control, digital guide, memory, fixed point, waiting and other modes; the blind acquisition capability of not less than 10 targets in an airspace coverage range is achieved in the multi-target mode, and the acquisition time is not more than 1 ms.

Drawings

Fig. 1 is a structural diagram of a multi-target measurement and control ground station system according to an embodiment of the present application.

Fig. 2 is a diagram illustrating a structure of a phased array antenna subsystem according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of an embodiment of an antenna feeder module according to an embodiment of the present application.

Fig. 4 is a schematic diagram illustrating coverage of an antenna feeder module in different areas according to an embodiment of the present application.

Fig. 5 is a structural diagram of a digital acquisition module according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of an example of a digital acquisition module according to an embodiment of the present application.

Fig. 7 is a block diagram of a digital beam forming module according to an embodiment of the present application.

Fig. 8 is a block diagram of a preferred embodiment of a digital beam forming module according to an embodiment of the present application.

Fig. 9 is a diagram of a receiving and demodulating subsystem according to an embodiment of the present application.

Fig. 10 is a diagram illustrating a structure and a connection relationship of a network time service module according to an embodiment of the present application.

Fig. 11 is a schematic structural diagram of an embodiment of a time-frequency controller according to the present application.

Fig. 12 is a schematic structural diagram of an embodiment of a slave clock unit according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

Fig. 1 is a structural diagram of the multi-target measurement and control ground station system of the present embodiment.

The system comprises: the system comprises a phased array antenna subsystem, a receiving and demodulating subsystem, a data processing and monitoring subsystem and a vehicle body.

The phased array antenna subsystem, the receiving demodulation subsystem and the data processing and monitoring subsystem are all integrated on the vehicle body.

Specifically, in this example, the phased array antenna subsystem is configured as shown in fig. 2, and includes an antenna feeder module, a digital acquisition module, and a digital beam forming module.

The antenna feed module comprises a plurality of digital-analog mixed planar array antennas and a blind-patch linear array antenna matched with the planar array antennas for use, and is used for receiving spatial signals pitching within the 0-90-degree airspace range and outputting multi-path radio frequency signals.

Specifically, in this example, an example structure of the planar array antenna and the blind patch array antenna is shown in fig. 3. As a more specific embodiment, the two planar array antennas are provided, and the two complementary blind line array antennas are provided on one planar array antenna respectively; when the antenna is not used, the planar array antenna and the blind patch array antenna are contracted in the vehicle body, so that the transportation is convenient; when the array antenna is applied, the planar array is converted into a vertical state, the blind patch linear array antenna is perpendicular to the planar array antenna and is positioned at the top of the planar array antenna to form two overhead linear arrays. Fig. 3 shows a posture of the planar array antenna and the blind patch array antenna in operation.

The antenna feeder module can work in a large-space wide-scanning multi-target mode and a long-distance mode. The multi-target mode is continuous tracking of not less than 10 targets in an airspace range, the normal gain of a long-distance mode is not less than 38dB, and the maximum gain of the multi-target mode is not less than 31.5 dB. According to the requirements of practical application, switching is performed in advance when the device is used. In some embodiments, the distance may be up to 1000KM, and the multi-target operation mode may be up to 220 KM.

In a long-distance mode, a wave array surface receives a spatial signal, and two-dimensional scanning of a wave beam on a pitching and azimuth plane is realized after control of amplitude limiting, filtering, low-noise amplification and the like; and forming a sum and difference beam pattern by using the two-dimensional sum and difference beam feed network.

Under a large-airspace wide-scanning multi-target mode, performing pitching 90-degree airspace synthesis coverage in a pitching direction through a planar array dual-forming beam plus a blind-supplementary forming linear array to meet the gain envelope requirement required on a pitching surface, wherein the planar array dual-forming beam covers 0-66 degrees, and the blind-supplementary forming linear array covers 66-90 degrees; on the azimuth plane, each planar array covers the azimuth +/-45 degrees through digital multi-beam scanning, and the two columns of blind-patch linear array antennas respectively cover the azimuth 90 degrees through wide beams. 128 radio frequency ports of two area arrays (size 48 x 64) output signals to a back-end digital receiver to complete digital beam scanning in azimuth.

Specifically, as shown in fig. 4, the coverage of the sub-area is: in the low elevation angle high gain area, the shaped beam covering of 0-9 degree airspace is realized by using a planar array antenna; in the middle elevation angle area, the shaped beam covering of a 9.0-66.0-degree airspace is realized by utilizing a planar array antenna; in the high elevation angle area, the shaped beam covering of a 66-90-degree airspace is realized by using the blind-filling linear array antenna.

In the long-range mode, the planar array antenna forms a two-dimensional analog phased array to form high-gain sum-beams and pitch/azimuth difference beams.

The digital acquisition module performs power division, filtering and amplification on the multi-channel radio frequency signals to obtain a plurality of target frequency band channels, each channel sets different signal amplification gains according to the size of the target signal, and then performs AD acquisition digitization and outputs the signals through optical fibers.

Specifically, in this example, the digital acquisition module adopts a structure as shown in fig. 5, and includes a receiving and amplifying unit, a one-to-many power divider, a band-pass filtering unit, an AGC control unit, and an AD acquisition unit.

The receiving amplification unit is connected with the antenna feed module and respectively amplifies each path of the multi-path radio frequency signals by the LNA; the power divider comprises a plurality of one-to-many power dividers, one of the amplified signals is used for dividing each amplified signal into a plurality of paths of sub-signals; the band-pass filtering unit is connected with the rear end of the one-to-many power divider and is used for performing band-pass filtering processing on each path of sub-signals respectively to form a plurality of sub-bands; the AGC control unit is connected with the band-pass filtering unit and respectively and independently performs AGC control on each sub-band according to the strength of the target signal in each different sub-band so as to adjust the size of the target signal; the AD acquisition unit is connected with the AGC control unit, and is used for carrying out down-conversion and AD acquisition on the signals after AGC adjustment and converting the signals into digital signals for output.

As a more specific embodiment, fig. 6 shows an example hardware structure diagram of the digital acquisition module.

The antenna feed module inputs 1-M multi-channel radio frequency signals, each channel of radio frequency signals is divided into 1-N channels through an N-in-one power divider after being subjected to low noise amplification by an LNA (low-noise amplifier), each channel is subjected to corresponding processing by a band-pass filtering unit and an AGC (automatic gain control) control unit, down-conversion is respectively completed in an AD acquisition unit/ADC-1-ADC-N, and then AD acquisition is converted into digital signals. As a more specific implementation scheme, an FPGA is connected behind the AD acquisition units/ADC-1-ADC-N, the number of the FPGAs is matched with one-minute multi-power divider, and one FPGA is correspondingly matched with each sub-band of the one-minute multi-power divider, and the sub-bands are converted into digital signals after being processed.

The power division function of 1-T division of the single-path radio frequency signal is achieved; the multichannel radio frequency signal channelizing function is achieved. The narrow-band filter is used for dividing an antenna input signal into T sub-bands, each sub-band receives a target signal, and the number of the sub-bands can be decomposed according to actual requirements, such as: 10 target signal receptions can be realized by dividing into 10 sub-bands.

Each sub-band is provided with an independent AGC control unit, and the size of a target signal can be adjusted by controlling AGC according to the strength of the target signal in different sub-bands.

AGC rear end AD data acquisition, AD inside has controllable DDC, and AD shifts the frequency to the baseband with the signal before digital-to-analog conversion, and AD inside is fixed frequency point, and AD internal frequency conversion is the first order frequency shift in the system. And after AD acquisition, the signals are converted into a digital domain and sent to the interior of the FPGA.

The FPGA carries out preprocessing on the digital signal and is used for transmitting preprocessing data to the digital beam forming module through the optical fiber transmission interface; wherein, the conveying rule is as follows: and in the radio frequency signals of different input paths, target signals of the same sub-band are transmitted to the same digital beam synthesis module.

Specifically, in the FPGA, the following preprocessing is performed:

a JESD204B standard interface is realized in the FPGA to carry out AD sampling synchronization, an AD data frame is synchronized according to an external synchronization signal, and the synchronization of sampling data of each channel is ensured.

A digital local oscillator is realized in the FPGA, 50kHz stepping adjustable frequency shift is realized through the digital local oscillator, the target signal frequency in a sub-band is shifted to zero intermediate frequency, digital shift of any frequency point is achieved, and secondary frequency shift is realized.

A variable bandwidth filter is implemented in the FPGA to filter out the interference signals in the sub-band.

A group delay equalizer of a digital channel is realized in the FPGA, and the inconsistency of in-band group delay is corrected, so that the problem that the group delay of signals in sub-bands fluctuates due to the nonlinear characteristic of devices in the analog channelization process is solved, and the great influence on the demodulation performance of back-end data is avoided.

Specifically, the digital beam forming module receives multiple paths of digitized target signals and performs digital beam forming, and each target correspondingly forms 1 digital beam signal and then outputs the digital beam signals.

In this example, the digital beam forming module adopts a structure as shown in fig. 7, and includes an amplitude measuring unit, an acquiring unit, and a tracking unit, where the amplitude measuring unit, the acquiring unit, and the tracking unit are connected to the FPGA, the amplitude measuring unit is connected to the AGC control unit, the acquiring unit is connected to the tracking unit, and the tracking unit is connected to the receiving and demodulating subsystem.

Specifically, the amplitude measuring unit measures the target signal intensity, and when the target signal intensity is greater than a preset signal intensity upper threshold, a measured value is given and provided to the AGC control unit to reduce the amplification gain; when the target signal intensity is smaller than a preset signal intensity lower threshold, a measured value is given and provided for an AGC control unit to improve amplification gain; the acquisition unit detects a space domain signal of the target signal, obtains space signal characteristics by analyzing the space domain signal, and outputs target energy information and azimuth information after acquisition; the tracking unit tracks the energy information and the azimuth information of the target, and outputs digital beam synthesis data for receiving and demodulating when tracking is normal.

Preferably, the digital beam forming module further comprises a calibration algorithm unit, and the digital beam forming module structure of the preferred embodiment is as shown in fig. 8.

The calibration algorithm unit is connected with the FPGA, the calibration algorithm unit is used for carrying out startup calibration, phase consistency and channel consistency difference among channels are calculated through external input signals, phase compensation and amplitude compensation parameters are calculated and sent to an amplitude phase compensation unit of the FPGA of the digital acquisition module, and the amplitude phase compensation unit is used for carrying out calibration through the obtained parameter adjustment signal characteristics.

Specifically, the digital beam forming module may adopt a VPX 6U standard chassis design, uses a backplane as a carrier, and the functional module is connected with the backplane and performs data interaction in a form of a plug-in card, including a VPX chassis, a VPX power supply, a beam forming board, and the like.

In this embodiment, the receiving and demodulating subsystem includes a plurality of receiving and demodulating modules, which are used to receive and demodulate a plurality of digital beam signals to form a PCM code stream, and output the PCM code stream to the data processing and monitoring subsystem through a gigabit ethernet.

Specifically, in this example, the example hardware configuration of the receiving and demodulating subsystem may adopt a scheme as shown in fig. 9, including: a VPX motherboard; and the plurality of VPX receiving and demodulating modules, the at least one VPX computer main board and the at least one VPX power supply main board are connected with the VPX main board. The selected VPX receiving and demodulating module has the functions of receiving and demodulating telemetering signals of a PCM-FM system, a PCM-BPSK system and a PCM-QPSK system, the PCM-FM system has the functions of multi-symbol detection (MSD), TPC decoding and the like, and system working parameters and transmission and demodulation data are set through a network.

And the VPX motherboard is used for completing data transmission between the computer motherboard and each functional board card.

And the VPX computer mainboard is used for receiving the local control of the demodulation module.

And the VPX power supply mainboard is used for providing power for the receiving and demodulating subsystem.

In this example, the data processing and monitoring subsystem is used for performing network time service, data display and real-time monitoring on other devices in the system. The data processing and monitoring subsystem comprises a network time service module and a real-time monitoring module.

The network time service module comprises an Ethernet switch which is connected with a plurality of receiving and demodulating modules and supports IEEE1588 protocol exchange and a time frequency controller connected to the switch, so that the time service network integrates a communication network and is used for carrying out unified network time service on other equipment in the system by combining a satellite positioning signal and an external time system signal to complete time synchronization.

The real-time monitoring module monitors and controls the state of the whole system, monitors the state of the system, monitors the ground in real time, plays back data afterwards and the like, realizes the transmission of control instructions and state information through an SNMP (simple network management protocol) so as to monitor the state of network data in real time, and manages the equipment state and subsystem interfaces of the system in a unified way.

As a specific embodiment of the network time service module, as shown in fig. 9, the network time service module includes: the time frequency controller, the Ethernet switch supporting IEEE1588 protocol exchange, the slave clock unit and the like.

The time frequency controller acquires a time code signal from the satellite positioning receiver, and generates an IEEE1588 master clock by combining an external time system signal to carry out network time service; the Ethernet switch realizes the IEEE1588 boundary clock function and is connected with the time frequency controller; the Ethernet switch synchronizes an IEEE1588 master clock to the slave clock units of each port of the switch; each receiving demodulation module, each antenna feeder module, each digital acquisition module and each real-time monitoring module are respectively connected with the Ethernet switch through a slave clock unit.

Through the cooperation of the time frequency controller, the Ethernet switch and the slave clock unit, the time service network integrates the communication network, and the satellite positioning signal and the external time system signal are combined to carry out unified network time service on other equipment in the system, so as to complete time synchronization, wherein the time synchronization comprises the following steps: frequency and phase synchronization.

A demodulation subsystem in the multi-target telemetry system is provided with a plurality of demodulation devices, each device needs to be timed independently, and each demodulation device can be connected to an internal exchanger supporting IEEE1588 protocol exchange independently. Therefore, the whole time service network integrates the communication network, and the problems of complexity and stability caused by the adoption of an extra time service cable are greatly simplified.

As a more specific implementation, the time-frequency controller adopts a structure as shown in fig. 10, including: the system comprises a 1588 time server PTP, a clock source, a second pulse unit and a PHY chip, wherein the clock source, the second pulse unit and the PHY chip are connected with the 1588 time server PTP; 1588 the PTP of the time server generates a time service master clock with the highest precision, acquires reference time according to the GPS/Beidou satellite positioning receiver, acquires an external time system signal through serial port connection, completes clock operation according to a clock source, sends 1pps through a second pulse unit, and outputs PTP package time to a slave clock unit through the PHY chip and the Ethernet.

As a more specific embodiment, the slave clock unit has a structure as shown in fig. 10, and includes a PHY chip and an FPGA connected to the PHY chip. The Ethernet PTP package is analyzed inside the FPGA, and the frequency deviation and the phase deviation between the master clock and the slave clock are determined by calculating the time delay sent by the master clock and the slave clock. Specifically, the FPGA captures an ethernet packet for processing, obtains PTP packet time received and output from the PHY chip, and calculates delay and offset deviation to adjust clock deviation, and acts on the antenna feeder module, the digital acquisition module, and the real-time monitoring module to perform time synchronization. When a 100MHz system clock is adopted in the FPGA, the actual time synchronization precision can reach about 10 ns.

According to the time service scheme, the time system and the communication are realized by adopting the same network, the number of cable connections among equipment in the system is greatly reduced, the time system is more robust in realization mechanism, the stability and the reliability of the time system can be greatly improved, the transmission path compensation function is realized, the synchronization precision of each equipment in the system is higher, and the ns level can be reached.

The data processing and monitoring subsystem of the embodiment has the functions of demodulating data received by the measurement and control ground station, carrying out network time service, monitoring the system state, monitoring the ground in real time, replaying data afterwards and the like in the aircraft test process. A plurality of devices are independently connected to a switch which internally supports IEEE1588 protocol exchange, and a time service network is integrated with a communication network; meanwhile, an SNMP (simple network management protocol) is adopted for multiple targets to realize high-efficiency control instruction and state information transmission, the state of network data is monitored in real time, the dynamic management function of the network is added, the fault alarm and the auxiliary decision of the state of system equipment are realized, the management interfaces of all subsystems are unified, and the complex cable connection caused by adopting extra time service is avoided.

A plurality of subsystems of the system all adopt a VPX architecture, modular stacking is realized, the design complexity of the system is greatly reduced, and the expandability and the universality of the system are effectively improved. The whole system is integrated on the vehicle body, and the vehicle body can adopt a single vehicle form of the cross-country chassis, thereby being beneficial to realizing high maneuverability, quick erection, withdrawal and the like of the system.

Claims

1. The multi-target measurement and control ground station system comprises a phased array antenna subsystem, a receiving demodulation subsystem, a data processing and monitoring subsystem and is characterized in that:

a phased array antenna subsystem comprising:

the digital acquisition module is used for performing power division, filtering and amplification on the multi-channel radio frequency signals to obtain a plurality of target frequency band channels, each channel is provided with different signal amplification gains according to the size of a target signal, and then AD acquisition and digitization are performed and then the signals are output through optical fibers; the digital beam synthesis module is used for receiving multi-path digital target signals and carrying out digital beam forming, and each target correspondingly forms 1 digital beam signal and then outputs the digital beam signals;

data processing and monitoring subsystem, including:

the network time service module comprises an Ethernet switch which is connected with a plurality of devices and supports IEEE1588 protocol exchange and a time frequency controller connected with the switch, so that the time service network integrates a communication network and is used for carrying out unified network time service on other devices in the system by combining satellite positioning signals and external time system signals to complete time synchronization; and

2. The multi-target measurement and control ground station system according to claim 1, wherein the antenna feeder module is configured to perform wide-scanning multi-target mode and long-distance mode in a large airspace, wherein:

in the low elevation angle and high gain area, the planar array antenna is utilized to realize 0-9 degree space domain shaped beam coverage; in the middle elevation angle area, the shaped beam covering of a 9.0-66.0-degree airspace is realized by utilizing a planar array antenna; in a high elevation angle area, the shaped beam coverage of a 66-90-degree airspace is realized by using a blind-patch linear array antenna;

3. The multiple-target measurement and control ground station system according to claim 1, wherein the digital acquisition module comprises:

4. The multiple-target measurement and control ground station system according to claim 3, wherein the digital acquisition module further comprises:

wherein, the pretreatment comprises the following steps:

5. The multiple target measurement and control ground station system according to claim 4, wherein the digital beam forming module comprises: the device comprises an amplitude measuring unit, a capturing unit and a tracking unit, wherein the amplitude measuring unit, the capturing unit and the tracking unit are connected with an FPGA (field programmable gate array), the amplitude measuring unit is connected with an AGC (automatic gain control) unit, the capturing unit is connected with the tracking unit, and the tracking unit is connected with a receiving and demodulating subsystem; wherein:

6. The system according to claim 5, wherein the digital beam forming module further comprises a calibration algorithm unit for performing a startup system calibration or an off-line calibration, calculating a phase consistency and a channel consistency difference between each channel through an external input signal, calculating a phase compensation and amplitude compensation parameter, and sending the calculated phase compensation and amplitude compensation parameter to an amplitude phase compensation unit of the FPGA of the digital acquisition module, wherein the amplitude phase compensation unit performs the calibration through the obtained parameter adjustment signal characteristic.

7. The multi-target measurement and control ground station system according to claim 1, wherein the network time service module comprises:

the time frequency controller is used for acquiring time code signals from the satellite positioning receiver, performing unified network time service by combining external time system signals and generating an IEEE1588 master clock;

each receiving demodulation board module is connected with the Ethernet switch through a slave clock unit;

the antenna feeder module, the digital acquisition module and the real-time monitoring module are respectively connected with the Ethernet switch through a slave clock unit;

through the cooperation of time frequency controller, ethernet switch, from the clock unit jointly, make time service network collect communication network as an organic whole, combine outside time system signal to each receive demodulation module, antenna feeder module, digital acquisition module, real-time monitoring module and carry out the network time service, accomplish time synchronization, time synchronization includes: frequency and phase synchronization.

8. The multi-target measurement and control ground station system of claim 7,

the slave clock unit comprises a PHY chip and an FPGA connected with the PHY chip; the FPGA is used for capturing and processing the Ethernet packet, acquiring the PTP packet time received and output from the PHY chip, calculating delay and offset deviation so as to adjust clock deviation, and acting on the antenna feeder module, the digital acquisition module and the real-time monitoring module to perform time synchronization.

9. The system of claim 1, further comprising a vehicle carrying subsystem, wherein the vehicle carrying subsystem comprises a movable vehicle body, and the phased array antenna subsystem, the receiving demodulation subsystem and the data processing and monitoring subsystem are integrated with the vehicle body.