CN118264309A - Equipment and control software for monitoring, positioning and interfering low-orbit satellite internet terminal - Google Patents

Abstract

The application discloses equipment and control software for monitoring, positioning and interfering a low-orbit satellite Internet terminal, and relates to the technical field of low-orbit satellite terminal monitoring and control, wherein the satellite terminal monitoring and control equipment comprises a signal source, an up-conversion module, a power division network module, a plurality of phased array transmitting subarrays, an antenna control unit, a GNSS module, an inertial navigation module, a receiver, a plurality of down-conversion modules and a plurality of phased array receiving subarrays; the signal source is used for generating L, S or C frequency band signals, and feeding L, S or C frequency band signals into a plurality of phased array transmitting subarrays after passing through the up-conversion module and the power division network module; the down-conversion module is used for down-converting signals received by the phased array receiving subarrays to L, S or C frequency bands and inputting the signals to the receiver; the antenna control unit is used for controlling the inertial navigation module and the GNSS module to compensate beam pointing. The application realizes the miniaturization of satellite terminal monitoring and controlling equipment, the whole set of subsystem meets the IP65 protection level, and the application meets various use scenes such as fixation, vehicle-mounted, ship-mounted, airborne, moving and the like through dust-proof, moisture-proof and salt fog-proof tests.

Description

Equipment and control software for monitoring, positioning and interfering low-orbit satellite internet terminal

Technical Field

The application relates to the technical field of low-orbit satellite terminal monitoring and control, in particular to a satellite monitoring and guiding terminal monitoring method and satellite terminal monitoring and control equipment.

Background

With the rapid development of satellite communication applications such as Space X star chain and Mate60 satellite direct communication in the United states, the satellite Space communication technology has become the focus field of the global technology industry. The giant low-orbit satellite constellation is combined with high-orbit satellites and navigation satellites to deeply integrate the technical conception of the mobile communication technologies such as 6G and the like to realize the space-earth integrated communication. No matter the government regulatory agencies and commercial operations agencies, the unprecedented test measurement and monitoring challenges presented by low-orbit satellites are faced.

At present, a scheme for monitoring and controlling a terminal mostly adopts a parabolic antenna or an omnidirectional antenna to receive uplink signals of a satellite terminal existing in a peripheral area by combining a receiver, a direction finder and other equipment, and the radius of the uplink signals is approximately 10 km in an open field. And the received terminal uplink signal (the signal has the problem of frequency switching in the single call process) can be analyzed to obtain parameters such as frequency points, bandwidth, modulation modes and the like used by the terminal, and the number of the terminals in parallel in the same scene can be determined. Meanwhile, the matched direction finding machine can give out the geographic position and the moving track of the terminal. And by combining equipment such as an interference antenna, a signal source and the like, the device sends out an analog simulation radio frequency signal, and can realize interference suppression on terminals in an area.

Currently, existing solutions have several drawbacks:

1. Because the geographic environment of the ground is special, the shielding is relatively large, the loss is large, the action distance is short, the applicability is not very strong because a parabolic antenna mode is adopted at present, the parabolic antenna is required to be matched with a power amplifier module for use, and the size and the weight of the power amplifier are relatively large, so that the power amplifier is not suitable for moving and mounting on aerial platforms such as unmanned aerial vehicles, airships and the like;

2. The time of beam switching and the scanning time of a target area are relatively long, uplink signals of a terminal may be missed during monitoring, and full acquisition cannot be realized;

3. Because most of the positioning methods are used on the ground, the attenuation of the received signals is serious, so that the received signal strength is low, the errors of the final measurement analysis and the positioning result are large, high-precision positioning cannot be realized, and the precise position of the terminal cannot be captured.

4. The main disadvantages of omni-directional antennas are low radiation efficiency, weak signals obtained, susceptibility to multipath and clutter interference. In addition, because the radiation direction evenly distributed of omnidirectional antenna can cause the waste of partial antenna resource this moment, when omnidirectional antenna carries out the location, need cooperate the direction finding machine to use, increased construction cost, and can't realize integrated design.

Disclosure of Invention

Therefore, the application provides a satellite monitoring and guiding terminal monitoring method and satellite terminal monitoring and controlling equipment, which are used for solving the problems that the volume of a paraboloid is large, the small-sized integrated design cannot be realized, the beam switching time is long, the full acquisition cannot be realized, and the positioning precision is low when the monitoring is carried out by adopting a paraboloid antenna in the prior art.

In order to achieve the above object, the present application provides the following technical solutions:

in a first aspect, a satellite monitoring device monitors a satellite in a target area, and after monitoring a downlink signal of the satellite, the satellite monitoring device and an antenna are automatically guided to monitor an uplink signal of a terminal.

The guidance monitoring technology can configure the strategy and tasks of guidance monitoring. The configuration of parameters such as the duration of the ground monitoring scanning, the stepping, the beam pointing, the azimuth angle, the rotating speed of the servo turntable and the like can be set, the strategy and the parameter setting can be supported and saved, and the loading and the execution of the parameters and the strategies can be directly carried out when the next task is carried out.

In the guide monitoring technology, after a guide monitoring task is created, the system automatically identifies task data information, and the automatic task is combined with task database data, so that consistency and usability of the task data are ensured. The manual task immediately invokes the execution and returns the receipt data information.

Preferably, the terminal signal is received by adopting phased array receiving antennas of four subarrays, the target uplink signal is received by four beams simultaneously by adjusting the beam directions of the subarrays, the signals received by the four subarrays are calculated and analyzed, and the phase difference of the signals received by each subarray is utilized to carry out phase comparison method direction finding by a single pulse direction finding technology.

Preferably, the detected uplink signal information of the terminal is visually displayed, wherein the detected uplink signal information comprises monitoring abnormality, and the monitoring task is set with strategy information which needs manual operation, so that the terminal can be quickly jumped to the operation interface of each module. The early warning data may be presented in a list or in a switching chart.

Preferably, the signal modulation type recognition mainly analyzes, detects and recognizes various satellite communication signal systems, and determines the parameter capacities of modulation patterns, carrier frequencies, bandwidths, symbol rates, communication protocols, signal characteristics and the like and certain data demodulation capacities; the time-frequency domain analysis, the modulation domain analysis and the system domain analysis can be performed on the scout signal.

Preferably, the smart interference to the terminal adopts a pseudo code sequence with larger correlation with the pseudo code sequence of the target signal to generate periodic cyclic pulse signals with the same working frequency point, the same working bandwidth, the same frame length, the same OFDM parameters and slightly higher transmitting power, thereby interfering the downlink timing synchronization of the low-orbit satellite Internet terminal and influencing the normal establishment of a downlink communication link between the terminal and the low-orbit satellite.

Preferably, in the interference suppression process, the uplink signal of the satellite communication terminal can be received and analyzed at the same time, the measurement and calculation are performed according to the received signal parameters, the information items such as the working frequency, the bit error rate, the transmission rate, the signal to noise ratio and the like of the signal are analyzed, the interference suppression effect is compared and evaluated with the measurement result when no interference exists, and the relevant parameters of the interference suppression are adjusted timely according to the evaluation condition.

On the other hand, the two-dimensional active phased array antenna design technology is characterized in that the receiving antenna design adopts a mode of splicing four subarrays, each Ku frequency band or Ka frequency band receiving subarray is a two-dimensional electric scanning active phased array receiving subarray developed by means of a beam forming transmitting chip and a high-efficiency array antenna, and each subarray is integrated with 256 fully polarized receiving antenna units, 64 Beamformer receiving chips, a passive power combination feed network, a signal driving chip, a beam control circuit, a power supply circuit, an interface and the like on a single printed circuit board.

Preferably, the servo turntable is used for installing a back feed antenna load, and the antenna turntable can be inversely arranged on an aerial platform such as an airship, an unmanned aerial vehicle and the like to perform ground scanning.

Preferably, after the device monitors and locates the terminal downlink signal, the system cooperates with the phased array antenna, the servo turntable device and the transceiver to perform signal detection, signal analysis, terminal location and terminal interference.

Preferably, the received uplink signals of the multiple paths of terminals can be measured simultaneously, and the equivalent radiation power (EIRP) of the target terminal is calculated by measuring the carrier frequency, the signal bandwidth, the carrier power, the signal-to-noise ratio (C/N), the Power Flux Density (PFD) and the like of the signals through parameter measurement algorithms in the system, including a signal-to-noise ratio algorithm, a carrier-to-noise ratio algorithm, a signal bandwidth algorithm, a power flux density algorithm and an equivalent radiation power algorithm.

Compared with the prior art, the application has at least the following beneficial effects:

The application provides a method for monitoring a satellite monitoring guide terminal, which monitors a satellite in a target area through satellite monitoring equipment, and automatically guides the terminal monitoring equipment and an antenna to monitor an uplink signal of the terminal after monitoring a downlink signal of the satellite. The satellite terminal is monitored daily, a multi-beam two-dimensional active phased array antenna mode is matched with a multi-channel broadband monitoring acquisition receiver to rapidly scan a ground target area, automatic multi-beam scanning, single-terminal gaze tracking monitoring, scanning and gaze parallel monitoring, communication service all-channel monitoring and the like are carried out, after uplink service signals are found, warning is carried out, corresponding evidences (spectrograms, waterfall diagrams and the like, demodulation information and the like) are saved, and a positioning function is started in an automatic or manual mode to accurately position the terminal; and the phased array transmitting antenna and the servo turntable are utilized to realize interference suppression on the terminal of the satellite downlink signal in the target area.

The application also provides a two-dimensional active phased array antenna design technology, which is characterized in that the receiving antenna design adopts a mode of splicing four subarrays, each Ku frequency band or Ka frequency band receiving subarray is a two-dimensional electric scanning active phased array receiving subarray developed by means of a beam forming transmitting chip and a high-efficiency array antenna, and each subarray is integrated with 256 full-polarization receiving antenna units, 64 Beamformer receiving chips, a passive power combination feed network, a signal driving chip, a beam control circuit, a power supply circuit, an interface and the like on a single printed circuit board.

Drawings

In order to more intuitively illustrate the prior art and the application, exemplary drawings are presented below. It should be understood that the specific shape and configuration shown in the drawings are not generally considered limiting conditions in carrying out the application; for example, those skilled in the art will be able to make routine adjustments or further optimizations for the addition/subtraction/attribution division, specific shapes, positional relationships, connection modes, dimensional proportion relationships, and the like of certain units (components) based on the technical concepts and the exemplary drawings disclosed in the present application.

FIG. 1 is a flow chart of a satellite-to-ground monitoring guidance provided in a first embodiment of the application;

fig. 2 is a diagram of a phased array receiving antenna according to a second embodiment of the present application;

Fig. 3 is a diagram of a phased array transmitting antenna according to a second embodiment of the present application;

fig. 4 is a schematic diagram of a Ku frequency band or Ka frequency band receiving sub-array according to a second embodiment of the present application;

fig. 5 is a schematic diagram of a Ku frequency band or Ka frequency band emission subarray according to a second embodiment of the present application;

FIG. 6 is a schematic diagram of a signal processing flow according to a first embodiment of the present application;

reference numerals illustrate:

1. phased array receiving subarrays; 2. a down-conversion module; 3. a receiver; 4. a GNSS module; 5. an inertial navigation module; 6. an antenna control unit; 7. a signal source; 8. an up-conversion module; 9. phased array transmit subarrays.

Detailed Description

The application will be further described in detail by means of specific embodiments with reference to the accompanying drawings.

In the description of the present application: unless otherwise indicated, the meaning of "a plurality" is two or more. The terms "first," "second," "third," and the like in this disclosure are intended to distinguish between the referenced objects without a special meaning in terms of technical connotation (e.g., should not be construed as emphasis on the degree of importance or order, etc.). The expressions "comprising", "including", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

The terms such as "upper", "lower", "left", "right", "middle", and the like, as used herein, are generally used for the purpose of facilitating an intuitive understanding with reference to the drawings and are not intended to be an absolute limitation of the positional relationship in actual products.

Example 1

Referring to fig. 1, the present embodiment provides a method for monitoring a star monitoring guide pair terminal, including:

S1: when the system is started, about 30 seconds are needed to acquire geographic information (longitude, latitude and altitude) and attitude information (heading, pitching and rolling) of the place where the system is located, and meanwhile, an ACU unit is started to calibrate the system. At this time, the system should be in a stationary state, if the system is required to work in motion, the system can be calibrated after the system is calibrated.

S2: and generating an optimal beam polling and tracking scheme according to the ephemeris data and the mission plan, and controlling the beam to monitor and receive the satellite signal.

(3) After the satellite downlink signals are found, the ground scanning is started, 4 wave beams are respectively scanned in a target area, the terminal uplink signals are monitored and collected, the satellite monitoring equipment can not be used for detecting the downlink signals, an airship, an unmanned aerial vehicle and other aerial platforms can be directly flown to a designated position, and the four wave beams of a phased array antenna are started to perform blind scanning and receiving on the terminal uplink signals in the target area.

(4) After a certain beam finds the terminal uplink signal of the target area, signal analysis is performed on the received signal, and the carrier frequency, the signal bandwidth, the carrier power, the signal-to-noise ratio (C/N), the Power Flux Density (PFD) and the like are analyzed to measure, and the equivalent radiation power (EIRP) of the target terminal is calculated.

(5) And finding out a terminal uplink signal of the target area, indicating that the beam direction is the approximate position of the terminal, adjusting the other 3 beams, simultaneously concentrating the 4 beams, and carrying out single-pulse direction finding on the terminal to obtain the accurate position of the target terminal.

(6) If the four channels all have target signals, the acquisition, analysis and positioning can be performed simultaneously; if only 1 channel has target signal, 1 channel can track wave beam and collect, and the other three channels can execute round inspection analysis work.

(7) And when the signals are analyzed, the phased array transmitting antenna can be started to transmit the signals in different modulation modes, different bandwidths and different powers.

The working principle of the method for monitoring the star monitoring and guiding the terminal monitoring provided by the embodiment is as follows.

The signals sent by the satellite terminals are directed to the communication satellites in a spot beam mode, adjustment is continuously made according to the change of satellite positions, and although the radio signals sent by the ground terminals are monitored in the air, the radio signals have better propagation paths than the radio signals monitored on the ground, the number of satellites is large, the positions are not fixed, and the monitoring positions are only very small in probability of being in the coverage area of the main lobe signals sent by the terminals, so that the radio signals can only be the side lobe signals of the detection terminals. The ground terminal is provided with two scanning modes, one is blind scanning, the ground coverage area of the detection equipment is directly and sequentially scanned, the other is satellite downlink signal guiding scanning, the satellite-to-satellite monitoring equipment can be used, when the satellite downlink signal is found in the area, the terminal can be known to communicate in the area, and at the moment, the strategies of four-beam scanning, positioning, ground interference and the like can be used for the ground phased array antenna.

The first step: after the ground scanning is started and an airship or an unmanned plane and other aerial platforms reach a designated position, equipment can be directly started to perform blind scanning on a target area; the method of monitoring and guiding the satellite can also be adopted, and when the downlink signal of the satellite is found, the ground scanning is started automatically.

And a second step of: when the subarea scanning is performed on the ground, the coverage area of the detection equipment on the ground is divided into 4 small areas, four beams are started to scan the small areas respectively, meanwhile, the servo turntable is rotated, the main lobe visual axis of the subarray is synchronously adjusted to perform continuous step scanning in the horizontal and elevation angles, and the detection of terminal signals in the target area are realized.

And a third step of: after locating the terminal uplink signals in the discovery area, adjusting the beam directions of the other three beams, simultaneously detecting the terminal signals, and when the signals received by the subarray enter the channel receiver, performing positioning algorithm related processing on the received four paths of signals to obtain the azimuth and elevation information of the terminal.

When the azimuth angle of the main lobe of the phased array rotates to the azimuth of the terminal of the interference source, each receiving subarray receives an uplink side lobe signal of a target signal, and the target can be scanned through a single pulse direction finding algorithm so as to accurately position the target, so that the area of the terminal is obtained.

Fourth step: after the position of the terminal is obtained by pressing, the phased array antenna can be used for pressing, and a terminal pressing module transmitter is started. The transmitting part is provided with a phased array antenna, and the half power beam angle of the downlink frequency band in the Ku frequency band or the Ka frequency band is less than 3 degrees.

In the terminal hold-down module, the signal source (transceiver) may select different modulation signal types.

Fifth step: in the interference suppression process, the uplink signal of the satellite terminal can be received and analyzed at the same time, the interference suppression effect is evaluated, and relevant parameters of the interference suppression are adjusted timely according to the evaluation condition so as to achieve the optimal interference effect.

According to the technology for monitoring the terminal by the satellite monitoring guidance, the satellite can be monitored in the target area through the satellite monitoring equipment, and after the satellite downlink signal is monitored, the terminal monitoring equipment and the antenna are automatically guided to monitor the uplink signal of the terminal.

The guidance monitoring technology can configure the strategy and tasks of guidance monitoring. The configuration of parameters such as the duration of the ground monitoring scanning, the stepping, the beam pointing, the azimuth angle, the rotating speed of the servo turntable and the like can be set, the strategy and the parameter setting can be supported and saved, and the loading and the execution of the parameters and the strategies can be directly carried out when the next task is carried out.

In the guide monitoring technology, after a guide monitoring task is created, the system automatically identifies task data information, and the automatic task is combined with task database data, so that consistency and usability of the task data are ensured. The manual task immediately invokes the execution and returns the receipt data information.

The technology for guiding the satellite monitoring to the terminal monitoring provided by the embodiment also refers to a terminal uplink signal receiving and measuring technology, which can measure the received uplink signals of multiple paths of terminals simultaneously, and measures the carrier frequency, the signal bandwidth, the carrier power, the signal-to-noise ratio (C/N), the Power Flux Density (PFD) and the like of the signal through parameter measurement algorithms in the system, including a signal-to-noise ratio algorithm, a carrier-to-noise ratio algorithm, a signal bandwidth algorithm, a power flux density algorithm and an equivalent radiation power algorithm, and calculates the equivalent radiation power (EIRP) of the target terminal.

The implementation scheme of each module of the control software of this embodiment is as follows:

1. command control module

The command control module is mainly used for monitoring and controlling all equipment in the system, and realizing the self-checking of the phased array antenna equipment, the two-dimensional servo turntable equipment, the upper computer, the master control server and the equipment of the power supply, the servo turntable and the calibration of the phased array antenna; the fact monitoring of each device state; and real-time control of the phased array antenna, the broadband receiver and the servo turntable is realized.

2. Guiding monitoring task management module

The guiding and monitoring means that the satellite monitoring equipment monitors the XL satellite in the target area, and after the satellite downlink signal is monitored, the terminal monitoring equipment and the antenna automatically guide to monitor the uplink signal of the terminal, so that the strategy and the task of guiding and monitoring can be configured.

3. Multi-beam control module

The multi-beam control realizes the beam planning and the configuration of multi-beam planning strategies for the four-beam earth monitoring phased array antenna, can configure the four-beam to simultaneously carry out regional scanning on the earth, directly adjusts the other three beams to come after one beam finds out signals, simultaneously detects the signals, carries out single-pulse direction-finding positioning, and can reconfigure the pointing directions of the four beams after the positioning is finished. Such as: one beam performs gaze tracking on the signal and the other three beams continue scanning in the area until a new terminal uplink signal is found or the task is cut off. It is also possible to directly forgo monitoring the signal and plan the four beams for zone scanning in the area until a new terminal uplink signal is found or the task is cut off.

4. Guide interference suppression module

After the uplink signal of the terminal is monitored and positioned, the system cooperatively controls the phased array antenna to execute interference suppression on the terminal, and when the interference suppression is carried out, the system can automatically mobilize a signal source (transceiver) and automatically configure parameters such as frequency, modulation mode, transmitting power and the like of a simulation signal according to the monitored uplink signal and the measured result of the parameters, and realize the interference suppression on the target terminal. The suppression modes and strategies include targeted interference, blocking interference, swept interference, forwarded interference, and smart interference.

5. Equipment cooperative control module

After the equipment monitors and locates the uplink signal of the terminal, the system cooperates with the phased array antenna, the servo turntable equipment and the transceiver to realize the functions of signal detection, signal analysis, terminal location and terminal interference.

6. Interference effect evaluation module

In the interference suppression process, the uplink signal of the satellite terminal can be received and analyzed at the same time, the measurement and calculation are carried out according to the received signal parameters, the information items such as the working frequency, the bit error rate, the transmission rate, the signal to noise ratio and the like of the signal are analyzed, the interference suppression effect is evaluated, and the relevant parameters of the interference suppression are adjusted timely according to the evaluation condition.

7. Monitoring and early warning display module

The visual display of the detected terminal uplink signal information comprises monitoring abnormality, and the monitoring task sets strategy information which needs manual operation, so that the operation interface of each module can be quickly skipped. The early warning data may be presented in a list or in a switching chart.

8. XL terminal signal parameter measurement

The received multipath signals can be measured simultaneously, and the equivalent radiation power (EIRP) of the target terminal is calculated by measuring the carrier frequency, the signal bandwidth, the carrier power, the signal-to-noise ratio (C/N), the Power Flux Density (PFD) and the like of the signals through parameter measurement algorithms in the system, including a signal-to-noise ratio algorithm, a carrier-to-noise ratio algorithm, a signal bandwidth algorithm, a power flux density algorithm and an equivalent radiation power algorithm.

The embodiment can control various devices integrated in the system in an instruction control mode to realize resource scheduling of the various devices.

Example two

Referring to fig. 2 and 3, the present embodiment provides a satellite terminal monitoring and controlling device (simply referred to as a monitoring and controlling device), where a receiving portion includes a phased array receiving subarray 1, a down-conversion module 2, a receiver 3, a GNSS module 4, an inertial navigation module 5, and an antenna control unit 6; the transmitting part comprises a signal source 7, an up-conversion module 8, a phased array transmitting subarray 9, an antenna control unit 6, a GNSS module 4 and an inertial navigation module 5. The whole set of monitoring equipment meets the IP65 protection level, and can meet various use scenes such as fixation, vehicle-mounted, ship-mounted, airborne, movement and the like through dust-proof, moisture-proof and salt fog-proof tests.

The signal source 7 is used for generating L, S or C frequency band signals, and up-converting L, S or C frequency band signals to a Ku frequency band or a Ka frequency band through the up-conversion module 8 and then feeding the signals into the phased array transmitting subarray 9; the down-conversion module 2 is used for down-converting the Ku frequency band or the Ka frequency band signals received by the phased array receiving subarrays 1 to L, S or the C frequency band and inputting the signals to the receiver 3; the antenna control unit 6 is used for controlling the inertial navigation module 5 and the GNSS module 4 to compensate beam pointing, and controlling the phased array transmitting subarray 9 and the plurality of phased array receiving subarrays 1.

Specifically, the phased array transmitting subarray 9 of the transmitting part adopts an active phased array antenna, a wideband digital signal generated by the signal source 7 is subjected to an up-conversion module 8 to generate an RF signal, the RF signal is fed into an RF input end of the phased array transmitting subarray 9, and is transmitted through the phased array transmitting subarray 9, and the interference effect of different transmitting powers is achieved by matching with the transmitting power control of the signal source 7.

The receiving part adopts a mode of combining four phased array receiving subarrays 1, the four phased array receiving subarrays 1 are active phased array antennas, each phased array receiving subarray 1 comprises an independent down-conversion channel, and an independent monitoring acquisition channel is connected into a multichannel receiver 3, so that the beam direction of the receiving part can be independently configured to finish the monitoring of a plurality of terminal targets at the same time, the four beams can simultaneously receive and position uplink signals of one terminal target, and in addition, the four beams can be synthesized into one beam, the G/T value of monitoring equipment is increased, and the monitoring capability of the monitoring equipment is improved.

The GNSS module 4 and the control inertial navigation module 5 of the monitoring and control equipment adopt a new generation of micro-electromechanical inertial/satellite integrated navigation system, which consists of a high-precision mapping satellite receiving board card, a three-axis MEMS gyroscope and a three-axis MEMS accelerometer, can provide centimeter-level positioning precision in a good satellite condition environment, has heading, pitching and rolling precision within 0.1 degree, and can maintain position, speed and attitude precision for a long time in satellite signal shielding, multipath and other environments. By adding the high-performance integrated navigation system and matching with the structural design of high strength and IP65, the monitoring equipment can work in the moving process. The beam is directed to the target satellite accurately under the cooperation of the high-performance GNSS module 4 and the control inertial navigation module 5.

The ultra-wideband monitoring acquisition of the receiver 3 and the ultra-wideband digital signal generation of the signal source 7 mainly comprise a high-speed AD/DA and a two-stage heterodyne mixer circuit, analog filters with different frequency bands are embedded between stages, the analog filters are controlled by an analog switch, the output range of a radio frequency channel is 1 MHz-8 GHz, the ultra-wideband monitoring acquisition and signal source is provided with a plurality of independent RX and TX channels, each channel is provided with an instantaneous bandwidth of 500MHz, and the ultra-wideband monitoring acquisition and signal source completely corresponds to the management requirements of a satellite Internet terminal.

The down-conversion module 2 of the monitoring device is mainly responsible for down-converting signals in Ku frequency band or Ka frequency band to L, S or C frequency band and then entering a signal input end of the receiver 3, and the up-conversion module 8 up-converts signals in L, S or C frequency band output by the signal source 7 to RF ends of phased array transmitting sub-arrays 9 fed in Ku frequency band or Ka frequency band. The conventional up-conversion module and down-conversion module generally work in the L frequency band, but in view of the emerging broadband internet service signal, the original L frequency band cannot cover the whole service frequency band, and in addition, the L frequency band itself has much interference of mobile communication, so the embodiment changes the L frequency band signal into the C frequency band signal, and the technology is mature and has application in multiple projects. Down-conversion to the L or S frequency band is also possible depending on different requirements.

The antenna control unit 6 (ACU) is embedded with a high-performance FPGA module, and can make beam switching and attitude compensation in microsecond level.

The implementation scheme of each device module in this embodiment is as follows:

1. Phased array receiving antenna

The Ku frequency band or Ka frequency band receiving subarrays are two-dimensional electric scanning active phased array receiving subarrays developed by means of beam forming transmitting chips and efficient array antennas, and 256 full-polarization receiving antenna units, 64 Beamformer receiving chips, a passive power combination feed network, a signal driving chip, a beam control circuit, a power supply circuit, an interface and the like are integrated on a single printed circuit board. And the signal phase and amplitude of each antenna unit are quickly changed by relying on the real-time computing capability of the FPGA, and all array element receiving signals of the subarrays are synthesized in a radio frequency power combining network to form a required directional beam in real time. The whole antenna subarray can be functionally divided into two areas of a radio frequency antenna and a control power supply. A schematic diagram of the subarray principle is shown in fig. 4.

The radio frequency antenna area realizes the radio frequency signal receiving-receiving radio frequency signals in the free space designated direction, the radio frequency signals are input from each unit antenna, fed into Beamformer receiving chips, amplified and amplitude-matched through a low-noise amplifier, an attenuator and a phase shifter, and then synthesized through a passive power-combining network and output through a radio frequency joint.

The control power supply area realizes the power supply and logic control of the antenna subarrays and is divided into a power supply module and a logic control module. The power supply module is responsible for converting an external input voltage (DC+12V) into a voltage required by the subarray; the logic control module takes the FPGA as a core and is responsible for realizing the functions of beam calculation, sensor control and the like. The beam resolving part resolves the amplitude and the phase of the antenna unit in real time according to the beam pointing command issued by the ACU and configures Beamformer chips so that the beam points to the target direction; the sensor control part is responsible for collecting information such as power consumption, temperature and the like of the antenna subarrays.

The Ku frequency band or Ka frequency band receiving subarray is compact in design, low in profile, free of a mechanical servo mechanism, firm and durable, and capable of conducting rapid directional switching in a large airspace range. The phased array antenna is flexible to use, a plurality of subarrays can be spliced and designed into phased array antennas with required caliber according to needs, quick iteration is performed according to the performance needs of clients, and a brand new antenna is not required to be designed. The full-industrial device supports DC+12V input voltage power supply, and the working temperature ranges from-40 ℃ to +70 ℃.

The test results of the antenna subarrays are as follows: the performance data of the antenna are all tested in normal temperature environment (25 ℃ and 290K) except the temperature-related curve, and the subarray power supply voltage is DC+12V. The antenna subarray pattern performance test section is phi=0°, and all polarization direction patterns are almost identical.

2. Phased array transmitting antenna

The Ku frequency band or Ka frequency band transmitting subarray is a two-dimensional electric scanning active phased array transmitting subarray developed by means of a beam forming transmitting chip and a high-efficiency array antenna, and 2304 full-polarization transmitting antenna units, 576 Beamformer transmitting chips, a passive power division feeding network, a signal driving chip, a beam control circuit, a power supply circuit, an interface and the like are integrated on a single printed circuit board. And the signal phase and amplitude of each antenna unit are quickly changed by the real-time computing capability of the FPGA, and the radiation signals of all array elements of the subarray are synthesized in space to form the required directional beam in real time. The whole antenna subarray can be functionally divided into two areas of a radio frequency antenna and a control power supply. A schematic diagram of the subarray principle is shown in fig. 5.

The radio frequency antenna area realizes the radiation radio frequency signals in the free space appointed direction, namely the radio frequency signals are input from a radio frequency interface, fed into Beamformer transmitting chips through a passive power division network, subjected to amplitude-phase configuration of the radio frequency signals through a phase shifter, an attenuator and a power amplifier, and then radiated to the appointed wave beam direction through subarray unit antennas.

The control power supply area realizes the power supply and logic control of the antenna subarrays, and is divided into a power supply module and a logic control module. The power supply module is responsible for converting an external input voltage (DC+12V) into a voltage required by the subarray; the logic control module takes the FPGA as a core and is responsible for realizing the functions of beam calculation, sensor control and the like. The beam resolving part resolves the amplitude and the phase of the antenna unit in real time according to the beam pointing command issued by the ACU and configures Beamformer chips so that the beam points to the target direction; the sensor control part is responsible for collecting information such as power consumption, temperature and the like of the antenna subarrays.

The Ku frequency band or Ka frequency band emission subarray is compact in design, low in profile, free of a mechanical servo mechanism, firm and durable, and capable of conducting rapid directional switching in a large airspace range. The phased array antenna is flexible to use, a plurality of subarrays can be spliced and designed into phased array antennas with required caliber according to needs, quick iteration is performed according to the performance needs of clients, and a brand new antenna is not required to be designed. The full-industrial device supports DC+12V input voltage power supply, and the working temperature ranges from-40 ℃ to +70 ℃.

The test results of the antenna subarrays are as follows: the performance data of the antenna are all normal temperature environment (25 ℃) tests except the temperature-related curves, and the subarray power supply voltage is DC+12V. The antenna subarray pattern performance test section is phi=0°, and all polarization patterns are almost identical.

3. Receiver with a receiver body

The system particularly adopts a high-performance SDR scheme for realizing ultra-wideband monitoring and acquisition technology, and has the following advantages compared with the traditional radio technology:

Flexibility: the SDR system can optimize signals transmitted in the system through configuration software, and can adapt to different radio specifications and requirements, so that the flexibility of the system is improved.

Upgradeability: the SDR system can upgrade the performance of the system by updating software, thereby improving the usability of the system.

Programmability: SDR technology can implement different signal processing algorithms through the programmability of embedded processors and digital signal processors, enabling decoding and encoding of different radio specifications.

The ultra-wideband monitoring and acquisition is mainly based on a high-performance AD/DA (signal processing board) and a two-stage heterodyne mixer circuit, analog filters with different frequency bands are embedded between stages, the ultra-wideband monitoring and acquisition is controlled by an analog switch, the output range of a radio frequency channel is 1 MHz-8 GHz, 4 independent RX channels are provided, each channel has an instantaneous bandwidth of 500MHz, 8 uplink channels of the whole XL terminal can be acquired simultaneously, and project requirements are completely met.

The multipath broadband digital signal source mainly comprises an FPGA (field programmable gate array), multipath AD/DA (signal processing board) and a two-stage heterodyne mixer circuit, analog filters with different frequency bands are embedded between stages, and the analog filters are controlled by analog switches, and each channel is provided with 8 independent TX channels, and each channel is provided with an instantaneous bandwidth of 500MHz, so that the project requirements are completely met.

The critical subsystems required for a high-speed ad\da to implement a complete software defined radio include a direct radio frequency sampled data converter, eCPRI and gigabit ethernet to radio frequency on a single highly programmable SoC. Each chip provides a plurality of radio frequency sample (8 4GS/s sample rate) analog-to-digital conversion (RF-ADC) and radio frequency sample (8 6.4GS/s sample rate) digital-to-analog conversion (RF-DAC) data converters. The data converter has the characteristics of high precision, high speed and energy saving, and has excellent dynamic range performance. Both are highly configurable and tightly integrated with Programmable Logic (PL) resources.

Signal processing flow

The signal processing flow is shown in fig. 6, and the signal parameter measurement mainly analyzes the signal type (beacon signal and service signal are identified according to the signal frequency domain characteristics), the carrier frequency, the signal bandwidth, the carrier power, the signal-to-noise ratio (C/N), the Power Flux Density (PFD) and the like to measure, and calculates the equivalent radiation power (EIRP) of the target satellite. The signal modulation type identification mainly analyzes, detects and identifies various satellite communication signal systems, and determines the parameter capacities of modulation patterns, carrier frequencies, bandwidths, symbol rates, communication protocols, signal characteristics and the like and certain data demodulation capacities; the time-frequency domain analysis, the modulation domain analysis and the system domain analysis can be performed on the scout signal.

In satellite signal monitoring, parameters such as carrier frequency, modulation scheme, spectrum 3dB bandwidth (or modulation symbol rate), signal-to-noise ratio and the like of a monitored signal need to be estimated. The parameters of the 13 communication signals such as BPSK, QPSK, UQPSK, 8PSK, 16APSK, 32APSK, 16QAM, 32QAM and 64QAM, QAM, OQPSK, O QAM which are commonly used in the current satellite communication system are estimated, wherein the I/Q branch amplitude ratio of the UQPSK signal is limited to be in the range of 1.05-3.16, namely the I/Q branch power ratio is 0.424-10 dB. When the amplitude ratio of the I/Q branch of the UQPSK signal is smaller than 1.05, the UQPSK signal can be classified as a QPSK signal with unbalanced I/Q branch amplitude; when the amplitude ratio of the I/Q branch of the UQPSK signal is larger than 3.16, the signal can be classified into BPSK signals, but the Q branch of the signal has-10 dB uncorrelated interference signals.

1) For the input multichannel digital signal, firstly, dividing the multichannel digital signal into data blocks with the length of N (generally N is equal to 1024, 2048, 4096, 8192, 16384, 32768 or 65536, etc.), adding a Hann window function to each data block, and performing fast Fourier transform (the frequency domain resolution is controlled to be near 10kHz, and the corresponding frequency domain step is near 7 kHz);

2) The spectra of 1024 data blocks are accumulated and averaged.

3) And (5) channel division.

4) Each carrier communication channel roughly estimates the carrier center frequency and the signal 3dB bandwidth of the carrier communication channel, and accurately estimates the signal-to-noise ratio SNR;

5) Each carrier communication channel is digitally down-converted to a zero intermediate frequency I/Q signal, digital decimation filtering filters out-of-band signals, and the sampling rate of the digital signals is around 4 times the symbol rate.

6) Each carrier communication signal phase angle is multiplied by 2, 4, 8, 12, 16, 16384-point fast fourier transform is performed on the signal with 2, 4, 8, 12, 16 times the phase angle, and 16 times the spectrum accumulation is averaged. Spectral peak searching, namely accurately estimating carrier center frequency: if the signal with the phase angle of 2, 4, 8, 12 or 16 times has higher spectral peaks in the frequency spectrums of a plurality of signals, the spectral peaks of the signal with the phase angle of high times are preferably selected to calculate the carrier center frequency so as to obtain higher carrier center frequency estimation precision. The signal spectrum with the phase angle of 2 times has obvious peak value, and the corresponding modulation mode of the signal is BPSK or UQPSK signal; the signal spectrum peak value with the phase angle of 4 times is larger than the signal spectrum peak value with the phase angle of 2 times, and the signal spectrum peak value is the UQPSK signal; and adding Gaussian noise to ensure that the SNR=0 dB, the signal spectrum with the phase angle of 6 times is integrated and averaged, the spectrum peak is searched, and the spectrum peak judgment threshold is set to be 5dB, so that the BPSK and the UQPSK can be separated.

7) Replacing the rough estimation value with the precisely estimated carrier center frequency, carrying out digital down-conversion to zero intermediate frequency (I/Q) signals again, filtering out-of-band signals by digital decimation filtering, and enabling the sampling rate of the digital signals to be near 4 times of the symbol rate; 16384-point fast Fourier transform is carried out on ERs_QAM (t) and ERsOQAM (t) signals, and 16 times of spectrum accumulation and averaging are carried out; spectral peak search, the modulation symbol rate is estimated accurately. The ers_qam (t) signal has a spectral peak at a frequency point Rs (while the ers_oqam (t) signal has no spectral peak), and the corresponding signal is a MPSK (M ≡4), MQAM or mapk signal; the ers_oqam (t) signal has a spectral peak at a frequency point Rs (while the ers_qam (t) signal has no spectral peak), and the corresponding signal is a signal such as OQPSK or O16 QAM; both the ers_qam (t) signal and the ers_oqam (t) signal have spectral peaks at the frequency point Rs, and the corresponding signals are BPSK or UQPSK signals.

8) The carrier center frequency and the modulation symbol rate of the accurate estimation replace the rough estimation value, the digital down-conversion is carried out to zero intermediate frequency I/Q signal again, the digital extraction filtering filters out the out-of-band signal, and then the sampling rate of the digital signal is 4 times of the symbol rate through interpolation and extraction filtering. And performing timing recovery on the MPSK, MQAM or MAPSK signals to obtain the optimal sampling position of the signals.

9) Adding Gaussian noise according to the signal-to-noise ratio SNR to make the signal-to-noise ratio of the polluted signal become 0, 2, 6 or 12dB, namely adding noise to make the SNR=12 dB if the signal-to-noise ratio SNR of the input signal is more than 12dB; if the signal-to-noise ratio of the input signal is between 6 and 12dB, adding noise to make the snr=6 dB; if the signal-to-noise ratio of the input signal is between 2-6 dB, adding noise to make its snr=2 dB; if the signal-to-noise ratio of the input signal is between 0 and 2dB, adding noise to make the snr=2 dB; if the signal-to-noise ratio of the input signal is less than 0dB, no processing is performed. And sampling MPSK, MQAM or MAPSK signals output by matched filtering by using a recovered clock, normalizing the instantaneous amplitude, counting the normalized instantaneous amplitude, calculating the deviation between the normalized instantaneous amplitude and 1, taking the absolute value of the deviation, and carrying out accumulated averaging.

10 Multiplying the phase angle of the 4 times symbol rate signal by 2,4, 6, 8, 12 and 16, performing half-band extraction filtering on the signal, performing 16384-point fast Fourier transform, accumulating and averaging the frequency spectrum for 32 times, performing peak search on the frequency spectrum, and recording peak amplitude; accumulating and averaging the noise signals after the spectrum peak is subtracted; the peak amplitude is divided by the accumulated and averaged noise amplitude, and this value is converted into dB.

11 According to the result, the modulation mode identification is carried out according to the signal identification tree.

The technical scheme provided by the application can realize automatic monitoring, signal measurement and terminal positioning of the uplink signal of the Ku frequency band or Ka frequency band low-orbit satellite terminal, and can perform interference suppression on the downlink signal of the satellite so as to form the basic management and control capability of the low-orbit satellite Internet terminal.

The system can realize daily monitoring of a low orbit satellite terminal, can rapidly scan a ground target area through a multi-beam two-dimensional active phased array antenna mode and a multi-channel broadband monitoring acquisition receiver, can perform automatic multi-beam scanning, single-terminal gaze tracking monitoring, scanning and gaze parallel monitoring, communication service full-channel monitoring and the like, prompts early warning and stores corresponding evidences (spectrograms, waterfall diagrams and the like, demodulation information and the like) after an uplink service signal is found, and can start a positioning function in an automatic or manual mode to accurately position the terminal; and the phased array transmitting antenna and the servo turntable are utilized to realize interference suppression on the terminal of the satellite downlink signal in the target area.

The device design adopts a multi-beam two-dimensional active phased array antenna mode under the overall aim of realizing small system, high power and high frequency band, and the crumple of the active antenna is from a band emission gain without a power amplifier module. The antenna realizes the light mobile antenna technology with high power amplification efficiency, low power consumption technology, low antenna loss, light weight technology, high gain and high tracking precision; and in the system policy, the motorized deployment and the integrated integration are realized. The integrated system is a main characteristic of the equipment system of the system, and fundamentally changes the thought of a large-scale, high-performance and high-cost system. The device adopts a miniaturized integrated design concept, is easy to maneuver and disperse and deploy, can be mounted on an air platform such as an unmanned plane, an airship and the like, is used in a communication manner in motion, can monitor, position and interfere radiation of a ground terminal, and can better adapt to the requirements of multi-domain combat and even global combat.

The method provided by the invention has the following advantages in uplink signal monitoring, terminal positioning and terminal interference for the low-orbit satellite Internet:

The multi-beam scanning acquisition, the accurate positioning of the terminal and the interference suppression strategies of various terminals are realized for the uplink signals of the low-orbit satellite Internet terminal.

The integrated design of the antenna subarray, the receiver, the signal source, the frequency converter, the GNSS, the inertial navigation module and other modules is realized, and the miniaturized integrated design of the equipment is realized.

The navigation system can completely work in moving by matching the high-strength and IP65 structural design with the centimeter-level positioning precision provided by the GNSS and inertial navigation module, and can enable the heading, pitching and rolling precision to be within 0.1 degrees, thereby meeting various use scenes such as fixation, vehicle-mounted, ship-mounted, airborne, moving and the like.

The control software realizes unified control of the monitoring equipment, centralized processing, management and statistics of satellite monitoring data, unified processing of various satellite monitoring evaluation indexes and automatic generation of monitoring evaluation reports.

The control software uses a multithreading task planning and scheduling technology to realize rapid and accurate planning and analysis of tasks.

The advantages of using the phased array antenna scheme of the present application over conventional parabolic antenna schemes are as follows:

1. The reaction speed is high: four beams are scanned in parallel, the beam switching speed is high, an electronic scanning mode without inertia can be realized, and the four beams can rapidly cover the whole direction-finding area;

2. The signal-to-noise ratio of the direction finding system is high: the narrow beam antenna has a gain better than 24dBi, and has a higher signal-to-noise ratio than an interference direction-finding system with only a few dBi to ten dBi, thereby being more beneficial to improving the direction-finding precision;

3. The direction finding precision is high: four-channel single-pulse direction finding is carried out according to a unified error formula of direction finding:

Δθ＝k*HPBW1/2/root(SNR)

it is known that the phased array antenna has high direction-finding accuracy due to narrow beam and high gain;

4. Broadband. The scanning bandwidth is 500MHz, can cover the whole bandwidth of 62.5 x 8 channel = 500MHz of XL terminal uplink, and is a four-channel receiver, 4 wave beams can be realized to work simultaneously, and the communication requirements (including star chain constellation, oneWeb constellation, china star network constellation, china G60 constellation and the like) of the currently known high-flux satellites are met.

5. The device shape is better. The traditional parabolic antenna scheme has the overall weight of being heavier and 85Kg; the power consumption is relatively high in working and is 1100W; and has a parabolic shape and a size of 0.8m. The height is higher and the size and shape are heavier. While the monitor positioning portion of the phased array antenna solution weighs 20Kg, the interference portion weighs 25Kg, and the overall mass is 45Kg, which is lighter than the weight of the parabolic antenna; the power consumption of the monitoring and positioning part of the phased array antenna scheme is 300W, the interference part is 500W, and the total power consumption is 800W; and the size of the phased array monitoring positioning is 0.6mx0.6m, and the interference part is 0.8mx0.8m, and the phased array monitoring positioning is a flat antenna. Therefore, the phased array antenna scheme has great advantages over the parabolic antenna in terms of quality, power consumption, size and morphology, and is more convenient to mount on aerial platforms such as unmanned aerial vehicles, airships and the like.

6. Beam switching is faster. The beam switching speed of the phased array antenna is faster than that of the parabolic antenna, the beam angle is smaller, the directional performance of the beam is better, and the interference effect is better. And with the deeper understanding and analysis of the downlink signals of the low-orbit satellite in the future, the advantage of fast beam switching can be combined with a smart interference mode to perform interference suppression on a plurality of cells and terminals.

Any combination of the technical features of the above embodiments may be performed (as long as there is no contradiction between the combination of the technical features), and for brevity of description, all of the possible combinations of the technical features of the above embodiments are not described; these examples, which are not explicitly written, should also be considered as being within the scope of the present description.

Claims (10)

1. A technology for monitoring a terminal by satellite monitoring guidance is characterized in that satellite monitoring equipment monitors satellites in a target area, and after satellite downlink signals are monitored, the satellite monitoring equipment and an antenna are automatically guided to monitor uplink signals of the terminal.

The guidance monitoring technology can configure the strategy and tasks of guidance monitoring. The configuration of parameters such as the duration of the ground monitoring scanning, the stepping, the beam pointing, the azimuth angle, the rotating speed of the servo turntable and the like can be set, the strategy and the parameter setting can be supported and saved, and the loading and the execution of the parameters and the strategies can be directly carried out when the next task is carried out.

In the guide monitoring technology, after a guide monitoring task is created, the system automatically identifies task data information, and the automatic task is combined with task database data, so that consistency and usability of the task data are ensured. The manual task immediately invokes the execution and returns the receipt data information.

2. The satellite terminal monitoring and controlling equipment is characterized in that a receiving antenna is designed in a mode of splicing four subarrays, each Ku frequency band or Ka frequency band receiving subarray is a two-dimensional electric scanning active phased array receiving subarray developed by means of a beam forming transmitting chip and a high-efficiency array antenna, and each subarray is integrated with 256 full-polarization receiving antenna units, 64 Beamformer receiving chips, a passive power combination feed network, a signal driving chip, a beam control circuit, a power supply circuit, an interface and the like on a single printed circuit board.

The control power supply area realizes power supply and logic control of the antenna subarrays and is divided into a power supply module and a logic control module. The power supply module is responsible for converting an external input voltage (DC+12V) into a voltage required by the subarray; the logic control module takes the FPGA as a core and is responsible for realizing the functions of beam calculation, sensor control and the like. The beam resolving part resolves the amplitude and the phase of the antenna unit in real time according to the beam pointing command issued by the ACU and configures Beamformer chips so that the beam points to the target direction; the sensor control part is responsible for collecting information such as power consumption, temperature and the like of the antenna subarrays.

3. The satellite terminal monitoring and controlling device based on claim 2, wherein the servo turntable is used for installing a back feed antenna load, and the antenna turntable can be inversely installed on an air platform such as an airship, an unmanned aerial vehicle and the like to perform ground scanning. Mainly comprises a mechanical table body and a servo turntable control part.

The servo turntable control system is integrated in the servo turntable external control cabinet, and the servo turntable is connected with the user control terminal through the Ethernet interface so as to realize remote control of the servo turntable and real-time feedback display function of state information of the servo turntable system.

4. The satellite terminal monitoring and control device based on claim 2, wherein the device cooperative control is based on a device cooperative scheduling technology, and the system cooperates with the phased array antenna, the servo turntable device and the transceiver to perform signal detection, signal analysis, terminal positioning and terminal interference after the device monitors and positions the terminal downlink signal.

5. The technology for monitoring the satellite monitoring and guiding the terminal monitoring based on the claim 1 is characterized in that the received uplink signals of the multiple terminals can be measured simultaneously, and the equivalent radiation power (EIRP) of the target terminal is calculated by measuring the signal carrier frequency, the signal bandwidth, the carrier power, the signal-to-noise ratio (C/N), the Power Flux Density (PFD) and the like through parameter measurement algorithms in the system, including a signal-to-noise ratio algorithm, a carrier-to-noise ratio algorithm, a signal bandwidth algorithm, a power flux density algorithm and an equivalent radiation power algorithm.

6. The technology for monitoring the terminal based on satellite monitoring guidance of claim 1 is characterized in that the phased array receiving antenna of four subarrays is adopted to receive the terminal signal, the four beams simultaneously receive the target uplink signal by adjusting the beam directions of the subarrays, the signals received by the four subarrays are calculated and analyzed, and the phase difference of the signals received by each subarray is utilized to conduct the opposite phase method direction finding by the single pulse direction finding technology.

7. The technology for monitoring the terminal based on the star monitoring guidance of claim 1 is characterized in that the detected uplink signal information of the terminal is visually displayed, the monitoring abnormality is included, the monitoring task is provided with strategy information which needs manual operation, and the operation interface of each module can be quickly skipped. The early warning data may be presented in a list or in a switching chart.

8. The technology for guiding the monitoring of the terminal based on the star monitoring of claim 1 is characterized in that parameters such as carrier frequency, modulation mode, spectrum 3dB bandwidth (or modulation symbol rate), signal to noise ratio and the like of a monitoring signal need to be estimated and system domain analysis of a frequency domain, a time domain and a modulation domain is carried out.

9. The technology for monitoring the satellite based on the satellite monitoring guidance and the terminal monitoring according to claim 1 is characterized in that the characteristic value of the low-orbit internet satellite synchronous signal is obtained through analysis: frequency point, bandwidth, level, frame length, OFDM parameters (including symbol duration, symbol guard interval duration, number of subcarriers, subcarrier modulation mode), pseudo code sequence, etc. A pseudo code sequence with larger correlation with a target signal pseudo code sequence is adopted to generate periodic and cyclic pulse signals with the same working frequency point, the same working bandwidth, the same frame length, the same OFDM parameters and slightly higher transmitting power, so that the downlink timing synchronization of the low-orbit satellite Internet terminal is interfered, and the normal establishment of a downlink communication link between the terminal and the low-orbit satellite is influenced.

10. The technology for monitoring the satellite monitoring and guiding the terminal monitoring based on the 1 is characterized in that a comprehensive interference effect evaluation mode is selected to evaluate interference suppression, uplink signals of the satellite communication terminal can be received and analyzed simultaneously in the interference suppression process, measurement and calculation are performed according to received signal parameters, information items such as the working frequency, the bit error rate, the transmission rate and the signal to noise ratio of the signals are analyzed, the interference suppression effect is compared and evaluated when the measurement result is not interfered, and relevant parameters of the interference suppression are adjusted timely according to the evaluation condition.