A radar installation training target support system and method

Abstract

The application discloses a radar equipment training target guarantee system and method, the system comprises a host computer, an antenna, a display control terminal and a power supply, the host computer is used for analyzing and processing radio frequency signals input from the antenna and outputting modulated virtual target radio frequency signals to the antenna, the antenna is used for receiving radio frequency signals radiated by a radar and radiating virtual target radio frequency signals generated by the host computer, the display control terminal is used for displaying relevant parameters of the radio frequency signals analyzed and processed by the host computer, control of relevant modulation parameters of the virtual target radio frequency signals and planning control of virtual target route information, and the power supply is used for providing required voltages for normal operation of the system. The application further discloses a radar equipment training target guarantee method. The system and method provide a realistic air target environment for radar equipment training.

Description

Technical Field

[0001] This invention relates to the field of radar training target support, specifically a radar training target support system and method. Background Technology

[0002] Currently, the aerial targets used in radar live-fire training are mostly physical flying targets, which are either civilian aircraft or special-purpose aircraft used in conjunction with the training. Civilian aircraft have relatively simple flight paths and cannot provide support for complex maneuvering routes; while special-purpose aircraft require a large amount of manpower, material resources, and financial resources. Summary of the Invention

[0003] To address the existing problems, this invention provides a radar-based training target support system and method, the specific solution of which is as follows:

[0004] A radar training target support system is characterized by comprising a host computer, a display and control terminal, an antenna, and a power supply; the host computer is electrically connected to the display and control terminal and the antenna, and the power supply provides the voltage required for the normal operation of the system.

[0005] The host receives radar radio frequency signals through an antenna, and after analyzing and processing the data uploaded by the display and control terminal, it radiates virtual target radio frequency signals outward through the antenna.

[0006] The antenna is used to receive radar radio frequency signals and virtual target radio frequency signals output to the external radiating host.

[0007] The display and control terminal is used to display, plan, and determine the virtual radar station, virtual target trajectory, and related modulation parameters of the virtual target radio frequency signal.

[0008] Preferably, the host includes a frequency source, an analog down-conversion channel, an analog-to-digital converter (ADC), a digital down-conversion unit (DDC), a baseband digital signal delay unit, a baseband digital signal Doppler frequency shift unit, a digital up-conversion unit (DUC), a digital-to-analog converter (DAC), an analog up-conversion channel, and a GPS / BDS positioning device.

[0009] The frequency source is used to provide clock signals for the normal operation of each module of the host, and to provide one local oscillator and two local oscillator signals for the analog down-conversion channel and the analog up-conversion channel;

[0010] The down-conversion channel is used to mix the radio frequency signal received from the antenna twice to an intermediate frequency signal, and output it to the analog-to-digital converter (ADC).

[0011] The analog-to-digital converter (ADC) is used to sample the intermediate frequency signal from the radio frequency module, form a digital intermediate frequency signal, and output it to the digital down-conversion unit (DDC).

[0012] The digital downconverter unit (DDC) is used to perform quadrature demodulation on the digital intermediate frequency signal from the analog-to-digital converter (ADC) to form I and Q baseband digital signals, and output them to the baseband digital signal delay unit.

[0013] The baseband digital signal delay unit is used to perform distance modulation on the baseband digital signal from the digital down-conversion unit (DDC) and output it to the baseband digital signal Doppler frequency shift unit.

[0014] The baseband digital signal Doppler frequency shift unit is used to speed modulate the baseband digital signal from the baseband digital signal delay unit and output it to the digital up-conversion unit (DUC).

[0015] The digital upconversion unit (DUC) is used to upconvert the I and Q baseband digital signals from the baseband digital signal Doppler frequency shift unit to digital intermediate frequency signals, and output them to the digital-to-analog converter (DAC).

[0016] The digital-to-analog converter (DAC) is used to convert the digital intermediate frequency signal from the digital up-conversion unit (DUC) into an analog intermediate frequency signal.

[0017] The upconversion channel is used to mix the intermediate frequency signal from the digital-to-analog converter (DAC) twice into an radio frequency signal and output it to the antenna.

[0018] The GPS / BDS positioning device is used to obtain the geographical location information of the target protection system and output the location information to the display and control terminal via a network cable.

[0019] Preferably, the antenna includes a receiving antenna and a transmitting antenna. The receiving antenna is used to receive the radio frequency signal radiated by the radar and output it to the host through a radio frequency cable. The transmitting antenna is used to receive the radio frequency signal output by the host through the radio frequency cable and radiate it outward.

[0020] Preferably, the display and control terminal includes a display terminal and a control terminal. The display terminal is used to display the virtual target track and receive the GPS / BDS geographical location information output by the host through a network cable, and display the geographical location of the virtual radar station on a flat map. The control terminal is used to determine the modulation parameters of the virtual target radio frequency signal and output them to the host through a network cable.

[0021] Preferably, a method for providing radar-based training target support system includes the following steps:

[0022] S1. Based on the actual geographical location information of the radar installation, mark the geographical location of the radar station on the planar map of the display terminal; simultaneously, calculate the scanning period T of the radar antenna based on the strength variation pattern of the received radar radio frequency signal energy; and determine the azimuth angle of the target protection system at the radar station based on the GPS / BDS positioning information (B1, L1, H1) of the target protection system and the actual geographical location information of the radar installation (B2, L2, H2), where B, L, and H are longitude, latitude, and altitude values, respectively.

[0023] S2, based on the data in step 1, virtually determine the azimuth of the main lobe of the antenna beam of the radar station at any given time;

[0024] S3 generates a virtual target flight path and displays it on a flat map on the display terminal;

[0025] S4 modulates the radio frequency signal parameters of the virtual target.

[0026] Preferably, the process of obtaining the data required for step S2 in step S1 is as follows: by inputting data through the keyboard of the control terminal, the geographical location of the virtual radar station is marked on the plane map of the display terminal. Specifically, based on the actual geographical location information of the radar (B2, L2, H2) and the Miller projection coordinate transformation formula... Where W represents the circumference of the Earth, and mill represents the Miller constant, which ranges from plus or minus 2 to 3. The Cartesian coordinates (X2, Y2) of the radar station on the planar map can be obtained.

[0027] Assume the maximum power of the radar radiated radio frequency signal received by the target protection system at time t1 is The maximum power of the radar radiated radio frequency signal received again at the next time t2 Since the times between the two maximum power signals received are adjacent, the radar antenna scanning period can be determined to be T = |t2 - t1|.

[0028] Based on the geographical location information (B1, L1, H1) and (B2, L2, H2) of the radar station and target support system, the conversion relationship between geographical location coordinates and geodetic rectangular coordinates is used. Where B, L, and H are the longitude, latitude, and altitude values, respectively; N is the radius of curvature of the ramusoidal circle at the location point of the geographic location data record; and e is the first eccentricity of the ellipsoid. The coordinates (X1, Y1, Z1) and (X2, Y2, Z2) of the two in the rectangular coordinate system with the Earth's center as the origin can be determined.

[0029] Based on the coordinates (X3, Y3, Z3) of the Earth's North Pole in a rectangular coordinate system with the Earth's center as the origin, we can determine the plane a1·x + b1·y + c1·z = 0 formed by the radar station, the Earth's center, and the North Pole, where a1 = Y1·Z3 - Z1·Y3, b1 = X3·Z1 - X1·Z3, and c1 = X1·Y3 - Y1·X3. We can also determine the plane a2·x + b2·y + c2·z = 0 formed by the target support system, the Earth's center, and the radar station, where a2 = Y1·Z2 - Z1·Y2, b2 = X2·Z1 - X1·Z2, and c2 = X1·Y2 - Y1·X2.

[0030] The angle between two planes can be determined using the formula for the positional relationship between two planes in analytic geometry. The azimuth angle of the target protection system relative to the radar station is: Both the radar station and the target support system are located in the Eastern Hemisphere;

[0031] Based on the fact that the radar signal energy received by the target protection system is at its maximum at time t1, it can be determined that the radar antenna beam is pointing towards the azimuth θ at time t1.

[0032] Preferably, the specific steps of step 3 are as follows:

[0033] S31, based on the coordinates of the virtual target on the planar map and the Miller projection coordinate transformation formula. The longitude and latitude of the virtual target's geographic location information can be obtained through the conversion relationship between geographic location coordinates and geodetic rectangular coordinates. The coordinates (X4, Y4, Z4) of the virtual target in a rectangular coordinate system with the Earth's center as the origin can be determined, where X4, Y4, and Z4 are all functions of H.

[0034] S32. Based on the coordinates (X1, Y1, Z1) of the radar station in a rectangular coordinate system with the Earth's center as the origin, the distance s between the virtual target and the radar station, and the coordinates (X4, Y4, Z4) of the virtual target, calculate the height H of the virtual target.

[0035] S33. Based on the starting point (B3,L3,H3), ending point (B4,L4,H4) of the virtual target and the transformation relationship between geographical coordinates and geodetic rectangular coordinates, the coordinates of the virtual target in the geodetic rectangular coordinate system can be obtained as (X'3,Y3',Z'3) and (X'4,Y4',Z'4).

[0036] S34, based on the set virtual target speed v, the time required for the virtual target to travel from the starting point to the ending point can be obtained. And the flight path of the virtual target in the geodetic rectangular coordinate system Where v x ,vy ,v z This represents the velocity components of the virtual target along the x, y, and z axes in the geodetic rectangular coordinate system.

[0037] S35, based on the time t required for the virtual target to travel from the starting point to the ending point. 3,4 By selecting the starting point (X3, Y3) and ending point (X4, Y4) of the virtual target on the planar map, the flight speed of the virtual target on the display terminal's planar map can be obtained.

[0038] Preferably, the modulation method in step 4 includes the following steps:

[0039] S41, based on the target support system's azimuth θ at the radar station, the radar station antenna scanning period T, and the virtual target's flight trajectory, if the azimuth angle change between the first and second detections of the virtual target by the radar is Δθ, then the time interval between the first and second transmissions of the virtual target's radio frequency signal is:

[0040] S42, based on the time interval Δt and the flight trajectory of the virtual target, the distances r1 and r2 of the virtual target relative to the radar when the radar detects the virtual target in two consecutive instances can be obtained;

[0041] S43, based on the distances r1 and r2 of the virtual target relative to the radar in two adjacent transmissions, the time delay between two adjacent transmissions of virtual signal pulses can be obtained as follows: Where c is the speed of light, Δτ is positive when the pulse is advanced, and Δτ is negative when the pulse is delayed;

[0042] S44, based on the time interval Δt and the flight speed of the virtual target, the flight distance of the virtual target when the radar detects the virtual target in two consecutive instances can be obtained as r. 1,2 In the triangle formed by the locations where the radar and the virtual target are detected in two adjacent instances, the angle between the line connecting the first detected virtual target to the radar and the virtual target's flight path is... The radial velocity of the virtual target relative to the radar when it is first detected is:

[0043] S45, based on the real-time velocity of the virtual target relative to the radar and the Doppler principle, can determine the frequency offset of the virtual target's radio frequency signal. Where f is the radar operating frequency, c is the speed of light, and the frequency offset is positive when the virtual target flies close to the radar and negative when it flies away from the radar.

[0044] The beneficial effects of this invention are as follows:

[0045] This invention can simulate multiple virtual routes, avoiding the problem of a single route, and can save a lot of manpower, material resources and financial resources. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a block diagram of the target protection system of the present invention;

[0048] Figure 2 This is a block diagram of the host computer of the present invention;

[0049] Figure 3 This is a flowchart of the method of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] like Figure 1 A radar training target support system includes a host, a display and control terminal, an antenna, and a power supply; the host is electrically connected to the display and control terminal and the antenna respectively, and the power supply provides the voltage required for the normal operation of the system;

[0052] The host receives radar radio frequency signals through the antenna, and after analyzing and processing the data uploaded by the display and control terminal, it radiates virtual target radio frequency signals outward through the antenna.

[0053] The antenna is used to receive radar radio frequency signals and to radiate virtual target radio frequency signals output by the host computer.

[0054] The display and control terminal is used to display, plan, and determine the virtual radar station, virtual target track, and modulation parameters related to the virtual target radio frequency signal.

[0055] like Figure 2The main unit includes a frequency source, an analog down-conversion channel, an analog-to-digital converter (ADC), a digital down-conversion unit (DDC), a baseband digital signal delay unit, a baseband digital signal Doppler frequency shift unit, a digital up-conversion unit (DUC), a digital-to-analog converter (DAC), an analog up-conversion channel, and a GPS / BDS positioning device.

[0056] The frequency source is used to provide clock signals for the normal operation of each module of the host, and to provide one local oscillator and two local oscillator signals for the analog down-conversion channel and the analog up-conversion channel;

[0057] The down-conversion channel is used to mix the radio frequency signal received from the antenna twice to an intermediate frequency signal and output it to the analog-to-digital converter (ADC).

[0058] The analog-to-digital converter (ADC) is used to sample the intermediate frequency (IF) signal from the radio frequency (RF) module, form a digital IF signal, and output it to the digital down-conversion unit (DDC).

[0059] The digital downconverter (DDC) unit is used to perform quadrature demodulation on the digital intermediate frequency signal from the analog-to-digital converter (ADC) unit to form I and Q baseband digital signals, and output them to the baseband digital signal delay unit.

[0060] The baseband digital signal delay unit is used to perform distance modulation on the baseband digital signal from the digital down-conversion unit (DDC) and output it to the baseband digital signal Doppler frequency shift unit.

[0061] The baseband digital signal Doppler frequency shift unit is used to speed modulate the baseband digital signal from the baseband digital signal delay unit and output it to the digital up-conversion unit (DUC).

[0062] The digital upconversion unit (DUC) is used to upconvert the I and Q baseband digital signals from the baseband digital signal Doppler frequency shift unit to digital intermediate frequency signals, and output them to the digital-to-analog converter (DAC).

[0063] The digital-to-analog converter (DAC) is used to convert the digital intermediate frequency (IF) signal from the digital up-converter (DUC) into an analog IF signal.

[0064] The upconversion channel is used to mix the intermediate frequency signal from the digital-to-analog converter (DAC) twice to the radio frequency signal and output it to the antenna.

[0065] The GPS / BDS positioning device is used to obtain the geographical location information of the target protection system and output the location information to the display and control terminal via network cable.

[0066] The antenna includes a receiving antenna and a transmitting antenna. The receiving antenna is used to receive the radio frequency signals radiated by the radar and output them to the host through the radio frequency cable. The transmitting antenna is used to receive the radio frequency signals output by the host through the radio frequency cable and radiate them outward.

[0067] The display and control terminal includes a display terminal and a control terminal. The display terminal is used to display the virtual target track and receive GPS / BDS geographical location information output by the host through the network cable and display the radar station's geographical location on a flat map. The control terminal is used to determine the modulation parameters of the virtual target's radio frequency signal and output them to the host through the network cable.

[0068] like Figure 3 A method for providing radar-based training target support system includes the following steps:

[0069] S1. Based on the actual geographical location information of the radar installation, mark the geographical location of the radar station on the planar map of the display terminal; at the same time, calculate the scanning period T of the radar antenna according to the strength variation pattern of the received radar radio frequency signal energy; and determine the azimuth of the target protection system at the radar station based on the GPS / BDS positioning information (B1, L1, H1) of the target protection system and the actual geographical location information of the radar installation (B2, L2, H2), where B, L, and H are longitude, latitude, and altitude values, respectively.

[0070] S2, based on the data in step 1, virtually determine the azimuth of the main lobe of the antenna beam at any given time of the radar station.

[0071] The process of obtaining the data required for step S2 in step S1 is as follows: By inputting data through the keyboard of the control terminal, the geographical location of the virtual radar station is marked on the plane map of the display terminal. Specifically, based on the actual geographical location information of the radar (B2, L2, H2) and the Miller projection coordinate transformation formula... Where W represents the circumference of the Earth, and mill represents the Miller constant, which ranges from plus or minus 2 to 3. The Cartesian coordinates (X2, Y2) of the radar station on the planar map can be obtained.

[0072] Assuming that the maximum power of the radar radiated radio frequency signal received by the target protection system at time t1 is P, and the maximum power of the radar radiated radio frequency signal is received again at time t2, and the times between the two maximum power signals are adjacent, then the radar antenna scanning period can be determined as T=|t2-t1|.

[0073] Based on the geographical location information (B1, L1, H1) and (B2, L2, H2) of the radar station and target support system, the conversion relationship between geographical location coordinates and geodetic rectangular coordinates is used. Where B, L, and H are the longitude, latitude, and altitude values, respectively; N is the radius of curvature of the ramusoidal circle at the location point of the geographic location data record; and e is the first eccentricity of the ellipsoid. The coordinates (X1, Y1, Z1) and (X2, Y2, Z2) of the two in the rectangular coordinate system with the Earth's center as the origin can be determined.

[0074] Based on the coordinates (X3, Y3, Z3) of the Earth's North Pole in a rectangular coordinate system with the Earth's center as the origin, we can determine the plane a1·x + b1·y + c1·z = 0 formed by the radar station, the Earth's center, and the North Pole, where a1 = Y1·Z3 - Z1·Y3, b1 = X3·Z1 - X1·Z3, and c1 = X1·Y3 - Y1·X3. We can also determine the plane a2·x + b2·y + c2·z = 0 formed by the target support system, the Earth's center, and the radar station, where a2 = Y1·Z2 - Z1·Y2, b2 = X2·Z1 - X1·Z2, and c2 = X1·Y2 - Y1·X2.

[0075] The angle between two planes can be determined using the formula for the positional relationship between two planes in analytic geometry. The azimuth angle of the target protection system relative to the radar station is: Both the radar station and the target support system are located in the Eastern Hemisphere;

[0076] Based on the fact that the radar signal energy received by the target protection system is at its maximum at time t1, it can be determined that the radar antenna beam is pointing towards the azimuth θ at time t1.

[0077] In summary, based on the Cartesian coordinates (X2, Y2) of the radar station on the planar map, the radar antenna scanning period T, and the radar antenna beam azimuth θ at time t1, the azimuth of the main lobe of the antenna beam at any time of the radar station can be virtually determined.

[0078] S3 generates a virtual target flight path and displays it on a flat map on the display terminal.

[0079] The virtual target's initial distance and flight speed from the radar station can be set via the display and control terminal. The starting and ending points of the virtual target can be selected near the virtual radar. By setting the ending point of the simulated target multiple times, the simulated target's maneuvering flight can be realized. The virtual target's position information can be changed on the display and control terminal's planar map through Miller projection coordinate transformation.

[0080] The specific steps of step 3 are as follows:

[0081] S31, based on the coordinates of the virtual target on the planar map and the Miller projection coordinate transformation formula. The longitude and latitude of the virtual target's geographic location information can be obtained through the conversion relationship between geographic location coordinates and geodetic rectangular coordinates. The coordinates (X4, Y4, Z4) of the virtual target in a rectangular coordinate system with the Earth's center as the origin can be determined, where X4, Y4, and Z4 are all functions of H.

[0082] S32. Based on the coordinates (X1, Y1, Z1) of the radar station in a rectangular coordinate system with the Earth's center as the origin, the distance between the virtual target and the radar station, and the coordinates (X4, Y4, Z4) of the virtual target, calculate the height H of the virtual target.

[0083] S33, based on the virtual target's starting point (B3,L3,H3), ending point (B4,L4,H4), and the transformation relationship between geographic coordinates and geodetic rectangular coordinates, the virtual target's coordinates in the geodetic rectangular coordinate system can be obtained as (X'3,Y3',Z'3) and (X'4,Y4',Z'4).

[0084] S34, based on the set virtual target speed v, the time required for the virtual target to travel from the starting point to the ending point can be obtained. And the flight path of the virtual target in the geodetic rectangular coordinate system Where v x ,v y ,v z This represents the velocity components of the virtual target along the x, y, and z axes in the geodetic rectangular coordinate system.

[0085] S35, based on the time t required for the virtual target to travel from the starting point to the ending point. 3,4 By selecting the starting point (X3, Y3) and ending point (X4, Y4) of the virtual target on the planar map, the flight speed of the virtual target on the display terminal's planar map can be obtained.

[0086] S4, Modulation of the virtual target's radio frequency signal parameters. Modulation of the virtual target's radio frequency signal parameters includes modulation of the virtual target's azimuth, range, and velocity relative to the radar station.

[0087] The modulation method in step 4 includes the following steps:

[0088] S41, based on the target support system's azimuth θ at the radar station, the radar station antenna scanning period T, and the virtual target's flight trajectory, the azimuth change between the first and second detections of the virtual target by the radar is Δθ. Therefore, the time interval between the first and second transmissions of the virtual target's radio frequency signal is:

[0089] S42, based on the time interval Δt and the flight trajectory of the virtual target, the distances r1 and r2 of the virtual target relative to the radar when the radar detects the virtual target in two consecutive instances can be obtained;

[0090] S43, based on the distances r1 and r2 of the virtual target relative to the radar in two adjacent transmissions, the time delay between two adjacent transmissions of virtual signal pulses can be obtained as follows: Where c is the speed of light, Δτ is positive when the pulse is advanced, and Δτ is negative when the pulse is delayed;

[0091] S44, based on the time interval Δt and the flight speed of the virtual target, the flight distance of the virtual target when the radar detects the virtual target in two consecutive instances can be obtained as r. 1,2 In the triangle formed by the locations where the radar and the virtual target are detected in two adjacent instances, the angle between the line connecting the first detected virtual target to the radar and the virtual target's flight path is... The radial velocity of the virtual target relative to the radar when it is first detected is:

[0092] S45, based on the real-time velocity of the virtual target relative to the radar and the Doppler principle, can determine the frequency offset of the virtual target's radio frequency signal. Where f is the radar operating frequency, c is the speed of light, and the frequency offset is positive when the simulated target is close to the radar and negative when it is far away from the radar.

[0093] This invention can simulate multiple virtual routes, avoiding the problem of a single route, and can save a lot of manpower, material resources and financial resources.

[0094] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radar installation training target support method characterized by comprising: The method comprises the following steps: S1, marking the geographical position of the radar station on the plane map of the display terminal according to the geographical position information of the radar installation; meanwhile, calculating the scanning period T of the radar antenna according to the change rule of the strength of the received radar radio frequency signal energy; and determining the azimuth angle of the target support system at the radar station according to the GPS / BDS positioning information (B1, L1, H1) of the target support system and the geographical position information (B2, L2, H2) of the radar installation, wherein B, L and H are the longitude, latitude and height values respectively; S2, virtually displaying the azimuth of the main lobe of the antenna beam of the radar station at any moment according to the data in step S1; S3, generating a virtual target flight path and displaying it on the plane map of the display terminal; S4, modulating the virtual target radio frequency signal parameters; The step S1 obtains data required by the step S2 by marking the geographical position of the virtual radar station on the display terminal plane map through the keyboard input of the control terminal. Specifically, the geographical position information (B2, L2, H2) of the radar installation and the Miller projection coordinate conversion formula are used wherein W represents the circumference of the earth, and mill represents the Miller constant, ranging from -2 to 3, to obtain the plane rectangular coordinates (X2, Y2) of the radar station on the plane map. Assuming that the target protection system receives the maximum power of the radar radiation radio frequency signal at time t1 At the next time t2, the maximum power of the radar radiation radio frequency signal is received again And the time adjacent between the two times of receiving the maximum power of the signal, it is determined that the radar antenna scanning period is T = |t2-t1|; According to geographical position information (B1, L1, H1) and (B2, L2, H2) of the radar station and the target support system, through a conversion relationship between geographical position coordinates and geodetic rectangular coordinates Wherein, B, L and H are longitude, latitude and height value respectively, N is the radius of curvature of the prime vertical of the geographical position data record position point, e is the first eccentricity of the ellipsoid, and the coordinate points (X1, Y1, Z1) and (X2, Y2, Z2) of the two in the rectangular coordinate system with the earth center as the origin are determined. According to the coordinate point (X3, Y3, Z3) of the north pole of the earth in the rectangular coordinate system with the earth center as the origin, a plane a1·x+b1·y+c1·z=0 composed of the radar station, the earth center and the north pole is determined, wherein a1=Y1·Z3-Z1·Y3, b1=X3·Z1-X1·Z3, c1=X1·Y3-Y1·X3, and a plane a2·x+b2·y+c2·z=0 composed of the target support system, the earth center and the radar station is determined, wherein a2=Y1·Z2-Z1·Y2, b2=X2·Z1-X1·Z2, c2=X1·Y2-Y1·X2; The included angle between two planes is determined according to a position relation formula of the two planes in analytic geometry The azimuth of the target protection system relative to the radar station is Wherein the radar station and the target protection system are located in the eastern hemisphere According to the maximum radar signal energy received by the target support system at t1, it is determined that the radar antenna beam is directed to the azimuth θ at t1.

2. The method of claim 1, wherein, The specific steps of step S3 are: S31, according to the coordinate of the virtual target on the plane map and the Miller projection coordinate conversion formula get the longitude and latitude in the virtual target geographic location information, through the conversion relationship between the geographic location coordinate and the geodetic rectangular coordinate determine the coordinate point (X4, Y4, Z4) of the virtual target in the rectangular coordinate system with the earth center as the origin, wherein X4, Y4, Z4 are functions of H, S32, according to the coordinate point (X1, Y1, Z1) of the radar station in the rectangular coordinate system with the earth center as the origin, the distance s of the virtual target and the radar station and the coordinate point (X4, Y4, Z4) of the virtual target, calculate the height H of the virtual target; S33, obtaining the coordinates (X'3, Y'3, Z'3), (X'4, Y'4, Z'4) of the virtual target in the rectangular coordinate system according to the starting point (B3, L3, H3) and the end point (B4, L4, H4) of the virtual target and the conversion relationship between the geographical position coordinates and the rectangular coordinates; S34, according to the set virtual target speed v, obtain the time required for the virtual target from the starting point to the end point and the flight path of the virtual target in the geodetic rectangular coordinate system where v x ,v y ,v z represent the speed components of the virtual target in the x, y, z axes of the geodetic rectangular coordinate system; S35, the time t required for the virtual target to move from the start point to the end point 3,4 and the start point (X3, Y3) and the end point (X4, Y4) of the virtual target selected on the planar map, the flying speed of the virtual target on the planar map of the display control terminal is obtained 3. The method of claim 2, wherein, The steps of the modulation method of step S4 comprise: S41, according to the target protection system in the radar station azimuth θ, radar station antenna scanning period T and the virtual target flight track, if the virtual target is detected by radar for the first time and the second time, the azimuth angle changes to Δθ, the time interval between the first time and the second time of the virtual target radio frequency signal transmission is S42, obtaining the distances r1 and r2 of the virtual target relative to the radar when the virtual target is detected by the radar twice in succession according to the time interval Δt and the virtual target flight path; S43, according to the distance r1 and r2 of the adjacent two virtual targets relative to the radar, the time delay of the adjacent two emitted virtual signal pulses is obtained as Wherein c is the speed of light, and Δτ is positive when the pulse is advanced, and Δτ is negative when the pulse is delayed. S44, according to the time interval Δt and the virtual target flight speed, the flight distance of the virtual target when the virtual target is detected by the radar for two adjacent times is r 1,2 Then, in the triangle formed by the positions of the radar and the virtual target when the virtual target is detected for two adjacent times, the included angle between the line connecting the radar and the virtual target when the virtual target is detected for the first time and the flight route of the virtual target is Then, the radial velocity of the virtual target when the virtual target is detected for the first time relative to the radar is S45, determining the frequency offset of the virtual target radar signal according to the real-time speed of the virtual target relative to the radar and the Doppler principle Wherein, f is the radar operating frequency, c is the speed of light, and the frequency offset is positive when the virtual target is close to the radar, and the frequency offset is negative when the virtual target is far away from the radar.

4. The system for providing a radar engagement training target based on any one of claims 1-3, wherein: The system comprises a host, a display and control terminal, an antenna and a power supply; the host is electrically connected with the display and control terminal and the antenna, and the power supply provides the required voltage for the normal operation of the system; The host receives the radar radio frequency signal through the antenna, combines the uploaded data of the display and control terminal, performs analysis and processing, and radiates the virtual target radio frequency signal outward through the antenna; The antenna is used for receiving the radar radio frequency signal and radiating the virtual target radio frequency signal output by the host outward; The display and control terminal is used for displaying, planning and determining the virtual radar station, the virtual target flight path and the modulation parameters of the virtual target radio frequency signal.

5. The system of claim 4, wherein: The host comprises a frequency source, an analog down-conversion channel, an analog-to-digital conversion unit (ADC), a digital down-conversion unit (DDC), a baseband digital signal delay unit, a baseband digital signal Doppler shift unit, a digital up-conversion unit (DUC), a digital-to-analog conversion unit (DAC), an analog up-conversion channel and a GPS / BDS positioning device; The frequency source is configured to provide a clock signal for the normal operation of each module of the host, and provide a first local oscillator signal and a second local oscillator signal for the analog down-conversion channel and the analog up-conversion channel; The down-conversion channel is configured to perform twice frequency mixing on the radio frequency signal received by the antenna to an intermediate frequency signal, and output the intermediate frequency signal to the ADC; The ADC is configured to sample the intermediate frequency signal from the radio frequency module to form a digital intermediate frequency signal, and output the digital intermediate frequency signal to the DDC; The DDC is configured to perform quadrature demodulation on the digital intermediate frequency signal from the ADC to form I and Q baseband digital signals, and output the I and Q baseband digital signals to the baseband digital signal delay unit; The baseband digital signal delay unit is configured to perform distance modulation on the baseband digital signal from the DDC, and output the baseband digital signal to the baseband digital signal Doppler shift unit; The baseband digital signal Doppler shift unit is configured to perform velocity modulation on the baseband digital signal from the baseband digital signal delay unit, and output the baseband digital signal to the DUC; The DUC is configured to perform up-conversion on the I and Q baseband digital signals from the baseband digital signal Doppler shift unit to a digital intermediate frequency signal, and output the digital intermediate frequency signal to the DAC; The DAC is configured to perform digital-to-analog conversion on the digital intermediate frequency signal from the DUC to an analog intermediate frequency signal; The up-conversion channel is configured to perform twice frequency mixing on the intermediate frequency signal from the DAC to a radio frequency signal, and output the radio frequency signal to the antenna; The GPS / BDS positioning device is configured to obtain geographical position information of the target support system, and output the position information to the display and control terminal through a network cable.

6. The system of claim 4, wherein: The antenna comprises a receiving antenna and a transmitting antenna, the receiving antenna is configured to receive the radio frequency signal radiated by the radar and output the radio frequency signal to the host through a radio frequency cable, and the transmitting antenna is configured to receive the radio frequency signal output by the host through the radio frequency cable and radiate outward.

7. The system of claim 4, wherein: The display and control terminal comprises a display terminal and a control terminal, the display terminal is configured to display a virtual target track and receive the GPS / BDS geographical position information output by the host through the network cable, and display the geographical position of the virtual radar station on a plane map; The control terminal is configured to determine the modulation parameters of the virtual target radio frequency signal and output the modulation parameters to the host through the network cable.

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