CN108872942A - The real-time keeping method in active primary reflection surface antenna ideal shape face based on datum mark - Google Patents

Abstract

The invention belongs to the technical field of radar antennas, and specifically relates to a method for maintaining the ideal shape of an active main reflector antenna in real time based on a reference point, which uses a set of laser ranging and angle measuring equipment to simultaneously realize the main reflector and the secondary reflector of the reflector antenna Displacement detection does not need to consider the factors of antenna deformation. It can be applied to static loads, such as gravity loads, steady-state wind loads, rain and snow, and slowly changing loads, such as temperature loads. It is also suitable for processing and installation errors. Realize the closed-loop real-time adjustment of the reflector and the real-time maintenance of the ideal shape of the active main reflector antenna.

Description

Real-time maintaining method of ideal shape surface of active main reflector antenna based on datum point

technical field

The invention belongs to the technical field of radar antennas, in particular to a reference point-based method for maintaining the ideal shape of an active main reflector antenna in real time, which is applied to the real-time maintenance of the ideal shape of the active main reflector antenna during service.

Background technique

Reflector antennas are widely used in deep space exploration, radio astronomy and other fields. With the development of technology, large-aperture and high-frequency bands are the main development directions. The larger the aperture, the higher the frequency band, and the more prominent the performance of the reflector antenna. For example, the 100-meter fully movable radio telescope built by the Federal Republic of Germany in the 1970s, the Green Bank 100-meter radio telescope built by the United States in 2000, and the 65-meter Tianma telescope built by China in 2012 can work in the millimeter wave band (30GHz-300GHz ).

The increase of the antenna diameter of the reflector makes the influence of external loads (gravity load, temperature load, wind load, etc.) cannot be ignored, and its shape will inevitably deviate from the ideal shape, which makes it difficult to meet the high-frequency requirements for the reflector shape. Accuracy requirements, which in turn lead to significant deterioration of electrical performance. In order to reduce the difficulty of processing and improve the electrical performance of the antenna, the current large-scale high-frequency reflector antenna mostly adopts an active main reflector structure, that is, the main reflector panel is equipped with an actuator, and the panel can be actively adjusted within a certain range. By adjusting the actuator in real time To maintain the high precision of the antenna shape. For example, the main reflector of the Shanghai 65-meter telescope is composed of 1008 panels, and the entire antenna structure weighs about 2640 tons. At the same time, it is affected by wind load and temperature deformation. It is required that under the action of 1104 actuators, its shape and surface accuracy should reach 0.3 mm. , the pointing accuracy reaches 3 arc seconds.

The key to the adjustment of the antenna shape of the active main reflector is the real-time measurement of the deformation of the shape, and then realize the real-time adjustment of the actuator to ensure the accuracy of the shape. However, at present, the real-time maintenance of the ideal shape of the reflector has not been realized in engineering . The shape and surface measurement methods used in engineering mainly include manual or UAV photogrammetry, laser ranging (laser total station/laser tracker) and radio holographic measurement. First of all, due to manual intervention, it is difficult to meet the real-time requirements, and the measurement process cannot be realized when the antenna is in service. Secondly, in addition to the adjustment of the active main reflector, the secondary reflector will also deviate from the ideal position under the action of external load. At present, the adjustment of the sub-reflector in engineering mostly adopts the empirical method. By measuring the far-field pattern of the antenna, according to the symmetry performance and gain value of the sidelobe of the far-field pattern, the adjustment process of the sub-reflector is guided according to experience. Usually, the number of adjustments is large. And it takes a long time. Obviously, the adjustment of the shape and surface of the active main reflector antenna needs to take into account both the adjustment of the active main reflector and the adjustment of the secondary reflector. At present, the closed-loop real-time adjustment of the reflector has not yet been realized.

Contents of the invention

The purpose of the present invention is to provide a real-time method for maintaining the ideal shape of the active main reflector antenna based on the reference point, so as to realize the closed-loop real-time adjustment of the reflector and the real-time maintenance of the ideal shape of the active main reflector antenna.

The technical scheme that realizes the object of the present invention is: the real-time maintenance method of the ideal shape surface of the active main reflector antenna based on the reference point, it is characterized in that: at least comprise the following steps:

Step 1, install laser measuring equipment and store data related to the sub-reflector;

Step 2, establishing a reference coordinate system and storing relevant data of the main reflecting surface.

Step 3, paste the target point and store the relevant data of the target point.

Step 4, calculating the relevant data of the sub-reflector in the reference coordinate system;

Step 5, calculating the spherical coordinates of the target point of the main reflector actuator in the secondary reflector coordinate system;

Step 6, calculating the coordinate value of the actuator target point in the secondary surface coordinate system during the service of the antenna;

Step 7, calculate the coordinate value of the reference point target point in the secondary surface coordinate system during the service of the antenna;

Step 8, calculating the coordinate value of the origin of the secondary surface coordinate system in the reference coordinate system during the service of the antenna;

Step 9, calculating the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the service of the antenna;

Step 10, calculating the normal adjustment of the main surface actuator during the service of the antenna;

Step 11, calculating the adjustment amount of the secondary surface pose during the service of the antenna;

Step 12: Repeat steps 5 to 11 continuously during the service of the antenna to realize real-time maintenance of shape and surface.

The first step to install the laser measuring equipment and store the related data of the sub-reflector is to install the laser rangefinder goniometer system on the back of the sub-reflector, reserve a hole of appropriate size at the apex of the sub-reflector, and move the laser probe to the sub-reflector. The position of the hole at the vertex of the surface, assuming that the measurement coordinate system coincides with the coordinate system of the secondary surface, is recorded as O _s -x _s y _s z _s , where O _s is the coordinate origin, located at the vertex of the secondary reflective surface; The positioning point of the sub-reflector’s pose: O _s point and a point D on the O _s -z _s axis, the coordinates of point D in the O _s -x _s y _s z _s coordinate system are Wherein, the superscript s represents the coordinate value in the O _s -x _s y _s z _s coordinate system.

The second step to establish a reference coordinate system and store relevant data on the main reflector is to establish a reference coordinate system at the apex position of the main reflector, which is recorded as O _r -x _{ry r z r , where} O _r is the coordinate origin, located at the main reflector The position of the vertex of the surface, the coordinate axes of the reference coordinate system are parallel to and in the same direction as the coordinate axes of the sub-reflector coordinate system; select three reference points A, B and C under the reference coordinate system, which are in O _r -x _r y _r The coordinates in the z _r coordinate system are recorded as and and are not coplanar on the plane perpendicular to the O _r -z _r axis, where the superscript r represents the coordinate value in the O _r -x _{ry r z r coordinate system} , the reference point can be independent of the reflector to avoid its Deformation displacement occurs, or the reference point is located at the position where the deformation displacement of the center of the reflector is small.

The step three of pasting the target point and storing the relevant data of the target point is to paste the target point at the connection position between the main reflector actuator and the panel, and record the coordinates of the target point under the O _r -x _{ry r z r coordinate system} as Determining the normal unit vector of the actuator target point Among them, the subscript a represents the a-th target point; paste the target point at the three reference point positions mentioned in step 2, ignoring the thickness of the target point, and its coordinates are the same as the coordinates of the reference points A, B and C.

The calculation of the relevant data of the secondary reflector in the reference coordinate system in the step 4 is to determine the coordinates of the vertex O _s of the secondary reflector in the reference coordinate system O _r -x _{ry r z r coordinate system} according to the ideal antenna design parameters Determine the coordinates of a point D on the secondary reflector O _s -z _s axis in step 1 in

The step 5 calculating the spherical coordinates of the main reflector actuator target point under the secondary reflector coordinate system includes:

(5a) Under the coordinate system O _s -x _s y _s z _s of the secondary reflector, determine the coordinate value of the target point of the main reflector actuator in

(5b) Under the coordinate system O _s -x _s y _s z _s of the secondary reflector, the coordinate value of the target point of the main reflector actuator convert to spherical coordinates in Where cart2sph is the conversion function from Cartesian coordinates to spherical coordinates in MATLAB numerical analysis software.

The step 6 to calculate the coordinate values of the actuator target point in the secondary surface coordinate system during the service of the antenna includes: .

(6a) Measure the distance from the target point of the actuator to the origin of the coordinate system of the sub-reflector using a laser ranging goniometer and elevation angle They are the first component and the second component of the spherical coordinates of the actuator target point after the deformation of the antenna in the sub-reflector coordinate system after the rigid body displacement, where the elevation angle Indicates the angle between the laser beam and the positive direction of the O _s -z _s axis after the antenna is deformed, and the superscript "'" indicates the data after the antenna is deformed;

(6b) Since the main factor affecting the electrical performance of the reflector antenna is the axial deformation of the reflector, the rotational displacement of the reflector nodes around the axis is ignored, and it is approximately considered that the actuator target point occurs in the secondary reflector coordinate system after the antenna is deformed. Third component of spherical coordinates after rigid body displacement

(6c) Calculate the coordinate value of the deformed actuator target point after rigid body displacement in the secondary reflector coordinate system Among them, sph2cart is the conversion function from spherical coordinates to Cartesian coordinates in MATLAB numerical analysis software.

The step 7 to calculate the coordinate values of the reference point target point in the secondary surface coordinate system during the service of the antenna includes:

(7a) Use the laser ranging goniometer to measure the distance from the reference point target point to the coordinate origin of the sub-reflector coordinate system and elevation angle They are respectively the first component and the second component of the spherical coordinates of the deformed reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system, where the subscript " _b " indicates the reference point A or B or C;

(7b) Approximately consider the third component of the spherical coordinates of the reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system in, symbol Indicates the third component of the vector, when " _b " indicates the reference point A, When " _b " indicates reference point B, When " _b " indicates reference point C,

(7c) Calculate the coordinate value of the reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system

The step eight of calculating the coordinate values of the origin of the secondary surface coordinate system in the reference coordinate system during the service of the antenna includes:

(8a) In step 7, let " _b " denote the reference points A, B and C in turn, then get the distances of the three reference points in turn and elevation

(8b) Solve the following equations and obtain the coordinate values of the origin of the subsurface coordinate system in the reference coordinate system during the service of the antenna

The calculation of the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the antenna service process in step nine includes:

(9a) In step 7, let " _b " denote the reference points A, B and C in sequence, then the coordinate values are obtained in sequence and

(9b) Establish the following equations:

Among them, T′ _s2r represents the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the service of the antenna;

(9c) Write step (9b) system of equations into following matrix form:

(9d) solving step (9c) system of equations to obtain the rotation matrix T′ _s2r :

where [] ^-1 means the inverse of the matrix.

The step ten calculating the normal adjustment of the main surface actuator during the service of the antenna includes the following steps:

(10a) Calculate the coordinates of the actuator target point in the reference coordinate system according to the following formula

(10b) Calculate the cosine value of the angle between the normal vector of the actuator target point and the axial direction of the reflector according to the following formula:

(10c) Calculate the normal adjustment amount Δn _a of the actuator according to the following formula:

Where Δn _a >0 means the actuator is stretched, and Δn _a <0 means the actuator is contracted.

The calculation of the secondary surface pose adjustment amount during the antenna service process in step eleven includes:

(11a) Determine the adjustment amount of point O _s according to the following formula

(11b) Calculate the coordinate value of point D in the reference coordinate system after the rigid body displacement of the secondary reflector

(11c) Determine the adjustment amount of point D according to the following formula (Δx _D , Δy _D , Δz _D )

Described step twelve specifically includes:

According to the calculation result of the adjustment amount in step (10c), each actuator on the main reflector surface is adjusted sequentially to keep the main reflector The ideal position of the active main reflector antenna is maintained, and the above process is repeated continuously during service to realize the real-time maintenance of the ideal shape of the active main reflector antenna.

Compared with the prior art, the present invention has the following advantages:

1. The present invention can realize the displacement detection of the main reflection surface and the secondary reflection surface of the reflective surface antenna at the same time only by using a set of laser ranging and angle measuring equipment, without considering the formation factors of the antenna deformation, and can be applied to static loads, such as gravity loads, Steady-state wind load, rain and snow are also applicable to slow-changing loads, such as temperature loads, and are also applicable to processing and installation errors, etc.;

2. The shape and surface detection process of the present invention does not require manual intervention, and automatic detection can be realized. According to the detection results, the actuator of the main reflective surface and the adjustable equipment of the secondary reflective surface can be adjusted in real time, so that the main reflective surface and the secondary reflective surface can be kept at the ideal design position at the same time , to realize the real-time maintenance of the ideal shape of the antenna during service.

The present invention will be further described below in conjunction with accompanying drawings and examples of implementation.

Description of drawings

Fig. 1 is the realization flowchart of the present invention;

Fig. 2 is a schematic diagram of an ideal reflector antenna and a coordinate system;

Fig. 3 is a schematic diagram of deformation reflector antenna and laser measurement;

Fig. 4 is a schematic diagram of the calculation process of the actuator adjustment amount;

Fig. 5 is a schematic diagram of the adjustment process of the secondary reflector;

Fig. 6 is the 35 meters reflector antenna model figure that the present invention uses;

Fig. 7 is the comparison diagram of deformation before and after adjustment of the target point of the 35-meter reflector antenna actuator used in the present invention;

Fig. 8 is a position comparison diagram before and after adjustment of the sub-reflector of the 35-meter reflector antenna used in the present invention.

Detailed ways

As shown in Figure 1, the real-time maintenance method of the ideal shape of the active main reflector antenna based on the reference point includes the following steps:

Step 1, installing laser measuring equipment and storing relevant data of the sub-reflector.

As shown in Figure 2, the laser ranging goniometer system is installed on the back of the sub-reflecting surface, and a hole of appropriate size is reserved at the apex of the sub-reflecting surface, and the laser probe is moved to the hole position at the apex of the sub-reflecting surface. The surface coordinate system coincides, recorded as O _s -x _s y _s z _s , where O _s is the coordinate origin, located at the apex of the sub-reflector; two sub-reflector pose orientation points are calibrated on the sub-reflector: O _s point and a point D on the O _s -z _s axis, the coordinates of point D in the O _s -x _s y _s z _s coordinate system are Wherein, the superscript s represents the coordinate value in the O _s -x _s y _s z _s coordinate system.

Step 2, establishing a reference coordinate system and storing relevant data of the main reflecting surface.

As shown in Figure 2, a reference coordinate system is established at the apex position of the main reflection surface, which is denoted as O _r -x _{ry r z r , where} O _r is the coordinate origin, located at the apex position of the main reflection surface, and the coordinate axes of the reference coordinate system are respectively Parallel to and in the same direction as the coordinate axes of the sub-reflector coordinate system; select three reference points A, B and C in the reference coordinate system, and their coordinates in the O _r -x _{ry r z r coordinate system} are respectively recorded as and and are not coplanar on the plane perpendicular to the O _r -z _r axis, where the superscript r represents the coordinate value in the O _r -x _{ry r z r coordinate system} , the reference point can be independent of the reflector to avoid its Deformation displacement occurs, or the reference point is located at the position where the deformation displacement of the center of the reflector is small;

Step 3, paste the target point and store the relevant data of the target point.

As shown in Figure 2, the target point is pasted at the position where the main reflector actuator is connected to the panel, and the coordinates of the target point are recorded in the O _r -x _{ry r z r coordinate system} as Determining the normal unit vector of the actuator target point Wherein, the subscript a represents the ath target point; paste the target point at the three reference point positions described in step 2, ignore the thickness of the target point, and its coordinates are the same as the coordinates of the reference points A, B and C;

Step 4, calculating data related to the sub-reflector in the reference coordinate system.

According to the ideal antenna design parameters, in the reference coordinate system O _r -x _{ry r z r coordinate system} , determine the coordinates of the sub-reflector vertex O _s point Determine the coordinates of a point D on the secondary reflector O _s -z _s axis in step 1 in

Step five, calculating the spherical coordinates of the target point of the actuator on the main reflector in the coordinate system of the secondary reflector.

(5a) Under the coordinate system O _s -x _s y _s z _s of the secondary reflector, determine the coordinate value of the target point of the main reflector actuator in

(5b) Under the coordinate system O _s -x _s y _s z _s of the secondary reflector, the coordinate value of the target point of the main reflector actuator convert to spherical coordinates in Where cart2sph is the conversion function from Cartesian coordinates to spherical coordinates in MATLAB numerical analysis software;

Step six, calculate the coordinate value of the actuator target point in the secondary surface coordinate system during the service of the antenna.

(6a) As shown in Figure 3, use the laser ranging goniometer to measure the distance from the target point of the actuator to the origin of the coordinate system of the secondary reflector and elevation angle They are the first component and the second component of the spherical coordinates of the actuator target point after the deformation of the antenna in the sub-reflector coordinate system after the rigid body displacement, where the elevation angle Indicates the angle between the laser beam and the positive direction of the O _s -z _s axis after the antenna is deformed, and the superscript "'" indicates the data after the antenna is deformed;

(6b) Since the main factor affecting the electrical performance of the reflector antenna is the axial deformation of the reflector, ignoring the rotational displacement of the reflector nodes around the axis, it is approximately considered that the actuator target point is a rigid body in the secondary reflector coordinate system after the antenna is deformed the third component of the displaced spherical coordinates

(6c) Calculate the coordinate value of the deformed actuator target point after rigid body displacement in the secondary reflector coordinate system Where sph2cart is the conversion function from spherical coordinates to Cartesian coordinates in MATLAB numerical analysis software;

Step 7, calculating the coordinate values of the reference point target point in the secondary surface coordinate system during the service of the antenna.

(7a) Use the laser ranging goniometer to measure the distance from the reference point target point to the coordinate origin of the sub-reflector coordinate system and elevation angle They are respectively the first component and the second component of the spherical coordinates of the deformed reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system, where the subscript " _b " indicates the reference point A or B or C;

(7b) Approximately consider the third component of the spherical coordinates of the reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system in, symbol Indicates the third component of the vector, when " _b " indicates the reference point A, When " _b " indicates reference point B, When " _b " indicates reference point C,

(7c) Calculate the coordinate value of the reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system

Step 8, calculating the coordinate values of the origin of the secondary surface coordinate system in the reference coordinate system during the service of the antenna.

(8a) In step 7, let " _b " denote the reference points A, B and C in turn, and then get the distance and elevation

(8b) Solve the following equations and obtain the coordinate values of the origin of the subsurface coordinate system in the reference coordinate system during the service of the antenna

Step 9, calculating the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the service of the antenna.

(9a) In step 7, let " _b " denote the reference points A, B and C in sequence, then the coordinate values are obtained in sequence and

(9b) Establish the following equations:

Among them, T′ _s2r represents the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the service of the antenna;

(9c) Write step (9b) system of equations into following matrix form:

(9d) solving step (9c) system of equations to obtain the rotation matrix T′ _s2r :

Where [] ^-1 represents the inverse of the matrix;

Step 10, calculating the normal adjustment of the main surface actuator during the service of the antenna.

As shown in Figure 4, the calculation process of the normal adjustment of the main surface actuator during the service of the antenna is as follows:

(10a) Calculate the coordinates of the actuator target point in the reference coordinate system according to the following formula

(10b) Calculate the cosine value of the angle between the normal vector of the actuator target point and the axial direction of the reflector according to the following formula:

(10c) Calculate the normal adjustment amount Δn _a of the actuator according to the following formula:

Where Δn _a >0 indicates that the actuator is elongated, and Δn _a <0 indicates that the actuator contracts

Step 11, calculating the adjustment amount of the secondary surface pose during the service of the antenna.

As shown in Figure 5, the pose of the sub-reflector can be determined according to the calibration point O _s and the position of a point D on the O _s -z _s axis, so the pose of the sub-reflector can be converted to the calculation point O _s and the displacement of point D, the specific steps are as follows:

(11a) Determine the adjustment amount of point O _s according to the following formula

(11b) Calculate the coordinate value of point D in the reference coordinate system after the rigid body displacement of the secondary reflector

(11c) Determine the adjustment amount of point D according to the following formula (Δx _D , Δy _D , Δz _D )

Step 12: Repeat steps 5 to 11 continuously during the service of the antenna to achieve real-time maintenance of shape and surface.

According to the calculation result of the adjustment amount in step (10c), each actuator on the main reflector surface is adjusted sequentially to keep the main reflector The ideal position of the active main reflector antenna is maintained, and the above process is repeated continuously during service to realize the real-time maintenance of the ideal shape of the active main reflector antenna.

Advantages of the present invention can be further illustrated by following simulation experiments:

1. Simulation conditions

For a 35-meter double-reflector antenna as shown in Figure 6, the method of the present invention is simulated and verified. When the antenna on the reflecting surface is flat, the main reflecting surface is deformed due to gravity deformation, and the secondary reflecting surface is translated and rotated. Assuming that a measuring system is installed at the apex position of the sub-reflecting surface, the adjustment amount of the actuator and the adjustment process of the sub-reflecting surface are given through the method of the present invention to verify the correctness of the method of the present invention. In this simulation case, under the reference coordinate system, the coordinates of the reference points are (1702.5,0,500), (0,1702.5,900), (-1474.4,-851.25,0), the unit is mm, and the coordinates of the positioning point of the secondary reflector They are (0,0,10882) and (0,0,10482) respectively, in millimeters.

2. Simulation results

Figure 7 shows the comparison diagram of the deformation before and after the adjustment of the target point of the antenna actuator on the main reflector. Before adjustment, the target point of the actuator deformed a lot, the deformation range was approximately ±3 mm, and the root mean square error was 1.34 mm. After adjustment, the deformation of the target point of the actuator is greatly reduced, approaching the position of the ideal reflective surface, the deformation range is approximately ±0.5 mm, the root mean square error is 0.28 mm, and the improvement percentage of the root mean square error is 79.1%.

Fig. 8 shows a comparison diagram of the position of the sub-reflecting surface before and after adjustment. Because the reflector antenna refers to the normal gravity direction as the y-axis direction, the displacement of the sub-reflector in the y-axis direction is relatively large, while the displacement of the sub-reflector in the x-axis direction is small, which is not considered in the figure. Before the adjustment, the sub-reflector is far away from the ideal position by about 6.2 mm, and the posture has a certain deflection. After adjustment, the sub-reflector is significantly closer to the ideal position, and the attitude has improved slightly.

Change the simulation conditions and disperse the three reference points, whose coordinates are (5702.5,0,200), (0,5702.5,200), (-5474.4,-2051.25,0), the unit is mm, and the shape adjustment result will be more accurate. Accurately, as shown in the "reference point dispersion-after adjustment" curve in Figure 7, the adjustment result of the sub-reflector is no longer given.

The simulation results show that the method of the present invention can be used in the real-time adjustment process of the antenna shape of the active main reflector, the main reflector and the secondary reflector can be adjusted to the ideal position at the same time, and the above process is continuously cycled during service to realize the active main reflector The real-time maintenance of the ideal shape of the surface antenna.

Claims (10)

1. The real-time method for keeping the ideal shape of the active main reflector antenna based on the reference point is characterized in that it includes at least the following steps: Step 1, install laser measuring equipment and store data related to the sub-reflector; Step 2, establishing a reference coordinate system and storing relevant data of the main reflector; Step 3, paste the target point and store the relevant data of the target point; Step 4, calculating the relevant data of the sub-reflector in the reference coordinate system; Step 5, calculating the spherical coordinates of the target point of the main reflector actuator in the secondary reflector coordinate system; Step 6, calculating the coordinate value of the actuator target point in the secondary surface coordinate system during the service of the antenna; Step 7, calculate the coordinate value of the reference point target point in the secondary surface coordinate system during the service of the antenna; Step 8, calculating the coordinate value of the origin of the secondary surface coordinate system in the reference coordinate system during the service of the antenna; Step 9, calculating the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the service of the antenna; Step 10, calculating the normal adjustment of the main surface actuator during the service of the antenna; Step 11, calculating the adjustment amount of the secondary surface pose during the service of the antenna; Step 12: Repeat steps 5 to 11 continuously during the service of the antenna to achieve real-time maintenance of shape and surface. 2. the real-time method for maintaining the ideal shape of the active main reflector antenna based on the reference point according to claim 1, characterized in that: the installation of laser measuring equipment and the storage of secondary reflector related data in the step 1 are carried out on the secondary reflector Install the laser ranging and goniometer system on the back, reserve a hole of appropriate size at the apex of the sub-reflecting surface, move the laser probe to the hole at the apex of the sub-reflecting surface, assume that the measurement coordinate system coincides with the sub-surface coordinate system, denoted as O _s - x _s y _s z _s , where O _s is the origin of the coordinates, located at the apex of the sub-reflector; on the sub-reflector, two pose positioning points of the sub-reflector are marked: O _s point and a point D on the O _s -z _s axis , the coordinates of point D in the O _s -x _s y _s z _s coordinate system are Wherein, the superscript s represents the coordinate value in the O _s -x _s y _s z _s coordinate system. 3. the real-time method for maintaining the ideal shape of an active main reflector antenna based on reference points according to claim 1, is characterized in that: described step 2 establishes a reference coordinate system and stores the relevant data of the main reflector on the main reflector The vertex position establishes a reference coordinate system, which is recorded as O _r -x _{ry r z r , where} O _r is the coordinate origin, located at the vertex position of the main reflector, and the coordinate axes of the reference coordinate system are parallel to the coordinate axes of the secondary reflector coordinate system and in the same direction; select three reference points A, B and C in the reference coordinate system, and their coordinates in the O _r -x _{ry r z r coordinate system} are respectively recorded as and and are not coplanar on the plane perpendicular to the O _r -z _r axis, where the superscript r represents the coordinate value in the O _r -x _{ry r z r coordinate system} , the reference point can be independent of the reflector to avoid its Deformation displacement occurs, or the reference point is located at the position where the deformation displacement of the center of the reflector is small. 4. The real-time method for maintaining the ideal shape of the active main reflector antenna based on the reference point according to claim 1, characterized in that: the step 3 of pasting the target point and storing the relevant data of the target point is activated on the main reflector Paste the target point at the connection position between the device and the panel, and record the coordinates of the target point in the O _r -x _{ry r z r coordinate system} as Determining the normal unit vector of the actuator target point Among them, the subscript a represents the a-th target point; paste the target point at the three reference point positions mentioned in step 2, ignoring the thickness of the target point, and its coordinates are the same as the coordinates of the reference points A, B and C. 5. the method for keeping the ideal shape of the active main reflector antenna based on the reference point in real time according to claim 1, characterized in that: said step 4 calculates the secondary reflector related data in the reference coordinate system according to the ideal antenna design parameters , in the reference coordinate system O _r -x _{ry r z r coordinate system} , determine the coordinates of the vertex O _s point of the sub-reflector Determine the coordinates of a point D on the secondary reflector O _s -z _s axis in step 1 in 6. the method for keeping the ideal shape of the active main reflector antenna based on the reference point in real time according to claim 1, is characterized in that: described step 5 calculates the target point of the main reflector actuator target point under the secondary reflector coordinate system Spherical coordinates include: (5a) Under the coordinate system O _s -x _s y _s z _s of the secondary reflector, determine the coordinate value of the target point of the main reflector actuator in (5b) Under the coordinate system O _s -x _s y _s z _s of the secondary reflector, the coordinate value of the target point of the main reflector actuator convert to spherical coordinates in Where cart2sph is the conversion function from Cartesian coordinates to spherical coordinates in MATLAB numerical analysis software. 7. The method for maintaining the ideal shape of the active main reflector antenna based on the reference point in real time according to claim 1, characterized in that: said step 6 calculates the target point of the actuator in the auxiliary surface coordinate system during the service of the antenna The coordinate values for include: . (6a) Measure the distance from the target point of the actuator to the origin of the coordinate system of the sub-reflector using a laser ranging goniometer and elevation angle They are the first component and the second component of the spherical coordinates of the actuator target point in the sub-reflector coordinate system after the deformation of the antenna, respectively, after the rigid body displacement, where the superscript "'" indicates the data after the deformation of the antenna; (6b) Since the main factor affecting the electrical performance of the reflector antenna is the axial deformation of the reflector, the rotational displacement of the reflector nodes around the axis is ignored, and it is approximately considered that the actuator target point occurs in the secondary reflector coordinate system after the antenna is deformed. Third component of spherical coordinates after rigid body displacement (6c) Calculate the coordinate value of the deformed actuator target point after rigid body displacement in the secondary reflector coordinate system Among them, sph2cart is the conversion function from spherical coordinates to Cartesian coordinates in MATLAB numerical analysis software. 8. The real-time method for maintaining the ideal shape of the active main reflector antenna based on the reference point according to claim 1, characterized in that: said step 7 calculates the value of the reference point target point under the secondary surface coordinate system in the antenna service process Coordinate values include: (7a) Use the laser ranging goniometer to measure the distance from the reference point target point to the coordinate origin of the sub-reflector coordinate system and elevation angle They are respectively the first component and the second component of the spherical coordinates of the deformed reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system, wherein the subscript "b" indicates the reference point A or B or C; (7b) Approximately consider the third component of the spherical coordinates of the reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system in, symbol Represents the third component of the vector, when "b" represents the reference point A, When "b" indicates reference point B, When "b" indicates reference point C, (7c) Calculate the coordinate value of the reference point target point after the rigid body displacement occurs in the sub-reflector coordinate system 9. the method for maintaining the ideal shape of the active main reflector antenna based on the reference point in real time according to claim 1 is characterized in that: described step 8 calculates that the secondary surface coordinate system origin is under the reference coordinate system in the antenna service process Coordinate values include: (8a) Let "b" denote the reference points A, B and C in turn in step 7, then the distances are obtained in turn and elevation (8b) Solve the following equations and obtain the coordinate values of the origin of the subsurface coordinate system in the reference coordinate system during the service of the antenna 10. The method for maintaining the ideal shape of the active main reflector antenna based on the reference point in real time according to claim 1, characterized in that: said step 9 calculates the rotation matrix from the secondary surface coordinate system to the reference coordinate system in the antenna service process include: (9a) In step 7, let "b" represent the reference points A, B and C in sequence, then the coordinate values are obtained in sequence and (9b) Establish the following equations: Among them, T′ _s2r represents the rotation matrix from the sub-surface coordinate system to the reference coordinate system during the service of the antenna; (9c) Write step (9b) system of equations into following matrix form: (9d) solving step (9c) system of equations to obtain the rotation matrix T′ _s2r : where [] ^-1 represents the inverse of the matrix; The step ten calculating the normal adjustment of the main surface actuator during the service of the antenna includes the following steps: (10a) Calculate the coordinates of the actuator target point in the reference coordinate system according to the following formula (10b) Calculate the cosine value of the angle between the normal vector of the actuator target point and the axial direction of the reflector according to the following formula: (10c) Calculate the normal adjustment amount Δn _a of the actuator according to the following formula: Where Δn _a >0 means the actuator is elongated, and Δn _a <0 means the actuator shrinks; The calculation of the secondary surface pose adjustment amount during the antenna service process in step eleven includes: (11a) Determine the adjustment amount of point O _s according to the following formula (11b) Calculate the coordinate value of point D in the reference coordinate system after the rigid body displacement of the secondary reflector (11c) Determine the adjustment amount of point D according to the following formula (Δx _D , Δy _D , Δz _D ) Described step twelve specifically includes: According to the calculation result of the adjustment amount in step (10c), each actuator on the main reflector surface is adjusted sequentially to keep the main reflector The ideal position of the active main reflector antenna is maintained, and the above process is repeated continuously during service to realize the real-time maintenance of the ideal shape of the active main reflector antenna.