Method for precise measurement of fixed directional antenna system based on multiple spatial measurement techniques

Abstract

The application provides a method for realizing precise measurement of a fixed direction antenna system based on multiple spatial measurement technologies, aiming at the actual situation that multiple sets of feeder systems are installed in a structure closed feeder house, and comprehensively using a static GPS measurement system, a total station measurement system, a laser tracker measurement system and a digital industrial photogrammetry system, the total station measurement system is arranged in the feeder house, indoor measurement reference points and outdoor measurement reference points are set, unification of the indoor measurement reference points in the structure closed feeder house and the outdoor measurement reference points of an antenna main reflector is realized, measurement error of a multi-beam antenna system coordinate system is reduced, and the precision of measurement and adjustment of the antenna main reflector and the feeder system is improved; the precise measurement and adjustment of the spatial absolute position and attitude of multiple sets of feeder systems based on the unified reference of the fixed direction antenna system in the structure closed feeder house is realized, and the measurement and adjustment efficiency of the spatial absolute position and attitude of the feeder system is improved.

Description

Technical Field

[0001] This invention relates to the field of antenna measurement technology, specifically to a method for achieving precise measurement of a fixed-pointing antenna system based on various spatial measurement techniques. Background Technology

[0002] With the rapid development of industries such as satellite communication, radar, and electronic countermeasures, fixed-pointing multi-beam antennas have become increasingly popular due to their versatility. By using a single ground station antenna to match multiple feed systems, they can simultaneously receive electromagnetic signals from multiple geostationary satellites and across multiple frequency bands. This improves the utilization efficiency of the antenna's main reflector and effectively reduces the construction cost of ground station antennas. Each feed system is installed in a structurally enclosed feed room. Precisely measuring the surface accuracy of the main reflector, while ensuring the beam pointing of the directional multi-beam antenna, and accurately measuring and adjusting the three-dimensional absolute position and attitude of the feed system within the enclosed feed room are crucial factors in guaranteeing the electrical performance of the fixed-pointing multi-beam antenna.

[0003] The applicant previously filed an invention patent application with publication number CN114966236A entitled "A Method for Measuring the Structural Indicators of a Directional Multibeam Antenna". This solution is designed for situations where the ground station antenna and multiple feed systems are all in an open state. Since the ground station antenna and multiple feed systems are all in an open state, this solution can be implemented by setting up a total station on the ground to establish a coordinate system O-XYZ for the multibeam antenna system. Based on the coordinate system O-XYZ, laser trackers, digital industrial photogrammetry equipment, etc., can be used to adjust the surface accuracy of the main reflector, the pointing of the main beam, the attitude of the sub-reflector of the feed system, and the attitude of the feed horn.

[0004] However, the actual problem encountered during the actual installation of the antenna system is that each feed system is installed in a structurally enclosed feed room, transmitting signals to the outside only through a wave-transmitting window. Furthermore, due to the limited size of the roof windows in the feed room, it is not possible to assemble the feed system outside and measure and adjust the relative positions of the sub-reflector and feed before hoisting it into the feed room. Instead, the sub-reflector, feed, and feed system bracket must be hoisted separately into the feed room and then assembled. At this time, the various feed systems inside the feed room lack a unified coordinate system with the main reflector of the antenna outside the feed room. As a result, the total station set up on the ground in the traditional solution cannot measure all the feed systems inside the feed room. It can only measure one feed system at a time. Moreover, each measurement requires repeatedly using the distance intersection method to restore the coordinate system of the multi-beam antenna system, resulting in large measurement errors and low measurement efficiency. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement techniques. The total station is positioned inside a structurally enclosed feed room near a side glass window. Since the field of view is limited at the feed room window, when establishing the GPS geodetic control network, the installation position of the observation piers with forced centering bases is controlled so that the total station inside the feed room can observe at least two observation piers with forced centering bases. This facilitates the restoration of the antenna origin O through spatial distance intersection, thereby establishing the coordinate system O-XYZ for the multi-beam antenna system.

[0006] The technical solution of this invention is as follows:

[0007] A method for precise measurement of a fixed-pointing antenna system based on multiple space measurement techniques includes the following steps:

[0008] Step 1: Construct at least 3 observation piers with forced alignment bases at the multi-beam antenna installation site, and ensure that at least 2 observation piers with forced alignment bases can be observed simultaneously from the window position of the feed room; use a static GPS measurement system to observe the observation piers and obtain the geodetic coordinates of the observation points in each observation pier;

[0009] Using the observation pier as the outdoor measurement reference point for the antenna main reflector, a total station measurement system is set up at the window position of the feed house. Using the total station measurement system, at least two of the four outdoor measurement reference points are used as references to measure the geodetic coordinates of the center of the antenna main reflector base. The coordinate system O-XYZ of the multi-beam antenna system is established with the center of the antenna main reflector base as the coordinate origin O.

[0010] Step 2: Inside the enclosed feed room, multiple indoor measurement reference points are evenly set around the overall installation area of ​​the feed system. The coordinates of the indoor measurement reference points in the O-XYZ coordinate system of the multi-beam antenna system are measured using a total station measurement system.

[0011] Step 3: Based on the coordinate system O-XYZ of the multi-beam antenna system, the main reflector of the antenna is measured and adjusted using a total station measurement system and a digital industrial photogrammetry system;

[0012] Step 4: Based on the multi-beam antenna system coordinate system O-XYZ and the indoor measurement reference point, use the laser tracker measurement system to simultaneously measure and adjust the spatial absolute position and attitude of multiple feed systems in the feed room.

[0013] Furthermore, in step 1, the process of using a static GPS measurement system to observe the observation piers and obtain the geodetic coordinates of the observation points in each observation pier is as follows: the GPS receiver is used to continuously observe the synchronous loop and long baseline composed of the observation points in each observation pier, the geodetic coordinates of the common observation points in the synchronous loop and long baseline are obtained by using the precise ephemeris calculation of the observation station, and the local area network adjustment is performed using the geodetic coordinates of the common observation points as the reference data to obtain the azimuth reference and the geodetic coordinates of the remaining observation points.

[0014] Furthermore, in step 1, a total station measurement system is used to measure the geodetic coordinates of the center of the antenna main reflector base, using at least two of the four outdoor measurement reference points as references, and the origin O of the multi-beam antenna system coordinate system is established by spatial distance intersection.

[0015] Furthermore, in step 1, a coordinate system transition method is used to establish the multi-beam antenna system coordinate system O-XYZ: Based on the coordinate origin O of the multi-beam antenna system coordinate system and the geodetic coordinates of an outdoor measurement reference point G4 observed by the total station measurement system, the geodetic azimuth angle α of the geodetic line OG4 is calculated; taking the upper machined surface of the antenna main reflector base as the reference plane P, the center of the antenna main reflector base as the coordinate system origin o, and the outdoor measurement reference point G4 as the x-axis direction of the coordinate system, a reference coordinate system o-xyz is established; by rotating the reference coordinate system o-xyz around the z-axis in the xoy plane by the geodetic azimuth angle α of the geodetic line OG4, the multi-beam antenna system coordinate system O-XYZ can be obtained.

[0016] Furthermore, in step 2, multiple feed systems are arranged on the track via brackets, and indoor measurement reference points are arranged on both sides of the track.

[0017] Furthermore, the measurement and adjustment of the antenna main reflector includes the measurement of the antenna main beam pointing and the surface accuracy measurement of the main reflector. The four corners of the main reflector are used as the measurement points of the antenna main reflector. Fixtures are installed to interchange spherical reflectors with the same sphere radius and photogrammetric hemispheres.

[0018] Furthermore, when performing antenna main beam pointing measurement and adjustment, a spherical reflector is installed on the fixture. In the multi-beam antenna system coordinate system O-XYZ, the normal deviation of the antenna main reflector measurement point relative to the theoretical model of the main reflector is measured and adjusted by a total station, so that the antenna main beam pointing gradually reaches the optimal level.

[0019] Furthermore, when measuring the surface accuracy of the main reflector, a digital industrial photogrammetry system is used. A photogrammetric hemisphere is mounted on the tooling, and photogrammetric data of the measurement points of the main reflector are acquired through the digital industrial photogrammetry system. The coordinates of the main reflector measurement points in the multi-beam antenna system coordinate system O-XYZ are measured using a total station, and the photogrammetric data of the main reflector measurement points are transformed into the multi-beam antenna system coordinate system O-XYZ. Through a seven-parameter coordinate system transformation method, the multi-beam antenna system coordinate system O-XYZ is transformed into the main reflector normal coordinate system O1-X1Y1Z1. In the O1-X1Y1Z1 coordinate system, the theoretical model of the antenna main reflector and the photogrammetric data of the antenna main reflector measurement points are imported. The photogrammetric data of the antenna main reflector measurement points are directly compared with the theoretical model. The normal deviation of the actual position of the antenna main reflector measurement points relative to the theoretical model of the main reflector is the adjustment amount. The root mean square value of the normal deviation of all antenna main reflector measurement points is calculated, which is the surface accuracy of the main reflector.

[0020] Furthermore, the sub-reflector, feed, and feed system bracket of the feed system are hoisted into the feed room through the roof window and assembled into multiple feed systems within the inclined track of the enclosed feed room. Then, in the multi-beam antenna system coordinate system O-XYZ, using indoor measurement reference points, a laser tracker measurement system is used to simultaneously measure and adjust the absolute spatial position and attitude of multiple feed systems within the enclosed feed room.

[0021] Furthermore, in step 4, firstly, using the seven-parameter coordinate system transformation method, an indoor measurement reference point with known coordinates in the multi-beam antenna system coordinate system is used to establish the feed room beam coordinate system O2-X2Y2Z2. Then, measurement points are established on each feed system, including the four corner positions of the sub-reflector and the front and rear center positions of the feed horn. The coordinates of the four corner positions of the sub-reflector and the front and rear center positions of the feed horn in the multi-beam antenna system coordinate system O-XYZ are transformed to the feed room beam coordinate system O2-X2Y2Z2. Then, using the laser tracker measurement system, the measured values ​​of the coordinates of the four corner positions of the sub-reflector are compared and adjusted with the theoretical coordinates in the feed room beam coordinate system O2-X2Y2Z2 to ensure that the absolute spatial position and attitude of the sub-reflector meet the requirements. At the same time, the measured values ​​of the center coordinates of the front and rear flanges of the feed system horn are compared and adjusted with the theoretical values ​​to ensure that the absolute spatial position and attitude of the feed system horn meet the requirements.

[0022] Beneficial effects

[0023] This invention proposes a method for precise measurement of fixed-pointing antenna systems based on multiple spatial measurement technologies. Addressing the practical issue of multiple feed systems installed within a structurally enclosed feed room, this method comprehensively utilizes various spatial measurement technologies, including static GPS measurement systems, total station measurement systems, laser tracker measurement systems, and digital industrial photogrammetry systems. By arranging the total station measurement system within the feed room and establishing indoor and outdoor measurement reference points, and adhering to the measurement principles of "unified reference, reference transfer, step-by-step control, and step-by-step improvement," the method achieves unification of the measurement reference inside the structurally enclosed feed room with the outdoor measurement reference of the antenna's main reflector. This reduces measurement errors in restoring the coordinate system of the multi-beam antenna system and improves accuracy. The accuracy of measurement and adjustment of the antenna main reflector and feed system was improved; it enabled the precise measurement and adjustment of the absolute spatial position and attitude of multiple feed systems simultaneously within a structurally enclosed feed room based on a unified benchmark of a fixed-pointing antenna system, thus improving the efficiency of measurement and adjustment of the absolute spatial position and attitude of the feed system; it also enabled the precise measurement of the surface accuracy of the main reflector while taking into account the beam pointing of the fixed-pointing multi-beam antenna, and the precise measurement and adjustment of the three-dimensional absolute spatial position and attitude of the feed system within a structurally enclosed feed room. Through testing, the simultaneous reception of corresponding satellite electromagnetic wave signals by eight feed systems met the performance requirements, verifying the feasibility, reliability, high efficiency, and high precision advantages of this scheme.

[0024] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0026] Figure 1 Schematic diagram of the observation pier and three-dimensional control network at the installation site of the dual-focus reflector multi-beam antenna system;

[0027] Figure 2 Schematic diagram of outdoor measurement reference points and indoor measurement reference points inside a structurally enclosed feeder room;

[0028] Figure 3 Schematic diagram of the coordinate system O-XYZ, the normal coordinate system O1-X1Y1Z1 of the main reflector, and the beam coordinate system O2-X2Y2Z2 of the feed room for the multi-beam antenna system.

[0029] Figure 4 Schematic diagram of the measurement point of the antenna main reflector and the normal coordinate system O1-X1Y1Z1 of the main reflector;

[0030] Figure 5Schematic diagram of spatial absolute position and attitude measurement and adjustment of the feed system. Detailed Implementation

[0031] In the field of antennas, especially in dual-focus reflector multi-beam antennas, parabolic toroidal multi-beam antennas, and other antennas with fixed azimuth, elevation, and polarization angles, the development direction of large ground-based antenna systems is to utilize a single ground station antenna matched with multiple feed systems to simultaneously receive electromagnetic wave signals from multiple geostationary satellites and across multiple frequency bands, achieving multi-purpose functionality from a single station. During antenna system installation, precise measurement and adjustment of the main reflector surface accuracy, main beam pointing, and feed system are essential conditions for ensuring that the antenna system's electrical performance specifications meet requirements. Since multiple feed systems are installed in a structurally enclosed feed room, traditional methods struggle to efficiently and accurately measure and adjust all feed systems. Therefore, this invention proposes a method for precise measurement of a fixed-pointing antenna system based on various spatial measurement technologies. This method integrates static GPS measurement systems, total station measurement systems, laser tracker measurement systems, and digital industrial photogrammetry systems. Specifically, by adjusting the placement of the total station measurement system, the steps involved in restoring the coordinate system of the multi-beam antenna system are reduced, thus lowering measurement errors and improving the accuracy of the antenna reflector and feed system measurement and adjustment. Ultimately, this method achieves precise measurement and adjustment of the pointing accuracy of the antenna's main reflector, the surface accuracy of the main reflector, and the absolute spatial position and attitude of the feed system. This successfully completes the structural installation measurement task for the fixed-pointing multi-beam antenna, ensuring that the antenna system's electrical performance indicators meet the required standards.

[0032] Specifically, the following steps are included:

[0033] Step 1: Construct at least three observation piers with forced alignment bases at the multi-beam antenna installation site. In this embodiment, four observation piers with forced alignment bases were constructed for observation. It is required that at least two observation piers with forced alignment bases can be observed simultaneously from the window position of the feed house. A static GPS measurement system is used to observe the observation piers and obtain the geodetic coordinates of the observation points on each pier. Specifically:

[0034] The observation points of the four observation piers with forced centering bases are G1-G4. Three dual-band GPS receivers were used to observe G1-G2-G4 and G2-G3-G4 respectively. Each synchronization loop was observed continuously for 12 hours, while the long baseline G2-G4 was observed continuously for 24 hours. When processing the GPS data in the WGS-84 coordinate system, the geodetic coordinates of G2 were obtained by calculating the precise ephemeris of the observation station. The calculation results of point G2 were used as the reference data for local area network adjustment to obtain the azimuth reference and the geodetic coordinates of points G1, G3, and G4.

[0035] Using observation piers G1, G2, G3, and G4 as outdoor measurement reference points for the antenna's main reflector, a total station measurement system was deployed at the window of the feed house. Using the total station system, at least two of the four outdoor reference points were used as references to measure the geodetic coordinates of the center of the antenna's main reflector base. The origin O of the multi-beam antenna system coordinate system was established through spatial distance intersection. Based on the origin O, a multi-beam antenna system coordinate system O-XYZ was established: with the center of the antenna's main reflector base as the origin O, the Z-axis points vertically upward along a straight line passing through O and perpendicular to the reference plane P; the X-axis points to the earth's north; and the Y-axis is determined by the right-hand rule. The coordinate system O-XYZ serves as a unified coordinate system for precision measurement tasks during antenna installation, including the pointing accuracy of the antenna's main reflector, the surface accuracy of the antenna's main reflector, and the absolute spatial position and attitude of the feed system.

[0036] Because the total station can only observe a limited number of outdoor measurement reference points from the window position in the feed room, a coordinate system transition method is used to establish the multi-beam antenna system coordinate system O-XYZ: Based on the origin O of the multi-beam antenna system coordinate system and the geodetic coordinates of an outdoor measurement reference point observed by the total station (assuming the outdoor measurement reference point is G4), the geodetic azimuth angle α of the geodetic line OG4 can be calculated. Using the machined surface at the top of the antenna main reflector base as the reference plane P, the center of the antenna main reflector base as the origin o, and the outdoor measurement reference point G4 as the x-axis direction, a reference coordinate system o-xyz is established. Rotating the reference coordinate system o-xyz around the z-axis in the xoy plane by the geodetic azimuth angle α of the geodetic line OG4 yields the multi-beam antenna system coordinate system O-XYZ. At this point, since the main reflector of the antenna is within the observation range of the total station measurement system, the installation measurement benchmark of the main reflector of the antenna outdoors has been unified under the coordinate system O-XYZ of the multi-beam antenna system.

[0037] Step 2: Inside the enclosed feed room, multiple indoor measurement reference points are evenly set around the overall installation area of ​​the feed system. The coordinates of these indoor reference points in the multi-beam antenna system coordinate system O-XYZ are measured using a total station. In this embodiment, multiple feed systems are arranged on a track via brackets; therefore, indoor measurement reference points are arranged on both sides of the track. These indoor measurement reference points unify the installation measurement references of each feed system within the room to the multi-beam antenna system coordinate system O-XYZ.

[0038] By using steps 1 and 2, the installation measurement references of the outdoor antenna main reflector and the various feed systems indoors are unified under the multi-beam antenna system coordinate system O-XYZ. This reduces the steps involved in restoring the multi-beam antenna system coordinate system. Compared with traditional solutions, this reduces the measurement error in restoring the multi-beam antenna system coordinate system and improves the accuracy of measurement and adjustment of the antenna main reflector and feed system.

[0039] Step 3: Measure and adjust the main reflector of the antenna:

[0040] The measurement and adjustment of the antenna main reflector mainly includes the measurement of the antenna main beam pointing and the measurement of the surface accuracy of the main reflector.

[0041] The antenna's main beam pointing, including the azimuth, elevation, and attitude angles of the multi-beam antenna, can be converted into coordinate values ​​of measurement points at key parts of the antenna structure in the O-XYZ coordinate system of the multi-beam antenna system for adjustment. The surface accuracy measurement of the main reflector is achieved by transforming the photogrammetric data to the multi-beam antenna system coordinate system using a coordinate transformation method for the antenna's main reflector measurement points. The measurement points on the antenna's main reflector are evenly distributed according to the main reflector structure, with the four corners of the main reflector used as measurement points. Fixtures are installed to interchange Leica RRR1.5″ spherical reflectors and photogrammetric hemispheres with the same spherical radius.

[0042] When measuring and adjusting the antenna's main beam pointing, a Leica RRR 1.5″ spherical reflector is installed on the fixture. In the O-XYZ coordinate system of the multi-beam antenna system, the normal deviation of the measurement point on the antenna's main reflector relative to the theoretical model of the main reflector is measured and adjusted using a total station, gradually bringing the antenna's main beam pointing to its optimal state. During adjustment, since the transition connector between the main reflector's brace and the main reflector is fixed using bolts, the antenna's main beam pointing is adjusted by adjusting the attitude of the transition connector using these bolts.

[0043] When measuring the surface accuracy of the primary reflector, a digital industrial photogrammetry system is used. A photogrammetric hemisphere is mounted on the fixture, and photogrammetric data of the primary reflector measurement points are acquired through this system. The coordinates of the primary reflector measurement points in the multi-beam antenna system coordinate system O-XYZ are measured using a total station, and the photogrammetric data of these points is also converted to the O-XYZ coordinate system. However, because the Z-axis of the O-XYZ coordinate system is perpendicular to the horizontal plane of the earth, and the X-axis points towards the north, while the adjustment screw of the primary reflector panel is along the normal direction of the primary reflector... To visually represent the adjustment direction and amount of the panel, before importing the theoretical model of the main reflector, the coordinate system O-XYZ of the multi-beam antenna system is transformed into the normal coordinate system O1-X1Y1Z1 of the main reflector using a seven-parameter coordinate system transformation method. The normal coordinate system O1-X1Y1Z1 is defined as follows: with the vertex of the main reflector as the origin O1, and the plane parallel to the antenna aperture plane where the vertex of the main reflector is located as the reference plane, the X1 axis points to the midpoint of the longest side, and the Y1 axis is determined by the right-hand coordinate system rule. Under the O1-X1Y1Z1 coordinate system, the theoretical model of the antenna main reflector (IGES format) and photogrammetric data of the measurement points of the antenna main reflector are imported. The measurement points of the antenna main reflector are directly compared with the theoretical model; the normal deviation of the actual position of the measurement point relative to the theoretical model of the main reflector is the adjustment amount. The root mean square (RMS) value of the normal deviation of all measurement points is calculated, which represents the surface accuracy of the main reflector.

[0044] Step 4: Simultaneously perform precise measurement and adjustment of the absolute spatial position and attitude of multiple feed systems:

[0045] Due to the limited window size on the roof of the feed system during the hoisting phase, it is necessary to hoist the sub-reflector, feed, and feed system bracket of each feed system separately to avoid collisions with the roof window. Since the assembly process after separate hoisting requires the relative positional accuracy between the sub-reflector and feed to be within 0.5mm, after assembling multiple feed systems within the inclined track of the enclosed feed room, the absolute spatial position and attitude of multiple feed systems are simultaneously measured and adjusted within the enclosed feed room using an indoor measurement reference point and a laser tracker measurement system in the O-XYZ coordinate system of the multi-beam antenna system. This ensures the accuracy of the absolute spatial position and attitude of the feed system while also guaranteeing the relative positional accuracy of the sub-reflector and feed, thus improving the efficiency of measuring and adjusting the absolute spatial position and attitude of the feed system.

[0046] The specific process is as follows:

[0047] First, using the seven-parameter coordinate system transformation method, and utilizing the known indoor measurement reference point with coordinates in the multi-beam antenna system coordinate system, a feed room beam coordinate system O2-X2Y2Z2 is established. O2-X2Y2Z2 is defined as follows: with the guide rail mounting surface as the reference plane, the indoor measurement reference point at its lowest corner position as the origin O2 of the coordinate system, the X2 axis points in the beam direction, the Z2 axis is vertically upward along the reference plane through point O2, and the Y2 axis is determined by the right-hand coordinate system rule (along the length of the guide rail).

[0048] Then, measurement points are established on each feed system, including the four corners of the sub-reflector and the center positions of the front and rear circles of the feed horn. The coordinates of the four corners of the sub-reflector and the center positions of the front and rear circles of the feed horn are transformed from the coordinate system O-XYZ of the multi-beam antenna system to the feed room beam coordinate system O2-X2Y2Z2.

[0049] Then, using a laser tracker measurement system, the measured values ​​of the coordinates of the four corners of the sub-reflector were compared with the theoretical coordinates in the feed room beam coordinate system O2-X2Y2Z2. The difference in the Y2 coordinates is eliminated by moving the trolley between the feed system and the guide rail, bringing the feed system closer to its theoretical position on the track. The differences in the X2 and Z2 coordinates reflect the front-to-back, height, azimuth, and pitch angle errors of the sub-reflector relative to the main reflector. By adjusting the mounting screws behind the sub-reflector, the absolute spatial position and attitude of the sub-reflector meet the requirements. Similarly, the measured values ​​of the center coordinates of the front and rear flanges of the feed system horn are compared with the theoretical values. The difference in the Y2 coordinates is also eliminated by moving the trolley, bringing the feed system horn closer to its theoretical position on the track. The differences in the X2 and Z2 coordinates reflect the front-to-back, height, azimuth, and pitch angle errors of the feed system horn relative to the main reflector. By adjusting the mounting screws in the front-to-back and up-down directions of the feed system horn, the absolute spatial position and attitude of the feed system horn meet the requirements.

[0050] In practice, the seven parameters of the transformation between the main reflector normal coordinate system O1-X1Y1Z1 and the feed room beam coordinate system O2-X2Y2Z2 and the multi-beam antenna system coordinate system O-XYZ can be calculated using a theoretical model. After obtaining the multi-beam antenna system coordinate system O-XYZ during the experimental stage, the corresponding coordinate system can be obtained by inputting the seven parameters of the known coordinate system transformation.

[0051] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0052] This embodiment uses a dual-focus reflector multi-beam antenna system project as an example. The system consists of three independent dual-focus reflector multi-beam antenna systems. Specifically, each of the three antenna main reflectors is housed in a separate, enclosed feed room, with eight feed systems installed in each room, covering different areas and operating independently. Taking one of the dual-focus reflector multi-beam antenna systems as an example, the main reflector size is... The pointing accuracy of the fixed-pointing antenna reflector was precisely measured and positioned, and the surface accuracy of the main reflector was accurately adjusted. After precise measurement and adjustment of the absolute spatial position and attitude of the eight feed systems in the enclosed feed room, the beam pointing accuracy of the antenna main reflector was better than 40″, the accuracy of the main reflector was better than 0.20mm, and the absolute spatial position and attitude of the feed system was better than ±1.5mm. Then, the electrical performance indicators of the eight feed systems of the multi-beam antenna system were tested simultaneously. The electromagnetic wave level values ​​received by the eight feed systems all met the design requirements, verifying the high efficiency, high precision, and high reliability of the invention.

[0053] like Figure 1 As shown, after obtaining the geodetic coordinates and azimuth reference of the G1-G4 observation piers on site through the static GPS measurement system, the geodetic coordinates of the center of the antenna main reflector base are measured and calculated, and the geodetic azimuth angle α of the geodetic line OG4 is calculated.

[0054] like Figure 2 As shown, observation piers G1, G2, G3, and G4 serve as outdoor measurement reference points for the main antenna reflector. Inside the enclosed feed room, a total station measurement system is arranged at the window position of the feed room. Multiple indoor measurement reference points are evenly set around the overall installation area of ​​the feed system.

[0055] like Figure 3 As shown, a coordinate system O-XYZ for the multi-beam antenna system is established with the machined surface P on the upper end of the antenna base as the reference plane and the center O of the base as the origin. The origin O is the center of the antenna main reflector base. The Z-axis points vertically upward along a straight line passing through point O and perpendicular to the reference plane P. The X-axis points to north, and the Y-axis is determined by the right-hand rule. This unifies the installation and measurement references of the outdoor antenna main reflector and the various feed systems indoors to the multi-beam antenna system coordinate system O-XYZ, reducing the steps involved in restoring the multi-beam antenna system coordinate system.

[0056] like Figure 4 As shown, the attitude of the antenna main reflector mounting connector is precisely measured and adjusted to ensure the accuracy of the measurement and adjustment of the azimuth, elevation, and polarization angles of the antenna main reflector. The connector between the antenna mount system's diagonal brace mechanism and the main reflector is fixed by bolt connection. To ensure that the bolt length behind the main reflector meets the actual adjustment amount after the main reflector is installed, the attitude of the transition connector is adjusted by adjusting the bolts to achieve the adjustment of the antenna main beam direction.

[0057] When measuring the surface accuracy of the primary reflector, a seven-parameter coordinate system transformation method is used to obtain the normal coordinate system O1-X1Y1Z1 of the antenna primary reflector from the multi-beam antenna system coordinate system O-XYZ. The theoretical model of the antenna primary reflector (IGES format) is then imported into the O1-X1Y1Z1 coordinate system. The measured points of the antenna primary reflector are directly compared with the theoretical model; the normal deviation of the actual position of the measured point relative to the theoretical model of the primary reflector is the adjustment amount. The root mean square (RMS) value of the normal deviation of all measured points is then calculated, which represents the surface accuracy of the primary reflector.

[0058] When performing precise measurements and adjustments to the absolute spatial position and attitude of multiple feed systems, a laser tracker measurement system is used in the structurally enclosed feed room. Based on the known coordinate values ​​of the indoor measurement reference point in the multi-beam antenna system coordinate system, the feed room beam coordinate system O2-X2Y2Z2 is established through a seven-parameter coordinate system transformation method. Under this coordinate system, the three-dimensional absolute spatial position and attitude of the feed system are precisely measured and adjusted.

[0059] While taking into account the beam pointing of the main reflector of the fixed-pointing multi-beam antenna, the surface accuracy of the main reflector of the antenna was precisely measured and adjusted. After the precise measurement and adjustment of the three-dimensional absolute position and attitude of the feed system in the enclosed feed room were completed, the simultaneous reception of the corresponding satellite electromagnetic wave signals by the eight feed systems was tested and met the index requirements, thus verifying the feasibility, reliability, high efficiency and high precision of the scheme.

[0060] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement techniques, characterized in that: Includes the following steps: Step 1: Construct at least 3 observation piers with forced centering bases at the multi-beam antenna installation site, and ensure that at least 2 observation piers with forced centering bases can be observed simultaneously from the window position of the feed room. The observation piers were observed using a static GPS measurement system to obtain the geodetic coordinates of the observation points on each observation pier. Using the observation pier as the outdoor measurement reference point for the antenna main reflector, a total station measurement system is set up at the window position of the feed house. Using the total station measurement system, at least two of the four outdoor measurement reference points are used as references to measure the geodetic coordinates of the center of the antenna main reflector base. The coordinate system O-XYZ of the multi-beam antenna system is established with the center of the antenna main reflector base as the coordinate origin O. Step 2: Inside the enclosed feed room, multiple indoor measurement reference points are evenly set around the overall installation area of ​​the feed system. The coordinates of the indoor measurement reference points in the O-XYZ coordinate system of the multi-beam antenna system are measured using a total station measurement system. Step 3: Based on the coordinate system O-XYZ of the multi-beam antenna system, the main reflector of the antenna is measured and adjusted using a total station measurement system and a digital industrial photogrammetry system; Step 4: Based on the multi-beam antenna system coordinate system O-XYZ and the indoor measurement reference point, use the laser tracker measurement system to simultaneously measure and adjust the spatial absolute position and attitude of multiple feed systems in the feed room.

2. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 1, characterized in that: In step 1, the process of using a static GPS measurement system to observe the observation piers and obtain the geodetic coordinates of the observation points in each observation pier is as follows: the GPS receiver is used to continuously observe the synchronous loop and long baseline composed of the observation points in each observation pier, the geodetic coordinates of the common observation points in the synchronous loop and long baseline are obtained by using the precise ephemeris calculation of the observation station, and the local area network adjustment is performed using the geodetic coordinates of the common observation points as the reference data to obtain the azimuth reference and the geodetic coordinates of the remaining observation points.

3. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 1, characterized in that: In step 1, a total station measurement system is used, with at least two of the four outdoor measurement reference points as references, to measure the geodetic coordinates of the center of the antenna main reflector base, and to establish the coordinate origin O of the multi-beam antenna system coordinate system through spatial distance intersection.

4. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 1, characterized in that: In step 1, the coordinate system O-XYZ of the multi-beam antenna system is established using a coordinate system transition method: Based on the origin O of the multi-beam antenna system coordinate system and the geodetic coordinates of an outdoor measurement reference point G4 observed by the total station measurement system, the geodetic azimuth angle α of the geodetic line OG4 is calculated; Taking the machined surface at the upper end of the antenna main reflector base as the reference plane P, the center of the antenna main reflector base as the origin o of the coordinate system, and the outdoor measurement reference point G4 as the x-axis direction of the coordinate system, a reference coordinate system o-xyz is established; By rotating the reference coordinate system o-xyz around the z-axis in the xoy plane by the geodetic azimuth angle α of the geodetic line OG4, the coordinate system O-XYZ of the multi-beam antenna system can be obtained.

5. The method for precise measurement of a fixed-pointing antenna system based on multiple space measurement technologies according to claim 1, characterized in that: In step 2, multiple feed systems are arranged on the track via brackets, and indoor measurement reference points are arranged on both sides of the track.

6. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 1, characterized in that: The measurement and adjustment of the antenna main reflector includes the measurement of the antenna main beam pointing and the surface accuracy measurement of the main reflector. The four corners of the main reflector are used as the measurement points of the antenna main reflector. Fixtures are installed to interchange spherical reflectors with the same sphere radius and photogrammetric hemispheres.

7. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 6, characterized in that: When performing antenna main beam pointing measurement and adjustment, a spherical reflector is installed on the fixture. In the multi-beam antenna system coordinate system O-XYZ, the normal deviation of the antenna main reflector measurement point relative to the theoretical model of the main reflector is measured and adjusted by a total station so that the antenna main beam pointing gradually reaches the optimal level.

8. The method for precise measurement of a fixed-pointing antenna system based on multiple space measurement technologies according to claim 6, characterized in that: When measuring the surface accuracy of the main reflector, a digital industrial photogrammetry system is used. A photogrammetric hemisphere is mounted on the fixture, and photogrammetric data of the measurement points of the main reflector are acquired through the digital industrial photogrammetry system. The coordinates of the measurement points of the main reflector in the multi-beam antenna system coordinate system O-XYZ are measured using a total station, and the photogrammetric data of the main reflector measurement points are transformed into the multi-beam antenna system coordinate system O-XYZ. The multi-beam antenna system coordinate system O-XYZ is transformed into the main reflector normal coordinate system O1-X1Y1Z1 using a seven-parameter coordinate system transformation method. In the O1-X1Y1Z1 coordinate system, the theoretical model of the antenna main reflector and the photogrammetric data of the antenna main reflector measurement points are imported. The photogrammetric data of the antenna main reflector measurement points are directly compared with the theoretical model. The normal deviation of the actual position of the antenna main reflector measurement points relative to the theoretical model of the main reflector is the adjustment amount. The root mean square value of the normal deviation of all antenna main reflector measurement points is calculated, which is the surface accuracy of the main reflector.

9. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 5, characterized in that: After the sub-reflector, feed, and feed system bracket of the feed system are hoisted into the feed room through the roof window, multiple feed systems are assembled in the inclined track of the structurally enclosed feed room. Then, in the multi-beam antenna system coordinate system O-XYZ, using indoor measurement reference points, a laser tracker measurement system is used to simultaneously measure and adjust the absolute spatial position and attitude of multiple feed systems in the structurally enclosed feed room.

10. The method for precise measurement of a fixed-pointing antenna system based on multiple spatial measurement technologies according to claim 9, characterized in that: In step 4, firstly, using the seven-parameter coordinate system transformation method, an indoor measurement reference point with known coordinates in the multi-beam antenna system coordinate system is used to establish the feed room beam coordinate system O2-X2Y2Z2. Then, measurement points are established on each feed system, including the four corner positions of the sub-reflector and the front and rear center positions of the feed horn. The coordinates of the four corner positions of the sub-reflector and the front and rear center positions of the feed horn in the multi-beam antenna system coordinate system O-XYZ are transformed to the feed room beam coordinate system O2-X2Y2Z2. Afterwards, using a laser tracker measurement system, the measured values ​​of the coordinates of the four corner positions of the sub-reflector are compared and adjusted with the theoretical coordinates in the feed room beam coordinate system O2-X2Y2Z2 to ensure that the absolute spatial position and attitude of the sub-reflector meet the requirements. At the same time, the measured values ​​of the center coordinates of the front and rear flanges of the feed system horn are compared and adjusted with the theoretical values ​​to ensure that the absolute spatial position and attitude of the feed system horn meet the requirements.

Images