CN111025032B - Aerial beam measuring system and method based on lift-off platform - Google Patents
Aerial beam measuring system and method based on lift-off platform Download PDFInfo
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Abstract
The invention discloses an antenna beam measuring system and method based on a lift-off platform, wherein a multi-rotor lift-off platform loading field intensity sensor is utilized to hover on a fixed scanning track point in the main beam radiation direction of a standard gain antenna in sequence, an optical motion step system is utilized to realize the accurate positioning of the space position of the lift-off platform, and based on the acquired information of field intensity amplitude, frequency points, positioning coordinates and the like, the included angle between two points, of which the radiation intensity is reduced by 3dB, on two sides of the main lobe in the maximum radiation direction is obtained through data processing, so that the antenna beam width measuring result of 3dB is obtained, and the accurate measurement of the antenna beam is realized.
Description
Technical Field
The invention relates to the technical field of antenna beam measurement. And more particularly to a system and method for antenna beam measurements with an airborne platform-mounted sensor in a microwave anechoic chamber.
Background
The distribution of the energy radiated by the antenna in space is generally non-uniform, which is the directivity of the antenna. Even the simplest antenna, an electric or magnetic basic element, has directivity. The antenna pattern typically has side lobes and back lobes in addition to the main lobe (main beam). The antenna beam is usually referred to as a main lobe or main beam, is a region where the antenna energy is most concentrated, and is also most commonly used, and refers to a graph for representing the relation between the radiation characteristics (field intensity amplitude, phase, polarization) of the antenna and the spatial angle. The complete antenna beam is a three-dimensional space pattern, which is drawn by measuring the radiation characteristics point by point on a spherical surface with a large enough radius r by taking the phase center of the antenna as the spherical center (coordinate origin).
The radar antenna beam is an important parameter for describing the radiation characteristic of the antenna, the radar antenna beam is directly related to the resolution and the RCS measurement precision of the radar, and if the difference between the measured value and the real value of the radar beam is large, misleading can be generated on the radar detection result, the precision of radar detection and target tracking is influenced, and the capability of weapon equipment for accurately striking the target is influenced. Therefore, how to improve the measurement accuracy of the radar antenna beam has more and more important significance.
In the prior art, radar antenna beam measurement methods include near-field measurement and far-field measurement. For a radar antenna (such as a vehicle-mounted radar antenna, an airborne radar antenna or a ship-based radar antenna) on a test site or loaded on weaponry, because the radar antenna does not have near-field test conditions (a test system is complex, measuring equipment is expensive, a microwave dark room is needed, and the like), antenna beams need to be measured by adopting a far field.
In far-field conditions, antenna beam measurement methods typically include a rotating antenna method and a fixed antenna method. In the rotating antenna method, as shown in fig. 1, during the measurement, an antenna to be measured is horizontally aligned with an auxiliary antenna, the antenna to be measured or the auxiliary antenna transmits a signal, the antenna to be measured rotates as required, the auxiliary antenna is fixed, the change of the receiving field intensity (or power density) caused by the change of the antenna direction is recorded, and the curve of the field intensity (or power density) changing along with the direction is drawn, so that an antenna beam in a certain plane is obtained.
In a microwave darkroom, a fixed antenna method is generally used, as shown in fig. 2, an antenna to be measured is fixed, a measuring device or a sensor is installed on a lift-off platform such as an airplane or an airship, the lift-off platform measures a specified space around the antenna, records direction data, and draws an antenna beam. However, because the existing lift-off platform generally adopts the GPS for positioning, the positioning accuracy is in the meter level, so that when a user measures an antenna beam by using the lift-off platform, the accuracy of a measurement result cannot be judged.
Therefore, it is desirable to provide a system and method for measuring antenna beams based on an elevated platform with higher accuracy.
Disclosure of Invention
The invention aims to provide an aerial beam measuring method device based on a lift-off platform, which sequentially performs hovering measurement on fixed scanning track points in the radiation direction of a main beam of a standard gain antenna by using a multi-rotor lift-off platform loading field intensity sensor, and realizes accurate positioning of the spatial position of the lift-off platform by using an optical motion capture system, thereby realizing accurate measurement of an aerial beam.
In order to achieve the purpose, the invention adopts the following technical scheme:
an antenna beam measuring system based on an elevated platform is applied to a microwave darkroom and comprises:
the multi-rotor lift-off platform is used for collecting field intensity information of a space target point, and is provided with a field intensity sensor and an optical detection target;
the optical motion capture system is used for measuring a first coordinate position of the multi-rotor lift-off platform based on the optical detector target;
the laser tracker is used for measuring a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle;
the control unit is used for carrying out flight control on the multi-rotor lift-off platform; and
and the processing unit is used for acquiring the measurement result of the antenna beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform.
Optionally, the spatial target point is a fixed scanning track point in the main beam radiation direction of the standard gain antenna.
Optionally, the measurement result of the antenna beam includes a beam width measurement result of a 3dB reduction in radiation intensity on both sides of a maximum radiation direction of a main lobe of the antenna beam.
Optionally, the optical motion capture system measures the first coordinate position of the multi-rotor lift-off platform by calculating the measurement trajectory and coordinates of the E-plane and H-plane of the antenna.
Optionally, the rigid body centroid of the optical detection target coincides with the center of the multi-rotor lift-off platform.
Optionally, the optical motion capture system uses an L-shaped calibration right angle to establish a system coordinate system and determine a coordinate origin, and uses a T-shaped calibration rod to calibrate the relative position relationship between the cameras.
Another object of the present invention is to provide an antenna beam measuring method based on an elevated platform, which is applied to the antenna beam measuring apparatus, and includes:
the multi-rotor lift-off platform collects field intensity information of a space target point, and is provided with a field intensity sensor and an optical detection target;
the optical motion capture system measures a first coordinate position of the multi-rotor lift-off platform based on the optical detector target;
the laser tracker measures a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle;
the control unit performs flight control on the multi-rotor lift-off platform; and
and the processing unit acquires the measurement result of the antenna beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform.
Optionally, the optical motion capture system measures a first of the multi-rotor lift-off platforms based on the photodetector target
The coordinate positions include:
measuring the size and position coordinates of the antenna aperture;
e-plane 3dB beam width measurement is carried out;
measuring the width of the H-plane 3dB wave beam;
the 3dB beamwidths for the E-plane and H-plane are calculated.
Optionally, performing E-plane 3dB beamwidth measurements comprises:
within the frequency range of the antenna, N frequency points are selected by a preset frequency range for calibration, wherein the frequency points at least comprise a highest frequency point and a lowest frequency point, and N is an integer greater than or equal to 3;
adjusting the output frequency of the signal generator to the lowest calibration frequency;
adjusting the output amplitude of the signal generator to stabilize the detected field strength at a first fixed value E0；
In a plane vertical to the main shaft of the antenna, the multi-rotor lift-off platform is moved upwards along the measuring track of the E surface, and the on-site strength display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a first field intensity value E1；
Recording a first position of the multi-rotor lift-off platform by using an optical motion capture system, and calculating and recording a first distance d between the first position and an initial position1；
In a plane vertical to the main axis of the antenna, the multi-rotor lift-off platform is moved downwards along the measuring track of the E surface, and the in-situ intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a second field intensity value E2；
Recording a second position of the multi-rotor lift-off platform by using the optical motion capture system, and calculating and recording a second distance d between the second position and the initial position2。
Optionally, performing H-plane 3dB beamwidth measurement comprises:
within the frequency range of the antenna, N frequency points are selected by a preset frequency range for calibration, wherein the frequency points at least comprise a highest frequency point and a lowest frequency point, and N is an integer greater than or equal to 3;
adjusting the output frequency of the signal generator to the lowest calibration frequency;
adjusting the output amplitude of the signal generator to stabilize the detected field strength at a first fixed value E0；
In a plane vertical to the main shaft of the antenna, the multi-rotor lift-off platform is moved to one side along the H-plane measuring track, and the in-situ intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a third field intensity value E3；
Recording a third position of the multi-rotor lift-off platform by using the optical motion capture system, and calculating and recording a third distance d between the third position and the initial position3；
In a plane vertical to the main shaft of the antenna, the multi-rotor lift-off platform is moved to the other side along the H-plane measuring track, and the on-site intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a fourth field intensity value E4；
Recording the fourth position of the multi-rotor lift-off platform by using the optical motion capture system, and calculating and recording the fourth distance d between the fourth position and the initial position4。
The invention has the following beneficial effects:
the invention provides an antenna beam measuring system and method based on an levitation platform, which are applied to a microwave darkroom, and the system comprises: the multi-rotor lift-off platform is used for collecting field intensity information of a space target point, and is provided with a field intensity sensor and an optical detection target; the optical motion capture system is used for measuring a first coordinate position of the multi-rotor lift-off platform based on the optical detector target; the laser tracker is used for measuring a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle; the control unit is used for carrying out flight control on the multi-rotor lift-off platform; and the processing unit is used for acquiring the measurement result of the antenna beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform.
The invention uses a multi-rotor lift-off platform loading field intensity sensor to hover on a fixed scanning track point in the radiation direction of a main beam of a standard gain antenna in sequence, and uses an optical motion step system to realize the accurate positioning of the space position of the lift-off platform, and based on the information of the collected field intensity amplitude, frequency points, positioning coordinates and the like, the included angle between two points of which the radiation intensity is reduced by 3dB on two sides of the maximum radiation direction of a main lobe is obtained through data processing, and the measurement result of the 3dB beam width of the antenna is obtained, thereby realizing the accurate measurement of the antenna beam.
Drawings
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Figure 1 shows a schematic diagram of a rotating antenna measurement method.
Fig. 2 shows a schematic diagram of a fixed antenna measurement method.
Fig. 3 shows a schematic structural diagram of an antenna beam measurement system based on an elevated platform in an embodiment of the present invention.
Fig. 4 shows a schematic diagram of an optical target reference direct structure in an embodiment of the present invention.
FIG. 5 illustrates capturing spatial representations in an embodiment of the present invention.
Fig. 6 shows a schematic diagram of a principle of spherical coordinate measurement in the embodiment of the present invention.
Fig. 7 shows a schematic diagram of the principle of the active disturbance rejection controller in the embodiment of the present invention.
Fig. 8 shows a control block diagram of a multi-rotor lift-off platform in an embodiment of the invention.
Fig. 9 is a schematic diagram illustrating a method and a path for tracing the value of a static positioning parameter according to an embodiment of the present invention.
Fig. 10 is a schematic diagram illustrating a dynamic positioning parameter value tracing method and a dynamic positioning parameter value tracing path according to an embodiment of the invention.
Detailed Description
In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
The terms "first," "second," and the like in the description and claims of the present invention and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or may alternatively include other gas steps or elements inherent to such process, method, or apparatus.
The invention provides an antenna beam measuring system and method based on an levitation platform, which are applied to a microwave darkroom, and the system comprises: the multi-rotor lift-off platform is used for collecting field intensity information of a space target point, and is provided with a field intensity sensor and an optical detection target; the optical motion capture system is used for measuring a first coordinate position of the multi-rotor lift-off platform based on the optical detector target; the laser tracker is used for measuring a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle; the control unit is used for carrying out flight control on the multi-rotor lift-off platform; and the processing unit is used for acquiring the measurement result of the antenna beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform.
The invention uses a multi-rotor lift-off platform loading field intensity sensor to hover on a fixed scanning track point in the radiation direction of a main beam of a standard gain antenna in sequence, and uses an optical motion step system to realize the accurate positioning of the space position of the lift-off platform, and based on the information of the collected field intensity amplitude, frequency points, positioning coordinates and the like, the included angle between two points of which the radiation intensity is reduced by 3dB on two sides of the maximum radiation direction of a main lobe is obtained through data processing, and the measurement result of the 3dB beam width of the antenna is obtained, thereby realizing the accurate measurement of the antenna beam.
The following description is made in conjunction with specific embodiments.
As shown in fig. 3, an aerial beam measurement system based on an airborne platform comprises an Optitrack optical motion capture system, a laser tracker, a multi-rotor airborne platform, an airborne field intensity sensor, a field intensity signal transmitting/receiving instrument device and the like. The components are described in detail below.
Optitrack optical motion capture system
In order to ensure the dynamic measurement precision and the antenna beam measurement range of the Optitrack optical motion capture system, the dynamic capture area is set to be 4m multiplied by 8m multiplied by 4m (high), a Prime 17W type camera is selected, the resolution is 1664 multiplied by 1088, the frame rate is 30 FPS-360 FPS (the number of transmission frames per second), and the delay is 2.8 ms. In order to realize the static calibration of the Optitrack optical motion capture system, an L-shaped calibration right angle is selected for establishing a system coordinate system and determining a coordinate origin, and an active T-shaped calibration rod is selected for calibrating the relative position relation between cameras.
In order to realize the unification of coordinate systems of optical instruments (an Optitrack optical motion capture system and a laser tracker), an optical target reference support is designed, and the origin points of the coordinate systems of the two optical measurement instruments are unified to the same physical position point as shown in fig. 4. In order to accurately identify the lift-off platform, rigid motion capture mark points with the diameter of 19mm are selected according to the size of the lift-off platform.
In order to capture the marker points accurately, the fields of view of the cameras should overlap, as shown in FIG. 5. The region where the fields of view overlap most should be the region where capture is most frequent. After the system calibration is completed, if the position of the camera is moved, the calibration must be performed again.
In order to realize the coordinate correction of the lift-off platform, the dynamic measurement coordinates need to be fed back to the flight control system, so that MTV-TKR software which supports development based on a NatNet SDK and has a real-time data flow interface is selected to realize the coordinate position feedback of the lift-off platform.
Laser tracker
In order to realize a quantity value tracing way of dynamic positioning parameters of the lift-off platform, two optical measurement instruments (an Optitrack optical motion capture system and a laser tracker) are compared to complete dynamic calibration of the Optitrack optical motion capture system and dynamic measurement of the lift-off platform.
The laser tracker adopts a spherical coordinate measuring principle, the distance from a target spherical reflector to a laser tracker host is S, the horizontal angle observation value is H, the vertical angle observation value is V, and the three-dimensional coordinates (x, y, z) of a target point can be calculated by formula 1 shown in figure 6.
Multi-rotor lift-off platform
The test environment, the test purpose and the positioning error of the multi-rotor lift-off platform are considered, the models of DJIM100 and the like are used as hardware platforms, and the symmetric motor wheelbase is 650 mm.
By designing the target combination bracket of the lift-off platform, the coincidence of the rigid body centroid of the target combination and the center of the lift-off platform is realized, and the dynamic capture and measurement of the lift-off platform are completed by an Optitrack optical motion capture system.
Airborne field intensity sensor
In order to realize the field intensity signal acquisition of a space target point, a field intensity sensor needs to be carried on the lift-off platform. The field intensity acquisition and verification of a target point are completed by adopting a portable frequency spectrograph module and a microstrip antenna. In the embodiment of the invention, the airborne field intensity sensor with small volume and light weight is selected and is suitable for being carried by a lift-off platform.
Multi-rotor lift-off platform control system design
In order to realize the flight control and the spatial hovering of the multi-rotor lift-off platform, a multi-rotor lift-off platform control system is developed, the attitude control of the lift-off platform is completed through a ground-end PC, and the accurate hovering of a specified target point in a microwave darkroom is realized.
In the embodiment of the invention, hardware processing performance, software development difficulty, price and the like are comprehensively considered, Pixhawk or Rocky2.0 open-source flight control hardware is adopted, a three-axis gyroscope, a three-axis accelerometer and a three-axis magnetoresimeter are arranged in a Pixhawk flight controller, and in addition, in the embodiment of the invention, indoor flight is realized, position information is provided by a motion capture system, and other distance sensors are not required to be additionally arranged.
The most widely used control algorithm of the autonomous flight control system is a PID (proportional integral derivative) control algorithm, which is a basic control algorithm adopted in the project. When the external Disturbance is considered to be overlarge, the PID control waits until an error occurs, compensation control is performed, and the ADRC (Auto Disturbance Rejection controller) is used for compensating the observed Disturbance to an output end at the first time, so that the defect of the PID control is effectively overcome, and the engineering applicability is very large. The active disturbance rejection controller mainly comprises four parts, namely a transition process arrangement, an extended state observer, nonlinear state error feedback and disturbance estimation compensation, and is shown in a schematic diagram of an Active Disturbance Rejection Controller (ADRC) in fig. 7. Therefore, the project is to adopt a mode of combining PID and ADRC.
The automatic control system corrects the position of the lift-off platform to a target point by controlling the flight attitude (vertical rising, vertical falling, horizontal forward, horizontal backward, horizontal left, horizontal right, counterclockwise spin and clockwise spin) of the lift-off platform, so that the lift-off platform can accurately hover at the target point, and the control block diagram of the multi-rotor lift-off platform shown in fig. 8 is provided.
The lift-off platform control software needs to cover the complete interface of the unmanned aerial vehicle control, such as connection control, position control (start position, end position), motion control (speed), preset trajectory (horizontal arc, etc.), state feedback (real-time position, real-time attitude, real-time hover error), etc.
Optical measurement-based levitation platform positioning and tracing method
The positioning and tracing of the antenna beam measuring device comprises static positioning of the lift-off platform and dynamic positioning and tracing of the lift-off platform. An OptiTrack optical motion capture system is adopted, and the existing laser tracker is utilized to realize static and dynamic measurement, positioning and tracing of the multi-rotor lift-off platform.
The static positioning parameter value of the lift-off platform is traced, and is shown in figure 9. In a calibrated capture area of the Optitrack optical motion capture system, 4 target balls are stably installed on an elevated platform according to a certain combination form by using a designed elevated platform target combination bracket, the center of mass of a rigid body of a target combination is coincided with the center of the elevated platform, the elevated platform is statically parked at an initial position on the ground in the capture area, the target balls are repeatedly measured by the Optitrack optical motion capture system for many times, the rigid body coordinates of the target balls obtained after calculation are the coordinates of the elevated platform, a static measurement result of the elevated platform is obtained by mathematical statistic analysis, static positioning parameters of the elevated platform are traced to the Optitrack optical motion capture system, and the Optitrack optical motion capture system realizes the magnitude tracing of the static positioning parameters of the elevated platform through calibration. The static measurement of the lift-off platform aims to realize the unification of the coordinate system of the lift-off platform and the Optitrack optical motion capture system.
Because there is no direct way to trace the source of the magnitude value of the dynamic positioning parameter of the lift-off platform based on the Optitrack optical motion capture system in the prior art, the method of comparing the dynamic calibration and the dynamic measurement of the Optitrack optical motion capture system with the laser tracker is adopted, and is shown in fig. 10.
The invention also provides an antenna beam measuring method based on the lift-off platform, which is applied to the antenna beam measuring device and comprises the following steps: the multi-rotor lift-off platform collects field intensity information of a space target point, and is provided with a field intensity sensor and an optical detection target; the optical motion capture system measures a first coordinate position of the multi-rotor lift-off platform based on the optical detector target; the laser tracker measures a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle; the control unit performs flight control on the multi-rotor lift-off platform; and the processing unit acquires the measurement result of the antenna beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform.
In a specific embodiment, the antenna beam measurement method based on the lift-off platform comprises the following steps:
a) the aerial beam calibration device based on the lift-off platform needs to carry out safety and other aspects of inspection, and the appearance and the internal functions of the instrument and equipment are inspected;
b) in a microwave laboratory, an antenna needs to be erected on a multi-dimensional adjustable support to simulate the angle of a radar antenna, the height of the antenna erection is H, H is not less than 2 meters, and the polarization direction of the antenna is vertical polarization;
c) measuring the size and position coordinates of the antenna aperture surface by using an optical measuring instrument, and determining measuring tracks and coordinates of an E surface and an H surface, wherein the plane to be measured is vertical to the antenna main shaft and is away from the antenna aperture surface by a distance S (the distance S is determined by the far-field distance of an antenna testing frequency point), and the intersecting line of the plane to be measured and the E surface of the antenna is the measuring track of the E surface; the intersection line of the plane to be measured and the H surface of the antenna is an H surface measuring track, and measuring points on the track are coordinates of measuring points of the probe;
d) the initial position of the probe is on the main shaft of the antenna, and the distance from the center of the probe to the center of the antenna aperture surface is S;
e) preheating equipment for calibration according to the requirements of instrument specifications, and measuring the beam width of the E-plane 3 dB;
f) in the frequency range of the antenna, at least 3 frequency points are selected for calibration every 10 octaves, and the frequency points comprise the highest frequency point and the lowest frequency point;
g) adjusting the output frequency of the signal generator to the lowest calibration frequency, and adjusting the output amplitude of the signal generator to stabilize the field intensity detected by the probe at a fixed value E0, such as (50 Shi 1) V/m;
h) in a plane perpendicular to the main shaft of the antenna, the unmanned aerial vehicle carrying the probe is moved upwards along the measuring track of the E surface, when the field intensity display value is (0.707E0 soil 1) V/m, the unmanned aerial vehicle stops moving and is stably hovered, and the field intensity value E1 displayed by the field intensity measuring equipment is read and stored;
i) recording the position 1 coordinate corresponding to the probe at the moment by using an optical capturing system, and calculating and recording the distance d1 from the initial position;
j) controlling the unmanned aerial vehicle to move the probe downwards along the E-plane measuring track, stopping moving and stably hovering the unmanned aerial vehicle when the field intensity display value is (0.707E0 soil 1) V/m, and reading and storing the field intensity value E2 displayed by the field intensity measuring equipment;
k) recording the position 2 coordinate corresponding to the probe at the moment by using an optical capturing system, and calculating and recording the distance d2 from the initial position;
so far the E plane completes the 3dB beamwidth measurement.
l) measuring the width of the H-plane 3dB wave beam, and hovering the probe at an initial position;
m) moving the unmanned aerial vehicle carrying the probe to one side horizontally along an H-plane measuring track in a plane perpendicular to the main shaft of the antenna, stopping moving and stably hovering the unmanned aerial vehicle when the field intensity display value is (0.707E0 soil 1) V/m, and reading and storing the field intensity value E3 displayed by the field intensity measuring equipment;
n) recording the position 3 coordinate corresponding to the probe at the moment by using the optical capturing system, and calculating and recording the distance d3 from the initial position;
o) controlling the unmanned aerial vehicle to horizontally move the probe to the other side along the H-plane measuring track, stopping moving and stably hovering the unmanned aerial vehicle when the field intensity display value is (0.707E0 soil 1) V/m, and reading and storing the field intensity value E4 displayed by the field intensity measuring equipment;
p) recording the position 4 coordinate corresponding to the probe at the moment by using an optical capturing system, and calculating and recording the distance d4 from the initial position; so far the H plane completes the 3dB beamwidth measurement.
q) adjusting the output frequency of the signal generator to the next calibration frequency, and repeating the steps g) to p) until the measurement of all the calibration frequency points is completed.
r) can respectively obtain the beam widths of 3dB on the E surface and the H surface through calculation.
The invention uses a multi-rotor lift-off platform loading field intensity sensor to hover on a fixed scanning track point in the radiation direction of a main beam of a standard gain antenna in sequence, and uses an optical motion step system to realize the accurate positioning of the space position of the lift-off platform, and based on the information of the collected field intensity amplitude, frequency points, positioning coordinates and the like, the included angle between two points of which the radiation intensity is reduced by 3dB on two sides of the maximum radiation direction of a main lobe is obtained through data processing, and the measurement result of the 3dB beam width of the antenna is obtained, thereby realizing the accurate measurement of the antenna beam.
The invention has been described in connection with various embodiments and implementations by way of example. However, other variations can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the independent claims. In the claims and the description, the word "comprising" does not exclude other elements or steps, and the absence of a quantity does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Although the present disclosure describes methods and processes with a particular order of steps, one or more steps in the methods and processes may be omitted or altered as appropriate. One or more steps may be performed in an order other than the order in which they are described, as appropriate.
While the present disclosure has been described, at least in part, in terms of methods, those of ordinary skill in the art will appreciate that the present disclosure also relates to various means for performing at least some of the described method aspects and features, whether by hardware means, software means, or any combination of both. Accordingly, the technical solutions of the present disclosure may be implemented in the form of a software product. Suitable software products may be stored in a pre-recorded memory device or other similar non-volatile or non-transitory computer readable medium, including, for example, a DVD, CD-ROM, USB flash drive, removable hard drive, or other storage medium. The software product includes instructions tangibly stored thereon, which enable a processing device (e.g., a personal computer, server, or network device) to perform examples of the methods disclosed herein.
It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.
Claims (8)
1. An antenna beam measurement system based on lift-off platform is applied to microwave darkroom, and is characterized by comprising:
the multi-rotor lift-off platform is used for collecting field intensity information of a space target point, and is provided with a field intensity sensor and an optical detection target;
an optical motion capture system for measuring a first coordinate position of the multi-rotor lift-off platform based on the optical detection target;
the laser tracker is used for measuring a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle;
the control unit is used for carrying out flight control on the multi-rotor lift-off platform; and
the processing unit is used for acquiring the measurement result of the antenna wave beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform;
the optical motion capture system measures a first coordinate position of the multi-rotor lift-off platform by calculating measurement tracks and coordinates of an E surface and an H surface of an antenna;
the optical motion capture system selects an L-shaped calibration right angle to establish a system coordinate system and determine a coordinate origin, and selects a T-shaped calibration rod to calibrate the relative position relationship between cameras.
2. The antenna beam measurement system of claim 1, wherein the spatial target point is a fixed trace point of a main beam radiation direction of a standard gain antenna.
3. The antenna beam measurement system of claim 2 wherein the antenna beam measurements comprise beam width measurements of 3dB reduction in radiation intensity across the maximum radiation direction of the main lobe of the antenna beam.
4. The antenna beam measurement system of claim 1, wherein a rigid body centroid of the optical detection target coincides with a center of the multi-rotor lift-off platform.
5. An elevated platform-based antenna beam measurement method, using the system of any one of claims 1-4, comprising:
the method comprises the following steps that a multi-rotor lift-off platform collects field intensity information of a space target point, and the multi-rotor lift-off platform is loaded with a field intensity sensor and an optical detection target;
an optical motion capture system measuring a first coordinate position of the multi-rotor lift-off platform based on the optical detection target;
the laser tracker measures a second coordinate position of the multi-rotor lift-off platform based on a spherical coordinate measuring principle;
the control unit performs flight control on the multi-rotor lift-off platform; and
and the processing unit acquires the measurement result of the antenna wave beam based on the field intensity information and the first coordinate position and the second coordinate position of the multi-rotor lift-off platform.
6. The antenna beam measurement method of claim 5,
measuring the size and position coordinates of the antenna aperture;
e-plane 3dB beam width measurement is carried out;
measuring the width of the H-plane 3dB wave beam;
the 3dB beamwidths for the E-plane and H-plane are calculated.
7. The antenna beam measurement method of claim 6, wherein said performing an E-plane 3dB beamwidth measurement comprises:
selecting N frequency points for calibration in a preset frequency range in the antenna frequency range, wherein the frequency points at least comprise a highest frequency point and a lowest frequency point, and N is an integer greater than or equal to 3;
adjusting the output frequency of the signal generator to the lowest calibration frequency;
adjusting the output amplitude of the signal generator to stabilize the detected field strength at a first fixed value E0；
In a plane vertical to the main axis of the antenna, the multi-rotor lift-off platform is moved upwards along the measuring track of the E surface, and the in-situ intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a first field intensity value E1；
Recording a first position of the multi-rotor lift-off platform using the optical motion capture system, calculating and recording a first distance d from the first position to an initial position1；
The initial position is on a main shaft of the antenna;
in a plane vertical to the main axis of the antenna, the multi-rotor lift-off platform is moved downwards along the measuring track of the E surface, and the in-situ intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a second field intensity value E2；
Recording a second position of the multi-rotor lift-off platform using the optical motion capture system, calculating and recording a second distance d from the second position to the initial position2。
8. The antenna beam measurement method of claim 6, wherein said performing an H-plane 3dB beam width measurement comprises:
selecting N frequency points for calibration in a preset frequency range in the antenna frequency range, wherein the frequency points at least comprise a highest frequency point and a lowest frequency point, and N is an integer greater than or equal to 3;
adjusting the output frequency of the signal generator to the lowest calibration frequency;
adjusting the output amplitude of the signal generator to stabilize the detected field strength at a first fixed value E0；
In a plane vertical to the main shaft of the antenna, the multi-rotor lift-off platform is moved to one side along the H-plane measuring track, and the on-site intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a third field intensity value E3；
Recording a third position of the multi-rotor lift-off platform by using the optical motion capture system, and calculating and recording a third distance d between the third position and the initial position3；
The initial position is on a main shaft of the antenna;
moving the multi-rotor lift-off platform to the other side along the H-plane measuring track in a plane vertical to the main shaft of the antenna, wherein the on-site intensity display value is (0.707E)0When +/-1) V/m, stopping moving and hovering the multi-rotor lift-off platform, reading and storing a fourth field intensity value E4；
Recording a fourth position of the multi-rotor lift-off platform using the optical motion capture system, calculating and recording a fourth distance d from the fourth position to the initial position4。
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| CN112798874B (en) * | 2020-12-23 | 2022-07-08 | 北京无线电计量测试研究所 | Electric field radiation sensitivity improvement test method and system |
| CN112904091B (en) * | 2021-01-13 | 2023-11-21 | 成都四威功率电子科技有限公司 | Control method of field intensity radiation automatic test system based on PID |
| CN113203897B (en) * | 2021-04-14 | 2022-11-01 | 之江实验室 | Side lobe suppression and beam forming method of arbitrary two-dimensional antenna array |
| CN115015862B (en) * | 2022-06-30 | 2023-04-14 | 广东纳睿雷达科技股份有限公司 | Dual-polarization radar calibration method and device and storage medium |
| CN116929289B (en) * | 2023-09-18 | 2024-01-05 | 中国科学院西安光学精密机械研究所 | Antenna attitude rapid measurement system and method |
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