CN110850405B - Bird dynamic RCS detection system and method - Google Patents
Bird dynamic RCS detection system and method Download PDFInfo
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Abstract
The invention belongs to the technical field of radio detection, and particularly relates to a bird dynamic RCS detection system and a detection method thereof, wherein the bird dynamic RCS detection system comprises: the vector network analyzer is at least provided with a first channel module for transmitting signals and a second channel module for receiving the signals; the rotary table assembly comprises a rotary table and a rotary table controller, the rotary table is used for bearing the birds, and the rotary table controller is used for controlling the rotary table to rotate in a stepping mode; the transmitting antennas are respectively connected with the first channel modules; the receiving antennas are respectively connected with the second channel modules; the high-speed camera is in signal connection with the vector network analyzer and is used for starting photographing according to the echo signal received by the second channel module of the vector network analyzer; and a computer. The invention solves the problems that the prior art can only detect the RCS of a static target and does not detect the dynamic RCS of a dynamic target, in particular the dynamic RCS of birds.
Description
Technical Field
The invention belongs to the technical field of radio detection, and particularly relates to a bird dynamic RCS detection system and method.
Background
At present, wings of a bird are considered to contribute little to Radar Cross Section (RCS) of the bird and can be ignored; however, some believe that birds in flight contribute significantly to their RCS due to flapping motion. Based on the suspicion of the above data and conclusions, bird wing contribution to RCS was to be reevaluated, i.e., dynamic bird RCS was measured. In the prior art, the method of measuring RCS of an object using a vector network is a common method, but the method is generally used for measuring RCS of a static object, and the method is hardly used for measuring dynamic RCS of a dynamic object, especially birds.
Disclosure of Invention
The invention provides a bird dynamic RCS detection system, and aims to solve the problem that the dynamic RCS of birds cannot be detected in the prior art.
The embodiment of the invention provides a bird dynamic RCS detection system, which comprises:
the vector network analyzer is at least provided with a first channel module for transmitting signals and a second channel module for receiving signals;
the rotary table assembly comprises a rotary table and a rotary table controller, the rotary table is used for bearing the birds, and the rotary table controller is used for controlling the rotary table to rotate in a stepping mode;
the transmitting antennas are respectively connected with the first channel modules;
the receiving antennas are respectively connected with the second channel modules;
the high-speed camera is in signal connection with the vector network analyzer and is used for starting photographing according to the echo signal received by the second channel module of the vector network analyzer; and
and the computer is connected with the vector network analyzer and the rotary table controller.
Further, the frame rate of the high-speed camera is 1000fps.
Still further, the turntable assembly further comprises a bracket disposed on the turntable for carrying the birds.
The embodiment of the invention also provides a bird dynamic RCS detection method based on the system of the embodiment, which comprises the following steps:
s101, transmitting a frequency sweeping signal through a first channel module of a vector network analyzer, and receiving the signal in real time;
s102, stimulating the flapping wings of the birds fixed in a microwave darkroom in an electric shock mode;
s103, receiving the echo signals of the birds through a second channel module of the vector network analyzer, judging whether the received echo signals are higher than a threshold value, if so, automatically triggering to record data, and sending a first synchronization signal to a high-speed camera for photographing and storing;
s104, converting the echo signals into bird dynamic RCS information;
and S105, controlling the rotary table to rotate the position of the bird according to a preset angle through the rotary table controller, and repeatedly measuring at a new angle.
Further, the step of stimulating the flapping wings of the birds fixed in the microwave dark room by means of electric shock comprises:
s201, fixing the claws of the birds on the rotary table by adopting a lead, and leading the other end of the lead to the outside of a microwave darkroom;
s202, transmitting an electric shock signal to the claws of the birds through a lead outside an electric shock microwave darkroom to stimulate the wings of the birds.
Still further, the method comprises the steps of:
s301, setting parameters of a vector network analyzer;
s302, calibrating the vector network analyzer according to the parameters of the vector network analyzer.
Still further, still include:
s401, transmitting a frequency sweep signal through a first channel module of the vector network analyzer;
s402, receiving and storing an echo signal of the background of the microwave darkroom through a second channel module of the vector network analyzer;
and S403, converting the echo signal of the background of the microwave darkroom into RCS information of the background of the microwave darkroom.
Still further, the method comprises the steps of:
s501, opening a high-speed camera to record a target area at a constant speed, and placing balls with different sizes on a rotary table in sequence;
s502, transmitting a frequency sweep signal through a first channel module of a vector network analyzer;
s503, receiving and storing the echo signal of the sphere through a second channel module of the vector network analyzer;
s504, synchronizing a second synchronization signal to the high-speed camera according to the echo signal of the sphere;
s505, photographing and storing the round ball photo through the high-speed camera according to the second synchronous signal;
s506, converting the echo signal of the sphere into RCS information of the sphere;
and S507, controlling the turntable to rotate the position of the ball according to a preset angle through the turntable controller, and repeating the steps S501-S506.
Still further, the method comprises the steps of:
s601, fixing claws of birds on the rotary table;
s602, transmitting a frequency sweep signal through a first channel module of a vector network analyzer;
s603, receiving and storing the echo signals of the static birds through a second channel module of the vector network analyzer;
s604, synchronizing a third synchronizing signal to the high-speed camera according to the echo signal of the static birds;
s605, photographing and storing the static photos of the static birds by the high-speed camera according to the third synchronous signal;
s606, converting the echo signals of the static birds into RCS information of the static birds;
s607, controlling the rotary table to rotate the position of the static birds according to a preset angle through the rotary table controller, and repeating S601-S606.
The invention achieves the following beneficial effects: the invention can detect the dynamic RCS of the birds by synchronously matching the vector network analyzer with the high-speed camera and realizing information interaction with the birds through the transmitting antenna and the receiving antenna, thereby realizing the dynamic RCS detection of the birds. And the position of the rotary birds of the rotary table is controlled by the computer and the rotary table controller, so that the dynamic RCS of the birds in different directions can be detected. The invention solves the problems that the prior art can only detect the RCS of a static target and does not detect the dynamic RCS of a dynamic target, in particular the dynamic RCS of birds.
Drawings
FIG. 1 is a schematic structural diagram of a bird dynamic RCS detection system provided in this embodiment;
FIG. 2 is a schematic view of the structural arrangement relationship between a bird dynamic RCS detection system and a microwave dark room;
FIG. 3 is a radar equation diagram provided by the present invention;
FIG. 4 is a formula diagram of a target RCS value provided by the present invention;
FIG. 5 is a graphical representation of another target RCS value provided by the present invention;
FIG. 6 is a diagram of the relationship between the transmission coefficient S21 and the port power according to the present invention;
FIG. 7 is a graphical representation of the target RCS value available transmission coefficient formula provided by the present invention;
FIG. 8 is a flow chart of a bird dynamics RCS detection method provided by an embodiment of the present invention based on the system of the first embodiment;
FIG. 9 is a flowchart of one method provided by S101 of FIG. 8;
FIG. 10 is a flow chart of another bird dynamics RCS detection method according to one embodiment of the present invention;
FIG. 11 is a flow chart of another bird dynamics RCS detection method provided by embodiments of the present invention based on the system described in the first embodiment;
FIG. 12 is a flow chart of another bird dynamics RCS detection method provided by embodiments of the present invention based on the system described in the first embodiment;
FIG. 13 is a flow chart of another bird dynamics RCS detection method based on the system of the first embodiment according to the present invention.
Wherein, 1, a microwave darkroom; 2. a high-speed camera; 3. a transmitting antenna; 4. a receiving antenna; 5. a vector network analyzer; 6. a computer; 7. a turntable controller; 8. a turntable; 9. a support; 10. and (4) a target.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The bird dynamic RCS detection device can be used for detecting the dynamic RCS of birds by synchronously matching the vector network analyzer 5 with the high-speed camera 2 and realizing information interaction with the birds through the transmitting antenna 3 and the receiving antenna 4, so that the dynamic RCS detection of the birds is realized. And the position of the birds rotated by the rotary table 8 is controlled by the computer 6 and the rotary table controller 7, so that the dynamic RCS of the birds in different directions can be detected. The invention solves the problems that only the RCS of a static target 10 can be detected, and the dynamic RCS of a dynamic target 10, in particular the dynamic RCS of birds, cannot be detected in the prior art.
Example one
As shown in fig. 1-2, the present embodiment provides a bird dynamic RCS detection system, which includes: the vector network analyzer 5 is provided with at least a first channel module for transmitting signals and a second channel module for receiving signals; the turntable 8 assembly comprises a turntable 8 and a turntable controller 7, the turntable 8 is used for bearing birds, and the turntable controller 7 is used for controlling the turntable 8 to rotate in a stepping mode; the transmitting antennas 3 are respectively connected with the first channel modules; the receiving antennas 4 are respectively connected with the second channel modules; the high-speed camera 2 is in signal connection with the vector network analyzer 5, so as to start photographing according to the echo signal received by the second channel module of the vector network analyzer 5; and the computer 6, the computer 6 is connected with the vector network analyzer 5 and the rotary table controller 7.
Wherein, the dynamic RCS of birds mainly means the contribution of the flapping of birds to RCS. The birds are common birds, such as hummingbirds, pigeons and the like, the highest wing-vibrating frequency of the hummingbirds is 15-80 times per second, and the wing-vibrating frequency of the pigeons is about 6-10 times per second; in addition, in consideration of cost performance, a high-speed camera 2 with a frame rate of 1000fps is selected, and the high-speed camera 2 is used for recording the state of the target 10 and analyzing the frequency of the flapping of the target 10. In the embodiment of the present invention, the target 10 is a tested object, i.e. a bird, such as a hummingbird, a pigeon, etc.; the device can be a ball, a bird, and the like, and can also be other objects needing to be detected, and in the embodiment, the object to be detected is the bird. The high-speed camera 2 includes a BNC (Bayonet Nut Connector, an image pickup device output wire, and a camera Connector) for activating the shutter of the high-speed camera 2 to take a picture. The vector network analyzer 5 is a time domain RCS test core device. The vector network analyzer 5 is further provided with a sweep source for emitting a sweep signal. It should be noted that, the frequency of flapping of birds is generally within 10Hz, which requires the scanning frequency of the vector network analyzer 5 to be above 10 Hz. The sweep frequency source is connected with the first channel module and then connected with a power amplifier, so that sweep frequency signals can be sent to the transmitting antenna 3 through the first channel module and transmitted. The vector network analyzer 5 includes: the Trigger Aux function is used for outputting two paths of square wave signals, one path of square wave signals is connected to the high-speed camera 2 through a BNC connecting line to serve as a synchronous signal, the other path of square wave signals is connected to an INPUT1 interface in a rear panel HandlerIO interface of the vector network analyzer 5, and the synchronous signal serves as an interrupt mark for judging that single scanning is finished, so that the data storage function is driven. The vector network analyzer 5 is further provided with a control interface, the Trigger Aux function is stored in the vector network analyzer 5 in the form of macro (macroinstruction) commands and displayed on the interface, and one measurement is completed by clicking a preset value button of a pull-down menu of macro, and data is automatically recorded. The turntable 8 is further provided with a support 9 for bearing the birds. The vector network analyzer 5, the turntable 8, the high-speed camera 2, the transmitting antenna 3 and the receiving antenna 4 are all arranged in the microwave darkroom 1. The turntable controller 7 may be disposed in the microwave darkroom 1 or outside the microwave darkroom 1. The turntable controller 7 may be a stepping motor for controlling the turntable 8 to rotate in steps. The above-mentioned computer 6 may be connected to the vector network analyzer 5 through a LAN. The vector network analyzer 5 may be remotely controlled using computer remote interface functionality.
In the embodiment of the invention, the testing principle of the RCS is as follows: by measuring the power of the radar echo, as shown with reference to FIG. 3, the radar equation is
The RCS value σ of the target 10 can be solved, in which radar equation
In, pr is the radar received echo power; pt is the emission power; g is the antenna gain; λ is the radar wavelength; r is the target distance. The radar equation indicates that under the same measurement environment, other parameters are unchanged, and the RCS value sigma of the target is in direct proportion to the radar received echo power Pr. Therefore, when the RCS theoretical value σ of the standard sphere is known, the target RCS value can be calculated by comparing the echo powers (P and P') of the target 10 to be measured and the standard sphere, and as shown in fig. 4, the target RCS value is expressed by the formula
That is, after removing the unit in the graph equation by the dB value, the target RCS value equation of σ = σ '-P' + P as shown in fig. 5 can be obtained. When RCS is measured in the high frequency region, the target 10 can be considered as a linear two-port network, pr is the input power of port one and Pt is the output power of port two, and with reference to FIG. 6, the transmission coefficient S is 21 The relationship with port power can be expressed as
Thus, referring to fig. 7, the target RCS value may be expressed as σ = S in terms of transmission coefficient 21 -S′ 21 + σ', therefore, by measuring the transmission coefficient S 21 To measure the target RCS. In the embodiment of the invention, the transmission coefficient S can be obtained by adopting the measurement function of the vector network analyzer 5 21 . In addition, for the echo data of birds, the photo data of the birds needs to be compared so as to analyze the relationship between the echo data of the birds and the flapping wings.
In the embodiment of the invention, the test process of the detection system of bird dynamic RCS comprises the following steps:
when detecting the dynamic RCS of a dynamic bird, a static bird is set on the turntable 8 or on the support 9 on the turntable 8, and the bird is electrically shocked to make the bird fly, and at this time, the bird flying is referred to as a dynamic bird. The method comprises the steps that a sweep frequency signal is sent out through a sweep frequency source in a vector network analyzer 5, the sweep frequency signal is further amplified through a first channel module through a power amplifier, then the sweep frequency signal is transmitted to a transmitting antenna 3 to be transmitted out, and an echo, namely an echo signal, of a target 10 is returned through interaction with a dynamic bird. The receiving antenna 4 receives the target echo and transmits the target echo to the vector network analyzer 5 through the second channel module for storage, and then the transmission coefficient S is obtained through the measurement function of the vector network analyzer 5 21 In addition, the Trigger Aux function of the vector network analyzer 5 is used for outputting two paths of square signals, one path of square signals is connected to the high-speed camera 2 through a BNC connecting line to serve as a synchronous signal, and the high-speed camera 2 is connected with the synchronous signalAnd receiving a synchronous signal to trigger and finish one-time photographing. And the other path is connected with an INPUT1 interface in a rear panel HandlerIO interface of the vector network analyzer 5, and an interrupt mark for judging that the single scanning is finished is taken as a synchronous signal so as to drive a data storage function. Thus, according to the set number of measurements, synchronization of the measurement data of the vector network analyzer 5 and the photograph can be completed. The target echo received by the receiving antenna 4 can obtain the frequency domain characteristics of the target 10, then the frequency domain characteristics are analyzed in the time domain through inverse fourier Transform (Transform function of the vector network analyzer 5), and background clutter outside a time domain door is filtered through time domain windowing, so that the RCS information of the target 10 in the wide frequency band is obtained. And finally, analyzing a dynamic picture obtained by photographing the dynamic birds by combining the high-speed camera 2, and further obtaining dynamic RCS information of the dynamic birds.
The bird dynamic RCS detection device can be used for detecting the dynamic RCS of birds by synchronously matching the vector network analyzer 5 with the high-speed camera 2 and realizing information interaction with the birds through the transmitting antenna 3 and the receiving antenna 4, so that the dynamic RCS detection of the birds is realized. And the computer 6 and the turntable controller 7 are used for controlling the position of the rotating birds of the turntable 8, so that the dynamic RCS of the birds in different directions can be detected. The invention solves the problems that only the RCS of a static target 10 can be detected, and the dynamic RCS of a dynamic target 10, in particular the dynamic RCS of birds, cannot be detected in the prior art.
Example two
As shown in fig. 8, fig. 8 is a flowchart of a method for detecting bird dynamics RCS according to a system of an embodiment of the present invention; the detection method of bird dynamic RCS comprises the following steps:
s101, transmitting a frequency sweeping signal through a first channel module of the vector network analyzer, and receiving the signal in real time.
The frequency sweeping signal can be transmitted through a frequency sweeping source of the vector network analyzer, transmitted through the first channel module, further amplified by a power amplifier and transmitted to the transmitting antenna. And returning target echoes, namely echo signals of the birds, through the interaction with the dynamic birds. And moreover, the signals are received in real time after the sweep frequency signals are transmitted, so that the phenomenon that the time for birds to vibrate wings is missed and the signals returned by the birds to vibrate wings cannot be acquired is avoided.
S102, stimulating the birds fixed in the microwave dark room to swing by means of electric shock.
Specifically, birds are fixedly placed on the rotary table, and the top end of the support can also be fixedly placed on the rotary table. Therefore, the positions of the birds are matched with the positions of the transmitting antenna, the receiving antenna, the high-speed camera and the like, and information interaction can be carried out more effectively. When the bird is not stimulated and flies, the bird may be referred to as a static bird. After the birds are fixed, the birds can be stimulated to vibrate the wings in an electric shock mode, and the birds do not move because the birds are fixed on the rotary table or the support, but the wings are vibrated in situ, so that the birds can be called dynamic birds. This facilitates detection of the bird's dynamic RCS; thus, the contribution of the bird wings to the RCS can be effectively detected and quantified by comparing the static RCS with the dynamic RCS.
S103, receiving the echo signals of the birds through a second channel module of the vector network analyzer, judging whether the received echo signals are higher than a threshold value, if so, automatically triggering to record data, and sending a first synchronization signal to the high-speed camera for photographing and storing.
The first synchronization signal is a path of pulse signal output by the vector network analyzer according to an echo signal returned by the dynamic birds and is used as a high-speed camera starting signal, namely a synchronization signal. The threshold may be a trigger threshold for controlling the high-speed camera to take a photograph. When the vector network analyzer measures dynamic birds, under the static condition of the birds, the amplitude of a bird echo signal is low, the amplitude of a first synchronous signal output by the vector network analyzer is also low and is lower than a threshold value, and then echo signal data recording and high-speed camera photographing cannot be triggered; however, when birds are stimulated, the birds vibrate the wings, and the amplitude of the echo signals is increased due to the fact that the wings are vibrated by the birds, so that the amplitude of the first synchronous signals output by the vector network analyzer is higher than a preset threshold value, and then an echo signal data recording program is triggered, and the high-speed camera is triggered to take pictures and store the pictures. Specifically, after the vector network analyzer receives echo signals of birds, two paths of square wave signals are output outwards through the Trigger Aux function of the vector network analyzer, one path of square wave signals is connected to the high-speed camera through the BNC connecting line and serves as a synchronous signal, after the high-speed camera receives the first synchronous signal, a shutter of the high-speed camera can be triggered to capture dynamic birds, and dynamic photos of the birds obtained through capture are stored. This facilitates recording of the status of the birds on the fly and the frequency of the flapping of the birds. And the other path is connected with an INPUT1 interface in a rear panel HandlerIO interface of the vector network analyzer, and the synchronous signal is used as an interrupt mark for judging the completion of single scanning, so that the data storage function is driven. Thus, according to the set measuring times, synchronization of vector network measuring data and photos can be completed. Further improve the detection accuracy of the developments RCS of birds, avoid interfering signal to influence the detection of birds developments RCS.
And S104, converting the echo signals into bird dynamic RCS information.
The above dynamic RCS information of birds includes dynamic RCS values of birds. After the vector network analyzer receives the echo signal of the dynamic bird, the transmission coefficient S can be obtained through the measurement function of the vector network analyzer 21 And calculating the dynamic RCS value of the birds by combining the test principle of RCS in figures 3-7.
And S105, controlling the rotary table to rotate the position of the bird according to a preset angle through the rotary table controller, and repeatedly measuring at a new angle.
The preset angle is an angle corresponding to a preset interval of the rotary table. Specifically, the starting position of the turntable is set to be consistent with the front alignment transmitting antenna of the high-speed camera of the dynamic birds, and the direction of the starting position of the turntable is 0. The turntable is controlled by the turntable controller to step by step according to the angle corresponding to the set interval through the computer, clockwise rotation is carried out, and S101 to S104 are automatically executed to complete detection and storage of bird dynamic RCS every time the dynamic birds rotate to one position, so that dynamic RCS of different positions of the dynamic birds can be detected, detection data at each time is recorded, and accuracy of dynamic RCS information of the dynamic birds can be improved.
In the embodiment of the invention, the sweep frequency signal is transmitted through the first channel module of the vector network analyzer through S101, and the signal is received in real time; s102, stimulating birds fixed in a microwave darkroom to swing in an electric shock mode; s103, receiving the echo signals of the birds through a second channel module of the vector network analyzer, judging whether the received echo signals are higher than a threshold value, if so, automatically triggering to record data, and sending a first synchronization signal to a high-speed camera for photographing and storing; s104, converting the echo signals into bird dynamic RCS information; and S105, controlling the rotary table to rotate the position of the bird according to a preset angle through the rotary table controller, and repeatedly measuring at a new angle. Like this, can be through vector network analyzer and high-speed camera synchronous coordination and realize the developments RCS that the information interaction detected birds through transmitting antenna and receiving antenna and birds, and then realize the developments RCS detection of birds. And the position of the birds rotated by the turntable is controlled by the computer and the turntable controller, so that the dynamic RCS in different directions of the birds can be detected. The invention solves the problems that the prior art can only detect the RCS of a static target and does not detect the dynamic RCS of a dynamic target, in particular the dynamic RCS of birds.
EXAMPLE III
As shown in fig. 9, which is a flowchart of one method provided in S102 of fig. 8; s102, stimulating birds fixed in a microwave dark room to swing by an electric shock mode comprises the following steps:
s201, fixing the claws of the birds on the rotary table by adopting a lead, and leading the other end of the lead to the outside of a microwave darkroom.
Wherein, can also bind the claw of this birds on the revolving stage with the rope, or on the support of revolving stage. And then one end of the lead is touched to the claws of the birds, so long as the lead is contacted with the birds, and the birds can be stimulated when the bird is electrified. Finally, the other end of the lead is arranged outside the microwave darkroom, so that a user can conveniently carry out electric shock operation to stimulate the birds.
S202, transmitting an electric shock signal to the claws of the birds through a lead outside the electric shock microwave darkroom to stimulate the wings of the birds.
After the birds are fixed, the birds can be stimulated to fly wings through the wire ends outside the microwave dark room of the motor by tools such as an electric rod and the like, and then the wings of the birds are flapped. It should be noted that, because the claws of birds are tied to the turntable or the bracket, the birds cannot fly away and only fly wings in situ.
Example four
As shown in fig. 10, on the basis of the second embodiment, the embodiment of the present invention further provides another flow chart of a bird dynamic RCS detection method based on the first embodiment; the detection method of bird dynamic RCS also comprises the following steps:
s301, setting parameters of the vector network analyzer.
And S302, calibrating the vector network analyzer according to the parameters of the vector network analyzer.
The parameter setting of the vector network analyzer must meet the microwave darkroom conditions and the target RCS test requirements. Taking Ku band testing as an example, the parameters of the vector network analyzer are set as follows: the scanning range is 14-18 GHz, the sweep frequency bandwidth is B =4GHz, the number N of sampling points is 1601, the frequency resolution delta f = B/N is 2.5MHz, the time domain dynamic range delta t = 1/(. DELTA.f) is 400ns, and the spatial maximum measurement distance L = (c × delta t)/2 is 60m; the vector network analyzer adopts a band-pass working mode, time-domain response can be given after inverse Fourier transform, a simulated pulse function irradiates a detected target, the width T of a pulse is equal to the bandwidth B of frequency sweep, namely T =1/B, so that the distance resolution force delta R = cT/2=c/2B is 0.0375m, and the medium-frequency bandwidth is set to be 100KHz in consideration of the scanning speed and the scanning precision.
Since the frequency of flapping of common birds (such as sparrows, pigeons, wild ducks and the like) is generally 8-15Hz, taking 10Hz as an example, the gap between adjacent flapping of a flying bird does not exceed 100ms, and the two measurement periods of the vector network analyzer are required to be less than 100ms, so that the contribution of a single flapping on the RCS of the bird can be distinguished. For the parameter setting of the vector network analyzer, the single measurement time is in direct proportion to the scanning bandwidth and the number of measurement points and in inverse proportion to the intermediate frequency bandwidth, and the stability (precision) of the measurement data is reduced along with the reduction of the number of measurement points and the increase of the intermediate frequency bandwidth; therefore, the measurement data precision is ensured by controlling the parameters such as the number of measurement points, the medium frequency bandwidth and the like on the premise of meeting the single measurement time.
On one hand, the vector network analyzer is calibrated through the set parameters, and the detection accuracy of the vector network analyzer is further improved; on the other hand, the balance between single measurement time and measurement data precision can be achieved, and the method effectively captures the frame-by-frame change of bird dynamic RCS along with the flapping motion and is more suitable for the detection of bird dynamic RCS.
EXAMPLE five
As shown in fig. 11, on the basis of the second embodiment, the embodiment of the present invention further provides another flow chart of a bird dynamic RCS detection method based on the first embodiment; the detection method of bird dynamic RCS also comprises the following steps:
s401, transmitting a sweep frequency signal through a first channel module of the vector network analyzer.
S402, receiving and storing the echo signal of the background of the microwave darkroom through a second channel module of the vector network analyzer.
And S403, converting the echo signal of the background of the microwave darkroom into RCS information of the background of the microwave darkroom.
Specifically, before detecting the dynamic RCS of the birds, a background test needs to be performed on the microwave dark room through the vector network analyzer and the high-speed camera, whether the background RCS exists in the background of the microwave dark room when no detection target exists is detected, if the background RCS exists, the background RCS of the microwave dark room needs to be eliminated in a result of detecting the target RCS, and if the background RCS exists in the microwave dark room and the background RCS exceeds a preset value, it is indicated that the microwave dark room has poor energy absorption capability and poor quality. If the background RCS does not exist in the microwave darkroom, the quality of the microwave darkroom is good, and the background RCS does not need to be eliminated when the target RCS is detected, so that the detection precision of the target dynamic RCS is further improved.
Example six
As shown in fig. 12, on the basis of the second embodiment, the embodiment of the present invention further provides another flow chart of a bird dynamic RCS detection method based on the first embodiment; the detection method of bird dynamic RCS also comprises the following steps:
s501, opening a high-speed camera to record a target area at a constant speed, and placing balls with different sizes on a turntable in sequence.
The spherical ball may be a metal ball, such as an iron ball, a steel ball, an aluminum ball, etc. The sphere can be called a standard sphere and is used as a standard detection target, namely, a reference for detecting the dynamic RCS of the birds. Specifically, the big and small spheres are observed reversely, and a plurality of groups of reference data can be obtained. The RCS accuracy of the sphere is improved.
And S502, transmitting a frequency sweeping signal through a first channel module of the vector network analyzer.
Specifically, after the sphere is fixed and started in S501, a sweep frequency signal may be transmitted through a sweep frequency source of the vector network analyzer, and the sweep frequency signal may be transmitted through the first channel module, further amplified by a power amplifier, and transmitted to the transmitting antenna. And returning a target echo, namely an echo signal of the spherical ball, through the interaction with the spherical ball.
And S503, receiving and storing the echo signal of the sphere through a second channel module of the vector network analyzer.
When the target echo is returned, the target echo is received by the receiving antenna and is transmitted to the vector network analyzer through the second channel module for storage, so that the RCS of the sphere is conveniently analyzed.
And S504, synchronizing a second synchronization signal to the high-speed camera according to the echo signal of the sphere.
Specifically, the second synchronization signal is a path of pulse signal output by the vector network analyzer according to an echo signal returned by the sphere, and is used as a high-speed camera start signal, that is, a synchronization signal. Specifically, after the vector network analyzer receives an echo signal of the sphere, two paths of square wave signals are output outwards through the Trigger Aux function of the vector network analyzer, one path of square wave signals is connected to the high-speed camera through the BNC connecting line and serves as a synchronous signal, and the high-speed camera receives the synchronous signal and triggers to complete one-time photographing. And the other path is connected with an INPUT1 interface in a HandlerIO interface of a rear panel of the vector network analyzer, and an interrupt mark for judging that the single scanning is finished is taken as a synchronous signal so as to drive a data storage function. Therefore, according to the set measuring times, the synchronization of the measuring data and the photo of the vector network analyzer can be completed.
And S505, photographing and storing the round ball photo according to the second synchronous signal through the high-speed camera.
Specifically, after the high-speed camera receives the second synchronization signal, the shutter of the high-speed camera can be triggered to capture the round ball, and the captured picture of the round ball is stored. This facilitates recording of the state of the ball.
And S506, converting the echo signal of the sphere into RCS information of the sphere.
The RCS information of the round ball includes an RCS theoretical value of the round ball. When the vector network analyzer receives the echo signal of the sphere, the transmission coefficient S can be obtained through the measurement function of the vector network analyzer 21 And the RCS theoretical value of the round ball is calculated by combining the test principle of the RCS in the figures 3-7.
And S507, controlling the rotary table to rotate the position of the round ball according to a preset angle through the rotary table controller, and repeating S501-S506.
Specifically, before detecting the target bird, the RCS theoretical value of the standard sphere is detected through the steps of S501 to S507. Therefore, the dynamic RCS value of the target bird can be calculated by comparing the echo power of the target bird to be detected with that of the standard sphere. Further, accuracy and efficiency of the dynamic RCS theoretical value of the birds are improved.
EXAMPLE seven
As shown in fig. 13, on the basis of the second embodiment, the embodiment of the present invention further provides another flow chart of a bird dynamic RCS detection method based on the first embodiment; the detection method of bird dynamic RCS also comprises the following steps:
s601, fixing the claws of the birds on the rotary table.
Specifically, the claws of the static birds are fixed on the rotary table, and can also be fixed at the top end of the support on the rotary table. Therefore, the positions of the static birds are matched with the positions of the transmitting antenna, the receiving antenna, the high-speed camera and the like, and information interaction can be carried out more effectively.
And S602, transmitting the frequency sweep signal through a first channel module of the vector network analyzer.
Specifically, after the static birds are fixed in S601, the sweep frequency signal may be transmitted through the sweep frequency source of the vector network analyzer, and the sweep frequency signal may be transmitted through the first channel module, further amplified by a power amplifier, and transmitted to the transmitting antenna. And returning target echoes, namely echo signals of the static birds, through the interaction with the static birds. Further, the frequency sweep signal emitted by the first channel module specifically interacts with birds at rest.
And S603, receiving and storing the echo signals of the static birds through a second channel module of the vector network analyzer.
Specifically, when the target echo returns, the target echo is received by the receiving antenna and is transmitted to the vector network through the second channel module for analysis and storage, so that the static RCS of the static birds can be analyzed conveniently.
And S604, synchronizing a third synchronizing signal to the high-speed camera according to the echo signal of the static bird.
Specifically, the third synchronization signal is a path of pulse signal output by the vector network analyzer according to an echo signal returned by the static birds, and is used as a high-speed camera start signal, that is, a synchronization signal. Specifically, after the vector network analyzer receives an echo signal of a static bird, two paths of square wave signals are output outwards through the Trigger Aux function of the vector network analyzer, one path of square wave signals is connected to the high-speed camera through the BNC connecting line and serves as a synchronous signal, and the high-speed camera receives the synchronous signal to Trigger and complete one-time photographing. And the other path is connected with an INPUT1 interface in a rear panel HandlerIO interface of the vector network analyzer, and the synchronous signal is used as an interrupt mark for judging the completion of single scanning, so that the data storage function is driven. Therefore, according to the set measuring times, the synchronization of the measuring data and the picture of the vector network analyzer can be completed.
And S605, taking a picture by the high-speed camera according to the third synchronous signal and storing the still picture of the static bird.
Specifically, after the high-speed camera receives the third synchronization signal, the shutter of the high-speed camera can be triggered to capture the static birds, and the captured still pictures of the static birds are stored. This facilitates recording of the status of static birds.
And S606, converting the echo signals of the static birds into RCS information of the static birds.
The RCS information of the static birds includes static RCS values of the static birds. After the vector network analyzer receives the echo signals of the static birds, the transmission coefficient S can be obtained through the measurement function of the vector network analyzer 21 And calculating the static RCS value of the static birds by combining the test principle of RCS in figures 3-7.
S607, controlling the rotary table to rotate the position of the static birds according to a preset angle through the rotary table controller, and repeating S601-S606.
The preset angle is an angle corresponding to a preset interval of the rotary table. Specifically, the starting position of the turntable is set to be consistent with the front alignment transmitting antenna of the high-speed camera of the static birds, and the direction of the starting position of the turntable is 0. Through the angle that computer control revolving stage controller control revolving stage corresponds according to setting for the interval step by step, clockwise rotation, static birds are every rotatory a position, then carry out S602 to S606 automatically and accomplish the detection and the storage of the static RCS of static birds, can detect the dynamic RCS in different positions of static birds like this to record the data that detect at every turn, can improve the accuracy of the static RCS information of static birds.
The static RCS of the static birds is detected before the dynamic RCS of the dynamic birds is detected, the static RCS is used for comparing the dynamic RCS, and the dynamic RCS can judge that the flapping of the birds contributes to the RCS of the birds.
It should be noted that, generally speaking, birds have a short flapping cycle, especially considering that their paws are tied to the rack, and the time for flapping the wings in situ is about 1-2 seconds; therefore, the measurement time is set to be longer than the flapping wing time, and then after the preset threshold value is triggered once, the dynamic RCS data and the static RCS data of the birds can be recorded simultaneously within the whole measurement times.
The terms "including" and "having," and any variations thereof in the description and claims of this application and the description of the figures above, are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein may be combined with other embodiments.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A bird dynamics RCS detection system, comprising:
the vector network analyzer is at least provided with a first channel module for transmitting signals and a second channel module for receiving echo signals of the birds;
the rotary table assembly comprises a rotary table and a rotary table controller, the rotary table is used for bearing the birds, and the rotary table controller is used for controlling the rotary table to rotate in a stepping mode;
the transmitting antennas are respectively connected with the first channel modules;
the receiving antennas are respectively connected with the second channel modules;
the high-speed camera with the frame rate of 1000fps is in signal connection with the vector network analyzer so as to start photographing according to an echo signal received by a second channel module of the vector network analyzer; and
the computer is connected with the vector network analyzer and the rotary table controller;
the vector network analyzer includes: the Trigger assists the Trigger Aux function and is used for outputting two paths of square wave signals, one path of square wave signals is connected to the high-speed camera through a BNC connecting line and serves as a synchronous signal, the other path of square wave signals is connected with an INPUT1 interface in a Handler IO interface behind the vector network analyzer, the synchronous signal serves as an interrupt mark for judging that the single scanning is finished, the data storage function is further driven, and the synchronization of the measurement data and the photo of the vector network analyzer is completed according to the set measurement times;
the method comprises the steps that target echoes received by a receiving antenna obtain frequency domain characteristics of a target, then the frequency domain characteristics are converted into a time domain for analysis through inverse Fourier transform, background clutter outside a time domain door is filtered through time domain windowing to obtain RCS information of the target in a wide frequency band, dynamic photos obtained by photographing dynamic birds are analyzed in combination with a high-speed camera to further obtain the dynamic RCS information of the dynamic birds, and the dynamic birds stimulate bird flapping by transmitting electric shock signals to claws of the birds through leads outside an electric shock microwave darkroom;
and the high-speed camera judges whether the amplitude of the synchronous signal is higher than a preset threshold value or not, and if the amplitude of the synchronous signal is higher than the preset threshold value, the high-speed camera takes pictures and stores the pictures.
2. The bird dynamic RCS detection system of claim 1, wherein the turntable assembly further includes a bracket disposed on the turntable for carrying the birds.
3. A method for detecting avian dynamic RCS based on the system of claim or 2, comprising the steps of:
s101, transmitting a frequency sweeping signal through a first channel module of a vector network analyzer, and receiving the signal in real time;
s102, stimulating the flapping wings of the birds fixed in a microwave darkroom in an electric shock mode;
s103, receiving the echo signals of the birds through a second channel module of the vector network analyzer, judging whether the received echo signals are higher than a threshold value, if so, automatically triggering to record data, and sending a first synchronization signal to a high-speed camera for photographing and storing;
s104, converting the echo signals into bird dynamic RCS information;
and S105, controlling the rotary table to rotate the position of the bird according to a preset angle through the rotary table controller, and repeatedly measuring at a new angle.
4. The method of claim 3, wherein the step of stimulating by electric shock the flapping wings of birds immobilized in a microwave dark room comprises:
s201, fixing the claws of the birds on the rotary table by adopting a lead, and leading the other end of the lead to the outside of a microwave darkroom;
s202, transmitting an electric shock signal to the claws of the birds through a lead outside an electric shock microwave darkroom to stimulate the wings of the birds.
5. The method for detecting avian dynamics RCS of claim 3, further comprising the steps of:
s301, setting parameters of a vector network analyzer;
s302, calibrating the vector network analyzer according to the parameters of the vector network analyzer.
6. The method of detecting avian dynamic RCS of claim 3, further comprising:
s401, transmitting a frequency sweep signal through a first channel module of the vector network analyzer;
s402, receiving and storing an echo signal of the background of the microwave darkroom through a second channel module of the vector network analyzer;
and S403, converting the echo signal of the background of the microwave darkroom into RCS information of the background of the microwave darkroom.
7. The method of detecting avian dynamic RCS of claim 3, further comprising the steps of:
s501, opening a high-speed camera to record a target area at a constant speed, and placing balls with different sizes on a rotary table in sequence;
s502, transmitting a frequency sweep signal through a first channel module of a vector network analyzer;
s503, receiving and storing the echo signal of the sphere through a second channel module of the vector network analyzer;
s504, synchronizing a second synchronization signal to the high-speed camera according to the echo signal of the sphere;
s505, photographing and storing the round ball photo through the high-speed camera according to the second synchronous signal;
s506, converting the echo signal of the round ball into RCS information of the round ball;
and S507, controlling the turntable to rotate the position of the ball according to a preset angle through the turntable controller, and repeating the steps S501-S506.
8. The method of detecting avian dynamic RCS of claim 3, further comprising the steps of:
s601, fixing claws of birds on the rotary table;
s602, transmitting a frequency sweeping signal through a first channel module of a vector network analyzer;
s603, receiving and storing the echo signals of the static birds through a second channel module of the vector network analyzer;
s604, synchronizing a third synchronizing signal to the high-speed camera according to the echo signal of the static birds;
s605, taking pictures according to the third synchronous signal through the high-speed camera and storing static pictures of the static birds;
s606, converting the echo signals of the static birds into RCS information of the static birds;
s607, controlling the rotary table to rotate the position of the static birds according to a preset angle through the rotary table controller, and repeating S601-S606.
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