A frequency beam scanning antenna based inter-frequency simultaneous multi-beam measurement method

Abstract

The application provides a frequency beam scanning antenna based on frequency simultaneous multi-beam measurement method, and relates to a radar measurement method, which utilizes multiple frequency beams generated by a frequency beam scanning antenna to transmit and receive electromagnetic signals simultaneously; first, a broadband signal is excited and echo signals reflected by a measured target are received, the distance of the measured target is calculated according to the echo signal arrival time; then, the spectrum of the echo signal is calculated and the spectrum is shifted, the difference between the original spectrum and the shifted spectrum is obtained, the minimum value between the peaks is obtained, and finally, the direction of the measured target is solved according to the directivity diagram at the minimum value frequency. The method has high accuracy and measurement rate, and the position information of multiple measured targets in the scanning range of the frequency beam scanning antenna can be obtained through one signal transmission and reception.

Description

Technical Field

[0001] This invention belongs to the field of radar measurement, and in particular relates to a method for simultaneous multi-beam measurement of different frequencies based on a frequency beam scanning antenna. Background Technology

[0002] Simultaneous multibeam scanning is a widely used radar measurement method. By using multiple antennas to simultaneously generate multiple beams, the position information of the target can be given through single-pulse transmission and reception. Simultaneous multibeam scanning therefore features high measurement speed and a simple measurement process, and is widely used in various radar measurement scenarios. With continuous research and significant technological advancements, a series of radar measurement systems based on simultaneous multibeam scanning have emerged.

[0003] Traditional simultaneous multi-beam methods utilize multiple antennas or transceiver channels, requiring complex comparison networks to obtain single-pulse signals containing the direction and position information of the target under test, resulting in high structural and design complexity. Furthermore, in traditional simultaneous multi-beam methods, the antenna beam pointing often remains unchanged with frequency, necessitating beam scanning to measure targets outside the beam range. The beam scanning function in traditional simultaneous multi-beam methods requires control via mechanical turntables, phase shifters, or switches; therefore, the maximum beam scanning rate is limited by the performance of these mechanical turntables, phase shifters, or switches. Summary of the Invention

[0004] The purpose of this invention is to provide a method for simultaneous multi-beam measurement at different frequencies based on a frequency beam scanning antenna. This method generates multiple beams simultaneously within the beam scanning range of the antenna, thereby measuring multiple targets at any position within the beam scanning range with a single transmitted signal. It also takes into account the advantages of traditional simultaneous multi-beam schemes, and has a high maximum measurement rate and accuracy, thus solving the technical problems of high complexity in structure and design and low measurement rate of traditional methods.

[0005] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0006] A method for simultaneous multi-beam measurement at different frequencies based on a frequency-beam scanning antenna is proposed. This method uses a frequency-beam scanning antenna with a radiation pattern of G(θ,f) at frequency f. The antenna transmits a broadband signal, which reaches a radar cross-section of σ at the speed of light c in free space. i And the angle between it and the normal to the horizontal plane is θ i The i-th target in the direction is reflected and after a delay τ i Received by a frequency beam scanning antenna, the spectrum of the received signal is S. i (f), the spectrum of the n signals superimposed is the total spectrum S(f); the measurement steps are as follows:

[0007] Step 1: Calculate the distance D from the i-th target to the frequency beam scanning antenna. i =cτ i / 2;

[0008] Step 2: Calculate the spectral shift width f required to measure the i-th target. ri According to the spectrum shift width f ri After shifting the spectrum, calculate the required hetero-frequency difference spectrum Δ for measuring the i-th target. i (f);

[0009] Step 3: Based on the frequency difference spectrum Δ i (f) Calculate the direction θ of the i-th measured target. ti ;

[0010] Step 4: Based on the inherent characteristic that the beam pointing of a frequency beam scanning antenna changes with frequency, calculate the direction θ in which the frequency beam scanning antenna beam is directly facing the target. ti The operating frequency f0 is used to define the frequency band f0-1.5f of the reflected signal from the i-th target in the total spectrum S(f). ri to f0+0.5f ri Spectrum filtering is performed, and steps 1 to 3 are repeated until no single minimum value corresponding to a frequency can be found in step 3.

[0011] At this point, the direction and distance information of all the measured targets can be obtained.

[0012] At this point, the direction and distance information of all the measured targets can be obtained.

[0013] Furthermore, by using a frequency beam scanning antenna, the direction of the pattern beam changes with the frequency within the beam scanning angle range, and different frequency signals are radiated in different directions.

[0014] Furthermore, in step 2, the required spectral shift width f for measuring the i-th target is calculated using the following formula. ri And the required heterofrequency difference spectrum Δ for the i-th measured target. i (f), where f is the frequency:

[0015]

[0016] f ri =f 1i -f 2i

[0017]

[0018] Furthermore, step 3 specifically includes the following steps: in the heterodyne spectrum Δ iFind the frequency f where the maximum value is located on (f). 1i The frequency f of the second largest extreme point. 2i Searching for the spectrum in f 1i with f 2i The frequency f of the minimum value between 0i The heterodyne beam pattern ζ was calculated. i (θ); in the heterodyne beam pattern ζ i Find the angle θ where the maximum value is located on (θ). 1i The angle θ where the second largest extreme point is located. 2i Finding the beam pattern ζ of different frequencies i (θ) at θ 1i With θ 2i The angle containing the minimum value between these two points is the direction θ of the i-th measured target. ti .

[0019] Furthermore, in step 3, the heterodyne beam pattern ζ is calculated using the following formula. i (θ):

[0020] ζ i (θ)=G(θ,f 0i )-G(θ,f 0i +f ri ).

[0021] The present invention provides a method for simultaneous multi-beam measurement at different frequencies based on a frequency beam scanning antenna, which has the following advantages:

[0022] (1) The present invention proposes a method for simultaneous multi-beam measurement based on frequency beam scanning antenna, which can realize multi-beam measurement in multiple directions at the same time. It has the ability to measure multiple targets at the same time with one signal transmission and reception, without the need for beam switching, and can improve the measurement rate.

[0023] (2) The present invention proposes a method for simultaneous multi-beam measurement of different frequencies based on a frequency beam scanning antenna, which can be implemented using only one frequency beam scanning antenna and only requires one transmit and receive channel, thus simplifying the antenna and its network.

[0024] (3) The present invention proposes a method for simultaneous multi-beam measurement of different frequencies based on a frequency beam scanning antenna. The extraction of measurement information can be completely completed by a computer, which can simplify the function of the receiver.

[0025] (4) The present invention proposes a method for simultaneous multi-beam measurement of different frequencies based on a frequency beam scanning antenna. Its measurement accuracy is adjustable. The accuracy can be adjusted to balance the data processing speed requirement and the accuracy requirement. Attached Figure Description

[0026] Figure 1 This is a block diagram illustrating the implementation principle of the present invention. Detailed Implementation

[0027] To better understand the purpose, structure, and function of this invention, the following detailed description of a method for simultaneous multi-beam measurement at different frequencies based on a frequency beam scanning antenna is provided in conjunction with the accompanying drawings.

[0028] The specific steps of this embodiment include:

[0029] First, a frequency beam scanning antenna is used to transmit and receive signals: the radiation pattern of the frequency beam scanning antenna at frequency f is G(θ,f); the frequency beam scanning antenna transmits a broadband signal once and receives the reflected signal, the spectrum of which is S(f), the speed of light in free space is c, and the delay of the echo signal from the i-th target to reach the frequency beam scanning antenna is τ. i The radar cross section of the i-th target is σ. i ;

[0030] The following are the steps for calculating and processing the received signal to implement the present invention:

[0031] Step 1: Calculation

[0032] Calculate the distance D from the i-th target to the frequency beam scanning antenna using the following formula. i :

[0033] D i =cτ i 2

[0034] Step 2: Calculate the frequency difference spectrum Δ i (f)

[0035] The required spectral shift width f for measuring the i-th target is calculated using the following formula. ri Where f is the frequency:

[0036]

[0037] f ri =f 1i -f 2i

[0038] The required heterofrequency difference spectrum Δ for measuring the i-th target is calculated using the following formula. i (f):

[0039]

[0040] Step 3: Determine the orientation information of the i-th target being measured:

[0041] In the heterodyne spectrum Δ iFind the frequency f where the maximum value is located on (f). 1i The frequency f of the second largest extreme point. 2i Searching for the spectrum in f 1i with f 2i The frequency f of the minimum value between 0i The beam pattern ζ of the different frequency difference is obtained according to the following formula. i (θ):

[0042] ζ i (θ)=G(θ,f 0i )-G(θ,f 0i +f ri )

[0043] In the heterodox beam pattern ζ i Find the angle θ where the maximum value is located on (θ). 1i The angle θ where the second largest extreme point is located. 2i Finding the beam pattern ζ of different frequencies i (θ) at θ 1i With θ 2i The angle containing the minimum value between these two points is the direction θ of the i-th measured target. ti ;

[0044] Step 4: Measure the position information of all targets being measured:

[0045] Based on the inherent characteristic that the beam pointing of a frequency beam scanning antenna changes with frequency, the direction θ in which the frequency beam scanning antenna beam is directly aligned with the target is calculated. ti The operating frequency f0 is used to define the frequency band f0-1.5f of the reflected signal from the i-th target in the total spectrum S(f). ri to f0+0.5f ri After filtering out the spectrum, repeat steps 2 to 3 until no single minimum value corresponding to a frequency can be found in step 3. At this point, the direction and distance information of all the measured targets can be obtained.

[0046] Based on the above description, the present invention can be realized.

[0047] Heterogeneous frequency difference spectrum Δ i (f) indicates that the phase difference f ri The difference in received signal amplitude at different frequencies is equivalent to the frequency difference beam pattern ζ. i (θ) During frequency beam scanning, the amplitude of the received signal changes with frequency. Due to the difference in frequency spectrum Δ i (f) in f 0i Nearby is a monotonic curve crossing zero, with the frequency difference spectrum Δ i (f) The logarithm of the amplitude changes drastically with frequency; even a slight angular deviation can cause a difference in the frequency spectrum Δ.i The amplitude change of (f) will result in a highly accurate measured target orientation value.

[0048] The present invention provides a method for simultaneous multi-beam measurement of different frequencies based on a frequency beam scanning antenna, which can quickly and accurately obtain the direction and distance information of multiple targets within the beam scanning range during a single signal transmission and reception process.

[0049] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for simultaneous multi-beam measurement at different frequencies based on a frequency beam scanning antenna, characterized in that, This method uses a frequency-beam scanning antenna with a radiation pattern of G(θ,f) at frequency f. The frequency-beam scanning antenna transmits a broadband signal, which reaches the radar cross section σ at the speed of light c in free space. i And the angle between it and the normal to the horizontal plane is θ i The i-th target in the direction is reflected and after a delay τ i Received by a frequency beam scanning antenna, the spectrum of the received signal is S. i (f), the spectrum of the n signals superimposed is the total spectrum S(f); the measurement steps are as follows: Step 1: Calculate the distance D from the i-th target to the frequency beam scanning antenna. i =cτ i / 2; Step 2: Calculate the spectral shift width f required to measure the i-th target. ri According to the spectrum shift width f ri After shifting the spectrum, calculate the required hetero-frequency difference spectrum Δ for measuring the i-th target. i (f); Step 3: Based on the frequency difference spectrum Δ i (f) Calculate the direction θ of the i-th measured target. ti ; Step 4: Based on the inherent characteristic that the beam pointing of a frequency beam scanning antenna changes with frequency, calculate the direction θ in which the frequency beam scanning antenna beam is directly facing the target. ti The operating frequency f0 is used to define the frequency band f0-1.5f of the reflected signal from the i-th target in the total spectrum S(f). ri to f0+0.5f ri Spectrum filtering is performed, and steps 1 to 3 are repeated until no single minimum value corresponding to a frequency can be found in step 3. At this point, the direction and distance information of all measured targets can be obtained; Using a frequency beam scanning antenna, within the beam scanning angle range, the direction of the pattern beam changes with the frequency, and at the same time, different frequency signals are radiated in different directions. In step 2, the required spectral shift width f for measuring the i-th target is calculated using the following formula. ri And the required heterofrequency difference spectrum Δ for the i-th measured target. i (f), where f is the frequency: ； ； 。 2. The method for simultaneous multi-beam measurement of different frequencies based on a frequency beam scanning antenna according to claim 1, characterized in that, Step 3 specifically includes the following steps: in the heterodyne spectrum Δ i Find the frequency f where the maximum value is located on (f). 1i The frequency f of the second largest extreme point. 2i Searching for the spectrum in f 1i with f 2i The frequency f of the minimum value between 0i The heterodyne beam pattern ζ was calculated. i (θ); in the heterodyne beam pattern ζ i Find the angle θ where the maximum value is located on (θ). 1i The angle θ where the second largest extreme point is located. 2i Finding the beam pattern ζ of different frequencies i (θ) at θ 1i With θ 2i The angle containing the minimum value between these two points is the direction θ of the i-th measured target. ti .

3. The method for simultaneous multi-beam measurement at different frequencies based on a frequency beam scanning antenna according to claim 2, characterized in that, In step 3, the heterodyne beam pattern ζ is calculated using the following formula. i (θ): 。

Images