CN113740808B - Cosine frequency offset frequency control array beam synthesis method - Google Patents
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Abstract
The application discloses a cosine frequency offset frequency control array beam synthesis method, which comprises the following steps: step 1, confirming a cosine frequency offset coefficient of a frequency control array according to array element numbers, accumulating and summing the cosine frequency offset coefficient according to preset sequence numbers, and marking accumulated and summed results as cosine frequency offset; step 2, performing shift operation on the cosine frequency offset according to a reference number, marking a shift operation result as slope-controllable cosine frequency offset, and calculating cosine frequency and phase correlation of the frequency control array according to the slope-controllable cosine frequency offset and the array element position, wherein the reference number is determined by the slope of the predicted directional diagram; and step 3, determining a cosine frequency offset frequency control array beam of the frequency control array according to the cosine frequency and the phase correlation. By the technical scheme, the frequency offset frequency control array beam width is reduced, and the beam controllability and the detection accuracy are improved.
Description
Technical Field
The application relates to the technical field of beam synthesis, in particular to a cosine frequency offset frequency control array beam synthesis method.
Background
In the technical field of antenna wave velocity synthesis, for beam synthesis of phased array antennas, the angular direction of a beam can be freely controlled, but the beam is independent of distance. And for the wave beam synthesis technology of the frequency control array antenna, wave beams related to the distance can be synthesized, and the method has a certain application prospect in the aspects of distance related interference suppression, distance fuzzy suppression, directional communication and the like. And the beam width of the frequency control array is reduced, so that the beam detection precision is improved.
Classical frequency control array antennas include constant frequency offset frequency control arrays proposed by U.S. air force laboratory Paul Antonik et al in 2006, a beam related to distance can be obtained, but the beam has obvious periodicity in distance, which can cause distance ambiguity, and the beam width is only related to the array element spacing and the array element number of the frequency control array antenna, and the beam width controllability is not strong.
Aiming at the problem of obvious beam periodicity, WASEEM KHAN et al propose a logarithmic frequency offset frequency control array, the frequency control array antenna can also obtain a beam related to the distance, and the beam has no periodic structure in a certain distance airspace range, so that the problem of distance ambiguity is solved, but the beam has the main problems of high sidelobe level, large beam main lobe width and poor beam controllability.
The scholars put forward a sine frequency offset frequency control array to converge the wave beams in a small angle-distance range, so that spherical wave beams are realized, the wave beams also solve the problem of periodicity in distance, and the wave beam width in the wave beam distance dimension and the wave beam width in the angle dimension are greatly reduced, but the sine frequency offset frequency control array has poor wave beam controllability and can not control the angle direction of the wave beams freely.
Disclosure of Invention
The application aims at: the beam width of the frequency offset frequency control array is reduced, and the beam controllability and the detection accuracy are improved.
The technical scheme of the application is as follows: the method for synthesizing the cosine frequency offset frequency control array beam comprises the following steps: step 1, confirming a cosine frequency offset coefficient of a frequency control array according to array element numbers, accumulating and summing the cosine frequency offset coefficient according to preset sequence numbers, and marking accumulated and summed results as cosine frequency offset; step 2, performing shift operation on the cosine frequency offset according to a reference number, marking a shift operation result as slope-controllable cosine frequency offset, and calculating cosine frequency and phase correlation of the frequency control array according to the slope-controllable cosine frequency offset and the array element position, wherein the reference number is determined by the slope of the predicted directional diagram; and step 3, determining a cosine frequency offset frequency control array beam of the frequency control array according to the cosine frequency and the phase correlation.
In any of the above technical solutions, in step 1, further, performing accumulation summation according to a preset sequence number and a cosine frequency offset coefficient, specifically including: step 11, selecting the greatest common divisor of the preset sequence numbers and the beam width adjusting parameter alpha as the sequence number of the preset value, and marking the sequence number as the summation sequence number; and step 12, multiplying the cosine frequency offset coefficient according to the summation sequence number and the frequency offset step length, and calculating the cosine frequency offset according to the result of the multiplying transformation by adopting a mode of accumulating and summing.
In any one of the above technical solutions, further, the preset value is1, and the calculation formula of the cosine frequency offset is:
Wherein Δf b (M) is cosine frequency offset, M is array element number, m=0, 1,..m-1, M is array element number in frequency control array, n is preset sequence number, α is beam width adjustment parameter, gcd (n, α) =1 is greatest common divisor filter function, and Δf is frequency offset step size.
In any of the above solutions, further, the calculating process of the beam width adjustment parameter α specifically includes: step 111, calculating reference cosine frequency deviation corresponding to each adjustment parameter and reference beam width corresponding to each reference cosine frequency deviation in a parameter range in a traversal mode, wherein the reference beam width is 3dB beam width; step 112, selecting the largest monotonic interval among the monotonic intervals of the reference beam widths, selecting the reference beam width closest to the target beam width from the largest monotonic interval, and recording the adjustment parameter corresponding to the selected reference beam width as the beam width adjustment parameter.
In any of the above solutions, further, selecting a largest monotonic interval among the monotonic intervals of the reference beam widths, and selecting a reference beam width closest to the target beam width among the largest monotonic intervals, and specifically further includes: selecting a maximum monotonic interval from the monotonic intervals of the reference beam width; according to preset protection parameters, the maximum monotonic interval is adjusted so as to reduce the maximum monotonic interval; and selecting the reference beam width closest to the target beam width in the reduced maximum monotonic interval.
In any of the above technical solutions, further, in step 2, a calculation formula of the slope-controllable cosine frequency offset is:
Δfc(m)＝circshift[Δfb(m)，i]
Wherein Deltaf c (m) is a slope-controllable cosine frequency offset, circshift [ ] is a right cyclic shift function, deltaf b (m) is a cosine frequency offset, m is an array element number, and i is a reference number.
In any of the above technical solutions, further, in step 2, the calculation formula of the cosine frequency f c (m) is:
fc(m)＝f0+Δfc(m)
Phase of phase The calculation formula of (2) is as follows:
Wherein r 0 is the coherent distance of the coherent point, c is the speed of light, x m is the position of the array element with the array element number m, x 0 is the position of the array element of the reference array element, θ 0 is the coherent angle of the coherent point, and f 0 is the reference frequency of the frequency control array.
In any one of the above technical solutions, further, the method further includes: according to the slope controllable cosine frequency offset, calculating a wave speed direction diagram of the frequency control array and a wave speed width corresponding to the wave speed direction diagram, wherein a calculation formula corresponding to the wave speed direction diagram P c (theta, r) is as follows:
Wherein θ is the observation angle, r is the observation distance, M is the element number, m=0, 1, & gt, M-1, M is the number of elements in the frequency control array, c is the speed of light, Δf c (M) is the slope-controllable cosine frequency offset, f 0 is the reference frequency of the frequency control array, x m is the element position of element number M, x 0 is the element position of the reference element, Is the phase of the phase.
The beneficial effects of the application are as follows:
According to the technical scheme, the cosine frequency offset coefficient is introduced, the cosine frequency offset coefficient is summed up and summed up according to the preset sequence number, the frequency offset among the array elements is set to be in a contracted cosine function summation form by utilizing the theory of number theory, and the stronger uncorrelation of the frequency offset among the array elements can be ensured. Then, a slope-controllable cosine frequency offset is calculated by adopting a shift operation mode to obtain the cosine frequency and the phase of the frequency control array, so that the cosine frequency offset frequency control array beam of the frequency control array is determined, a spherical beam is formed by frequency design combining the cosine frequency offset and a number theory, the periodic structure in the cosine frequency offset frequency control array beam is eliminated, and the width of the beam distance dimension is further reduced
In a preferred implementation manner of the application, the corresponding beam width adjustment parameters are selected from the largest monotonic interval in the monotonic intervals of the reference beam width so as to ensure the cosine frequency offset calculated by adopting the cosine function summation form, and the slope-controllable cosine frequency offset is obtained through shift operation according to the selected reference number, thereby realizing the purpose of freely controlling the beam angle-distance dimension direction of the frequency control array and further improving the beam controllability and the detection precision.
Drawings
The advantages of the foregoing and/or additional aspects of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic flow chart of a cosine frequency offset frequency-controlled array beam synthesis method according to one embodiment of the present application;
FIG. 2 is a graph of correspondence between adjustment parameters and reference beamwidth in accordance with one embodiment of the present application;
FIG. 3 is a plot of predicted pattern slope versus reference number according to one embodiment of the application;
FIG. 4 is a frequency offset simulation diagram of a cosine frequency offset coefficient according to one embodiment of the present application;
FIG. 5 is a wave velocity pattern simulation diagram of a cosine frequency offset coefficient according to one embodiment of the present application;
FIG. 6 is a frequency offset simulation diagram of a cosine frequency offset according to one embodiment of the present application;
FIG. 7 is a wave velocity pattern simulation diagram of a cosine frequency offset according to one embodiment of the present application;
FIG. 8 is a frequency offset simulation diagram of a slope-controllable cosine frequency offset in accordance with an embodiment of the present application;
FIG. 9 is a wave velocity pattern simulation diagram of a slope-controllable cosine frequency offset in accordance with an embodiment of the present application;
FIG. 10 is an enlarged view of a main lobe according to one embodiment of the application, reference number 3;
fig. 11 is an enlarged view of a main lobe according to one embodiment of the application, reference number 6.
Detailed Description
In order that the above-recited objects, features and advantages of the present application will be more clearly understood, a more particular description of the application will be rendered by reference to the appended drawings and appended detailed description. It should be noted that, without conflict, embodiments of the present application and features in the embodiments may be combined with each other.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited to the specific embodiments disclosed below.
As shown in fig. 1, this embodiment provides a cosine frequency offset frequency control array beam synthesis method, which is applicable to a frequency control array antenna, where a plurality of array elements are disposed in the frequency control array, and the method includes:
Step 1, confirming a cosine frequency offset coefficient of a frequency control array according to array element numbers, accumulating and summing the cosine frequency offset coefficient according to preset sequence numbers, and marking accumulated and summed results as cosine frequency offset;
specifically, the cosine frequency offset coefficient in this embodiment is set as follows:
wherein M is the number of array elements, m=0, 1.
Those skilled in the art will appreciate that the cosine frequency offset coefficient Δf a (m) is characterized by: the frequency deviation is alternately increased and decreased for two times, and the corresponding cosine frequency deviation is periodically increased and decreased along with the increase of the sequence number of the array element.
According to the law of frequency control array frequency offset design, the frequency offset is alternately lifted, the distance dimension beam width can be reduced, the characteristic can be enhanced by periodic lifting frequency offset, and the problem caused by the periodic lifting frequency offset is that the beam pattern has periodicity.
Therefore, in order to solve the problem of beam pattern periodicity, the embodiment selects a specific cosine frequency offset coefficient for accumulation and summation, and because the cosine frequency offset coefficients participating in summation are selected to have different periods, the obtained cosine frequency offset is ensured to be in ascending and descending alternation, the obtained cosine frequency offset is ensured to be non-periodic, and the problem of beam pattern periodicity is solved.
Further, the accumulating and summing is performed according to the preset sequence number and the cosine frequency offset coefficient, which specifically comprises the following steps:
Step 11, selecting the greatest common divisor of the preset sequence numbers and the beam width adjusting parameter alpha as the sequence number of the preset value, and marking the sequence number as the summation sequence number; the preset value can be set according to actual requirements, and in order to highlight the aperiodicity of the cosine frequency offset, the preset value is set to be 1 in this embodiment.
Preferably, the present embodiment further provides a process for calculating the beam width adjustment parameter α, which specifically includes:
Step 111, calculating reference cosine frequency deviation corresponding to each adjustment parameter and reference beam width corresponding to each reference cosine frequency deviation in a parameter range in a traversal mode, wherein the reference beam width is 3dB beam width;
Specifically, the set parameter range is [12, 53], and the cosine frequency offset and the corresponding reference beam width corresponding to each adjustment parameter are calculated in a traversing manner.
Note that, the method of calculating the reference beam width in this embodiment is not limited, and a conventional method of calculating the 3dB beam width may be used, and the calculated 3dB beam width is used as the reference beam width, and the calculation result is shown in table 1.
TABLE 1
Therefore, a correspondence curve between the adjustment parameter and the reference beam width can be obtained, and as shown in fig. 2, each monotonic section in the correspondence curve, including a monotonic increasing section and a monotonic decreasing section, can be obtained by analyzing the correspondence curve.
Step 112, selecting the largest monotonic interval among the monotonic intervals of the reference beam widths, selecting the reference beam width closest to the target beam width in the largest monotonic interval, and recording the adjustment parameter corresponding to the selected reference beam width as the beam width adjustment parameter, wherein the target beam width is a set value and can be set according to the actual requirement.
Specifically, the largest monotonic interval including the largest value range of the adjustment parameter is selected from the obtained monotonic intervals, and the interval may be a monotonic increasing interval or a monotonic decreasing interval.
In a preferred implementation manner of this embodiment, in order to ensure the validity of each beam width value in the selected maximum monotonic interval, the cosine frequency offset corresponding to the selected beam width adjustment parameter is located in the monotonic interval, so that a preset protection parameter is set, and the value thereof may be 1, at this time, after selecting the maximum monotonic interval in the monotonic intervals of the reference beam width, the maximum monotonic interval is adjusted according to the preset protection parameter so as to reduce the maximum monotonic interval, and the maximum monotonic interval is adjusted to [ α 1+1,α2 -1], so that the finally selected interval is the reduced maximum monotonic interval [ α 1,α2 ] = [28, 33].
If the two monotone sections have the same range, a section with a smaller value of the adjustment parameter is selected as the largest monotone section selected.
Thereafter, the reference beam widths corresponding to the respective adjustment parameters in the selected maximum monotonic interval are determined as shown in table 2.
TABLE 2
In this embodiment, the target beam width is set to 1.00km, and in the interval [ α 1,α2 ] = [28, 33], the reference beam widths closest thereto are respectively 0.94km and 1.06km, and the corresponding adjustment parameters are 29 and 30, so that the beam width adjustment parameters may be set to any one of 29 and 30, that is, α=29 or α=30.
Step 12, performing multiplication transformation on the cosine frequency offset coefficient according to the summation sequence number and the frequency offset step length, and calculating the cosine frequency offset according to the result of the multiplication transformation in a cumulative summation mode, wherein a preset value is set to be 1, and a calculation formula of the cosine frequency offset is as follows:
Wherein Δf b (M) is cosine frequency offset, M is array element number, m=0, 1,..m-1, M is array element number in frequency control array, n is preset sequence number, α is beam width adjustment parameter, gcd (n, α) =1 is greatest common divisor filter function, and Δf is frequency offset step size.
It should be noted that the sum-and-algebraic operation is performed by the Ramahogany algebraThe method is a number theory function, and is characterized in that the summation result has orthogonality, so that the cosine frequency offset can be ensured to have stronger uncorrelation, and further, the synthesized wave beam does not have a periodic structure.
And 2, performing shift operation on the cosine frequency offset according to the reference number, marking a shift operation result as slope-controllable cosine frequency offset, and calculating the cosine frequency and the phase of the frequency control array according to the slope-controllable cosine frequency offset and the array element position.
Note that, the reference numerals in this embodiment are determined by the predicted pattern slope, and the specific process is not limited. The nearest expected pattern slope can be selected from the comparison table of the beam pattern slope and the reference number according to the expected beam pattern slope, and the corresponding reference number is searched for as the reference number in the step 2, wherein the comparison table of the beam pattern slope and the reference number can be determined according to historical experience, the number of array elements, the accuracy requirement and the like.
The comparison table of the beam pattern slope and the reference number in this embodiment is shown in table 3.
TABLE 3 Table 3
| Reference numerals | Beam pattern slope k |
| i＝1 | -15.0°/5km |
| i＝2 | -12.0°/5km |
| i＝3 | -8.0°/5km |
| i＝4 | -7.5°/5km |
| i＝5 | -1.5°/5km |
| i＝6 | 0.0°/5km |
| i＝7 | 2.5°/5km |
| i＝8 | 4.5°/5km |
| i＝9 | 8.0°/5km |
| i＝10 | 11.5°/5km |
| i＝11 | 12.0°/5km |
| i＝12 | 15.0°/5km |
That is, when the desired beam pattern slope is 3 °/5km, the beam pattern slope 2.5 °/5km is selected as the predicted pattern slope in table 3, and the corresponding number i=7 is used as the reference number.
When the reference number is determined according to the slope of the predicted pattern, the reference number can also be determined according to a corresponding relation curve, as shown in fig. 3, the corresponding relation curve is a monotonically increasing curve, the curve can be formed by interpolation fitting according to the rule of the slope and the reference number, and then the reference number is determined according to the slope of the predicted pattern.
Note that, the value of the reference number i is related to the positive and negative of the beam pattern slope, and the corresponding relationship is as follows:
Reference numerals When the cosine frequency offset frequency control array beam pattern slope is positive, the beam pointing direction is the positive direction angle direction, wherein,To round the symbol up.
Reference numeralsWhen the slope of the cosine frequency offset frequency control array beam pattern is zero, the beam pointing direction does not change along with the distance.
Reference numeralsAnd when the cosine frequency offset frequency control array beam pattern slope is negative, the beam pointing direction is a negative direction angle direction.
In this embodiment, the calculation formula of the slope-controllable cosine frequency offset is:
Δfc(m)＝circshift[Δfb(m)，i]
Wherein Δf c (m) is a slope-controllable cosine frequency offset, Δf b (m) is a cosine frequency offset, m is an array element number, circshift [ ] is a right cyclic shift function, namely circshift [ Δf b (m), i ] represents that the cosine frequency offset Δf b (m) is circularly shifted to the right by i bits, i is a reference number.
Further, the calculation formula of the cosine frequency f c (m) is:
fc(m)＝f0+Δfc(m)
Phase of phase The calculation formula of (2) is as follows:
Wherein r 0 is the coherent distance of the coherent point, c is the speed of light, x m is the position of the array element with the array element number m, x 0 is the position of the array element of the reference array element, θ 0 is the coherent angle of the coherent point, and f 0 is the reference frequency of the frequency control array.
And step 3, determining a cosine frequency offset frequency control array beam of the frequency control array according to the cosine frequency and the phase correlation.
Specifically, according to the array signal processing theory and the array element position in the frequency control array, the corresponding cosine frequency offset frequency control array beam can be deduced from the calculated cosine frequency and the phase correlation, and the specific process is not repeated.
On the basis of the embodiment, the method further comprises: according to the slope controllable cosine frequency offset, calculating a wave speed direction diagram of the frequency control array and a wave speed width corresponding to the wave speed direction diagram, wherein a calculation formula corresponding to the wave speed direction diagram P c (theta, r) is as follows:
Wherein θ is the observation angle, r is the observation distance, M is the element number, m=0, 1, & gt, M-1, M is the number of elements in the frequency control array, c is the speed of light, Δf c (M) is the slope-controllable cosine frequency offset, f 0 is the reference frequency of the frequency control array, x m is the element position of element number M, x 0 is the element position of the reference element, Is the phase of the phase.
In order to verify the above method in this embodiment, the number of array elements m=12, the reference frequency f 0 =2 GHz, the coherent distance r 0 =30 km of the coherent point, the coherent angle θ 0 =50°, and the array element positions with the array element numbers M are:
xm＝m×0.5λ0
Where the reference wavelength lambda 0 = 0.15m.
The observation airspace is as follows: the range of the observation distance r is more than 0km and less than 100km, and the range of the observation angle theta is more than-90 DEG and less than 90 deg.
As shown in fig. 4 and 5, the calculation results corresponding to the cosine frequency offset coefficient Δf a (m) are shown in table 4.
TABLE 4 Table 4
At this time, the corresponding wave velocity pattern expression is:
Wherein θ is an observation angle, r is an observation distance, x m is an array element position, and c is a light velocity.
Corresponding beam coherent phaseThe method comprises the following steps:
Wherein r 0 is a coherent distance, and θ 0 is a coherent angle.
According to the wave velocity direction diagram P a (theta, r) of the cosine frequency offset coefficient, the corresponding cosine frequency offset coefficient frequency control array beam width r a can be calculated.
Note that, the beam width in this embodiment refers to a width corresponding to a decrease of 3dB in the maximum amplitude of the main beam of the beam pattern in the distance dimension, and the calculation process is as follows:
The maximum value of the main lobe of the cosine frequency offset coefficient frequency control array beam pattern P a (theta, r) is A p, the first A p/2 value position is searched for in the positive direction and the negative direction of the distance dimension from the position of the maximum value A p of the main lobe of the distance dimension, wherein the position of the A p/2 value in the positive direction of the distance dimension is marked as A 1, the position of the negative A p/2 value is marked as A 2, and therefore, the cosine frequency offset coefficient frequency control array beam width r a＝A2-A1.
The calculated result of the beam width r a of the cosine frequency offset coefficient frequency control array is r a =7.95 km.
Similarly, in this embodiment, the beam width adjustment parameter α=29 is taken as an example, and as shown in fig. 6 and 7, the calculation result corresponding to the cosine frequency offset Δf b (m) is shown in table 5.
TABLE 5
| Cosine frequency offset | Value taking |
| Δfb(0) | 8.7kHz |
| Δfb(1) | 5.0kHz |
| Δfb(2) | -10.0kHz |
| Δfb(3) | 5.0kHz |
| Δfb(4) | -8.7kHz |
| Δfb(5) | 20.0kHz |
| Δfb(6) | -10.0kHz |
| Δfb(7) | -5.0kHz |
| Δfb(8) | 10.0kHz |
| Δfb(9) | -10.0kHz |
| Δfb(10) | -18.7kHz |
| Δfb(11) | 40.0kHz |
At this time, the corresponding wave velocity pattern expression is:
corresponding beam coherent phase The method comprises the following steps:
The calculated beam width r b =9.81 km.
As shown in fig. 8 and 9, two sets of reference numbers, i=3 and i=6, respectively, are selected. The calculation results corresponding to the slope-controllable cosine frequency offset Deltaf c (m) are shown in Table 6.
TABLE 6
At this time, the corresponding wave velocity pattern expression is:
corresponding beam coherent phase The method comprises the following steps:
Since the value of the reference number i is related to the positive and negative of the beam pattern slope, for reference number i=3, the reference number is satisfied In fig. 9 (a), the slope of the cosine frequency offset frequency control array beam pattern is positive, the beam pointing direction is the positive direction angle direction, and the corresponding beam width r c =9.81 km can be seen.
As shown in FIG. 10, the slope of the main lobe of the beam is marked by a dotted line, the slope of the beam pattern of the cosine frequency offset frequency control array is negative, the beam pointing direction is a negative direction angle direction, and the slope of the beam pointing direction is-8 degrees/5 km.
For reference number i=6, the reference number is satisfiedIn fig. 9 (b), the slope of the cosine frequency offset frequency control array beam pattern is zero, the beam pointing direction does not change with distance, and the corresponding beam width r c =9.81 km.
As shown in FIG. 11, the slope of the main lobe of the beam is marked by a dotted line, the slope of the beam pattern of the cosine frequency offset frequency control array is zero, and the direction of the beam is not changed along with the distance. The beam slope was 0/5 km.
The technical scheme of the application is explained in detail with reference to the attached drawings, and the application provides a cosine frequency offset frequency control array beam synthesis method, which comprises the following steps: step 1, confirming a cosine frequency offset coefficient of a frequency control array according to array element numbers, accumulating and summing the cosine frequency offset coefficient according to preset sequence numbers, and marking accumulated and summed results as cosine frequency offset; step 2, performing shift operation on the cosine frequency offset according to a reference number, marking a shift operation result as slope-controllable cosine frequency offset, and calculating cosine frequency and phase correlation of the frequency control array according to the slope-controllable cosine frequency offset and the array element position, wherein the reference number is determined by the slope of the predicted directional diagram; and step 3, determining a cosine frequency offset frequency control array beam of the frequency control array according to the cosine frequency and the phase correlation. By the technical scheme, the frequency offset frequency control array beam width is reduced, and the beam controllability and the detection accuracy are improved.
The steps in the application can be sequentially adjusted, combined and deleted according to actual requirements.
The units in the device can be combined, divided and deleted according to actual requirements.
Although the application has been disclosed in detail with reference to the accompanying drawings, it is to be understood that such description is merely illustrative and is not intended to limit the application of the application. The scope of the application is defined by the appended claims and may include various modifications, alterations and equivalents of the application without departing from the scope and spirit of the application.
Claims (5)
1.A cosine frequency offset frequency control array beam synthesis method is characterized by comprising the following steps:
Step 1, confirming a cosine frequency offset coefficient of a frequency control array according to array element numbers, accumulating and summing the cosine frequency offset coefficient according to preset sequence numbers, and marking accumulated and summed results as cosine frequency offset;
step 2, performing shift operation on the cosine frequency offset according to a reference number, marking a shift operation result as slope-controllable cosine frequency offset, and calculating cosine frequency and phase-coherent phase of the frequency control array according to the slope-controllable cosine frequency offset and the array element position, wherein the reference number is determined by the slope of the predicted directional diagram;
step 3, according to the cosine frequency and the phase, determining the cosine frequency offset frequency control array beam of the frequency control array,
In the step 1, the accumulating and summing is performed according to a preset sequence number and the cosine frequency offset coefficient, which specifically includes:
Step 11, selecting the greatest common divisor of the preset sequence numbers and the beam width adjustment parameter alpha as the sequence number of the preset value, and marking the sequence number as the summation sequence number;
Step 12, multiplying the cosine frequency offset coefficient according to the summation sequence number and the frequency offset step length, calculating the cosine frequency offset according to the result of the multiplying transformation by adopting a mode of accumulating and summing,
The preset value is 1, and the calculation formula of the cosine frequency offset is as follows:
wherein Δf b (M) is the cosine frequency offset, M is the number of array elements, m=0, 1, …, M-1, M is the number of array elements in the frequency control array, n is a preset sequence number, α is the beam width adjustment parameter, gcd (n, α) =1 is the greatest common divisor filtering function, and Δf is the frequency offset step size;
the calculation process of the beam width adjustment parameter alpha specifically comprises the following steps:
Step 111, calculating reference cosine frequency deviation corresponding to each adjustment parameter and reference beam width corresponding to each reference cosine frequency deviation in a parameter range in a traversal mode, wherein the reference beam width is 3dB beam width;
Step 112, selecting the largest monotonic interval among the monotonic intervals of the reference beam widths, selecting the reference beam width closest to the target beam width from the largest monotonic interval, and recording the adjustment parameters corresponding to the selected reference beam width as the beam width adjustment parameters.
2. The method of cosine frequency offset frequency control array beam synthesis according to claim 1, wherein selecting a largest monotonic interval among the monotonic intervals of the reference beam widths, and selecting a reference beam width closest to a target beam width among the largest monotonic intervals, specifically further comprising:
Selecting the largest monotonic interval in the monotonic intervals of the reference beam width;
according to preset protection parameters, the maximum monotonic interval is adjusted so as to reduce the maximum monotonic interval;
And selecting the reference beam width closest to the target beam width in the reduced maximum monotonic interval.
3. The method of cosine frequency offset frequency-controlled array beam synthesis as set forth in claim 1, wherein in the step 2, the calculation formula of the slope-controllable cosine frequency offset is:
Δfc(m)＝circshift[Δfb(m),i]
Wherein Δf c (m) is the slope-controllable cosine frequency offset, circshift [ ] is a right cyclic shift function, Δf b (m) is the cosine frequency offset, m is an array element number, and i is a reference number.
4. The method of cosine frequency offset frequency array beam synthesis as set forth in claim 3, wherein in the step 2, a calculation formula of the cosine frequency f c (m) is:
fc(m)＝f0+Δfc(m)
The phase of the phase The calculation formula of (2) is as follows:
Wherein r 0 is the coherent distance of the coherent point, c is the light speed, x m is the array element position with the array element number m, x 0 is the array element position of the reference array element, θ 0 is the coherent angle of the coherent point, and f 0 is the reference frequency of the frequency control array.
5. The cosine frequency offset frequency control array beam synthesis method according to any one of claims 1 to 4, further comprising:
According to the slope controllable cosine frequency offset, calculating a wave speed direction diagram of the frequency control array and a wave speed width corresponding to the wave speed direction diagram, wherein a calculation formula corresponding to the wave speed direction diagram P c (theta, r) is as follows:
wherein θ is an observation angle, r is an observation distance, M is an element number, m=0, 1, …, M-1, M is the number of elements in the frequency control array, c is a light speed, Δf c (M) is the slope-controllable cosine frequency offset, f 0 is a reference frequency of the frequency control array, x m is an element position of element number M, x 0 is an element position of reference element, Is the phase of the phase.
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| CN108196231A (en) * | 2018-03-26 | 2018-06-22 | 电子科技大学 | A kind of S-shaped interfering beam implementation method based on novel frequency control battle array technology |
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| CN108196231A (en) * | 2018-03-26 | 2018-06-22 | 电子科技大学 | A kind of S-shaped interfering beam implementation method based on novel frequency control battle array technology |
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