CN116299201A - Frequency control array antenna based on image double wave mixing and target detection method - Google Patents

Frequency control array antenna based on image double wave mixing and target detection method Download PDF

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CN116299201A
CN116299201A CN202211534615.3A CN202211534615A CN116299201A CN 116299201 A CN116299201 A CN 116299201A CN 202211534615 A CN202211534615 A CN 202211534615A CN 116299201 A CN116299201 A CN 116299201A
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frequency
signal
signals
frequency control
array
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朱睿
刘宇
刘泉华
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Beijing Institute of Technology BIT
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Beijing Institute of Technology BIT
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/282—Transmitters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/42—Simultaneous measurement of distance and other co-ordinates
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/411—Identification of targets based on measurements of radar reflectivity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Abstract

The invention discloses a frequency control array antenna based on image double wave mixing, wherein the peak value of a frequency control array radiation waveform is discrete in the angle direction, so that the distance of a target can be measured only according to the echo time of the peak value waveform, and the azimuth angle of the target can be obtained through configuration of the array phase. The method solves the problem that the traditional frequency control array cannot distinguish the target distance and angle information, and can enhance the detection capability of the radar based on the frequency control array; the target detection method can directly form the periodically transmitted pulse radar-like waveform by using a plurality of single-frequency wave signals, and does not need a complex frequency synthesis and intermediate frequency signal generation system. Meanwhile, the problem that the distance and angle information of the traditional frequency control array are difficult to separate is solved.

Description

Frequency control array antenna based on image double wave mixing and target detection method
Technical Field
The invention belongs to the technical field of frequency control array antennas, and particularly relates to a frequency control array antenna based on image double-wave mixing and a target detection method.
Background
The frequency control array is a special antenna array, wherein each antenna unit transmits radio frequency signals with different frequencies according to a certain rule, so that wave beams in the space can be related to propagation distance, propagation angle and propagation time, and the target resolution, crosstalk resistance and other capacities of the radar can be enhanced. However, unlike conventional phased arrays that employ a uniform frequency source to drive the antenna, frequency controlled arrays require the production of multiple frequency signals, and the initial phase of each signal typically needs to be kept consistent or with a specific distribution, which presents challenges for implementing a frequency controlled array. In a typical implementation method of a frequency control array, a plurality of coherent frequency sources are required to generate a required frequency, so that a signal generating system is complex, and an initial phase relationship between each channel is difficult to guarantee. In a classical frequency control array, the frequencies of the antenna units are distributed in an arithmetic progression, and the peak value of the generated radiation pattern is presented as a curve related to both distance and angle, so that the angular position of the target cannot be clearly determined by using the peak echo time of the pattern as target detection. In some more intensive frequency-controlled array studies, a radiation intensity peak fixed at a specific distance and angle can be achieved by making specific changes in the radiation frequency of each antenna over time. However, this method requires more accurate control of the radiation waveforms of the respective antennas, which is difficult to realize in engineering.
Disclosure of Invention
Therefore, the invention aims to provide a frequency control array antenna based on image double wave mixing and a target detection method, wherein two image frequency control array signals with opposite frequency change trends form interference in space, so that amplitude peaks of array radiation signals only propagate in a specific angle direction, the ambiguity in the distance and the angle direction is eliminated, and the radar detection capability is improved.
A frequency control array antenna comprises two groups of signal generating units;
the frequency of the signals generated by the first group of signal generating units on each node is from f 0 Starting, gradually increasing from left to right according to the frequency step delta f; at the nth node, the frequency of the signal unit is f 0 ++ (n-1) Δf; and the initial phase difference between adjacent nodes generating signals is
Figure BDA0003970594290000011
The frequency of the signal generated by the second group signal generating unit at each node is equal to the frequency of the signal generated by the second group signal generating unit at each node 0 Starting, gradually reducing from left to right according to the frequency step delta f; at the nth node, the frequency of the signal unit is f 0 - (n-1) Δf; and the initial phase difference between adjacent nodes generating signals is
Figure BDA0003970594290000012
And superposing signals corresponding to the same node serial number generated by the two groups of signal units, and radiating the signals through an antenna.
Preferably, the spacing between adjacent antennas is d equal to lambda/2, lambda being the frequency f 0 Is in free space.
A target detection method based on a frequency control array antenna comprises the following steps:
(1) Selecting a phase
Figure BDA0003970594290000021
The two groups of signal generating units respectively generate signals and radiate the signals through the antenna;
(2) Echo signals are measured by a wide beam receiving antenna, and if the detected echo signal peaks, this is indicated in
Figure BDA0003970594290000022
The presence of a target in the direction;
(3) Measuring the first peak time t r The target to antenna array distance is then:
R＝c·t r /2
(4) If no echo peak is detected, other phases are selected
Figure BDA0003970594290000023
Repeating (1) - (3).
The invention has the following beneficial effects:
according to the frequency control array antenna based on image double wave mixing, the peak value of the frequency control array radiation waveform is discrete in the angle direction, so that the distance of a target can be measured only according to the echo time of the peak value waveform, and meanwhile, the azimuth angle of the target can be obtained through configuration of the array phase. The invention solves the problem that the traditional frequency control array can not distinguish the target distance and angle information, and can enhance the detection capability of the radar based on the frequency control array.
The target detection method can directly form the periodically transmitted pulse radar-like waveform by using a plurality of single-frequency wave signals, and does not need a complex frequency synthesis and intermediate frequency signal generation system. Meanwhile, the problem that the distance and angle information of the traditional frequency control array are difficult to separate is solved.
Drawings
Fig. 1 is a schematic diagram of a frequency control array antenna according to the present invention;
figure 2 shows an antenna array of 16 nodes at deltaf=67,
Figure BDA0003970594290000024
normalized radiation waveform at that time;
fig. 3 and 4 are waveform diagrams when the waveforms propagate forward for t=2.01s and t=2.02s, respectively.
Detailed Description
The invention will now be described in detail by way of example with reference to the accompanying drawings.
As shown in fig. 1, the frequency control array antenna of the present invention includes two sets of signal generating units. In the first group, the frequency of the signal unit is from f 0 Starting, gradually increasing from left to right according to the frequency step delta f; at the nth node, the frequency of the signal unit is f 0 ++ (n-1) Δf; if the array length is N, the frequency of the last node is f 0 +(N-1)Δf。
In another group, the frequency of the signal unit is from f 0 Starting, gradually reducing from left to right according to the frequency step delta f; at the nth node, the frequency of the signal unit is f 0 - (n-1) Δf; if the array length is N, the frequency of the last node is f 0 -(n-1)Δf。
Wherein f 0 Δf and
Figure BDA0003970594290000031
the value of (2) is not strictly limited, and can be arbitrarily selected. But require->
Figure BDA0003970594290000032
The initial frequencies of the two sets of signal units are identical, the frequency steps are identical, but the frequency change directions are opposite.
The array lists the frequency distributions and also has specific phase characteristics. Between two nodes, the initial frequency difference of two adjacent signal units is as follows for two groups of signal units
Figure BDA0003970594290000033
On each node, the output signals of the corresponding two groups of signal units are superimposed: at the first node, the first group of cells has a frequency f 0 The same frequency as the second group of units is f 0 Is added to the signals of (a); at the nth node, the first group of cell frequencies is f 0 The signal of + (n-1) Δf is f as the second group of cell frequencies 0 The signals of- (n-1) Δf are added.
And the signals overlapped by the nodes are radiated out through the antennas of the nodes. The spacing of adjacent antennas is d. Typically d is equal to λ/2, λ being the frequency f 0 Is in free space.
For the first forward increasing frequency array, the signal of its nth antenna element can be expressed as:
Figure BDA0003970594290000034
Figure BDA0003970594290000035
here, the
Figure BDA0003970594290000036
Is adjacent to the nodeThe initial phase difference of the points, Φ, is the fixed phase difference that occurs during signal generation, which is a constant.
At time t, the array factor at a distance R from the antenna array position, offset from the array normal θ, can be calculated by summing the radiation fields of all the elements. For an array with increasing forward frequency, its array factor can be written as:
Figure BDA0003970594290000037
Figure BDA0003970594290000038
here beta n ＝2πf n The wave number of the electromagnetic wave of the corresponding frequency of the nth unit in the free space is given by c, which is the speed of light.
For an array of decreasing frequency, the signal of its nth antenna element can be expressed as:
Figure BDA0003970594290000039
Figure BDA00039705942900000310
at time t, the array factor at a distance R from the antenna array position, offset from the array normal θ, can be calculated by summing the radiation fields of all the elements. For an array of decreasing frequency, its array factor can be written as:
Figure BDA00039705942900000311
Figure BDA00039705942900000312
Figure BDA0003970594290000041
the phase difference of adjacent units in the two arrays is ensured to be consistent through phase control
Figure BDA0003970594290000042
The array factors of the two arrays are added to obtain the total array factor:
Figure BDA0003970594290000043
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure BDA0003970594290000044
Figure BDA0003970594290000045
here:
ω RF ＝2πf 0
the above equation shows that electromagnetic waves generated by two sets of signal units interfere.
The meaning of each parameter appearing in the above formula is as follows:
t is the time of observation; the distance between the R observation point and the first unit in the center of the array; θ represents the angle of the observation point relative to the array method phase; f (f) 0 Representing the center frequency; Δf represents the frequency difference of adjacent cells; beta n Representing the propagation wave number of the electromagnetic wave with the frequency corresponding to the nth unit in the corresponding array in the free space; c represents the speed of light; d represents the spacing of adjacent antenna elements;
Figure BDA0003970594290000046
representing the initial phase difference of adjacent cells.
According to the above-mentioned theory,the relationship between the radiation intensity and the distance, the angle and the propagation time of the frequency control array proposed by the invention can be obtained, and as shown in fig. 2, an array of 16 nodes, Δf=67,
Figure BDA0003970594290000047
normalized radiation waveform at that time.
The bright spots in fig. 2 represent peaks of the composite radiation signal, which occur at specific angles. After a certain time, the upper waveform propagates forward as shown in fig. 3 and 4.
The visible waveform propagates in a far-distance direction.
By changing
Figure BDA0003970594290000048
The propagation angle of the beam peak can be controlled and can be calculated by the following formula:
Figure BDA0003970594290000049
wherein K is an integer.
And at time t, the conditions for the occurrence of the beam peak are:
Figure BDA00039705942900000410
in the above formula, L is an integer.
Based on the characteristics of the array, the detection of the distance and the azimuth angle of the target can be realized, and the specific flow is as follows:
(1) Selecting a phase
Figure BDA0003970594290000051
The antenna beam is then along +.>
Figure BDA0003970594290000052
The angle propagates.
(2) The echo signal is measured by a wide beam receiving antenna and if the detected microwave signal peaks, it is indicated that there is an object in this direction.
(3) Measuring the first peak time t r The target to antenna array distance is then:
R＝c·t r /2
(4) If no echo peak is detected, other phases are selected
Figure BDA0003970594290000053
Repeating (1) - (3).
The method has the advantage that the method can directly form the periodically transmitted pulse radar-like waveform by using a plurality of single-frequency wave signals without complex frequency synthesis and an intermediate frequency signal generation system. Meanwhile, the problem that the distance and angle information of the traditional frequency control array are difficult to separate is solved.
From the above beam characteristics, it is known. The peak value of the frequency control array radiation waveform is discrete in the angle direction, so that the distance of the target can be measured only according to the echo time of the peak value waveform, and the azimuth angle of the target can be obtained through the configuration of the array phase. The invention solves the problem that the traditional frequency control array can not distinguish the target distance and angle information, and can enhance the detection capability of the radar based on the frequency control array.
In summary, the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (3)

1. The frequency control array antenna is characterized by comprising two groups of signal generating units;
the frequency of the signals generated by the first group of signal generating units on each node is from f 0 Starting, gradually increasing from left to right according to the frequency step delta f; at the nth node, the frequency of the signal unit is f 0 ++ (n-1) Δf; and the initial phase difference between adjacent nodes generating signals is
Figure FDA0003970594280000011
The frequency of the signal generated by the second group signal generating unit at each node is equal to the frequency of the signal generated by the second group signal generating unit at each node 0 Starting, gradually reducing from left to right according to the frequency step delta f; at the nth node, the frequency of the signal unit is f 0 - (n-1) Δf; and the initial phase difference between adjacent nodes generating signals is
Figure FDA0003970594280000012
And superposing signals corresponding to the same node serial number generated by the two groups of signal units, and radiating the signals through an antenna.
2. A frequency controlled array antenna according to claim 1, wherein adjacent antennas are spaced apart by a distance d equal to λ/2, λ being the frequency f 0 Is in free space.
3. A method of target detection based on the frequency controlled array antenna of claim 1, comprising:
(1) Selecting a phase
Figure FDA0003970594280000013
The two groups of signal generating units respectively generate signals and radiate the signals through the antenna;
(2) Echo signals are measured by a wide beam receiving antenna, and if the detected echo signal peaks, this is indicated in
Figure FDA0003970594280000014
The presence of a target in the direction;
(3) Measuring the first peak time t r The target to antenna array distance is then:
R＝c·t r /2
(4) If no echo peak is detected, other phases are selected
Figure FDA0003970594280000015
Repeating (1) - (3).
CN202211534615.3A 2022-11-29 2022-11-29 Frequency control array antenna based on image double wave mixing and target detection method Pending CN116299201A (en)

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