Phased array dynamic wave control method with low sidelobe and directional signal modulation

Abstract

The invention provides a phased array dynamic wave control method with low sidelobe and directional signal modulation. The method comprises the following steps: firstly, determining a phase modulation vector and an amplitude modulation vector of a signal directional time domain according to a phased array; setting a main lobe interval and a side lobe interval, and establishing a dynamic airspace response according to the main lobe interval and the side lobe interval; constructing a dynamic wave control weight optimization function, minimizing the optimization function through a global optimization algorithm, and solving an optimal wave control weight estimation value; and finally, applying the obtained optimal wave control weight to a receiving and transmitting channel of the phased array. According to the phased array dynamic wave control method provided by the invention, the wave control freedom degree of the time domain can be utilized, and the formed wave beam sidelobe level is reduced along with the increase of the pulse accumulation number.

Description

Technical Field

[0001] The present invention belongs to the field of electronic information technology, especially the field of phased array and array signal processing technology, and particularly relates to designing phased array wave control weights by using array signal processing methods, specifically a phased array dynamic wave control method with both low sidelobe and directional signal modulation. Background Art

[0002] Phased array technology refers to the process of controlling the amplitude and phase of multiple sensor elements to synthesize the signals of multiple elements, form a pre-set synthetic beam, and enhance or weaken the signal in a specific direction. Phased arrays are widely used in radar, wireless communication, microphones, medical diagnosis, radio astronomy and other fields. For example, using phased array technology, radars in the military field can achieve fast electronic scanning of beams, avoiding time-consuming traditional mechanical scanning. For another example, the current fifth-generation mobile communications and the future sixth-generation mobile communications use phased array technology at the base station end to achieve multi-user wavelength division multiplexing and improve the spectrum efficiency of the communication system. Phased arrays can work in the transmitting and receiving states. Compared with a single element, a phased array has higher amplitude and phase degrees of freedom and can synthesize any beam. The amplitude and phase of a single sensor in a phased array are the key parameters for achieving beam control, where the amplitude and phase are collectively referred to as weights. The control of the amplitude and phase of all elements is generally called beam control.

[0003] Low sidelobe technology in phased arrays refers to making the sidelobe level of the beam as low as possible below the mainlobe level. This is because the mainlobe of the beam points to the location of the target, while the sidelobe will be away from the target and may point to interference. Therefore, reducing the sidelobe level is conducive to reducing interference and improving the signal-to-noise ratio of the mainlobe received signal. For example, radar can suppress sidelobe clutter and intentional or unintentional interference from the sidelobe by reducing the sidelobe technology. Wireless communication can reduce interference between different users through low sidelobe technology. Traditional low sidelobe wave control methods include window function method, convex optimization-based pattern synthesis method, and global optimization-based pattern synthesis method. Among them, the window function method can directly obtain the weight parameters in analytical form, but it is generally only applicable to uniform arrays. Convex optimization method and global optimization method require iterative solution, which means that the computational complexity of both is high. The computational complexity of convex optimization is less than that of global optimization, but the application range of global optimization is wider than that of convex optimization.

[0004] The above three wave control methods can meet the application of general scenarios, but they all have a common feature, that is, the wave control weight remains fixed within a working cycle. For radar, a working cycle refers to a coherent processing cycle. For wireless communication, a working cycle refers to the transmission cycle of a message. The wave control weight remains unchanged, which means that on the one hand, there is only a difference in amplitude between the main lobe and the side lobe, and on the other hand, the degree of freedom in the time domain is not utilized. The only difference in amplitude between the main lobe and the side lobe means that a high-sensitivity receiver can still receive the same information as the main lobe from the side lobe, or a high-power jammer can still make the signal entering from the side lobe interfere with the main lobe signal. How to use the degree of freedom in the time domain to further enhance the wave control performance of the phased array is rarely studied. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to propose a phased array dynamic wave control method with both low sidelobe and directional signal modulation.

[0006] In order to solve the above technical problems, the technical solution of the present invention is:

[0007] A phased array dynamic wave control method with low sidelobe and directional signal modulation comprises the following steps:

[0008] Step 1: Determine the directional time-domain amplitude and phase modulation parameters of the signal: The directional time-domain phase modulation vector is set to in, is the phase modulation vector The lth element of l=1,2,...,L, n is any integer, satisfying 1≤n≤L. The directional time-domain amplitude modulation vector is set to α=[α1,α2,...,α L ], where α l is the lth element of the amplitude modulation vector α. For wireless communication, L is equal to the base number of the code element. For radar, L is set to the number of pulses in the coherent processing cycle.

[0009] Step 2: Setting the main lobe interval and side lobe interval: Set the maximum main lobe gain direction to θ0. The main lobe interval is Ω g =[θ l ,θ u ], where θ0 is contained in the main lobe interval Ω g Inside, θ l is the minimum angle covered by the main lobe, θ u The maximum angle covered by the main lobe. The main lobe interval Ω g It can be determined according to the application scenario or directly selected as the 3dB beam range. The sidelobe interval is set to Ω s =[-90°,θ u ′]∪[θ l′,90°], where θ u ′ and θ l ′ is divided into two end angles of the sidelobe interval, and θ u ′≤θ l ,θ u ≤θ l ′.

[0010] Step 3: Dynamic spatial response modeling of the main lobe interval and the side lobe interval: Assume that the dynamic wave control weights are w1, w2, ..., w L ,in is the phased array wave control weight vector corresponding to the lth time domain modulation parameter, l=1,2,...,L, represents a complex vector with M rows and 1 column, and M represents the number of elements in a one-dimensional phased array. Then the corresponding weight w in the main lobe is l Dynamic spatial response F l (θ) is

[0011]

[0012] The corresponding weight w in the side lobe l The spatial response F l (θ′) is

[0013]

[0014] in, is the complex imaginary unit, (·) H represents the complex conjugate transpose, a(θ) is the array steering vector corresponding to the direction θ, which can be obtained according to the array geometric parameters and the signal wavelength.

[0015] Step 4: Design of dynamic wave control weight optimization function: Take L-1 groups of phase sequences φ m,l =2π(l-1)(m-1) / L, the mth phase sequence can be expressed as φ m,1 ,φ m,2 ,...,φ m,L , where l = 1, 2, ..., L, and m is any value in 1, 2, ..., L except n. Then L-1 groups of sequences exp(jφ m,1 ),exp(jφ m,2 ),...,exp(jφ m,L ) are all Orthogonal. Construct the following wave control weight optimization function:

[0016]

[0017] in,

[0018]

[0019] G main represents the main lobe gain after time domain accumulation, G ASL represents the spatial sidelobe gain after time domain accumulation, G DSL Represents the Doppler domain sidelobe gain after time domain accumulation. θ i Represents the main lobe interval Ω g The discretized i-th angle grid point, N θ Represents the main lobe interval Ω g The total number of grid points discretized. i ′ represents the main lobe interval Ω s The discretized i-th angle grid point, N θ′ Represents the main lobe interval Ω s The total number of grid points discretized. Coefficient D1 is used to set the optimization degree of the main lobe gain, coefficient D2 is used to set the optimization degree of the spatial side lobe gain, coefficient D3 is used to set the optimization degree of the signal time domain modulation directivity, and coefficient D4 is used to set the optimization degree of the signal time domain modulation quality.

[0020] Step 5: Minimize the optimization function: Obtain the optimal wave control weight estimate by minimizing the aforementioned wave control weight optimization function. Since the optimization function is complex and nonlinear, a global optimization algorithm is required.

[0021] Step 6: Dynamic wave control weight application: get the optimal weight Finally, it can be applied to the phased array transceiver channel.

[0022] Preferably, in step 6, for the communication system, The order of the messages to be sent is selected.

[0023] Preferably, in step 6, for the radar, before performing target detection, it is generally set α=[1,1,...,1], generate the corresponding The corresponding transmission and reception order can be arranged arbitrarily. After obtaining the prior information such as the target speed, the phase and amplitude information of each pulse can be obtained according to the speed, and then the corresponding and α, generating the corresponding The corresponding transmission and reception order cannot be changed.

[0024] As a preference, in step 4, the main lobe gain G after time domain accumulation is main Can also be changed to

[0025] Where max{·} means finding the maximum value of a set.

[0026] Preferably, in step 5, the global optimization algorithm may adopt a particle swarm algorithm or a genetic algorithm.

[0027] The present invention has the following characteristics and beneficial effects:

[0028] 1. The phased array dynamic wave control method proposed in the present invention can utilize the wave control freedom in the time domain, and the sidelobe level of the formed beam decreases as the number of pulse accumulation increases.

[0029] 2. The phased array dynamic wave control method proposed in the present invention can perform time domain amplitude and phase modulation on the signal in a specific direction, and the modulation information is disrupted in other directions, so it can be used to implement physical layer encryption of the communication channel.

[0030] 3. The phased array dynamic wave control method proposed in the present invention only performs specific amplitude and phase processing on the main lobe signal in the receiving state, while the signal entering from the side lobe will be converted into background noise due to the disrupted time domain amplitude and phase relationship, which is beneficial to resist side lobe clutter and side lobe interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 It is a flowchart of the overall process of the method of the present invention.

[0033] Figure 2 It is a schematic diagram of the directional 16-pulse constant amplitude and constant phase modulation performance of the method of the present invention.

[0034] Figure 3 It is a schematic diagram of the directional 32-pulse constant amplitude and constant phase modulation performance of the method of the present invention.

[0035] Figure 4 It is a schematic diagram of the directional 32-pulse constant amplitude linear phase modulation performance of the method of the present invention. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0037] Example 1

[0038] This embodiment provides a phased array dynamic wave control method with both low side lobe and directional signal modulation, such as Figure 1 As shown, the following steps are included:

[0039] Step 1: Determine the phase modulation vector and amplitude modulation vector of the signal directional time domain according to the phased array.

[0040] Specifically, the directional time-domain phase modulation vector is set to in, is the phase modulation vector The lth element of l=1,2,...,L, n is any integer, satisfying 1≤n≤L. The directional time-domain amplitude modulation vector is set to α=[α1,α2,...,α L ], where α l is the lth element of the amplitude modulation vector α.

[0041] In this embodiment, for wireless communication, L is equal to the base number of the code element.

[0042] Step 2: Set the main lobe interval and the side lobe interval, and establish a dynamic spatial domain response according to the main lobe interval and the side lobe interval.

[0043] Specifically, in this embodiment, the direction with the maximum main lobe gain is set to θ0. The main lobe interval is Ω g =[θ l ,θ u ], where θ0 is contained in the main lobe interval Ω g Inside, θ l is the minimum angle covered by the main lobe, θ u The maximum angle covered by the main lobe. The main lobe interval Ω g It can be determined according to the application scenario or directly selected as the 3dB beam range. The sidelobe interval is set to Ω s =[-90°,θ u ′]∪[θ l ′,90°], where θ u ′ and θ l ′ is divided into two end angles of the sidelobe interval, and θ u ′≤θ l ,θ u ≤θ l ′.

[0044] Furthermore, the dynamic spatial response modeling of the main lobe interval and the side lobe interval is as follows: Let the dynamic wave control weights be w1, w2, ..., w L , where w l ∈￡ M×1 is the phased array wave control weight vector corresponding to the lth time domain modulation parameter, l=1,2,...,L,￡ M×1represents a complex vector with M rows and 1 column, and M represents the number of elements in a one-dimensional phased array. Then the corresponding weight w in the main lobe is l Dynamic spatial response F l (θ) is

[0045]

[0046] The corresponding weight w in the side lobe l The spatial response F l (θ′) is

[0047]

[0048] in, is the complex imaginary unit, (·) H represents the complex conjugate transpose, a(θ) is the array steering vector corresponding to the direction θ, which can be obtained according to the array geometric parameters and the signal wavelength.

[0049] Step 3: Design of dynamic wave control weight optimization function: Take L-1 groups of phase sequences φ m,l =2π(l-1)(m-1) / L, the mth phase sequence can be expressed as φ m,1 ,φ m,2 ,...,φ m,L , where l = 1, 2, ..., L, and m is any value in 1, 2, ..., L except n. Then L-1 groups of sequences exp(jφ m,1 ),exp(jφ m,2 ),...,exp(jφ m,L ) are all Orthogonal. Construct the following wave control weight optimization function:

[0050]

[0051] in,

[0052]

[0053] G main represents the main lobe gain after time domain accumulation, G ASL represents the spatial sidelobe gain after time domain accumulation, G DSL Represents the Doppler domain sidelobe gain after time domain accumulation. θ i Represents the main lobe interval Ω g The discretized i-th angle grid point, N θ Represents the main lobe interval Ω g The total number of grid points discretized. i ′ represents the main lobe interval Ω s The discretized i-th angle grid point, N θ′ Represents the main lobe interval Ωs The total number of grid points discretized. Coefficient D1 is used to set the optimization degree of the main lobe gain, coefficient D2 is used to set the optimization degree of the spatial side lobe gain, coefficient D3 is used to set the optimization degree of the signal time domain modulation directivity, and coefficient D4 is used to set the optimization degree of the signal time domain modulation quality.

[0054] Furthermore, in this embodiment, the optimization function is minimized: the optimal wave control weight estimation value is obtained by minimizing the aforementioned wave control weight optimization function. Since the optimization function is complex and nonlinear, a global optimization algorithm is required.

[0055] Step 4: Apply the obtained optimized beam control weights to the receiving and transmitting channels of the phased array.

[0056] In this embodiment, for the communication system, The order of the messages to be sent is selected.

[0057] In this embodiment, a uniform linear array with an array element spacing of half a wavelength is set, the number of array elements M is 16, and the number of time domain modulation pulses L is 16. is a vector of all 0s, that is, n = 1, and α is a vector of all 1s. Set θ0 = 0°, θ u '=-9.90°,θ l =-8.99°,θ u =8.99,θ l ′=9.90. Fixed D1=20, D2=8, D3=1, D4=8. Use particle swarm algorithm as global optimization algorithm. The directional pattern after time domain accumulation is calculated based on the optimized wave control weights. like Figure 2 (a) is shown. The signal phases at 0° and 28° are shown in Figure 2 (b) The signal amplitudes at 0° and 28° are shown in Figure 2 As shown in (c), the sidelobe level of the beam is -24.8 dB, and the amplitude and phase modulation of the preset signal is maintained in the 0° direction, but the amplitude and phase modulation is disrupted in the 28° direction.

[0058] Example 2

[0059] The difference between this embodiment and embodiment 1 is that it includes the following steps:

[0060] Step 1: Determine the phase modulation vector and amplitude modulation vector of the signal directional time domain according to the phased array; wherein, for the radar, L is set to the number of pulses in the coherent processing cycle.

[0061] Step 2: setting the main lobe interval and the side lobe interval, and establishing a dynamic spatial domain response according to the main lobe interval and the side lobe interval;

[0062] Step 3: Construct a dynamic wave control weight optimization function, the expression is as follows:

[0063]

[0064] Among them, G main represents the main lobe gain after time domain accumulation, G ASL represents the spatial sidelobe gain after time domain accumulation, G DSL represents the Doppler domain sidelobe gain after time domain accumulation;

[0065] Among them, the main lobe gain after time domain accumulation G main Can also be changed to

[0066] Where max{·} means finding the maximum value of a set.

[0067] Then, the optimization function is minimized by a global optimization algorithm to obtain the optimal wave control weight estimate;

[0068] In this embodiment, the minimum optimization algorithm adopts a genetic algorithm.

[0069] Step 4: Apply the obtained optimized beam control weights to the receiving and transmitting channels of the phased array.

[0070] In this embodiment, for radar, before performing target detection, it is generally set α=[1,1,...,1], generate the corresponding The corresponding transmission and reception order can be arranged arbitrarily. After obtaining the prior information such as the target speed, the phase and amplitude information of each pulse can be obtained according to the speed, and then the corresponding and α, generating the corresponding The corresponding transmission and reception order cannot be changed.

[0071] Other technical features in this embodiment are the same as those in Embodiment 1, and therefore are not described in detail in this embodiment.

[0072] Example 3

[0073] The difference between this embodiment and embodiment 1 is that, in this embodiment, the number of time domain modulation pulses L is set to 32, and the other parameters are the same as above. The directional diagram after time domain accumulation is as follows Figure 3 (a) is shown. The signal phases at 0° and 28° are shown in Figure 3 (b) The signal amplitudes at 0° and 28° are shown in Figure 3 As shown in (c), the sidelobe level of the beam is -28.0dB, which is about 3dB lower than the 16 pulses, which is consistent with the relationship of doubling the pulses. At the same time, the amplitude and phase modulation of the preset signal is maintained in the 0° direction, but the amplitude and phase modulation is disrupted in the 28° direction.

[0074] Example 4

[0075] The difference between this embodiment and embodiment 1 is that, in this embodiment, the number of time domain modulation pulses L is set to 32, and the phase modulation vector is That is, n = 2, and the other parameters are the same as above. The directional pattern after time domain accumulation is as follows Figure 4 (a) is shown. The signal phases at 0° and 28° are shown in Figure 3 (b) The signal amplitudes at 0° and 28° are shown in Figure 3 As shown in (c), the sidelobe level of the beam is -28.5dB. At the same time, the amplitude and phase modulation of the preset signal is maintained in the 0° direction, but the amplitude and phase modulation is disrupted in the 28° direction.

[0076] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments including components are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A phased array dynamic wave control method with both low sidelobe and directional signal modulation, characterized in that: The steps include: Step 1: determining a phase modulation vector and an amplitude modulation vector in a signal directional time domain according to a phased array; Step 2: setting the main lobe interval and the side lobe interval, and establishing a dynamic spatial domain response according to the main lobe interval and the side lobe interval; Step 3: Construct a dynamic wave control weight optimization function, the expression is as follows: Among them, G main represents the main lobe gain after time domain accumulation, G ASL represents the spatial sidelobe gain after time domain accumulation, G DSL represents the Doppler domain sidelobe gain after time domain accumulation; Then, the optimization function is minimized by a global optimization algorithm to obtain the optimal wave control weight estimate; Step 4: Apply the obtained optimized beam control weights to the transceiver channel of the phased array.

2. According to claim 1, a phased array dynamic wave control method with both low sidelobe and directional signal modulation is characterized in that: In step 1, the directional time-domain phase modulation vector is set to in, is the phase modulation vector The lth element of n is an arbitrary integer satisfying 1≤n≤L; the directional time-domain amplitude modulation vector is set to α=[α1,α2,...,α L ], where α l is the lth element of the amplitude modulation vector α.

3. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 2, characterized in that: In the step 1, for wireless communication, L is equal to the base number of the code element.

4. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 2, characterized in that: In step 1, for radar, L is the number of pulses in a coherent processing cycle.

5. A phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 3 or 4, characterized in that: In step 2, the maximum direction of the main lobe gain is set to θ0, and the main lobe interval is set to Ω g =[θ l ,θ u ], where θ0 is contained in the main lobe interval Ω g Inside, θ l is the minimum angle covered by the main lobe, θ u is the maximum angle covered by the main lobe; the side lobe interval is set to Ω s =[-90°,θ u ′]∪[θ l ′,90°], where θ u ′ and θ l ′ is divided into two end angles of the sidelobe interval, and θ u ′≤θ l ,θ u ≤θ l ′.

6. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 5, characterized in that: The main lobe interval Ω g It is a 3dB beam.

7. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 5, characterized in that: The dynamic airspace corresponding modeling method is: assuming that the dynamic wave control weights are w1, w2, ..., w L , where w l ∈￡ M×1 is the phased array wave control weight vector corresponding to the lth time domain modulation parameter, l = 1, 2, ..., L, where ￡ M×1 represents a complex vector with M rows and 1 column, where M represents the number of elements in a one-dimensional phased array; then the corresponding weight w in the main lobe l Dynamic spatial response F l (θ) is: The corresponding weight w in the side lobe l The spatial response F l (θ′) is: in, is the complex imaginary unit, (·) H represents the complex conjugate transpose, and a(θ) is the array steering vector corresponding to the direction θ.

8. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 7, characterized in that: The construction method of the dynamic wave control weight optimization function is: Take L-1 groups of phase sequence φ m,l =2π(l-1)(m-1) / L, the mth phase sequence can be expressed as φ m,1 ,φ m,2 ,...,φ m,L , where l = 1, 2, ..., L, and m is any value in 1, 2, ..., L except n; Then L-1 groups of sequences exp(jφ m,1 ),exp(jφ m,2 ),...,exp(jφ m,L ) are all Orthogonal, construct the following wave control weight optimization function: in, Among them, θ i Represents the main lobe interval Ω g The discretized i-th angle grid point, N θ Represents the main lobe interval Ω g The total number of grid points discretized; θ i ′ represents the main lobe interval Ω s The discretized i-th angle grid point, N θ′ Represents the main lobe interval Ω s The total number of discretized grid points; coefficient D1 is used to set the optimization degree of the main lobe gain, coefficient D2 is used to set the optimization degree of the spatial side lobe gain, coefficient D3 is used to set the optimization degree of the signal time domain modulation directionality, and coefficient D4 is used to set the optimization degree of the signal time domain modulation quality.

9. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 1, characterized in that: The global optimization algorithm uses a particle swarm algorithm or a genetic algorithm to obtain the optimal wave control weight estimation value by minimizing the wave control weight optimization function.

10. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 9, characterized in that: In step 4, for the communication system, The order of the messages to be sent is selected.

11. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 9, characterized in that: In step 4, for the radar, before performing target detection, set Generate the corresponding The corresponding transmission and reception order can be arranged arbitrarily; after obtaining the prior information of the target speed, the phase and amplitude information of each pulse can be obtained according to the speed, and then the corresponding and α, generating the corresponding The corresponding transmission and reception order remains unchanged.

12. The phased array dynamic wave control method with low sidelobe and directional signal modulation according to claim 1, characterized in that: In step 3, the main lobe gain G after time domain accumulation main , expressed as follows: Where max{·} means finding the maximum value of a set.

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