Distributed fully coherent radar space synthetic gain distribution simulation modeling method

Abstract

The invention relates to a distributed full-coherent radar space synthetic gain distribution simulation modeling method, and belongs to the field of radar signal processing. Comprising the following steps: constructing a distributed full-coherent radar model, and calculating a time delay difference value and a phase difference value of each transmitting radar and a reference radar so as to obtain coherent parameters at a target position; calculating a vector included angle and an attenuation coefficient from each radar to a space point; calculating a signal from each transmitting radar to a space point; and calculating emission space synthesis gain distribution data. According to the distributed full-coherent radar space synthesis gain distribution simulation modeling method provided by the invention, the distributed full-coherent radar space synthesis gain distribution in any array form can be obtained at low cost, and the blank in the technical field is effectively filled up. Compared with a real machine equipment experiment mode, the method has the advantages that simulation is carried out through a computer, the cost for obtaining the distributed full-coherent radar space synthesis gain distribution data is remarkably reduced, and data support is provided for layout optimization technology research.

Description

Technical Field

[0001] The present invention relates to the field of radar signal processing, and in particular to a simulation modeling method for spatial synthesis gain distribution of a distributed fully coherent radar. Background Art

[0002] In application scenarios such as long-range search, tracking, surveillance, and target identification, large-aperture, high-power large-scale phased array radars play an increasingly important role. However, with the continuous improvement of the requirements for power and accuracy, the development of large-scale phased array radars is constrained by a variety of negative factors such as the surge in construction costs and the sharp drop in mobility. Distributed fully coherent radars have emerged. The electromagnetic signals emitted by N transmitting radars of a distributed fully coherent radar are coherently superimposed in space after precise synchronization and compensation. In theory, N 2 of spatial synthetic gain. However, in actual applications, there are measurement errors in coherent parameter estimation and target positioning, and it is impossible to ensure that the target point is within the range with the maximum synthetic gain. Therefore, how to maximize the signal coherent superposition range under limited resources is an important research issue. The coherent superposition range of distributed fully coherent radar in the target airspace is mainly affected by factors such as radar performance parameters, synchronization accuracy and array geometry, among which the array geometry parameters have the most significant impact. In response to this problem, the present invention proposes a new distributed fully coherent radar spatial synthetic gain distribution simulation modeling method, which provides prior data support for the research on the optimization of radar array of this system.

[0003] At present, domestic and international experts and scholars have conducted in-depth research on the problem of radar array optimization. The China Electronics Science Research Institute proposed a research and analysis method for the signal correlation to the morphological constraints of distributed MIMO radars. According to the signal correlation constraints, the corresponding relationship between the working frequency points of the air-space distributed radar and the maximum spacing of each node is given; from the perspective of cost-effectiveness, the relationship between the effect of increasing the number of nodes on improving the equivalent synthetic gain is analyzed. The 38th Institute of China Electronics Technology Group Corporation studied the array and use of large random arrays and proposed a design and analysis method for random array and detection performance optimization. Abroad, mainly the Lincoln Laboratory in the United States has done a lot of research on distributed fully coherent radars and achieved certain results. Lehigh University in the United States proposed an optimal linear unbiased estimator for the target positioning problem in the wide-area distribution application scenario of MIMO radar, which helps to analyze the relationship between sensor position, target position and positioning accuracy. At present, there are few simulation modeling studies on the spatial synthetic gain distribution of distributed fully coherent radars.

[0004] In actual engineering applications, a combination of simulation analysis and real machine experiments is used for single radars to analyze and verify the energy distribution of radar transmission signals. However, due to the large number of components of distributed fully coherent radars, physical experiments face difficulties, high time costs and equipment costs. Summary of the invention

[0005] The technical problems to be solved by the present invention are:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a distributed fully coherent radar spatial synthetic gain distribution simulation modeling method to provide prior data support for the distributed fully coherent radar array optimization.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A distributed fully coherent radar spatial synthesis gain distribution simulation modeling method, characterized by comprising:

[0009] Constructing a distributed fully coherent radar model, wherein the distributed fully coherent radar model includes a plurality of transmitting radars in a fully coherent working mode;

[0010] The time delay and phase difference of each radar reaching the target position are calculated based on the coordinate values ​​of each transmitting radar and the target; a reference radar is determined, and the time delay difference and phase difference between each transmitting radar and the reference radar are respectively calculated based on the time delay and phase difference between each transmitting radar and the reference radar, that is, the coherent parameters at the target position;

[0011] Based on the cosine theorem, the first angle between the vector from each radar to the space point and the vector from the coordinate origin to the space point is calculated; based on the cosine theorem, the second angle between the space point and the position vector of the transmitting radar and the position vector from the target point to the transmitting radar is calculated; based on the second angle and the vector from each radar to the space point, the attenuation coefficient is calculated;

[0012] Based on the coordinates of each transmitting radar and the spatial point, the time delay and phase difference of each radar reaching the spatial point are calculated; based on the coherent parameters at the target position, the time delay and phase difference of each radar reaching the spatial point, and the attenuation coefficient, the signal of each transmitting radar reaching the spatial point is calculated;

[0013] Based on the signals of each transmitting radar at a spatial point and the first angle, the superimposed signal of the distributed fully coherent radar at the spatial point is calculated; based on the ratio of the superimposed signal power to the signal power of each radar, the spatial synthetic gain distribution data of each radar component is obtained.

[0014] A further technical solution of the present invention is: the time delay and phase difference of each radar reaching the target position are calculated based on the coordinate values ​​of each transmitting radar and the target, using the following formula:

[0015]

[0016] φ m =2πf0τ m

[0017] Among them, (x m ,y m ,z m ) is the coordinate of the mth transmitting radar position in the Cartesian coordinate system, c is the speed of light, (R t ,α t ,β t ) is the spatial spherical coordinate of the scattering point target, f0 is the operating frequency, τ m is the time delay of each radar reaching the target position, φ m is the phase difference between each radar reaching the target position.

[0018] A further technical solution of the present invention is as follows: the time delay difference and phase difference of each transmitting radar and the reference radar are calculated based on the time delay and phase difference between each transmitting radar and the reference radar, respectively, using the following formula:

[0019] Δτ m =τ m -τ1

[0020] Δφ m =2πf0Δτ m

[0021] Among them, τ1 is the time delay of the reference radar.

[0022] A further technical solution of the present invention is as follows: the first angle between the vector from each radar to the space point and the vector from the coordinate origin to the space point is calculated based on the cosine theorem, using the following formula:

[0023]

[0024] in, is the vector from the radar to the space point, is the vector from the origin to the space point, (r, α, β) is the spherical coordinates of any point in space, θ m,P is the first angle.

[0025] A further technical solution of the present invention is as follows: the second angle between the space point and the transmitting radar position vector and the target point and the transmitting radar position vector is calculated based on the cosine theorem, using the following formula:

[0026]

[0027] in, is the position vector from the target point to the transmitting radar, θ m,P,Q is the second angle.

[0028] A further technical solution of the present invention is as follows: the attenuation coefficient is calculated based on the second angle and the vectors of each radar to a space point, using the following formula:

[0029]

[0030] A further technical solution of the present invention is as follows: the time delay and phase difference of each radar reaching the spatial point are calculated based on the coordinate values ​​of each transmitting radar and the spatial point, using the following formula:

[0031]

[0032] φ m,P =2πf0τ m,P

[0033] Among them, τ m,P is the time delay of the radar reaching the space point, φ m,P is the phase difference between the radar and the spatial point.

[0034] A further technical solution of the present invention is as follows: based on the coherent parameters at the target position, the time delay and phase difference of each radar reaching the spatial point, and the attenuation coefficient, the signal of each transmitting radar reaching the spatial point is calculated using the following formula:

[0035]

[0036] A further technical solution of the present invention is as follows: based on the signals of each transmitting radar at the spatial point and the first angle, the superposition signal of the distributed fully coherent radar at the spatial point is calculated using the following formula:

[0037]

[0038] A further technical solution of the present invention is as follows: the ratio of the superimposed signal power to the power of each radar signal is based on the following formula:

[0039]

[0040] Among them, s1(t,r,α,β) is the transmission signal of T1 radar.

[0041] The beneficial effects of the present invention are:

[0042] The invention provides a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method, which can realize the energy distribution and transmission gain distribution simulation of the distributed fully coherent radar transmission signal in space for any number of unit radars and any array form on a computer, effectively saving the cost of physical experiments, providing prior data support for the optimization of distributed fully coherent radar array, and filling the gap in the research of this technology. It has the following advantages:

[0043] 1. The distributed fully coherent radar spatial synthesis gain distribution simulation modeling method provided by the present invention can obtain the spatial synthesis gain distribution of distributed fully coherent radars in any array form at a low cost, effectively filling the gap in this technical field. Compared with the actual equipment experiment method, the method of the present invention uses computer simulation to significantly reduce the cost of obtaining the distributed fully coherent radar spatial synthesis gain distribution data, providing data support for array optimization technology research.

[0044] 2. Compared with direct physical testing, the distributed fully coherent radar spatial synthesis gain distribution simulation modeling method proposed in the present invention can more flexibly obtain the spatial synthesis gain distribution of any array form, any radar parameters, and any airspace. It is not restricted by the experimental site, equipment construction cost, etc., and can effectively shorten the experimental cycle and significantly improve the experimental efficiency, and quickly and efficiently obtain the spatial synthesis gain distribution data. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0046] Figure 1 Flow chart of the embodiment of the present invention;

[0047] Figure 2 The present invention transmits radar and spatial point distribution map;

[0048] Figure 3 Schematic diagram of the airspace range of the model of the present invention;

[0049] Figure 4 Matlab simulation results of the model of the present invention - spatial synthesis gain distribution profile. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0051] The present invention provides a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method, comprising the following steps:

[0052] S01: Input model parameters. Define radar parameters, target location coordinates, and location coordinates of each transmitting radar of the distributed fully coherent radar. Set the signal sampling rate and time window width according to the radar parameters; design the corresponding spatial resolution according to the requirements of obtaining spatial synthetic gain distribution data. Set the synchronization error parameters between radars according to the actual scene requirements. The default value is 0.

[0053] S02: Calculate the coherent parameters. Calculate the time delay and phase difference of each radar to the target position. Select a radar among the transmitting radars or set a virtual radar as the reference radar, calculate the time delay difference and phase difference between each transmitting radar and the reference radar, so as to obtain the coherent parameters at the target position.

[0054] S03: Calculate the angle and attenuation coefficient of the vector from each radar to the spatial point. Use the cosine theorem to calculate the angle between the vector from each radar to the spatial point and the vector from the origin of the coordinate system to the spatial point. Use the cosine theorem to calculate the angle between the spatial point and the transmitting radar position vector and the target point and the transmitting radar position vector. Query the directional pattern gain corresponding to the angle deviation from the radar directional pattern, divide it by the square of the distance from the radar to the spatial point, and obtain the attenuation coefficient of the radar corresponding to the spatial point.

[0055] S04: Calculate the signal of each transmitting radar reaching the spatial point. Set an initial signal, calculate the time delay difference and phase difference of the radar reaching the spatial point, introduce the time delay difference and phase difference to the initial signal, and then perform coherent parameter compensation to obtain the signal of each transmitting radar reaching the spatial point.

[0056] S05: Calculate the transmission spatial synthesis gain distribution data. The signal transmitted by each radar to the spatial point is multiplied by the attenuation coefficient, and then multiplied by the cosine value of the vector angle to the spatial point. Finally, the signals are added together to obtain the superimposed signal at the spatial point. The average power of the superimposed signal and the average power of the signal of a single radar at the spatial point are calculated, and the ratio of the two is calculated, that is, the transmission coherent gain at the spatial point when the distributed fully coherent radar performs transmission coherence based on the target point. The above process is repeated to traverse all spatial points, calculate the corresponding transmission coherent gain, and obtain the spatial synthesis gain distribution data of the distributed fully coherent radar in this array.

[0057] Embodiment 1:

[0058] An embodiment of the present invention provides a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method, comprising the following steps:

[0059] S01: Set model parameters. Define the number of distributed fully coherent radar transmitting radars as M, and the transmitting radars are denoted as (T1, T2, …, T M ), the coordinates of the mth transmitting radar position in the Cartesian coordinate system are (x m ,y m ,zm ). The parameters of each transmitting radar are exactly the same, the transmitting power is p, the operating frequency is f0; the transmitting pattern gain is set to μ(θ), where θ refers to the angle between the transmitting radar and the beam center; in the fully coherent working mode, the transmitting signal of each transmitting radar is s(t), and the speed of light is c. There is an isotropic scattering point target Q in space, and its spatial spherical coordinates are (R t ,α t ,β t ); Any point P in space, its spatial spherical coordinates are denoted as (r, α, β). The above transmitting radar and spatial point distribution diagram are as follows Figure 2 shown.

[0060] S02: Calculate the coherent parameters. The transmission delay coherent parameters of each transmitting radar are recorded as (Δτ1, Δτ2, …, Δτ M ); the transmission phase coherence parameters are recorded as (Δφ1, Δφ2,…, Δφ M ). Here we assume that T1 is the reference radar, then Δτ1=0s, Δφ1=0. τ m Indicates that the signal is from T m The propagation delay to the target point Q. The transmission coherent parameters of each transmitting radar can be calculated as follows:

[0061]

[0062] φ m =2πf0τ m

[0063] Δτ m =τ m -τ1

[0064] Δφ m =2πf0Δτ m

[0065] Among them, τ1 is the time delay of the reference radar.

[0066] S03: Calculate the vector angle and attenuation coefficient of each radar reaching the spatial point. Figure 2 As shown, θ m,P represents the coordinate origin and T m The angle to the space point P is calculated as follows:

[0067]

[0068] The attenuation coefficient of the radar to space is related to the target distance and the beam pattern gain. Here, it is assumed that the wave velocity center of each transmitting radar points to the target point Q, then the angle from the spatial point P to the beam center can be expressed as θ m,P,Q , thus obtaining the pattern gain μ(θ m,P,Q); μ(θ m,P,Q ) divided by the square of the distance from the radar to the space point to obtain the attenuation coefficient ξ m,P , the specific calculation method is as follows.

[0069]

[0070] S04: Calculate the signal of each transmitting radar at the spatial point. According to the above calculated parameters, the signal s transmitted by each transmitting radar to the spatial point P can be obtained. m (t,r,α,β),τ m,P To transmit radar T m Propagation delay to spatial point P, φ m,P is the phase difference introduced during the propagation process, and the specific calculation method is as follows.

[0071]

[0072] φ m,P =2πf0τ m,P

[0073]

[0074] Among them, p m is the power of the radar signal.

[0075] S05: Calculate the transmission space synthesis gain distribution data. First, calculate the superposition signal of the distributed fully coherent radar at the spatial point P, and the calculation method is as follows.

[0076]

[0077] Then the transmission coherent gain of the distributed fully coherent radar at the spatial point P is calculated. By calculating the ratio of the superimposed signal power to the single radar signal power, the transmission coherent gain G can be quantified. P (r, α, β), where T1 transmit signal is taken as the reference, and the calculation method is as follows.

[0078]

[0079] By traversing the transmission coherent gain of the spatial points near the target point Q, the (T1, T2, ..., T M ) spatial synthesis gain distribution data under the array form. Define the spatial azimuth range as Ψ, the elevation range as Υ, and the distance range as d. The schematic diagram of the spatial range is as follows: Figure 3 As shown, the blue part is the airspace range. Define the distance sampling rate Δd, the airspace azimuth sampling rate Δα, and the airspace pitch sampling rate Δβ. The coordinates of the spatial point P (r, α, β) can be expressed as follows. The simulation results of the spatial synthetic augmented distribution profile obtained by several typical array arrangements are shown in Figure 1. Figure 4 shown.

[0080] r=r t +nΔd-d / 2

[0081] α=α t +lΔα-Ψ / 2

[0082] β=β t +kΔβ-Υ / 2

[0083]

[0084] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A distributed fully coherent radar spatial synthesis gain distribution simulation modeling method, characterized in that: include: Constructing a distributed fully coherent radar model, wherein the distributed fully coherent radar model includes a plurality of transmitting radars in a fully coherent working mode; The time delay and phase difference between each radar and the target position are calculated based on the coordinate values ​​of each transmitting radar and the target; Determine the reference radar, and calculate the time delay difference and phase difference between each transmitting radar and the reference radar based on the time delay and phase difference between each transmitting radar and the reference radar, that is, the coherence parameters at the target position; Based on the cosine theorem, the first angle between the vector from each radar to the space point and the vector from the coordinate origin to the space point is calculated; based on the cosine theorem, the second angle between the space point and the position vector of the transmitting radar and the position vector from the target point to the transmitting radar is calculated; based on the second angle and the vector from each radar to the space point, the attenuation coefficient is calculated; Based on the coordinates of each transmitting radar and the spatial point, the time delay and phase difference of each radar reaching the spatial point are calculated; based on the coherent parameters at the target position, the time delay and phase difference of each radar reaching the spatial point, and the attenuation coefficient, the signal of each transmitting radar reaching the spatial point is calculated; Based on the signals of each transmitting radar at a spatial point and the first angle, the superimposed signal of the distributed fully coherent radar at the spatial point is calculated; based on the ratio of the superimposed signal power to the signal power of each radar, the spatial synthetic gain distribution data of each radar component is obtained.

2. According to claim 1, a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method is characterized in that: The time delay and phase difference between each radar and the target position are calculated based on the coordinate values ​​of each transmitting radar and the target, using the following formula: f m =2πf0τ m Among them, (x m ,y m , z m ) is the coordinate of the mth transmitting radar position in the Cartesian coordinate system, c is the speed of light, (R t , α t , β t ) is the spatial spherical coordinate of the scattering point target, f0 is the operating frequency, τ m is the time delay of each radar reaching the target position, φ m is the phase difference between each radar and the target position.

3. According to claim 2, a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method is characterized in that: The time delay difference and phase difference between each transmitting radar and the reference radar are calculated based on the time delay and phase difference between each transmitting radar and the reference radar, respectively, using the following formula: Dt m =t m -t1 Df m =2πf0Δτ m Among them, τ1 is the time delay of the reference radar.

4. According to claim 3, a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method is characterized in that: The first angle between the vector from each radar to the space point and the vector from the coordinate origin to the space point is calculated based on the cosine theorem using the following formula: in, is the vector from the radar to the space point, is the vector from the origin to the space point, (r, α, β) is the spherical coordinates of any point in space, θ m，P is the first angle.

5. According to claim 4, a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method is characterized in that: The second angle between the space point and the transmitting radar position vector and the target point and the transmitting radar position vector is calculated based on the cosine theorem using the following formula: in, is the position vector from the target point to the transmitting radar, θ m，P，Q is the second angle.

6. According to claim 5, a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method is characterized in that: The attenuation coefficient is calculated based on the second angle and the vectors of each radar to the space point, using the following formula:

7. A distributed fully coherent radar spatial synthesis gain distribution simulation modeling method according to claim 6, characterized in that: The time delay and phase difference between each radar and the spatial point are calculated based on the coordinate values ​​of each transmitting radar and the spatial point, using the following formula: f m，P =2πf0τ m，P Among them, τ m，P is the time delay of the radar reaching the space point, φ m，P is the phase difference between the radar and the spatial point.

8. According to claim 7, a distributed fully coherent radar spatial synthesis gain distribution simulation modeling method is characterized in that: The signal of each transmitting radar reaching the spatial point is calculated based on the coherent parameters at the target position, the time delay and phase difference of each radar reaching the spatial point, and the attenuation coefficient, using the following formula:

9. The distributed fully coherent radar spatial synthesis gain distribution simulation modeling method according to claim 8, characterized in that: The superposition signal of the distributed fully coherent radar at the spatial point is calculated based on the signal of each transmitting radar at the spatial point and the first angle, using the following formula:

10. A distributed fully coherent radar spatial synthesis gain distribution simulation modeling method according to claim 9, characterized in that: The ratio of the superimposed signal power to the power of each radar signal is calculated using the following formula: Among them, s1(t, r, α, β) is the transmission signal of T1 radar.

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