Double-antenna three-dimensional rotating baseline direction finding method, device and system

Abstract

The invention belongs to but is not limited to the technical field of radio detection direction finding, and discloses a double-antenna three-dimensional rotating baseline direction finding method, device and system. Inter-channel phase deviation table compensation is carried out, equal-frequency-interval full-working-frequency-band measurement is carried out on phase deviation between two measurement channels in advance, and a channel phase deviation compensation table AB is formed; the compensation module is used for compensating inherent phase deviation between the channel A and the channel B; after the double-antenna three-dimensional rotating baseline direction finding device starts to work, a baseline formed by the antennas AB rotates anticlockwise at an angular velocity omega, two receiving channels synchronously collect data, and phase difference is calculated for the data corresponding to the baselines AB; based on a two-dimensional joint search method, through combination of coarse search and fine search, an azimuth angle and a pitch angle are estimated. According to the technical scheme provided by the invention, the direction finding range and reliability of a traditional system are greatly expanded, meanwhile, the cost is basically not increased, and the large-scale application of the technical system can be promoted.

Description

Technical Field

[0001] The present invention belongs to but is not limited to the technical field of radio detection and direction finding, and in particular relates to a dual-antenna three-dimensional rotating baseline direction finding method, device and system. Background Art

[0002] Passive direction finding and positioning is one of the important technologies in related fields such as electromagnetic spectrum monitoring, drone monitoring and electronic countermeasures. Multi-baseline interferometers based on a combination of long and short baselines are widely used due to their high precision, such as 5-element array and 7-element array interferometers. In order to improve the deambiguation capability and direction finding accuracy, traditional interferometers usually require more than 5 antennas and receiving channels. The system is complex, costly, large in size and weight, and has poor frequency band adaptability. To solve this problem, the rotating baseline direction finding technology based on time-varying baseline technology has attracted much attention and has effectively complemented the traditional interferometer. It has begun to be widely used, especially in the field of small and low-cost radio detection.

[0003] At present, the most common form of rotating baseline direction finding system is that two omnidirectional antennas form a one-dimensional linear array. The equipment is driven to rotate around the center of the linear array by the rotation of the platform (such as a drone) or a rotating mechanism (such as a motor). This one-dimensional rotating baseline composed of two antennas has a simple system design and low volume cost. Li Teng et al. discussed the feasibility, calculation method and performance limit of the rotating baseline direction finding technology based on the dual-antenna one-dimensional linear array in the article "Multi-hypothesis NLS positioning algorithm based on the fuzzy phase difference of the rotating interferometer [J]. Journal of Electronics and Information Technology, 2012, 34(4): 956-962.", and Zhang Min et al. discussed in detail the feasibility, calculation method and performance limit of the rotating baseline direction finding technology based on the dual-antenna one-dimensional linear array in the article "Rotating long baseline interferometer direction finding method and performance analysis [J]. Journal of Electronics, 2013, 41(12): 2423-2429.". Li Dong et al. discussed in detail a method to improve the rotating direction finding accuracy of the dual-antenna one-dimensional linear array in the article "Method for improving the direction finding accuracy of the rotating baseline phase interferometer [J]. Telecommunication Technology, 2022, 62(7): 936-940."

[0004] The above method and system have the following deficiencies and defects: The theoretical measurement range of the pitch angle (angle of deviation from the rotation plane) of the rotating baseline system based on the dual-antenna one-dimensional linear array is 0 to 90°, that is, it is impossible to effectively distinguish whether the measured target is above or below the rotation plane, which greatly limits the application scope of the system. When the rotation plane is not on the ground, such as the rotating baseline direction-finding system on drones and the direction-finding equipment deployed on the roof, serious errors may occur, and the original aerial target may be identified as a ground target, and the ground target may also be identified as an aerial target. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a dual-antenna three-dimensional rotating baseline direction finding method, device and system, aiming to solve the problem that the current dual-antenna one-dimensional rotating baseline direction finding technology cannot identify whether the target is above or below the rotating plane. Without increasing the number of antennas and receiving channels, the difficulty and cost of engineering are fully considered.

[0006] The present invention is implemented in this way: a dual-antenna three-dimensional rotating baseline direction finding method comprises the following steps:

[0007] Step 1: Compensate the phase deviation between channels by table. The phase deviation between two measurement channels is measured in full working frequency band with equal frequency intervals in advance to form a channel phase deviation compensation table AB, which is used to compensate for the inherent phase deviation between channels A and B.

[0008] Step 2: After the dual-antenna three-dimensional rotating baseline direction-finding device starts working, the baseline formed by antennas AB rotates counterclockwise at an angular velocity Ω, and the two receiving channels collect data synchronously, and the phase difference of the corresponding data of baseline AB is calculated;

[0009] Step three, based on the two-dimensional joint search method, estimate the azimuth and elevation angles by combining coarse search and fine search.

[0010] Further, the method for calculating the phase difference includes:

[0011] (1) In the coordinate system of the rotating baseline itself, the target azimuth angle is α and the pitch angle is β, and the phase deviation compensation table generated in advance is used to perform phase deviation compensation;

[0012] (2) The phase difference of baseline AB is:

[0013]

[0014] Among them, f is the signal frequency, d is the length from antenna A to the rotation center O, k is the height of the vertical rod, t is the time, and n AB (t) is the random noise when measuring the baseline AB phase difference, and mod is the modulo operation. Based on the sine component of the pitch angle, it is determined whether the incoming wave direction is above or below the rotation plane.

[0015] Further, the coarse search includes:

[0016] 1) Assume that the 2N potential azimuths are Assume that M potential pitch angles are

[0017] 2) Under the assumption of the i-th azimuth angle and the j-th elevation angle, calculate the phase difference at time t:

[0018] 3) After the phase difference calculations at all times t are completed, the phase difference sequence Δφ corresponding to (α(i), β(j)) is obtained AB (t,i,j), and the sum of the errors between it and the true phase difference sequence is used as the confidence judgment value of the angle combination (α(i), β(j)): F(i,j) = sum[abs(Δφ AB (t)-Δφ AB (t,i,j))], the lower this value is, the higher the confidence is;

[0019] 4) Select the angle combination (α(i r ),β(j r ))(r=0,1,...,V-1) is used as the potential incoming wave direction.

[0020] Further, refined searches include:

[0021] 1) For V potential angle combinations (α(i r ),β(j r ))(r=0,1,...,V-1), set the azimuth search range α0 and the search precision parameter T, the elevation search range β0 and the search precision parameter Z, and construct a new local two-dimensional search matrix [α(p),β(q)] with a dimension of (T+1)×(Z+1).

[0022]

[0023]

[0024] 2) According to F(i,j)=sum[abs(Δφ AB (t)-Δφ AB (t,i,j))] calculate the confidence judgment value and obtain a new confidence judgment matrix;

[0025] 3) Take the angle combination corresponding to the minimum confidence judgment value as the estimation result (α', β');

[0026] 4) For the pitch angle β close to When , the pitch angle is set to β', the confidence judgment value is calculated and the azimuth is searched again. The search accuracy is determined by the parameter W: Update the bearing estimate based on the new search results.

[0027] Another object of the present invention is to provide a dual-antenna three-dimensional rotating baseline direction finding device for realizing the dual-antenna three-dimensional rotating baseline direction finding method. The three-dimensional rotating baseline system is composed of two antennas forming a three-dimensional array, which are respectively recorded as antenna A and antenna B, wherein antenna A is located in the rotation plane, connected to the rotation axis through a cross bar, and the spacing is adjustable, with a maximum distance of L meters from the rotation center O. At the same time, counterweights are placed at symmetrical positions of the rotation center to maintain balance; a vertical rod is arranged along the rotation axis, the length of the vertical rod is adjustable, and the longest is K meters, and antenna B is located at the upper end of the vertical rod.

[0028] Furthermore, when the device is working, antenna A is driven by a rotating mechanism or a rotating platform to rotate counterclockwise, and antenna B is located on the rotation axis and does not rotate; the two antennas are respectively connected to two receiving channels, and data is collected synchronously during operation to form a baseline AB. The phase difference of the baseline AB is measured, and the azimuth and elevation angles are estimated by measuring multiple groups of phase differences.

[0029] Another object of the present invention is to provide a dual-antenna three-dimensional rotating baseline direction finding system for implementing the dual-antenna three-dimensional rotating baseline direction finding method, comprising:

[0030] A phase deviation compensation table acquisition module is used to measure the phase deviation between different channels of the three-dimensional direction finding system at fixed frequency intervals through a signal source and a power divider in an indoor test environment to obtain a phase deviation compensation table between different channels;

[0031] Phase difference measurement module, used to calculate the phase difference between channels AB;

[0032] The azimuth and elevation angle estimation module is based on a two-dimensional joint search method and combines coarse search with fine search to achieve rapid estimation of azimuth and elevation angles.

[0033] Another object of the present invention is to provide a computer device, the computer device comprising a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, the processor executes the steps of the dual-antenna three-dimensional rotating baseline direction finding method.

[0034] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, enables the processor to execute the steps of the dual-antenna three-dimensional rotating baseline direction finding method.

[0035] Another object of the present invention is to provide an information data processing terminal, which includes the dual-antenna three-dimensional rotating baseline direction finding system.

[0036] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0037] First, the present invention designs a brand-new three-dimensional rotating baseline direction-finding system based on dual antennas, fully considering the difficulty and cost of implementation, without adding antennas and receiving channels, changing the antenna array form, expanding the rotating array from a one-dimensional array to a three-dimensional array, realizing the expansion of the pitch angle estimation range, and solving the shortcomings and defects of the existing system;

[0038] The azimuth and elevation angle estimation method of the present invention transforms the nonlinear estimation problem into an azimuth and elevation angle joint search problem, has a stable algorithm, a small amount of calculation, high estimation accuracy, and is simple and practical.

[0039] The method and system design of the present invention have achieved significant technical progress in solving the problems and defects of the prior art, and greatly expanded the direction-finding range of the traditional rotating baseline direction-finding system.

[0040] Extended direction-finding range: By simply expanding the one-dimensional baseline system (which can be viewed as a two-dimensional baseline system after rotation) into a three-dimensional baseline system, the theoretical elevation angle direction-finding range of the traditional rotating baseline direction-finding system is extended from 0 to 90 degrees to -90 to 90 degrees.

[0041] Improve the stability and robustness of the system: Through the joint search of azimuth and elevation angles, the present invention enhances the stability and robustness of the system under various conditions.

[0042] Second, as auxiliary evidence of the inventiveness of the claims of the present invention, it is also reflected in the following important aspects:

[0043] (1) The expected benefits and commercial value of the technical solution of the present invention after transformation are:

[0044] At present, rotating baseline direction finding technology is widely used in military and civilian fields such as electronic reconnaissance, electronic countermeasures, UAV control, and radio management due to its favorable factors such as cost, volume, and power consumption. The technical solution proposed in the present invention greatly expands the direction finding range and reliability of the traditional system, while basically does not increase the cost, and can promote the large-scale application of this technical system.

[0045] (2) The technical solution of the present invention fills the technical gap in the industry at home and abroad:

[0046] The traditional dual-antenna one-dimensional rotating baseline direction-finding system has the problem of limited elevation angle observation range, which makes it impossible to be effectively applied in many scenarios. The technical solution of the present invention proposes a new system design and calculation method to effectively solve this problem.

[0047] Third, the present invention proposes a dual-antenna three-dimensional rotating baseline direction finding method and its device and system, which mainly solves the problems of the prior art in direction finding accuracy and efficiency, and achieves significant technical progress. The following is a detailed technical solution and the technical problems it solves and the technical progress it achieves:

[0048] Technical issues solved:

[0049] 1) Direction finding accuracy problem:

[0050] By compensating for phase deviation between channels, the system error is reduced and the direction finding accuracy is improved.

[0051] Using the 3D rotating baseline and 2D joint search method, high-precision estimation of azimuth and elevation angles is achieved.

[0052] 2) Direction finding efficiency issue:

[0053] By combining coarse search and fine search, the amount of calculation is reduced and the direction finding efficiency is improved.

[0054] Technological progress achieved:

[0055] 1) Improved direction finding accuracy:

[0056] The application of phase deviation compensation technology significantly improves the accuracy of the direction finding system.

[0057] The combination of 3D rotating baseline and 2D joint search method enables high-precision simultaneous estimation of azimuth and elevation angles.

[0058] 2) Improved direction finding efficiency:

[0059] The combination of coarse search and fine search makes the direction finding process more efficient and reduces computing time and resource consumption.

[0060] 3) Enhanced system adaptability and flexibility:

[0061] The antenna spacing and vertical pole length are adjustable, allowing the system to adapt to different direction finding requirements and environments.

[0062] 4) Provides a complete direction finding solution:

[0063] The present invention not only provides a direction finding method, but also provides a corresponding direction finding device and system, thereby providing a complete solution for practical applications.

[0064] In summary, the present invention solves the problems of the prior art in terms of direction finding accuracy and efficiency through innovative technical solutions, achieves significant technological progress, and has broad application prospects and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a schematic diagram of a dual-antenna three-dimensional rotating baseline system provided by an embodiment of the present invention;

[0066] Figure 2 is a flow chart of a dual-antenna three-dimensional rotating baseline direction finding method provided by an embodiment of the present invention;

[0067] Figure 3 is a structural diagram of a dual-antenna three-dimensional rotating baseline system provided by an embodiment of the present invention;

[0068] Figure 4 Schematic diagram of a typical ground dual-antenna three-dimensional rotating baseline direction finding system provided by an embodiment of the present invention;

[0069] Figure 5 Schematic diagram of a typical dual-antenna three-dimensional rotating baseline direction finding system on a rotary-wing UAV provided by an embodiment of the present invention;

[0070] Figure 6 It is a schematic diagram of the working process of the ground dual-antenna three-dimensional rotating baseline direction finding system provided by an embodiment of the present invention;

[0071] Figure 7 It is a schematic diagram of the measurement results of the incoming wave phase difference at an elevation angle of +60 degrees and an azimuth angle of 30 degrees under the typical direction finding parameter conditions provided by an embodiment of the present invention;

[0072] Figure 8 It is a schematic diagram of a rough search result of an incoming wave direction under typical direction finding parameter conditions provided by an embodiment of the present invention for an elevation angle of +60 degrees and an azimuth angle of 30 degrees;

[0073] Fig. 9 It is a schematic diagram of accurate search results for the incoming wave direction at an elevation angle of +60 degrees and an azimuth angle of 30 degrees under typical direction finding parameter conditions provided by an embodiment of the present invention;

[0074] Fig.10 It is a schematic diagram of the working process of the dual-antenna three-dimensional rotating baseline direction finding system for unmanned aerial vehicles provided by an embodiment of the present invention;

[0075] Fig.11 It is a schematic diagram of the measurement results of the incoming wave phase difference at an elevation angle of -60 degrees and an azimuth angle of 30 degrees under the typical direction finding parameter conditions provided by an embodiment of the present invention;

[0076] Fig.12 It is a schematic diagram of a rough search result of an incoming wave direction under typical direction finding parameter conditions provided by an embodiment of the present invention for an elevation angle of -60 degrees and an azimuth angle of 30 degrees;

[0077] Fig.13 It is a schematic diagram of accurate search results for the incoming wave direction under typical direction finding parameter conditions provided by an embodiment of the present invention, with an elevation angle of -60 degrees and an azimuth angle of 30 degrees. DETAILED DESCRIPTION

[0078] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0079] Example 1

[0080] 1) Step 1: Compensate for phase deviation between channels

[0081] In a laboratory environment, use a signal source and a power divider to measure the phase deviation of the two receiving channels (channel A and channel B) in the direction finding system. Select multiple frequency points, and at each frequency point, record the phase deviation between channel A and channel B to form a phase deviation compensation table AB. This compensation table will be used to compensate for the inherent phase deviation between channels during the actual direction finding process. 2) Step 2: The dual-antenna three-dimensional rotating baseline direction finding device starts working

[0082] The baseline AB formed by antenna A and antenna B rotates counterclockwise at an angular velocity Ω. The two receiving channels collect data synchronously and calculate the phase difference of the baseline AB. In this step, the rotation angle and the corresponding phase difference data need to be recorded in real time.

[0083] 3) Step 3: Estimation of azimuth and elevation angles based on a two-dimensional joint search method

[0084] The azimuth and elevation angles are estimated using a combination of coarse and fine search methods.

[0085] Coarse search: Set the initial range and step size of the potential azimuth and elevation angles, calculate the phase difference sequence under each potential angle combination, and compare it with the actual phase difference sequence to obtain the total error. Select the angle combination with the smallest error as the potential incoming wave direction.

[0086] Refined search: Set a smaller search range and step size near the potential angle combination determined by the rough search, perform a more detailed search, and finally obtain the estimated values ​​of the azimuth and elevation angles.

[0087] Example 2

[0088] 1) Antenna configuration

[0089] The three-dimensional rotating baseline system consists of antenna A and antenna B. Antenna A is connected to the rotation axis through a crossbar and is located on the rotation plane. The length of the crossbar is adjustable and can reach a maximum of L meters. Antenna B is installed on the vertical rod, which is set along the rotation axis and has an adjustable length of up to K meters. In order to keep the system balanced, counterweights are placed at symmetrical positions at the rotation center.

[0090] 2) Rotation mechanism

[0091] The rotating mechanism drives antenna A to rotate counterclockwise, and antenna B is fixed on the rotating shaft and does not rotate. The two antennas are connected to two receiving channels respectively, and collect data synchronously during operation to form baseline AB.

[0092] 3) Data processing and direction finding

[0093] The dual-antenna three-dimensional rotating baseline direction finding system includes the following modules:

[0094] Phase deviation compensation table acquisition module: used to measure the phase deviation between different channels at fixed frequency intervals through a signal source and a power divider in a laboratory environment to obtain a phase deviation compensation table.

[0095] Phase difference measurement module: used to calculate the phase difference between channels AB.

[0096] Azimuth and elevation angle estimation module: Based on the two-dimensional joint search method, the azimuth and elevation angles are quickly estimated by combining coarse search and fine search.

[0097] 4) System workflow

[0098] Antenna A is rotated by the rotating mechanism, while antenna B is fixed. The two receiving channels collect data synchronously, and the baseline AB measures the phase difference. According to the phase difference data and the pre-acquired phase deviation compensation table, the inherent phase deviation between channels is compensated. Then, the azimuth and elevation angles are estimated by combining the coarse search and the fine search method to achieve direction finding.

[0099] -Phase difference calculation: In the coordinate system where the rotating baseline is located, the target azimuth angle is φ and the pitch angle is θ. The phase deviation compensation table is used to compensate for the phase deviation.

[0100] - Coarse search: Set 2N potential azimuth angles and M potential elevation angles. Under each assumed angle, calculate the phase difference and compare it with the actual phase difference sequence. The angle combination with the smallest error sum is taken as the potential incoming wave direction.

[0101] - Fine search: Set the search range and precision parameters near the angle combination determined by the rough search, build a new local two-dimensional search matrix, calculate the confidence judgment value again, and finally get the most accurate azimuth and elevation estimation results. When the elevation angle is close to 0 degrees, set the elevation angle to 0 and search the azimuth angle again.

[0102] like Figure 1As shown, a dual-antenna three-dimensional rotating baseline system provided by an embodiment of the present invention comprises two antennas forming a three-dimensional array, which are respectively denoted as antenna A and antenna B, wherein antenna A is located in a rotating plane, connected to the rotating axis through a cross bar, and has an adjustable spacing, with a maximum distance of L meters from the rotation center O, and counterweights are placed at symmetrical positions of the rotation center to maintain balance; a vertical rod is arranged along the rotating axis, and the length of the vertical rod is adjustable, with a maximum of K meters, and antenna B is located at the upper end of the vertical rod; when working, antenna A is driven by a rotating mechanism or a rotating platform to rotate counterclockwise, and antenna B is located on the rotating axis and does not rotate; the two antennas are respectively connected to two receiving channels, and synchronously collect data when working to form a baseline AB, and the phase difference of the baseline AB is measured, and the azimuth and elevation angles are estimated by measuring multiple groups of phase differences.

[0103] like Figure 2 As shown, the dual-antenna three-dimensional rotating baseline direction finding method provided by the embodiment of the present invention specifically includes the following steps:

[0104] Step 1: Compensate the phase deviation between channels by table. The phase deviation between two measurement channels is measured in full working frequency band with equal frequency intervals in advance to form a channel phase deviation compensation table AB, which is used to compensate for the inherent phase deviation between channels A and B.

[0105] Step 2: After the dual-antenna three-dimensional rotating baseline direction-finding device starts working, the baseline formed by antennas AB rotates counterclockwise at an angular velocity Ω, and the two receiving channels collect data synchronously, and the phase difference of the corresponding data of baseline AB is calculated;

[0106] Step three, based on the two-dimensional joint search method, estimate the azimuth and elevation angles by combining coarse search and fine search.

[0107] Further, the method for calculating the phase difference includes:

[0108] a) In the coordinate system of the rotating baseline itself, assuming that the target azimuth angle is α and the pitch angle is β, the phase deviation compensation table generated in advance is used to perform phase deviation compensation;

[0109] b) The phase difference of baseline AB is:

[0110]

[0111] Where f is the signal frequency, d is the length from antenna A to the rotation center O, k is the height of the vertical rod, Ω is the baseline rotation angular velocity, t is the time, n AB (t) is the random noise when measuring the baseline AB phase difference, and mod is the modulo operation. Since the sine component of the pitch angle is introduced, it can be determined whether the incoming wave direction is above or below the rotation plane.

[0112] Furthermore, the two-dimensional search method for estimating the azimuth and elevation angles is as follows:

[0113] 1) To reduce the amount of calculation, a rough search is first performed, assuming that 2N potential azimuths are Assume that M potential pitch angles are Obviously, the settings of N and M determine the amount of calculation and search accuracy;

[0114] 2) Under the assumption of the i-th azimuth angle and the j-th elevation angle, calculate the phase difference at time t:

[0115] 3) After the phase difference calculations at all times t are completed, the phase difference sequence Δφ corresponding to (α(i), β(j)) is obtained AB (t,i,j), and the sum of the errors between it and the true phase difference sequence is used as the confidence judgment value of the angle combination (α(i), β(j)): F(i,j) = sum[abs(Δφ AB (t)-Δφ AB (t,i,j))], obviously the lower this value is, the higher the confidence is;

[0116] 4) Select the angle combination (α(i r ),β(j r ))(r=0,1,...,V-1) as the potential incoming wave direction;

[0117] 5) High-precision search, for V potential angle combinations (α(i r ),β(j r ))(r=0,1,...,V-1), set the azimuth search range α0 and the search precision parameter T, the elevation search range β0 and the search precision parameter Z, and construct a new local two-dimensional search matrix [α(p),β(q)] with a dimension of (T+1)×(Z+1). and

[0118] 6) According to the definition in step 3), F(i,j) = sum[abs(Δφ AB (t)-Δφ AB (t,i,j))] calculate the confidence judgment value and obtain a new confidence judgment matrix;

[0119] 7) Take the angle combination corresponding to the minimum confidence judgment value as the estimation result (α', β');

[0120] 8) For the pitch angle β close to The special treatment of the phase difference is obviously based on the phase difference calculation formula. It can be seen that the phase difference formula will degenerate into In this case, the azimuth angle in the rough estimated potential angle combination obtained in step c4) is inaccurate;

[0121] 9) In view of the above situation, the pitch angle is set to β', the confidence judgment value is calculated, and the azimuth angle is searched again. The search accuracy is determined by the parameter W: This step should improve the search accuracy and update the azimuth estimate based on the new search results, and the process is now complete.

[0122] like Figure 3 As shown, an embodiment of the present invention provides a dual-antenna three-dimensional rotating baseline direction finding system for implementing the dual-antenna three-dimensional rotating baseline direction finding method, comprising:

[0123] A phase deviation compensation table acquisition module is used to measure the phase deviation between different channels of the three-dimensional direction finding system at fixed frequency intervals through a signal source and a power divider in an indoor test environment to obtain a phase deviation compensation table between different channels;

[0124] Phase difference measurement module, used to calculate the phase difference between channels AB;

[0125] The azimuth and elevation angle estimation module is based on a two-dimensional joint search method and combines coarse search with fine search to achieve rapid estimation of azimuth and elevation angles.

[0126] Example 1: A ground dual-antenna three-dimensional rotating baseline direction-finding system measures the direction of an aerial radiation source (such as a drone). The target azimuth is 30°, the pitch is 60°, the phase difference measurement error is 20°, the horizontal rod is 10 times the wavelength, and the vertical rod is 5 times the wavelength.

[0127] The schematic diagram of the ground dual-antenna three-dimensional rotating baseline direction finding system in the embodiment of the present invention is shown in Figure 4 , including a rotating mechanism, a receiving antenna array, a receiver and signal processing board, and a display and control module, to achieve the estimation of the azimuth and elevation angles of the radiation source of the aerial target.

[0128] In this embodiment, Figure 4 As shown, the antenna array consists of two omnidirectional antennas, typically fiberglass antennas, denoted as antenna A and antenna B, where antenna A is located in the rotation plane and connected to the rotation axis through a crossbar with adjustable spacing, and weights are placed at symmetrical positions at the rotation center to maintain balance. A vertical rod is set along the rotation axis with an adjustable length, and antenna B is located at the upper end of the vertical rod.

[0129] In this embodiment, the rotating mechanism is typically a motor (the higher the theoretical speed, the more conducive it is to measurement, but too high a speed can easily cause the cross bar to break, so a suitable motor should be rotated as needed), antenna A is driven by the motor to rotate counterclockwise at a set angular velocity such as 2π radians per second, and antenna B does not rotate.

[0130] In this embodiment, the receiver is composed of two synchronous receiving channels (typically, a receiver based on the AD9361 chip).

[0131] In this embodiment, the signal processing board is composed of two programmable devices, FPGA and DSP, which digitally processes the signal, calculates the baseline AB phase difference, and estimates the target angle.

[0132] In this embodiment, the display and control module is composed of a microprocessor, a display screen, etc., and is connected to the signal processing board through a network port. Its main functions include result display, user control command sending, etc.

[0133] In this embodiment, the system direction finding process is as follows: Figure 6 As shown:

[0134] (1) Generate a phase deviation compensation table between two receiving channels in advance through actual measurement;

[0135] (2) The motor drives the antenna to start rotating, collects data synchronously, and measures the phase difference between the AB channels. The results are as follows: Figure 7 As shown;

[0136] (3) Based on the AB phase difference sequence, the azimuth and elevation angles are roughly estimated, such as Figure 8 As shown in the figure, the lowest confidence judgment value appears near the true value of azimuth and pitch (the rough estimate result is 27° for azimuth and 59.72° for pitch);

[0137] (4) The azimuth and elevation angles are accurately estimated by the joint search method of azimuth and elevation. The results are as follows: Fig. 9 As shown (the precise estimation results are 29.86° in azimuth and 59.72° in elevation);

[0138] (5) For targets with an elevation angle close to ±90°, re-search the azimuth angle with a finer resolution.

[0139] (6) The processing results are reported and displayed.

[0140] Example 2: The UAV-mounted dual-antenna three-dimensional rotating baseline direction-finding system locates the interference source, the target azimuth is 30°, the pitch is -60°, the phase difference measurement error is 20°, the horizontal rod is 10 times the wavelength, and the vertical rod is 5 times the wavelength.

[0141] In this embodiment, the schematic diagram of the UAV-mounted dual-antenna three-dimensional rotating baseline system is as follows: Figure 5 , consists of a receiving antenna, a UAV system, a receiver and signal processing board, a data transmission module and a ground display and control system.

[0142] In this embodiment, the receiving antenna uses two omnidirectional antennas (typically dipole antennas), which have substantially the same amplitude / phase response in the horizontal 360-degree direction. The two antennas are denoted as A and B, respectively, and are fixed on the drone through an adjustable crossbar and an adjustable vertical rod.

[0143] In this embodiment, the UAV is a rotor-type UAV (typically such as the Tianying M8-240 eight-rotor UAV, etc.), and the base line composed of antennas A and B is driven to rotate by the rotation of the UAV itself.

[0144] In this embodiment, the receiver is composed of two synchronous receiving channels (typically, a receiver based on the AD9361 chip).

[0145] In this embodiment, the signal processing board is composed of two programmable devices, FPGA and DSP, which digitally processes the signal, calculates the baseline AB phase difference, and estimates the target angle.

[0146] In this embodiment, the data transmission module (such as the Huazhiyi V21 digital image transmission) is responsible for transmitting the data collected and processed by the system to the ground display and control station.

[0147] In this embodiment, the system direction finding process is as follows: Fig.10 As shown:

[0148] (1) Generate a phase deviation compensation table between two receiving channels in advance through actual measurement;

[0149] (2) The drone takes off and hovers at a specified altitude;

[0150] (3) The drone spins, collects data synchronously, and measures the phase difference between the AB channels. The results are as follows: Fig.11 As shown;

[0151] (4) Based on the AB phase difference sequence, the azimuth and elevation angles are roughly estimated, such as Fig.12 As shown in the figure, the lowest confidence judgment value appears near the true value of azimuth and pitch (the rough estimate result is 27° in azimuth and -62.27° in pitch);

[0153] (5) The azimuth and elevation angles are accurately estimated by the joint search method of azimuth and elevation. The results are as follows: Fig.13 As shown (the precise estimation result is azimuth 29.29°, pitch -60.27°);

[0154] (6) For targets with an elevation angle close to ±90°, re-search the azimuth angle with a finer resolution.

[0155] (7) The processing results are reported and displayed.

[0156] Combining the processing results of Example 1 (pitch angle +60°) and Example 2 (pitch angle -60°), it can be seen that the method of the present invention expands the measurement range of the pitch angle to [-90° to 90°].

[0157] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0158] 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 modification, equivalent substitution and improvement made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A dual-antenna three-dimensional rotating baseline direction finding method, characterized in that: The following steps are involved: Step 1: Compensate the phase deviation between channels by table. The phase deviation between two measurement channels is measured in full working frequency band with equal frequency intervals in advance to form a channel phase deviation compensation table AB, which is used to compensate for the inherent phase deviation between channels A and B. Step 2: After the dual-antenna three-dimensional rotating baseline direction-finding device starts working, the baseline formed by antennas AB rotates counterclockwise at an angular velocity Ω, and the two receiving channels collect data synchronously, and the phase difference of the corresponding data of baseline AB is calculated; Step three, based on the two-dimensional joint search method, estimate the azimuth and elevation angles by combining coarse search and fine search.

2. The dual-antenna three-dimensional rotating baseline direction finding method according to claim 1, characterized in that: Methods for calculating phase difference include: (1) In the coordinate system of the rotating baseline itself, the target azimuth angle is α and the pitch angle is β, and the phase deviation compensation table generated in advance is used to perform phase deviation compensation; (2) The phase difference of baseline AB is: Among them, the length of AO is d, the height of the vertical rod BO is k, and n AB (t) represents the random error measured at different times. Based on the sinusoidal component of the pitch angle, it is determined whether the incoming wave direction is above or below the rotation plane.

3. The dual-antenna three-dimensional rotating baseline direction finding method according to claim 1, characterized in that: Coarse searches include: 1) Assume that the 2N potential azimuths are Assume that M potential pitch angles are 2) Under the assumption of the i-th azimuth angle and the j-th elevation angle, calculate the phase difference at time t: 3) After the phase difference calculations at all times t are completed, the phase difference sequence Δφ corresponding to (α(i), β(j)) is obtained AB (t,i,j), and the sum of the errors between it and the true phase difference sequence is used as the confidence judgment value of the angle combination (α(i), β(j)): F(i,j) = sum[abs(Δφ AB (t)-Δφ AB (t,i,j))], the lower this value is, the higher the confidence is; 4) Select the angle combination (α(i r ),β(j r ))(r=0,1,...,V-1) is used as the potential incoming wave direction.

4. The dual-antenna three-dimensional rotating baseline direction finding method according to claim 1, characterized in that: Refine Search includes: 1) For V potential angle combinations (α(i r ),β(j r ))(r=0,1,…,V-1), set the azimuth search range α0 and the search precision parameter T, the elevation search range β0 and the search precision parameter Z, and construct a new local two-dimensional search matrix [α(p),β(q)] with a dimension of (T+1)×(Z+1). 2) According to F(i,j)=sum[abs(Δφ AB (t)-Δφ AB (t,i,j))] calculate the confidence judgment value and obtain a new confidence judgment matrix; 3) Take the angle combination corresponding to the minimum confidence judgment value as the estimation result (α', β'); 4) For the pitch angle β close to When , the pitch angle is set to β', the confidence judgment value is calculated and the azimuth angle is searched again. The search accuracy is determined by the parameter W: Update the bearing estimate based on the new search results.

5. A dual-antenna three-dimensional rotating baseline direction finding device for implementing the dual-antenna three-dimensional rotating baseline direction finding method according to any one of claims 1 to 4, characterized in that: The three-dimensional array is composed of two antennas, which are denoted as antenna A and antenna B. Antenna A is located in the rotation plane and is connected to the rotation axis through a cross bar. The spacing is adjustable and the maximum distance from the rotation center O is L meters. At the same time, counterweights are placed at symmetrical positions of the rotation center to maintain balance. A vertical rod is set along the rotation axis. The length of the vertical rod is adjustable and the maximum length is K meters. Antenna B is located at the upper end of the vertical rod.

6. The dual-antenna three-dimensional rotating baseline direction finding device according to claim 5, characterized in that: When the device is working, antenna A is driven by a rotating mechanism or a rotating platform to rotate counterclockwise, and antenna B is located on the rotating axis and does not rotate. The two antennas are respectively connected to two receiving channels, and collect data synchronously when working to form a baseline AB. The phase difference of the baseline AB is measured, and the azimuth and elevation angles are estimated by measuring multiple groups of phase differences.

7. A dual-antenna three-dimensional rotating baseline direction finding system for implementing the dual-antenna three-dimensional rotating baseline direction finding method according to any one of claims 1 to 4, characterized in that: include: A phase deviation compensation table acquisition module is used to measure the phase deviation between different channels of the three-dimensional direction finding system at fixed frequency intervals through a signal source and a power divider in an indoor test environment to obtain a phase deviation compensation table between different channels; Phase difference measurement module, used to calculate the phase difference between channels AB; The azimuth and elevation angle estimation module is based on a two-dimensional joint search method and combines coarse search with fine search to achieve rapid estimation of azimuth and elevation angles.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the dual-antenna three-dimensional rotating baseline direction finding method according to any one of claims 1 to 4.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the dual-antenna three-dimensional rotating baseline direction finding method according to any one of claims 1 to 4.

10. An information data processing terminal, characterized in that: The information data processing terminal includes the dual-antenna three-dimensional rotating baseline direction finding system described in claim 7.

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