Direction finding device and method based on spatial two-dimensional four-array-element interferometer

Abstract

The invention relates to the field of radio direction finding, in particular to a direction finding device and method based on a spatial two-dimensional four-array-element interferometer, and solves the problems that in the prior art, a direction finding technology is limited in precision and sensitive to environmental conditions. The system comprises direction finding receiving equipment, a frequency conversion receiving processor, an interference subsystem, a main control system and a server, the direction-finding receiving equipment comprises an array antenna; the array antenna comprises an array directional diagram; the array directional diagram comprises a unit directional diagram, a unit spacing, a feed amplitude and a feed phase. According to the invention, the high-precision and high-tracking-sensitivity direction finding effect of instantaneous wide-coverage multi-signal direction finding and sum-difference amplitude comparison of the interferometer is realized, the phase discrimination error control problem is effectively solved, and the direction finding precision is ensured; by changing the phase of the feed excitation signal of the antenna unit, the change of the beam direction of the antenna pattern is realized, and the accurate control of the radiation beam direction and the radiation mode of the antenna is realized.

Description

Technical Field

[0001] The invention relates to the field of radio direction finding, and in particular to a direction finding device and method based on a spatial two-dimensional four-element interferometer. Background Art

[0002] Radio direction finding technology is widely used in spectrum monitoring, radar countermeasures, communication countermeasures and navigation countermeasures. It is an important means to obtain the direction of non-cooperative signals. The direction finding results are usually used for electronic countermeasure direction guidance, radiation source tracking and other applications. It is the basic component of electromagnetic spectrum warfare and network-electronic countermeasures. The accuracy of direction finding directly affects the effectiveness of subsequent reconnaissance missions.

[0003] Radio direction finding usually has two branches: amplitude comparison direction finding and phase comparison direction finding, which lead to a variety of test methods such as Watson-Watt direction finding method, correlation interferometer direction finding method, sum-difference angle measurement method, and spatial spectrum estimation method. Different test methods have different application scenarios, each with its own advantages and disadvantages, and different considerations in hardware design / software processing. In general, it is difficult for radio direction finding to achieve a root mean square error of 0.5°, especially in the W band. Due to the larger phase detection error and greater difficulty in phase calibration, a direction finding error better than 3° has not been reported.

[0004] There is an urgent need for a new type of direction finding device and direction finding method that can solve the above problems. Summary of the invention

[0005] The present invention provides a direction-finding device and method based on a spatial two-dimensional four-element interferometer, which solves the problems of limited accuracy and sensitivity to environmental conditions of the direction-finding technology in the prior art.

[0006] The technical solution of the present invention is implemented as follows: a direction-finding device based on a spatial two-dimensional four-element interferometer comprises a direction-finding receiving device, a frequency conversion receiving processor, an interference subsystem, a main control system and a server; the main control system is respectively connected to the frequency conversion receiving processor, the interference subsystem and the server; the direction-finding receiving device, the frequency conversion receiving processor and the interference subsystem are electrically connected to each other; the direction-finding receiving device comprises an array antenna for signal detection, parameter detection, interferometer angle measurement and real-time pulse measurement; the array antenna comprises: an array directional pattern realized by arranging unit antenna feeds; the array directional pattern comprises: a unit directional pattern of amplitude and phase data that varies with spatial angles; a unit spacing that determines the relative position between unit antenna feeds in the array; and a feed amplitude and a feed phase that affect the excitation state of each unit antenna feed.

[0007] In one embodiment, the array antenna further includes an array factor obtained by calculating the amplitude and phase of each unit antenna feed; the array factor calculation formula of the array antenna is:

[0008]

[0009] Among them, it is a two-dimensional uniform planar array composed of M*N units; An and Am are the feeding amplitudes of the nth and mth unit antennas respectively, βn and βm represent the corresponding feeding phases, and dx and dy are the unit spacings along the X-axis and Y-axis; e is a natural constant, i and j are phase and radian related parameters, φ represents the phase, and θ represents the radian.

[0010] In a preferred embodiment, the array factor also includes calculation of a unit antenna feed weighted phase quantity for precise control of the direction of the array antenna radiation beam.

[0011] Furthermore, the frequency conversion receiving processor includes a power supply component, a 4-channel frequency conversion component, a clock component, a signal detection component, a signal sorting component and a system control component; the 4-channel frequency conversion component is respectively connected to the clock component and the signal detection component; the signal detection component, the signal sorting component and the system control component are connected in sequence; the system control component controls the connection to the system main control.

[0012] Furthermore, the interference subsystem includes a DBF array, an instantaneous frequency measurement module, an interference digital processing module, a transmission up-conversion channel, and an amplitude comparison direction finding module; the system main control parallel port controls the connection to the interference subsystem.

[0013] In different embodiments, the array antenna may be a planar array antenna, a spherical array antenna, or a cylindrical array antenna; and also includes a spatial spectrum direction finding auxiliary direction finding means for improving the fusion of direction finding results.

[0014] In a preferred embodiment, the frequency conversion receiving processor further includes a mobile characteristic compensation component for continuous tracking of the radiation source on the mobile platform.

[0015] A direction-finding method based on a spatial two-dimensional four-element interferometer is characterized in that it includes signal detection, signal processing and signal control processes; the signal detection process specifically includes: detecting signals of different bands, parameter detection, interferometer angle measurement and real-time pulse measurement; the signal processing process specifically includes: after signal detection, signal sorting and model identification are performed on signals of different bands; the signal control process specifically includes: after signal processing, system control, detection result reporting, library table and interface management are performed on signals of different bands.

[0016] In a preferred embodiment, the signal control process achieves a change in the antenna pattern beam pointing direction by changing the phase of the unit antenna feed; specifically, by adjusting the weighted phase amount of each unit antenna feed; and by controlling the array pattern and array factor to achieve radiation pattern and beam control.

[0017] In one embodiment, the antenna resolution is improved by increasing the unit spacing between unit antenna feeds; specifically, the antenna aperture length is increased to achieve the purpose of narrowing the antenna beam.

[0018] The invention discloses a direction-finding device and method based on a spatial two-dimensional four-element interferometer. By increasing the spacing of the unit antenna feeds and increasing the antenna aperture length, the antenna beam becomes narrower and the antenna resolution is improved. The invention realizes the interferometer's instantaneous wide-coverage multi-signal direction-finding and the direction-finding effect of high-precision and high-tracking sensitivity of the sum-difference ratio, effectively solves the problem of phase-detection error control, and ensures the direction-finding accuracy. By changing the phase of the antenna unit feed excitation signal, the antenna pattern beam pointing direction is changed, and the precise control of the antenna radiation beam direction and radiation mode is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 : System block diagram of the present invention;

[0021] Figure 2 : Signal flow diagram of direction finding receiving equipment;

[0022] Figure 3 :Digital hardware functional block diagram of direction finding receiving equipment;

[0023] Figure 4 :Schematic diagram of the geometric relationship of unit antenna feeding;

[0024] Figure 5 : K-band array element design layout diagram;

[0025] Figure 6 : Array element design layout diagram for Ka band;

[0026] Figure 7 : Array element design layout diagram for W band. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention discloses a direction-finding device based on a space two-dimensional four-element interferometer, comprising a direction-finding receiving device, a frequency conversion receiving processor, an interference subsystem, a main control system and a server; the main control system is respectively connected to the frequency conversion receiving processor, the interference subsystem and the server; the direction-finding receiving device, the frequency conversion receiving processor and the interference subsystem are electrically connected to each other; the direction-finding receiving device comprises an array antenna for signal detection, parameter detection, interferometer angle measurement and real-time pulse; the array antenna comprises: an array pattern realized by arranging unit antenna feeds; the array pattern comprises: a unit pattern of amplitude and phase data that varies with spatial angles; a unit spacing that determines the relative position between unit antenna feeds in the array; and a feed amplitude and a feed phase that affect the excitation state of each unit antenna feed. In one embodiment, the antenna beam is narrowed by increasing the unit spacing between unit antenna feeds, specifically increasing the antenna aperture length, thereby improving the antenna resolution.

[0029] In one embodiment, the array antenna further includes an array factor obtained by calculating the amplitude and phase of each unit antenna feed; the array factor calculation formula of the array antenna is:

[0030]

[0031] Among them, it is a two-dimensional uniform planar array composed of M*N units; An and Am are the feeding amplitudes of the nth and mth unit antennas respectively, βn and βm represent the corresponding feeding phases, and dx and dy are the unit spacings along the X-axis and Y-axis; e is a natural constant, i and j are phase and radian related parameters, φ represents the phase, and θ represents the radian.

[0032] In a preferred embodiment, the array factor also includes calculation of a unit antenna feed weighted phase quantity for precise control of the direction of the array antenna radiation beam.

[0033] The calculation formula of the unit antenna feed weighted phase quantity can be calculated by the array factor formula of the array antenna.

[0034] Array factor of array antenna: Array factor is an important parameter that describes the radiation characteristics of array antenna. It reflects the gain change of the antenna in different directions. By adjusting the feeding amplitude and phase of each unit, the radiation pattern of the antenna can be controlled.

[0035] Weighted phase: In the design of array antennas, beam scanning and pointing control can be achieved by applying different phase offsets to each antenna element. Phase weighting is achieved by applying a phase offset to the feed signal of each element.

[0036] like Figure 4The geometric relationship diagram of the unit antenna feeding is shown in the figure. Assume that the initial position of the unit antenna is at point Ο(x0,y0,z0), and the phase of its far-field radiation pattern is φ0(θ i ,φ j ), after moving it to 01(x1,y1,z1), it is obvious that the phase of the far-field pattern of the unit antenna feed at the 01 position changes, which is calculated as φ1(θ i ,φ j The phase change between the two is Δφ=φ1(θ i ,φ j )-φ1(θ i ,φ j ), the phase difference is the array factor of the binary array.

[0037] The calculation of phase difference is related to the path difference of electromagnetic wave propagation, and is based on the far field (θ i ,φ j ) direction as an example, from point O1(x1,y1,z1) to point O(x0,y0,z0) (θ i ,φ j ) direction, and the intersection point is M(x,y,z). Then the two positions along (θ i ,φ j ) direction is |ΟM|, where the length is r, then Δφ=360*r / λ0, where λ0 is the wavelength at the antenna operating frequency.

[0038] The specific derivation of r is as follows:

[0039] Known:

[0040] ①The coordinates of point M: x = x0 + rsinθ i cosφ j ,y=y0+rsinθ i sinφ j ,z=z0+rcosθ i

[0041] ②ΟM⊥Ο1M

[0042] ③Let d x =x1-x0,d y =y1-y0,d z =z1-z0

[0043] but:

[0044]

[0045] Again [(sinθ i cosφ j )2+(sinθ i sinφ j)2+cos2θ i ]=1

[0046] rounding (r=0 is discarded).

[0047] When it is a planar array, d z =0, then: r = d x sinθ i cosφ j +d y sinθ i sinφ j .

[0048] It can be further calculated that compared with the unit at position O(x0,y0,z0), the increased weighted phase amount of the far-field radiation pattern of the unit at position O1(x1,y1,z1) is: ejΔφ=ejβ(dxsinθicosφj+dysinθisinφj)(β=2π / λ0).

[0049] Furthermore, the frequency conversion receiving processor includes a power supply component, a 4-channel frequency conversion component, a clock component, a signal detection component, a signal sorting component and a system control component; the 4-channel frequency conversion component is respectively connected to the clock component and the signal detection component; the signal detection component, the signal sorting component and the system control component are connected in sequence; the system control component controls the connection to the system main control.

[0050] Furthermore, the interference subsystem includes a DBF array, an instantaneous frequency measurement module, an interference digital processing module, a transmission up-conversion channel, and an amplitude comparison direction finding module; the system main control parallel port controls the connection to the interference subsystem.

[0051] In different embodiments, the array antenna may be a planar array antenna, a spherical array antenna, or a cylindrical array antenna; and also includes a spatial spectrum direction finding auxiliary direction finding means for improving the fusion of direction finding results.

[0052] In a preferred embodiment, the frequency conversion receiving processor further includes a mobile characteristic compensation component for continuous tracking of the radiation source on the mobile platform.

[0053] Spherical array antenna is a common antenna structure, which is widely used in communication systems, radar systems and satellite communications. It consists of multiple antenna elements, which are evenly distributed on the sphere to form a spherical array. Spherical array antenna has high gain, directivity and anti-interference ability, and can receive and transmit target signals. The design and implementation of spherical array antenna is a complex and important process, which needs to consider multiple factors, including the location and number of antenna elements, the shape and size of the antenna array, etc.

[0054] The following is the general process of implementing a spherical array antenna:

[0055] ① Requirements analysis: First, it is necessary to clearly define the requirements for designing spherical array antennas, including operating frequency bands, gain requirements, directivity requirements, etc. These requirements will guide the subsequent design and optimization process.

[0056] ② Antenna element selection: Select the appropriate antenna element based on demand analysis. Common antennas

[0057] ③Components include microstrip antennas, dipole antennas, etc. Selecting appropriate antenna components can meet design requirements and simplify the subsequent optimization process.

[0058] ④ Antenna element layout: Determine the layout of the antenna elements on the sphere. Usually, a uniform distribution is used so that the distance between each antenna element is equal. The rationality of the layout will directly affect the performance of the antenna.

[0059] ⑤Array calibration: Due to manufacturing and installation errors, the actual performance of the antenna array may differ from the theoretical design. Therefore, array calibration is required to adjust the phase and amplitude of the antenna elements so that the actual performance of the array is close to the theoretical design.

[0060] ⑥ Optimization algorithm: Use optimization algorithm to optimize the spherical array antenna. Common optimization algorithms include genetic algorithm, particle swarm optimization algorithm, etc. By adjusting the position, number and phase of antenna elements and other parameters, the performance indicators of the antenna are optimized.

[0061] ⑦ Performance evaluation: Evaluate the performance of the optimized spherical array antenna. Evaluation indicators include gain, radiation pattern, beam width, beam offset, etc. Through simulation and experimental verification, evaluate whether the antenna meets the design requirements.

[0062] The specific implementation of spherical array antenna is a comprehensive task, which requires the combination of knowledge in multiple fields such as electromagnetic theory, signal processing and optimization algorithm. Through scientific and reasonable optimization, high-performance applications of spherical array antenna in fields such as communication and radar can be achieved.

[0063] Cylindrical array antennas are mainly used for omnidirectional multi-beam coverage and solving the mutual coupling problem of conformal arrays. Through specific design and analysis, this type of antenna can achieve broadband high-gain circular polarization and perform beam scanning coverage in multiple directions. The research and design of cylindrical array antennas involve the research of broadband high-gain circular polarization antenna units, the design of array forms, mutual coupling analysis, beamforming, and the design of multi-path unequal power dividers.

[0064] The working principle of cylindrical array antenna is based on phase control and beam forming. By adjusting the phase of each antenna, the transmission or reception time of the signal can be controlled so that the signal is superimposed in a specific direction, thereby enhancing the strength of the target signal. This phase control realizes beam forming, which concentrates energy in a specific direction, thereby increasing the reception or transmission sensitivity of the signal in a specific direction while reducing interference in other directions.

[0065] Cylindrical array antennas have a variety of application scenarios. For example, in the U.S. Navy's distributed combat system, cylindrical passive phased array antennas are used to achieve omnidirectional multi-beam scanning coverage. This type of antenna is not only suitable for military applications, but can also be used in communications, radar, remote sensing and other fields to provide high-precision and high-efficiency signal transmission and processing.

[0066] In a preferred embodiment, the frequency conversion receiving processor, in addition to being applied to a fixed platform, also includes a mobile characteristic compensation component for continuous tracking of radiation sources on a mobile platform.

[0067] On fixed platforms, direction finding technology is mainly used to accurately measure the direction of the radiation source; on mobile platforms, direction finding technology is used to continuously track the radiation source and compensate for the mobility characteristics of the platform.

[0068] On a fixed platform, the main indicators of direction finding technology include system receiving sensitivity, system direction finding sensitivity and system direction finding accuracy. System receiving sensitivity refers to the minimum signal strength that the receiver can detect under a certain signal-to-noise ratio. System direction finding sensitivity refers to the field strength value when the radiation value of the signal source is gradually weakened at any azimuth with a strong signal as the reference until the direction indicator swings and deviates from the reference value parameter. System direction finding accuracy is to use a transmitting signal source on a standard site to measure the difference between the direction indicator and the actual azimuth, usually expressed as the root mean square value (RMS).

[0069] On mobile platforms, direction finding technology needs to take into account the impact of the platform's mobility on direction finding accuracy. If the antenna is less than 1 meter from the roof, the impact of the vehicle body on mobile direction finding cannot be ignored. The error value caused by the impact of the vehicle body is very sensitive to the frequency and the direction of arrival of the radio wave relative to the front of the vehicle, especially within the range of ±(30°~60°) and ±(120°~150°) away from the front of the vehicle.

[0070] In addition, this direction finding technology is widely used in both military and civilian fields. In the military, passive positioning systems such as digital radio frequency memory (DRFM) technology and precise positioning and identification system (PLAID) can achieve high-precision target positioning in a short time. In the civilian field, direction finding technology is used for radio monitoring, communication monitoring, etc.

[0071] A direction-finding method based on a spatial two-dimensional four-element interferometer includes signal detection, signal processing and signal control processes; the signal detection process specifically includes: detecting signals of different bands, parameter detection, interferometer angle measurement and real-time pulse detection; the signal processing process specifically includes: after signal detection, signal sorting and model identification are performed on signals of different bands; the signal control process specifically includes: after signal processing, system control, detection result reporting, library table and interface management are performed on signals of different bands.

[0072] In a preferred embodiment, the signal control process achieves a change in the antenna pattern beam pointing direction by changing the phase of the unit antenna feed; specifically, by adjusting the weighted phase amount of each unit antenna feed, precise control of the antenna radiation beam direction can be achieved; and radiation pattern and beam control are achieved by controlling the array pattern and array factor.

[0073] In a preferred embodiment, the signal control process achieves a change in the antenna pattern beam pointing direction by changing the phase of the unit antenna feed; specifically, by adjusting the weighted phase amount of each unit antenna feed, precise control of the antenna radiation beam direction can be achieved; and radiation pattern and beam control are achieved by controlling the array pattern and array factor.

[0074] Radiation patterns mainly include radiation belt patterns, antenna radiation patterns, etc. Radiation belt patterns refer to the mathematical description of the average distribution state of radiation belts formed by analyzing, processing and processing radiation belt data detected in space using modern computer means. Radiation belt patterns include radiation belt electron AE patterns and proton AP patterns, which are further subdivided into two modes: solar activity peak year and low year. Antenna radiation pattern defines the radiation intensity and phase of the antenna in all directions, and is a key factor in determining antenna performance. Antenna radiation pattern is mainly determined by factors such as the shape, size, material and feeding method of the antenna.

[0075] The methods of controlling the radiation pattern mainly include changing the shape and size of the antenna, using different feeding methods, and using advanced materials and process technologies. These methods can change the radiation pattern by adjusting the physical structure and parameters of the antenna, thereby achieving more precise signal transmission and control.

[0076] First, changing the shape and size of the antenna is a direct and effective method. The shape and size of the antenna are the main factors affecting its radiation pattern, and different shapes and sizes will lead to different radiation patterns. For example, using a specific array antenna structure can achieve beamforming and scanning, thereby better controlling the radiation pattern.

[0077] Secondly, different feeding methods can also be used to control the radiation pattern. The feeding method affects the current distribution of the antenna, thereby affecting its radiation pattern. For example, phase control can be used to achieve beam switching and scanning of multi-beam antennas, further accurately controlling the radiation direction.

[0078] Finally, the use of advanced materials and process technologies is also an effective means of controlling radiation patterns. Metamaterials and other advanced materials can change the electromagnetic properties of antennas, thereby achieving more flexible radiation pattern control. These technological advances make antenna design more intelligent and efficient.

[0079] In one embodiment, the antenna resolution is improved by increasing the unit spacing between unit antenna feeds; specifically, the antenna aperture length is increased to achieve the purpose of narrowing the antenna beam.

[0080] The invention discloses a direction-finding device and method based on a spatial two-dimensional four-element interferometer. By increasing the spacing of the unit antenna feeds and increasing the antenna aperture length, the antenna beam becomes narrower and the antenna resolution is improved. The invention realizes the interferometer's instantaneous wide-coverage multi-signal direction-finding and the direction-finding effect of high-precision and high-tracking sensitivity of the sum-difference ratio, effectively solves the problem of phase-detection error control, and ensures the direction-finding accuracy. By changing the phase of the antenna unit feed excitation signal, the antenna pattern beam pointing direction is changed, and the precise control of the antenna radiation beam direction and radiation mode is realized.

[0081] The present invention is not limited to the millimeter wave frequency band, but can also be applied to scenarios in other frequency bands that require ultra-high direction finding accuracy.

[0082] The present invention is not only applicable to signal tracking and extraction under normal electromagnetic noise levels, but also can be applied to signal tracking and extraction under high electromagnetic noise levels.

[0083] The invention has extremely high direction finding sensitivity and can realize long-distance direction finding, thus achieving the advantages of discovering and responding to the enemy first.

[0084] Of course, without departing from the spirit and essence of the invention, technicians familiar with the field should be able to make various corresponding changes and modifications based on the invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the invention.

Claims

1. A direction-finding device based on a spatial two-dimensional four-element interferometer, characterized in that: It includes a direction finding receiving device, a frequency conversion receiving processor, an interference subsystem, a main control system and a server; the main control system is respectively connected to the frequency conversion receiving processor, the interference subsystem and the server; the direction finding receiving device, the frequency conversion receiving processor and the interference subsystem are electrically connected to each other; The direction finding receiving device comprises an array antenna for signal detection, parameter detection, interferometer angle measurement and real-time intra-pulse; The array antenna comprises: an array pattern realized by feeding unit antennas into an array; The array pattern includes: a unit pattern of amplitude and phase data that varies with spatial angle; a unit spacing that determines the relative position between unit antenna feeds in the array; and a feed amplitude and feed phase that affect the excitation state of each unit antenna feed.

2. The direction-finding device based on a spatial two-dimensional four-element interferometer according to claim 1, characterized in that: The array antenna also includes an array factor obtained by calculating the amplitude and phase of each unit antenna feed; The calculation formula of the array factor of the array antenna is: Among them, a two-dimensional uniform planar array composed of M*N units; An and Am are the amplitudes of the nth and mth unit antenna feeds, respectively, βn and βm represent the corresponding feed phases, and dx and dy are the unit spacings along the X-axis and Y-axis; e is a natural constant, i and j are phase and radian related parameters, φ represents the phase, and θ represents the radian.

3. The direction finding device based on a spatial two-dimensional four-element interferometer according to claim 2, characterized in that: The array factor also includes the calculation of the unit antenna feed weighted phase quantity used for precise control of the direction of the array antenna radiation beam.

4. A direction finding device based on a spatial two-dimensional four-element interferometer according to any one of claims 1 to 3, characterized in that: The frequency conversion receiving processor comprises a power supply component, a 4-channel frequency conversion component, a clock component, a signal detection component, a signal sorting component and a system control component; the 4-channel frequency conversion component is connected to the clock component and the signal detection component respectively; the signal detection component, the signal sorting component and the system control component are connected in sequence; The system control component controls the connection to the system main control.

5. The direction-finding device based on a spatial two-dimensional four-element interferometer according to claim 4, characterized in that: The interference subsystem includes a DBF array, an instantaneous frequency measurement module, an interference digital processing module, a transmission up-conversion channel, and an amplitude comparison direction finding module; the system main control parallel port controls the connection to the interference subsystem.

6. The direction-finding device based on a spatial two-dimensional four-element interferometer according to claim 5, characterized in that: The array antenna may be a planar array antenna, a spherical array antenna or a cylindrical array antenna; It also includes spatial spectrum direction finding auxiliary direction finding means for improving the fusion of direction finding results.

7. The direction-finding device based on a spatial two-dimensional four-element interferometer according to claim 6, characterized in that: The frequency conversion receiving processor also includes a moving characteristic compensation component for continuous tracking of the radiation source on the mobile platform.

8. A direction finding method based on a spatial two-dimensional four-element interferometer, characterized in that: Including signal detection, signal processing and signal control processes; The signal detection process specifically includes: detecting signals of different bands, parameter detection, interferometer angle measurement and real-time intra-pulse; The signal processing process specifically includes: after signal detection, performing signal sorting and model identification on signals of different bands; The signal control process specifically includes: after signal processing, performing system control, detection result reporting, library table and interface management on signals of different bands.

9. The method for direction finding based on a spatial two-dimensional four-element interferometer according to claim 8, characterized in that: The signal control process achieves a change in the antenna pattern beam pointing direction by changing the phase of the unit antenna feed; Specifically, it is done by adjusting the weighted phase amount of each unit antenna feed; Radiation pattern and beam steering are achieved by controlling the array pattern and array factor.

10. The direction finding method based on a spatial two-dimensional four-element interferometer according to claim 9, characterized in that: The antenna resolution is improved by increasing the unit spacing between unit antenna feeds; specifically, the antenna aperture length is increased to achieve the purpose of narrowing the antenna beam.

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