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CN-121995308-A - Dual-band broadband direction finding system and method based on antenna group gating

CN121995308ACN 121995308 ACN121995308 ACN 121995308ACN-121995308-A

Abstract

The invention discloses a dual-band broadband direction finding system and method based on antenna group gating, wherein the system comprises an antenna array, a signal conversion unit, a channel gating unit, a digital processing unit and a control and interaction unit, wherein the antenna array is used for integrally covering a first antenna group and a second antenna group based on uniform geometric framework arrangement to realize uniform output of a cross-band direction finding result, the signal conversion unit is used for converting radio frequency signals into signals which can be processed by the digital processing unit, the channel gating unit is used for realizing configurable connection of the first antenna group or the second antenna group and a receiving channel of the digital processing unit, the digital processing unit is used for completing signal sampling, feature extraction and direction estimation operation and outputting the direction finding result, and the control and interaction unit is used for outputting parameters and results. According to the invention, the high-frequency direction-finding antenna group and the low-frequency direction-finding antenna group are respectively constructed under the unified hexagonal geometric framework, so that the system has the advantages of omni-directional coverage, direction-finding sensitivity and engineering realization feasibility under the wide-band condition.

Inventors

  • CHENG PEI
  • SUN YOUWEI
  • LI JIFENG
  • LIU JUAN

Assignees

  • 扬州宇安电子科技股份有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (10)

  1. 1. The dual-band broadband direction finding system based on antenna group gating is characterized by comprising an antenna array, a signal conversion unit, a channel gating unit, a digital processing unit and a control and interaction unit; The antenna array is used for integrating a first antenna group covering a first frequency band and a second antenna group covering a second frequency band based on uniform geometric framework arrangement to realize uniform output of a cross-frequency band direction finding result; the signal conversion unit is used for converting the radio frequency signals received by the antenna array into signals which can be processed by the digital processing unit; The channel gating unit is used for realizing configurable connection between the first antenna group or the second antenna group and the digital processing unit receiving channel based on a mapping rule; the digital processing unit is used for completing signal sampling, feature extraction and direction estimation operation, generating and outputting an initial direction finding result to the control and interaction unit; The control and interaction unit is used for working mode configuration, antenna group selection and calibration data management, receives the initial direction finding result output by the digital processing unit, and outputs a final direction finding result to the outside after processing.
  2. 2. The antenna group gating-based dual-band broadband direction finding system according to claim 1, wherein the unified geometrical frame is a uniform hexagonal structure, and six array planes are arranged around the same central coordinate system; the first frequency band is 6-18GHz, and the first antenna group is respectively provided with at least one array element on the adjacent array surfaces at two sides of each vertex angle to form 12 high-frequency array elements distributed in the circumferential direction; the second frequency band is 2-6GHz, and the second antenna group is respectively provided with at least one array element at the center of each array surface to form 6 low-frequency array elements distributed in the circumferential direction.
  3. 3. The antenna group gating-based dual-band broadband direction finding system according to claim 1 or 2, wherein the digital processing unit provides at least 6 synchronous receiving channels for a radio frequency system on chip or an FPGA digital receiver; The channel gating unit is a switch and interface network, the mapping rule is stored in a static mapping table form, and antenna access combinations and corresponding control words under different working modes are predefined.
  4. 4. The antenna group gating-based dual-band broadband direction finding system according to claim 1, wherein the feature extraction of the digital processing unit comprises amplitude extraction and phase difference extraction, and outputs unified format feature data comprising amplitude, phase difference, frequency point identification and time information; the direction estimation of the digital processing unit is realized in a combined mode, wherein rough measurement is used for determining an azimuth range based on amplitude response difference, and precise measurement is used for completing precise angle calculation by combining amplitude and phase difference characteristics.
  5. 5. The antenna group gating-based dual-band broadband direction finding system according to claim 2, wherein the calibration data managed by the control and interaction unit is a phase-amplitude feature library, the phase-amplitude feature library is established by the system through darkroom calibration or turntable calibration, and a feature table containing amplitude ratio and phase difference information is formed by taking frequency bands, frequency point indexes, antenna groups, channel combinations and angles as organization dimensions.
  6. 6. The antenna group gating-based dual-band broadband direction finding system according to claim 5, wherein the digital processing unit is implemented in a FPGA modular design, and the FPGA modular design is divided into a data path and a control path; the processing flow of the data path sequentially comprises AD sampling, digital channelizing, FFT operation, amplitude and phase extraction, characteristic data generation, amplitude-power mapping and attenuation compensation, antenna remapping, amplitude comparison rough measurement, phase comparison accurate measurement, angle mapping and output; The control path has the processing flows of local oscillation, frequency point and attenuation configuration management, loading and selecting of calibration table and table look-up data, array amplitude judgment, channel gating control, region judgment and direction finding mapping and external interface interaction in sequence.
  7. 7. The antenna group gating-based dual-band broadband direction finding system according to claim 3, wherein the 6 low-frequency array elements of the second antenna group can be directly connected to the 6-channel synchronous receiving channel of the digital processing unit without additional gating switching; the first antenna group is connected with the target area antenna and the receiving channel through the channel gating unit, and accurate measurement data acquisition can be completed only by one-time gating switching.
  8. 8. A dual-band broadband direction finding method based on antenna group gating, which is applied to the dual-band broadband direction finding system based on antenna group gating as claimed in any one of claims 1 to 7, and is characterized by comprising the following steps: S1, the control and interaction unit issues a monitoring frequency band and a working mode, and the channel gating unit completes configurable connection of the first antenna group or the second antenna group and a receiving channel of the digital processing unit according to a static mapping table; S2, the signal conversion unit converts the radio frequency signals received by the antenna array into signals which can be processed by the digital processing unit, and the digital processing unit finishes signal sampling and amplitude and phase difference characteristic extraction and outputs unified format characteristic data; S3, if the signal belongs to a first frequency band of 6-18GHz, limiting the azimuth to a certain vertex angle area by comparing the amplitude of the 6 array surfaces, switching the channel gating unit only once, connecting the high-frequency array elements in the vertex angle area into a receiving channel, extracting amplitude and phase characteristics, then removing phase ambiguity of the interferometer by using a rough amplitude comparison measurement result, and realizing accurate angle estimation by using an interferometer method; s4, if the signal belongs to a second frequency band of 2-6GHz, determining a vertex angle sector where a target is located by comparing six paths of amplitude, selecting two array surface low-frequency array elements corresponding to the vertex angle sector, and directly carrying out amplitude comparison or phase comparison direction finding based on the through channel data; And S5, the digital processing unit completes the matching of the amplitude and the phase based on the amplitude and phase feature library, and outputs a direction finding result under the definition of unified coordinates to the control and interaction unit.
  9. 9. The dual-band broadband direction finding method based on antenna group gating according to claim 8, wherein in the step S3, the vertex angle area determination of the first band is realized by six-sided parallel amplitude search, the array plane with the largest amplitude is determined by comparing the amplitude data of the 6 array planes, and the corresponding azimuth area is the hexagonal vertex angle range where the largest array plane is located.
  10. 10. The method for dual-band wideband direction finding based on antenna group gating according to claim 8 or 9, wherein in step S5, before outputting the direction finding result, the control and interaction unit performs verification on the operation result of the digital processing unit, combines with validity judgment of calibration data, and returns to step S2 to perform feature extraction and direction finding calculation again if the error exceeds a preset threshold.

Description

Dual-band broadband direction finding system and method based on antenna group gating Technical Field The invention relates to the technical field of direction finding, in particular to a dual-band broadband direction finding system and method based on antenna group gating. Background In modern electronic countermeasure and reconnaissance tasks, the direction finding requirement for signals of a wide frequency band (especially 2-18 GHz) is increasingly urgent, and the frequency band covers most military and civil radio frequency signals and is a core working frequency band for electronic reconnaissance and interference. The current main flow direction-finding technology is mainly divided into two types of amplitude comparison direction-finding (amplitude comparison method) and interferometer phase direction-finding (phase comparison method), but the two types of technology have inherent defects in wide-frequency-band application: The method determines the target azimuth by comparing the amplitude differences of the signals received by different antenna array elements, has simple structure and low hardware cost, but the direction-finding precision is limited by the width of the antenna lobe, the theoretical precision can only reach about one tenth of the width of the antenna lobe, the high-precision direction-finding requirement is difficult to meet, and in a low frequency band (2-6 GHz), the signal wavelength is long, so that the antenna pattern is wide, the amplitude difference identification degree is further reduced, and the precision defect is more prominent. The phase comparison method carries out azimuth calculation based on the phase difference of signals received by different antenna array elements, the direction finding precision is far higher than that of the amplitude comparison method, but the phase ambiguity problem is obvious that the antenna base line length needs to be increased to improve the precision, and when the base line length exceeds half wavelength of signals, an ambiguity angle is introduced to cause the uncertainty of azimuth solution. The prior art generally eliminates ambiguity by setting a plurality of baseline combinations of different lengths, which undoubtedly increases the hardware complexity, volume and cost of the system, which is not beneficial to engineering deployment. In order to give consideration to the direction-finding precision and the system complexity, the existing high-precision direction-finding system mostly adopts a combined thought of 'rough comparison measurement and precise comparison measurement', namely, the approximate range of the target azimuth is determined by a comparison method, and then the range is utilized to assist the comparison method to finish the fuzzy resolution and the precise measurement. However, in a 2-18GHz wide-band coverage scene, the thought still faces engineering realization problems that on one hand, high-band (6-18 GHz) signals are short in wavelength, interference direction finding is easy to generate a plurality of fuzzy periods, and the fuzzy difficulty is remarkably increased, on the other hand, in order to reduce the hardware scale, most systems acquire data by adopting a mode of polling a plurality of antenna array elements by a single-channel radio frequency switch, a group of direction finding data can be completed by multiple times of switching, so that the direction finding time delay is increased, the switching control is complex, and in a pulse signal or agile signal scene, the problem of phase consistency is caused by non-simultaneous sampling, and the direction finding precision is further influenced. In summary, the existing direction finding technology is difficult to realize the comprehensive performance requirements of 360-degree omni-directional coverage, high sensitivity, high precision and quick response in a wide frequency range of 2-18GHz, and the problems of high hardware complexity, poor engineering floor property and the like are generally existed. Therefore, a direction-finding system structure and a matching implementation method capable of combining broad-band adaptability, rapid direction-finding capability and high-precision calculation under the condition of limited receiving channels are needed, so as to solve the contradiction between time delay, precision and complexity of broad-band direction-finding in the prior art and improve the real-time performance, stability and engineering floor property of the broad-band direction-finding system. The above disclosure of background art is only for aiding in understanding the concept and technical solution of the present application and does not necessarily give technical teaching. Disclosure of Invention The invention aims to provide a dual-band broadband direction finding system and method based on antenna group gating, which respectively construct a high-frequency direction finding antenna group and a low-frequency direction finding antenna group