High-precision direction finding method and device based on SDR equipment
By using a high-bandwidth, low-latency data link based on SDR equipment and array manifold correction, combined with a multi-signal classification algorithm, the problems of data transmission delay and insufficient direction finding accuracy in high-precision direction finding systems are solved, achieving high-precision and fast-adaptive direction finding results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-04-03
AI Technical Summary
In the existing technology, high-precision direction finding systems have problems such as data transmission delay and bandwidth limitations, insufficient direction finding accuracy, and poor algorithm adaptability. In particular, the deviation between the array manifold and the theoretical model caused by array antenna manufacturing errors and deployment errors affects the direction finding accuracy and real-time performance.
By employing a high-bandwidth, low-latency data link based on SDR equipment, combined with a high-resolution multi-signal classification direction finding algorithm and an array manifold correction mechanism, high-speed transmission of multi-channel signals is achieved through fiber optic and PCIE links. Amplitude and phase consistency correction and array manifold correction are performed to improve direction finding accuracy and algorithm adaptability.
It achieves high-precision direction finding, solves the problems of limited direction finding accuracy, large delay and poor algorithm adaptability, improves the real-time performance and cross-platform adaptability of the system, and supports multiple working modes and frequency bands.
Smart Images
Figure CN121791981A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of communication technology, and in particular relates to a high-precision direction finding method and device based on SDR equipment. Background Technology
[0002] With the rapid development of wireless communication, radar detection and precise positioning technologies, array signal processing is increasingly widely used in target direction finding, azimuth estimation, beamforming and other fields. Software Defined Radio (SDR), as a highly flexible and programmable hardware and software integration platform, can generate, acquire and process various signals through software configuration. Therefore, it is widely used in scientific research and engineering to build various prototype systems. In high-precision direction finding scenarios, it is typically necessary to use a multi-channel array antenna to receive signals from the target and determine the signal incident direction using a high-resolution direction estimation algorithm (such as the MUSIC algorithm). However, the applicant has found that the following problems still exist in actual engineering implementation: (1) Data transmission delay and bandwidth limitation: High sampling rate and multi-channel signals need to be transmitted to the host for processing after acquisition. If the interface bandwidth is insufficient or the delay is too large, it will limit the real-time performance and accuracy. (2) Insufficient direction finding accuracy: In traditional systems, due to manufacturing errors, deployment errors and inconsistent characteristics of the array antenna and radio frequency link, the array manifold deviates from the theoretical model, which directly affects the performance of high-resolution algorithms. (3) Insufficient algorithm adaptability: Traditional direction finding systems do not adequately correct array manifolds and are not easy to migrate quickly under different array structures or frequency bands; Therefore, there is an urgent need to propose a direction finding device and method that can improve measurement accuracy and stability. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art by providing a high-precision direction finding method and device based on SDR equipment. By combining a high-bandwidth, low-latency data link architecture with a high-resolution multi-signal classification direction finding algorithm and an array manifold correction mechanism, accurate direction finding of different directional ranges of the array antenna can be achieved, thereby solving the problems of limited direction finding accuracy, large delay, and poor algorithm adaptability in the prior art.
[0004] The objective of this invention is achieved through the following technical solution: A high-precision direction finding method based on SDR equipment includes the following steps: Transmit test signal; Acquire multi-channel radio frequency signal data received by a multi-channel array antenna; The acquired multi-channel radio frequency signal data is transmitted to the front-end card for protocol parsing and caching, and then transmitted to the host. The host computer preprocesses the acquired signal data to perform amplitude and phase consistency correction on the signal data from the antenna array normal direction; Array manifold correction; Based on the corrected array manifold, a multi-signal classification algorithm is run to estimate the orientation. Output the azimuth estimation results.
[0005] In one implementation, signal transmission and reception parameters are configured on the SDR platform to transmit test signals and acquire multi-channel radio frequency signal data received by the multi-channel array antenna.
[0006] In one implementation, the acquired multi-channel radio frequency signal data is transmitted to the fronthaul card via an optical fiber link.
[0007] In one implementation, the front-end card transmits multi-channel radio frequency signal data to the host via a high-speed PCIe bus.
[0008] In one implementation, the acquired signal data is preprocessed, including: Suppose the signal received by the reference channel is: ; The signal received by the i-th channel is: ; Calculate the correction factor: ; In actual direction finding, the received signal of each channel is multiplied by the corresponding correction factor: ; in, Let be the amplitude error factor of the i-th channel compared to the reference channel. Let be the phase error of the i-th channel compared to the reference channel. The signal received by the reference channel, For signals in space, The signal received by the i-th channel. This is a complex exponential expression. For the correction system of the i-th channel, This is the signal received after correction for the i-th channel.
[0009] In one implementation, the array manifold correction includes: Divide the entire azimuth range into several directional intervals; Within each interval, the actual response of the antenna array is measured using a test signal source at a known location; The measured values are compared with the theoretical model to obtain the correction parameters; Establish an array manifold correction library.
[0010] In one embodiment, the array manifold correction further includes: Given M array elements, with respect to the direction θ For narrowband plane waves, the method for calculating the ideal array manifold vector is as follows: ; in, k For space wavenumber, , Let m be the position vector of the m-th element. The unit vector is the direction of incidence. Select several correction signal sources with known directions; SDR acquires the output signals of each channel of the array; Calculate the actual array manifold vector; The corrected vector is obtained by comparing it with the vector of the ideal array manifold. Save the correction vectors to form an array manifold correction library.
[0011] In one implementation, calculating the actual array manifold vector includes: Normalizing the reference array elements yields the relative amplitudes and phases in each direction: ; in, For the m-th channel in the direction Complex response under corrected signal; The correction vector is calculated as follows: .
[0012] In one implementation, a multi-signal classification algorithm is run to estimate the direction, including: Load the corrected array manifold into the MUSIC algorithm core module; Calculate the spatial spectrum and find the peak position to obtain the incident azimuth angle of the signal.
[0013] The present invention also provides a high-precision direction finding device based on an SDR device, comprising: The SDR signal transmission and acquisition unit is used to transmit test signals and synchronously acquire multi-channel radio frequency signal data received by the array antenna. The fronthaul card is connected to the SDR signal transmission and acquisition unit to receive multi-channel radio frequency signal data and transmit it to the host. The host computer runs digital modeling tools based on SDR. The host computer is used to preprocess multi-channel radio frequency signal data, estimate and correct array manifolds, and run multi-signal classification and direction finding algorithms.
[0014] The beneficial effects of this invention are as follows: Compared with existing technologies, this invention, based on fiber optic and PCIE links, achieves high-speed, low-latency transmission of multi-channel broadband signals (high data transmission efficiency). Through array manifold correction, it effectively compensates for manufacturing and deployment errors, improves the performance of the MUSIC algorithm (significantly improves direction finding accuracy), and can quickly correct for different array structures and frequency bands, facilitating cross-platform deployment (strong system adaptability). At the same time, the SDR platform can adjust parameters through software to achieve support for multiple working modes and frequency bands, smoothly solving the problems of limited direction finding accuracy, large latency, and poor algorithm adaptability in existing technologies. Attached Figure Description
[0015] The invention will now be described in more detail with reference to embodiments and the accompanying drawings. Figure 1 A flowchart of the present invention is shown; Figure 2 A schematic diagram of the array manifold correction of the present invention is shown; Figure 3 A schematic diagram of the direction-finding device of the present invention is shown; Figure 4 The real-time radiation pattern and numerical results output by this invention are displayed; In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale. Detailed Implementation
[0016] The invention will now be further described with reference to the accompanying drawings.
[0017] This invention provides a high-precision direction finding method based on SDR equipment, such as... Figure 1 As shown, it includes the following steps: Step S1: Transmit a test signal; Step S2: Acquire multi-channel radio frequency signal data received by the multi-channel array antenna; Step S3: Transmit the acquired multi-channel radio frequency signal data to the front-end card for protocol parsing and buffering, and then transmit the data to the host. Step S4: Use the host to preprocess the acquired signal data to perform amplitude and phase consistency correction on the signal data from the antenna array normal direction; Step S5: Array manifold correction; Step S6: Based on the corrected array manifold, run a multi-signal classification algorithm to estimate the orientation; Step S7: Output the azimuth estimation result; It should be noted that in steps S1 and S2, an SDR device with multi-channel synchronous acquisition capability is selected and connected to the array antenna. The array antenna adopts an equidistant linear array or planar array structure, and the number of channels can be determined according to the direction finding accuracy requirements, such as 2, 4, 8 or more channels. The signal transmission and reception parameters are configured on the SDR platform to transmit test signals and collect multi-channel radio frequency signal data received by the multi-channel array antenna. In step S3, the collected multi-channel radio frequency signal data is transmitted to the front-end card through the optical fiber link. The signal data received by the optical fiber is parsed and buffered, and the data is transmitted to the computer host memory in real time through the PCI Express (PCIE) bus. That is, multi-channel synchronous sampling is realized by using SDR hardware, the data is transmitted to the front-end card through optical fiber, and then sent to the host at high speed through PCIe, realizing high bandwidth and high synchronization accuracy data acquisition, providing the basic conditions for high-precision direction finding. Furthermore, in step S4, a digital modeling tool based on the SDR is used, such as running the bhSDR API interface of the USRP4320 using MATLAB, to call a self-written / optimized array signal processing program. Specifically, this includes the following steps: Collection preparation: Set the transmitted signal waveform on the host's SDR software platform and define parameters such as acquisition bandwidth, sampling rate, and gain; Complete the physical connection and initial calibration of the RF channel at the array antenna end; Data acquisition and transmission: Multi-channel sampling is started synchronously to receive signals from each element of the array; Data is transmitted to the fronthaul card via fiber optic cable, and then sent to the host memory at high speed through the PCIe interface to ensure that the data packets arrive completely in chronological order. Preprocessing stage: The amplitude and phase deviation of each channel are measured using a signal source with a known direction, and then compensated in subsequent processing to perform amplitude and phase consistency correction. It should be noted that, during the preprocessing stage, the signal received by the reference channel is assumed to be: ; The signal received by the i-th channel is: ; Calculate the correction factor: ; In actual direction finding, the received signal of each channel is multiplied by the corresponding correction factor: ; in, Let be the amplitude error factor of the i-th channel compared to the reference channel. Let be the phase error of the i-th channel compared to the reference channel. The signal received by the reference channel, For signals in space, The signal received by the i-th channel. This is a complex exponential expression. For the correction system of the i-th channel, The signal received after correction for the i-th channel is used to ensure that the response of each channel is consistent in the 0° direction; In one embodiment, such as Figure 2 As shown, array manifold correction includes: Divide the entire azimuth range into several directional intervals; Within each interval, the actual response (array manifold vector) of the antenna array is measured using a test signal source at a known location. The measured values are compared with the theoretical model to obtain the correction parameters (amplitude correction coefficient, phase correction coefficient). Establish an array manifold correction library; It should be noted that the entire azimuth range can be divided into several directional intervals in a manner that each interval is 5°. In this embodiment, array manifold correction is to correct the theoretical array manifold by actually measuring the array's response to the known signal, so that the array response model used by the direction finding algorithm matches the real system, thereby improving the direction estimation accuracy. Specifically, assuming there are M array elements, for the direction θ For narrowband plane waves, the method for calculating the ideal array manifold vector is as follows: ; in, k For space wavenumber, , Let m be the position vector of the m-th element. The unit vector is the direction of incidence. Step S501: Select several correction signal sources with known directions, which are generated by the SDR device; Step S502: SDR acquires the output signals of each channel of the array; Step S503: Calculate the actual array manifold vector; Step S504: Construct the correction matrix or correction factor; Step S505: Model correction during actual direction finding; It should be noted that, in this embodiment, as in step S501, the correction signal source should be located in the far field of the array, with a known direction, and emit a known waveform (such as a narrowband continuous wave). The correction angle can cover the array's working range (e.g., every...). (One point); In step S502, it can be sampled by AD and converted into a digital signal. At the same time, in order to reduce the influence of noise, it can be integrated for a long time or averaged multiple times. Further, in step S503, the actual array manifold vector is calculated, including: Normalizing the reference array elements yields the relative amplitudes and phases in each direction: ; in, For the m-th channel in the direction Complex response under corrected signal; In step S504, the correction vector is obtained by comparing it with the ideal array manifold vector. ; Saving these correction vectors creates an array manifold correction library; In step S505, the Multi-Signal Classification (MUSIC) algorithm, etc., calls the corrected manifold when constructing the array manifold matrix: ; in," "This is element-wise complex multiplication."
[0018] It should be noted that in this embodiment, through array manifold correction (traditional array direction finding often only uses known signals to calibrate amplitude and phase errors in a single direction, while this embodiment measures the actual response of the array in multiple azimuth angle intervals and establishes a manifold calibration library covering all azimuth angles), that is, constructing the measured array manifold of the corresponding azimuth, and comparing it with the theoretical array manifold to obtain the correction factor, effectively compensating for manufacturing and deployment errors and greatly improving the performance of the MUSIC algorithm; In one embodiment, step S6 includes: Load the corrected array manifold into the MUSIC algorithm core module; Calculate the spatial spectrum and find the peak position to obtain the incident azimuth angle (DOA) of the signal. In this embodiment, the real-time radiation pattern and numerical results are displayed as follows: Figure 4 As shown.
[0019] In one embodiment, the present invention also provides a high-precision direction-finding device based on an SDR device, such as... Figure 3 As shown, it includes: The SDR signal transmission and acquisition unit is used to transmit test signals and synchronously acquire multi-channel radio frequency signal data received by the array antenna. The fronthaul card is connected to the SDR signal transmission and acquisition unit to receive multi-channel radio frequency signal data and transmit it to the host. The host computer runs digital modeling tools based on SDR. The host computer is used to preprocess multi-channel radio frequency signal data, estimate and correct array manifolds, and run multi-signal classification and direction finding algorithms. It should be noted that the host uses digital modeling tools based on SDR, such as using MATLAB to run the bhSDR API interface of USRP4320 and call self-written / optimized array signal processing programs.
[0020] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0021] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.
Claims
1. A high-precision direction finding method based on SDR equipment, characterized in that, Includes the following steps: Transmit test signal; Acquire multi-channel radio frequency signal data received by a multi-channel array antenna; The acquired multi-channel radio frequency signal data is transmitted to the front-end card for protocol parsing and caching, and then transmitted to the host. The host computer preprocesses the acquired signal data to perform amplitude and phase consistency correction on the signal data from the antenna array normal direction; Array manifold correction; Based on the corrected array manifold, a multi-signal classification algorithm is run to estimate the orientation. Output the azimuth estimation results.
2. The high-precision direction finding method based on SDR equipment according to claim 1, characterized in that, Configure signal transmission and reception parameters on the SDR platform to transmit test signals and collect multi-channel RF signal data received by the multi-channel array antenna.
3. The high-precision direction finding method based on SDR equipment according to claim 1, characterized in that, The acquired multi-channel radio frequency signal data is transmitted to the fronthaul card via an optical fiber link.
4. The high-precision direction finding method based on SDR equipment according to claim 1, characterized in that, The front-end card transmits multi-channel RF signal data to the host via a high-speed PCIe bus.
5. A high-precision direction finding method based on SDR equipment according to claim 1, characterized in that, The acquired signal data undergoes preprocessing, including: Suppose the signal received by the reference channel is: ； The signal received by the i-th channel is: ； Calculate the correction factor: ； In actual direction finding, the received signal of each channel is multiplied by the corresponding correction factor: ； in, Let be the amplitude error factor of the i-th channel compared to the reference channel. Let be the phase error of the i-th channel compared to the reference channel. The signal received by the reference channel, For signals in space, The signal received by the i-th channel. This is a complex exponential expression. For the correction system of the i-th channel, This is the signal received after correction for the i-th channel.
6. The high-precision direction finding method based on SDR equipment according to claim 1, characterized in that, The array manifold correction includes: Divide the entire azimuth range into several directional intervals; Within each interval, the actual response of the antenna array is measured using a test signal source at a known location; The measured values are compared with the theoretical model to obtain the correction parameters; Establish an array manifold correction library.
7. A high-precision direction finding method based on SDR equipment according to claim 6, characterized in that, The array manifold correction also includes: Given M array elements, with respect to the direction θ For narrowband plane waves, the method for calculating the ideal array manifold vector is as follows: ； in, k For space wavenumber, , Let m be the position vector of the m-th element. The unit vector is the direction of incidence. Select several correction signal sources with known directions; SDR acquires the output signals of each channel of the array; Calculate the actual array manifold vector; The corrected vector is obtained by comparing it with the vector of the ideal array manifold; Save the correction vectors to form an array manifold correction library.
8. A high-precision direction finding method based on an SDR device according to claim 7, characterized in that, Calculating the actual array manifold vectors includes: Normalizing the reference array elements yields the relative amplitudes and phases in each direction: ； in, For the m-th channel in the direction Complex response under corrected signal; The correction vector is calculated as follows: 。 9. A high-precision direction finding method and apparatus based on SDR equipment according to claim 8, characterized in that, Run a multi-signal classification algorithm for orientation estimation, including: Load the corrected array manifold into the MUSIC algorithm core module; Calculate the spatial spectrum and find the peak position to obtain the incident azimuth angle of the signal.
10. A high-precision direction-finding device based on SDR equipment, characterized in that, include: The SDR signal transmission and acquisition unit is used to transmit test signals and synchronously acquire multi-channel radio frequency signal data received by the array antenna. The fronthaul card is connected to the SDR signal transmission and acquisition unit to receive multi-channel radio frequency signal data and transmit it to the host. The host computer runs digital modeling tools based on SDR. The host computer is used to preprocess multi-channel radio frequency signal data, estimate and correct array manifolds, and run multi-signal classification and direction finding algorithms.