Verification system and method of radio direction finder

Abstract

The invention discloses a verification system and method of a radio direction finder, and relates to the technical field of radio. The system comprises a signal simulation device and a direction finder to be tested. The signal simulation device comprises a control unit, a signal source unit, N paths of power dividers and M phase shifting units, N is greater than or equal to 1, M is greater than or equal to 1, and N and M are positive integers; the signal simulation device is used for simulating the antenna array to send a target radio frequency signal to each channel of the to-be-tested direction finder; and the to-be-tested direction finding machine is used for carrying out direction finding on the target radio frequency signals received by the channels by using an internal direction finding algorithm to obtain the direction indication degree of each target radio frequency signal, and the direction indication degree of each target radio frequency signal is used for determining a verification result. Therefore, the accuracy and verification efficiency of direction finding capability verification and robustness verification of the radio direction finding machine are improved.

Description

Technical Field

[0001] The present application relates to the field of radio technology, and in particular to a verification system and method for a radio direction finder. Background Art

[0002] In the field of radio monitoring and direction finding, verifying the direction finding capabilities of a direction finder is crucial for ensuring its reliability and accuracy. Traditional direction finding verification methods typically require combining a direction finding antenna array with a complete direction finding system, and then testing it in a field or anechoic chamber environment.

[0003] However, this method of verifying direction-finding capabilities places high demands on the antenna array, test site, and environment, which can significantly impact the accuracy of the verification results. Furthermore, building this type of direction-finding system requires numerous devices and is complex. Furthermore, the robustness of the direction-finding algorithm within the direction-finder is typically verified only through data collection verification or software simulation. When these methods are used for robustness verification, the accuracy of the results is also affected by the antenna array and test environment. Summary of the Invention

[0004] The main purpose of this application is to provide a verification system and method for a radio direction finder to improve the accuracy and verification efficiency of the direction finding capability verification and robustness verification of the radio direction finder.

[0005] To achieve the above-mentioned object, the present application provides a verification system for a radio direction finder, comprising a signal simulation device and a direction finder to be tested;

[0006] The signal simulation device includes a control unit, a signal source unit, an N-way power splitter, and M phase shift units, where N≥1, M≥1, and N and M are positive integers; the signal simulation device is used to simulate the antenna array sending a target radio frequency signal to each channel of the direction finder to be measured;

[0007] The direction finder to be tested is used to use an internal direction finding algorithm to perform direction finding on the target radio frequency signals received by each channel to obtain the directionality of each target radio frequency signal, and the directionality of each target radio frequency signal is used to determine the verification result.

[0008] Optionally, the control unit is respectively connected to the signal source unit and each phase shifting unit, and the N-way power splitter is respectively connected to the signal source unit and each phase shifting unit; the control unit is used to send a control instruction to the signal source unit, and determine the signal phase angle value corresponding to each array element in the antenna array according to the simulated antenna array pattern, and send the signal phase angle value corresponding to each array element to the corresponding phase shifting unit; the signal source unit is used to generate an initial signal according to the control instruction, and transmit the initial signal to the N-way power splitter; the N-way power splitter is used to divide the initial signal into N equal-phase RF signals, and output each of the RF signals to the corresponding phase shifting unit; the phase shifting unit is used to adjust the phase of the RF signal according to the received signal phase angle value to obtain the target RF signal, and output the target RF signal to the corresponding channel of the direction finder to be measured.

[0009] Optionally, the signal simulation device further includes M switching units, each of the switching units being connected to a phase shifting unit and one output end of the N-way power divider, and different switching units are connected to different phase shifting units; the control unit is further used to determine a target phase shifting unit connected to the channel of the direction finder to be measured from all the phase shifting units, and control the switch unit correspondingly connected to the target phase shifting unit to be closed.

[0010] Optionally, when each target phase shift unit receives the radio frequency signal for the first time, the phase shift angle of each target phase shift unit is set to 0°; the direction finder to be measured is specifically used to receive each target radio frequency signal sent by each target phase shift unit when the phase shift angle is set to 0°, and determine the correction coefficient corresponding to each channel based on each target radio frequency signal.

[0011] Optionally, the control unit is further used to determine the number of array element switching times based on the number of channels of the direction finder to be measured, the number of array elements in the simulated antenna array, and the internal direction finding algorithm of the direction finder to be measured, and when the number of array element switching times is greater than zero, determine the switching scheme based on the number of array element switching times; when the number of array element switching times is greater than zero, the control unit is specifically used to send the signal phase angle value corresponding to each array element to the corresponding target phase shift unit in batches according to the switching scheme.

[0012] Optionally, the verification result includes a direction-finding capability verification result; the signal simulation device is specifically used to send the target radio frequency signal to each channel of the direction finder to be tested multiple times; in the process of sending the target radio frequency signal each time, the control unit is specifically used to adjust the signal phase angle value corresponding to each array element according to a first preset step; the direction finder to be tested is specifically used to correct the target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain the corrected target radio frequency signal, and process the corrected target radio frequency signal using an internal direction-finding algorithm to obtain the directionality of the target radio frequency signal; the direction-finding capability verification result is determined based on the directionality of each target radio frequency signal and the reference incoming wave direction of the target radio frequency signal.

[0013] Optionally, the verification result includes a robustness verification result; the signal simulation device is specifically used to send the target RF signal to each channel of the direction finder to be tested multiple times; in each process of sending the target RF signal, the control unit is specifically used to adjust the deviation of the signal phase angle value corresponding to each array element according to a second preset step; the direction finder to be tested is specifically used to correct the target RF signal received by any channel using the correction coefficient corresponding to the channel to obtain the corrected target RF signal, and process the corrected target RF signal using an internal direction finding algorithm to obtain the directionality of the target RF signal; the robustness verification result is determined based on the directionality of each target RF signal and the directionality after the corresponding signal phase angle value is adjusted.

[0014] Optionally, the signal source unit includes a processing control module, a frequency conversion module and a local oscillator module; the local oscillator module is used to generate a fixed frequency and a variable frequency; the processing control module is used to generate a basic signal based on the control instruction and the fixed frequency, and output the basic signal to the frequency conversion module; the frequency conversion module is used to perform a secondary frequency conversion on the basic signal based on the variable frequency to obtain the initial signal.

[0015] Optionally, the switch unit is an absorptive switch unit, comprising a first switch, a first RF load, a second switch, and a second RF load; a first end of the first switch is connected to one output end of the N-way power divider, a second end of the first switch is connected to the first RF load, and a third end of the first switch is connected to the third end of the second switch; a first end of the second switch is connected to the corresponding phase shift unit, and a second end of the second switch is connected to the second RF load.

[0016] In addition, to achieve the above-mentioned purpose, the present application also provides a verification method for a radio direction finder, which is characterized in that it is applied to the verification system of the radio direction finder as described above, and the method includes: a signal simulation device simulates an antenna array to send a target radio frequency signal to each channel of the direction finder to be tested; wherein the target radio frequency signal is obtained by a phase shifting unit adjusting the radio frequency signal output by the N-way power divider according to the signal phase angle value sent by the control unit; the direction finder to be tested uses an internal direction finding algorithm to find the direction of the target radio frequency signal received by each channel to obtain the directionality of each target radio frequency signal, and the directionality of each target radio frequency signal is used to determine the verification result.

[0017] The verification system of the radio direction finder of the present application uses the control unit, signal source unit, N-way power splitter and phase shift unit in the signal simulation device to simulate the antenna array to send the target radio frequency signal to each channel of the direction finder to be tested. Therefore, there is no need to build an antenna array or other verification equipment, which improves the efficiency of direction finding capability verification and robustness verification. Moreover, since the verification test can be implemented without relying on the antenna array and the external test environment, the accuracy of the direction finding capability verification results and the robustness verification results will not be affected, thereby improving the accuracy of the verification results. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of a verification system for a radio direction finder according to an embodiment of the present application;

[0019] Figure 2 is a structural diagram of a switch unit according to an embodiment of the present application;

[0020] Figure 3 1 is a schematic structural diagram of a verification system for a radio direction finder according to an example of the present application;

[0021] Figure 4 is a schematic diagram of an exemplary direction-finding antenna array of the present application;

[0022] Figure 5 is a flow chart of a verification method for a radio direction finder according to an embodiment of the present application;

[0023] In the figure, 100 is a signal simulation device; 110 is a control unit; 120 is a signal source unit; 130 is an N-way power divider; 140 is a phase shift unit; 150 is a switch unit; and 200 is a direction finder to be tested.

[0024] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0026] A direction finder is a device used to determine the direction of a radio signal's source—that is, the position of the signal source relative to the finder. In the field of direction finding technology, verifying the direction finding capability of a direction finder is a critical step in ensuring its reliability and accuracy. Traditional direction finding capability verification methods typically require combining a direction finding antenna array with a complete direction finding system, and then testing it in a field or anechoic chamber environment.

[0027] This testing method requires complex system setup and strict site environment requirements. Specifically, the test system typically consists of a transmitting system, a direction-finding system under test, and a field-strength measurement system. These systems need to be arranged in an isosceles triangle configuration, with the transmitting system antenna at one vertex, the direction-finding system antenna under test, and the field-strength measurement system antenna at the other two vertices. Both antennas must be at the same distance from the transmitting system antenna and at least 10λ (λ is the wavelength of the lowest frequency supported by the system under test).

[0028] Secondly, the test site must meet strict environmental conditions. The distance between the transmitting system antenna, the antenna of the direction-finding system under test, and the antenna of the field-strength measurement system and the edge of the site must not be less than 5λ. This demanding site environment not only increases the complexity of the test but also limits its flexibility and operability. Furthermore, the test process requires a large amount of equipment, including the transmitting system, direction-finding antenna array, field-strength measurement system, and turntable. The setup and commissioning of this equipment is complex and time-consuming, further increasing the difficulty and cost of the test.

[0029] Finally, traditional methods for verifying the robustness of the direction-finding algorithm within a direction-finder typically rely on data collection verification or software simulation. For example, real data collected by the direction-finding system is fed into the algorithm to obtain the directionality, which is then compared with the actual angle at the time of data collection to verify the algorithm's accuracy. Alternatively, a certain deviation is artificially added to simulated data such as phase difference, and then fed back into the algorithm to obtain the directionality, which is then compared with the simulated ideal angle.

[0030] It can be seen that the current direction-finding capability verification method and robustness verification method are both affected by the direction-finding antenna array itself and external signals in the test environment, reducing the accuracy of the verification results; moreover, before verification is carried out, a large amount of equipment is required to build a test environment to implement the verification process, which increases the difficulty and cost of verification testing and reduces the efficiency of verification testing.

[0031] To this end, an embodiment of the present application provides a verification system and method for a radio direction finder. A signal simulation device is used to replace the direction-finding antenna array and some equipment. Before performing the verification test, there is no need to set up a hardware test environment. The signal simulation device can directly simulate the antenna array to send target radio frequency signals to each channel of the direction finder to be tested, so as to realize the direction-finding capability and robustness verification of the radio direction finder, thereby improving the accuracy and efficiency of the verification test.

[0032] Figure 1 Schematic diagram of the verification system of the radio direction finder of the embodiment of the present application, such as Figure 1 As shown, the verification system of the radio direction finder may include a signal simulation device 100 and a direction finder to be tested 200 , and the signal simulation device 100 and the direction finder to be tested 200 are communicatively connected.

[0033] The signal simulation device 100 includes a control unit 110, a signal source unit 120, an N-way power splitter 130, and M phase shifting units 140, where N ≥ 1 and M ≥ 1, and N and M are positive integers. The signal simulation device 100 is used to simulate an antenna array transmitting a target RF signal to each channel of a direction finder 200 to be tested. The direction finder 200 to be tested is used to perform direction finding on the target RF signal received on each channel using an internal direction finding algorithm to obtain the directionality of each target RF signal, which is used to determine the verification result.

[0034] First, it should be noted that the direction finder 200 to be tested is a radio direction finder whose direction-finding capability and robustness need to be verified. Direction-finding capability refers to the performance of the direction finder in determining the direction of a radio signal's source. It is a core metric for measuring direction finder performance and is directly related to the reliability and accuracy of the direction finder in practical applications. Furthermore, the antenna array described in the embodiments of this application refers to a direction-finding antenna array. In practical applications, the direction-finding antenna array is used to receive radio signals from a specific direction and then transmit the radio signals to the direction finder for direction finding.

[0035] In this embodiment, the signal simulation device 100 can simulate the process of an antenna array receiving a signal and forwarding it to a direction finder. Specifically, the signal simulation device 100 can generate its own signal and simulate the process of each element in the direction-finding antenna array receiving the signal from different directions and then transmitting the signal to the direction finder 200 under test. The direction finder 200 under test then performs direction finding on the received signal. Finally, based on the direction finding results and the simulated signal arrival direction, the direction finding capability verification results and robustness verification results are obtained.

[0036] The entire verification test process does not require the participation of the direction-finding antenna array and some equipment of the transmission system, realizing single-machine verification of the direction-finding capability and robustness of the direction-finding algorithm of the direction-finding machine, and improving the accuracy and efficiency of the verification.

[0037] In this embodiment, the signal simulation device 100 may include a control unit 110, a signal source unit 120, an N-way power splitter 130, and M phase shifting units 140. The number N of power splitting channels of the N-way power splitter 130 and the number M of phase shifting units 140 may be greater than or equal to the number of channels of the direction finder 200 to be measured, and N may be equal to or different from M. For example, the signal simulation device 100 may include a 9-way power splitter and 9 phase shifting units 140.

[0038] Furthermore, the control unit 110 can receive instructions or requests from the host computer and control other unit modules in the signal simulation device 100 according to the instructions or requests, so that the signal simulation device 100 can simulate the direction-finding antenna array to send the target RF signal to each channel of the direction-finder 200 to be measured. The signal source unit 120 can generate the required signal and transmit the signal to the N-way power splitter 130; the N-way power splitter 130 then splits the signal power into N channels and outputs them to each phase shifter 140. The phase shifter 140 can be composed of a phase shifter. The phase shifter 140 can adjust the phase of the signal by adjusting the phase shift angle to obtain the corresponding target RF signal; each phase shifter 140 then sends its obtained target RF signal to the corresponding channel of the direction-finder 200 to be measured.

[0039] It should be noted that during the verification test, each channel of the direction finder 200 to be tested is connected to a phase shifter 140, and different channels of the direction finder 200 to be tested are connected to different phase shifters 140. The phase shift angle set for each phase shifter 140 may be different, and therefore the resulting target RF signal may also be different. The phase shift angle of each phase shifter 140 is controlled by the control unit 110.

[0040] The direction finder 200 under test can use its internal direction-finding algorithm to perform direction-finding on the target RF signals received on each channel to obtain the direction-indicating value of each target RF signal. Finally, based on the error between the direction-indicating value of each target RF signal and the corresponding simulated incoming wave direction, a verification result of the direction-finding capability of the direction finder 200 under test can be obtained. Similarly, the robustness of the direction-finding algorithm within the direction finder 200 under test can also be verified.

[0041] During application, the control unit 110 of the signal simulation device 100 can adjust the phase shift angle of each phase shift unit 140 multiple times to simulate the situation where each element of the antenna array receives signals from different directions multiple times, so as to make the verification test result more accurate.

[0042] In order to facilitate understanding of the verification process and verification principle of the verification system of the radio direction finder of the embodiment of the present application, the various components and functions of the verification system of the embodiment of the present application are first introduced in detail below.

[0043] In some embodiments, the control unit 110 in the signal simulation device 100 can be implemented as a hardware device such as a single-chip microcomputer or a microcontroller unit 110. For example, an STM32 single-chip microcomputer can be used as the core. The communication interface and connection relationship of the control unit 110 are described in detail below, using the STM32 single-chip microcomputer as an example.

[0044] The control unit 110 may include two SPI interfaces, which are designated as interface 1 and interface 2. The control unit 110 may function as a master device to establish a communication connection with the signal source unit 120 via interface 1, or may function as a master device to establish a communication connection with each phase shift unit 140 via interface 2. Specifically, the control unit 110 may communicate with the signal source unit 120, which functions as a slave device, via four communication lines: SCK, MOSI, MISO, and SS. The control unit 110 may be connected to M phase shift units 140, which function as slave devices, using the SCK, MOSI, and MISO lines. The control unit 110 may also extend N SS control lines, each connected to each of the M phase shift units 140.

[0045] When the control unit 110 needs to communicate with a certain phase shift unit 140, the control unit 110 can set the SS control line of the phase shift unit 140 to a low level to achieve communication. At this time, the MISO line of the phase shift unit 140 needs to be set to a high impedance state, so that the control unit 110 communicates with M phase shift units 140.

[0046] In some embodiments, the signal source unit 120 may include a processing control module, a frequency conversion module, and a local oscillator module. The local oscillator module is configured to generate a fixed frequency and a variable frequency. The processing control module is configured to generate a base signal based on a control instruction and the fixed frequency, and output the base signal to the frequency conversion module. The frequency conversion module is configured to perform a secondary frequency conversion on the base signal based on the variable frequency to obtain an initial signal.

[0047] In this embodiment, the local oscillator module may include multiple sets of local oscillators. For example, the local oscillator module may output a reference clock and two local oscillator frequencies. Based on instructions from the processing control module, the local oscillator module may control each local oscillator to generate a fixed frequency and a variable frequency. The fixed frequency is used for the first frequency conversion, and the variable frequency is used for the second frequency conversion.

[0048] As an example, if the local oscillator module includes a reference clock (CLK), a local oscillator 1 (LO1), and a local oscillator 2 (LO2), the operating principle of the local oscillator module is as follows:

[0049] First, CLK generates a stable, fixed frequency for the DDS chip. This fixed frequency serves as the synchronization reference for the DDS chip, helping it synchronize the clocks of various modules during operation. The DDS chip outputs signals of different frequencies by varying the step size of the phase accumulator, a process that relies on a stable and accurate reference clock.

[0050] Furthermore, local oscillator 1 (LO1) generates a fixed local oscillator frequency and sends it to the frequency conversion module. The frequency conversion module uses this local oscillator frequency to perform a first frequency conversion on the base signal. This step is generally used to convert the signal to an intermediate frequency (IF1) for subsequent processing. Finally, local oscillator 2 (LO2) dynamically generates a variable frequency and outputs it to the frequency conversion module. After the first stage of mixing, to refine the frequency adjustment and achieve the final target frequency, the frequency conversion module uses the variable frequency to perform a second frequency conversion on the base signal after the initial frequency conversion, obtaining the initial signal.

[0051] In this embodiment, the processing control module may be composed of an FPGA chip with an ARM core, a DDS chip, and an EEPROM chip.

[0052] The ARM core in the FPGA chip can receive control commands, such as frequency hopping commands and modulation commands, from the control unit 110 through interface 1 of the control unit 110. After receiving the control command from the control unit 110, the ARM core can first generate a sinusoidal digital signal based on a specified fixed frequency. Alternatively, after receiving the control command from the control unit 110, the ARM core can use the AD converter inside the FPGA chip to collect the external input baseband signal. The ARM core in the FPGA chip then processes the signal and outputs it to the FPGA chip through the internal DA converter.

[0053] Furthermore, after the FPGA chip receives the signal processed by the ARM core, the FPGA chip can control the DDS chip to output an intermediate frequency signal. The intermediate frequency signal output by the DDS chip is used to modulate the signal output by the ARM core to achieve AM and FM modulation of internal and external signals, thereby obtaining the basic signal of this embodiment. Specifically, the FPGA chip can control the DDS chip to perform frequency hopping and various modulations such as FSK (Frequency Shift Keying), WFM (Wideband Frequency Modulation), NFM (Narrowband Frequency Modulation), BPSK (Binary Phase Shift Keying), and QPSK (Quadrature Phase Shift Keying).

[0054] In addition, an EEPROM chip can be attached to the ARM core to store signal calibration values. It's important to note that calibration values are a set of parameters set to compensate for errors in hardware during manufacturing, environmental changes, or long-term use. These parameters are used to adjust the device's operating state to ensure its output is as close to the theoretical ideal as possible.

[0055] In this embodiment, the frequency conversion module can be composed of a two-stage mixing circuit, an amplification circuit, a filtering circuit, an attenuation circuit for calibration and output power control, etc. The frequency conversion module can receive the basic signal output by the processing control module, and then perform a secondary frequency conversion on the basic signal according to the variable frequency to obtain the required initial signal.

[0056] Specifically, the two-stage mixer circuit receives a base signal output by the processing and control module. The first mixer in the two-stage mixer circuit mixes the base signal's frequency with a first local oscillator frequency generated by the local oscillator module, generating a new signal containing the original signal frequency, the local oscillator frequency, and their sum and difference frequencies. The second mixer in the two-stage mixer circuit receives a variable frequency generated by the local oscillator module and uses it to perform a second frequency conversion on the new signal. This second frequency conversion adjusts the base signal's frequency to the desired target frequency.

[0057] Furthermore, amplifier circuits can adjust the gain of the signal before and after mixing to ensure the signal strength is appropriate. Filter circuits can be used to selectively allow signals within a specific frequency range to pass through while suppressing unwanted frequency components (such as spurious frequencies generated during the mixing process). Attenuation circuits can precisely reduce signal strength, which is important for calibration purposes because it helps adjust the final output signal level to the ideal state. Furthermore, attenuation circuits can also be used to control the output power, ensuring that the output remains at a stable level regardless of changes in input signal strength.

[0058] Thus, by processing the signal through the above functional modules, the required initial signal can be obtained. After obtaining the initial signal, the signal source unit 120 outputs the initial signal to the N-way power splitter 130.

[0059] In some embodiments, the N-way power splitter 130 may be an N-way broadband 0° power splitter. The N-way power splitter 130 primarily splits an input signal into N signals of equal power and phase. The N-way power splitter 130 can split the initial signal into N RF signals of equal phase.

[0060] The N-way power splitter 130 of this embodiment is backward compatible with radio direction finding receivers with fewer than N channels. Therefore, the signal simulation device 100 of the embodiment of the present application can be used to verify a direction finder 200 to be tested with fewer than N channels. For example, if the signal simulation device 100 includes a 9-way power splitter, the signal simulation device 100 can perform verification tests on a direction finder 200 to be tested with 9 channels, 5 channels, 3 channels, or a single channel.

[0061] In some embodiments, the signal simulation device 100 further includes M switch units 150 , each switch unit 150 is connected to a phase shift unit 140 and one output end of the N-way power divider 130 , and different switch units 150 are connected to different phase shift units 140 .

[0062] Specifically, the number of switch units 150 is the same as the number of phase shift units 140, each switch unit 150 is connected to a phase shift unit 140, and different switch units 150 are connected to different phase shift units 140. The other end of each switch unit 150 is connected to an N-way power divider 130, and each switch unit 150 is connected to one output of the N-way power divider 130. The port of the N-way power divider 130 that is not connected to the switch unit 150 needs to be connected to a 50Ω RF load so as not to cause signal reflection and affect the phase consistency of other access ports. By setting M switch units 150, it is possible to select the output channel specified by the N-way power divider 130 to be connected to the phase shift unit 140, so that some phase shift units 140 receive the RF signal sent by the N-way power divider 130.

[0063] In some embodiments, the switch unit 150 is an absorptive switch unit 150, and includes a first switch, a first RF load, a second switch, and a second RF load. A first end S1 of the first switch is connected to one output end of the N-way power divider 130, a second end S2 of the first switch is connected to the first RF load, and a third end S3 of the first switch is connected to a third end S3 of the second switch. A first end S1 of the second switch is connected to a corresponding phase shift unit 140, and a second end S2 of the second switch is connected to the second RF load.

[0064] It should be noted that the first RF load and the second RF load may be formed by one or more resistors. For example, the first RF load and the second RF load may both be a 50Ω RF load.

[0065] In this embodiment, the GPIO interface of the control unit 110 is connected to each switch unit 150. In actual application, the GPIO interface of the control unit 110 needs to be configured as push-pull output, so that the control unit 110 can control the on and off of each switch unit 150 through the GPIO interface.

[0066] Figure 2 Schematic diagram of the structure of the switch unit of the embodiment of the present application.

[0067] like Figure 2 As shown, taking a switch unit 150 as an example, the switch unit 150 of this embodiment can be an absorptive switch. Each switch unit 150 can be constructed using a PIN tube according to the frequency, or a dedicated chip can be directly used and the 1-bit LVTTL level signal output through the GPIO port of the control unit 110 can be used to control the on and off.

[0068] The switch unit 150 includes a first switch, a first RF load, a second switch, and a second RF load. The first switch and the second switch can be single-pole double-throw switches. The first end S1 of the first switch can be connected to an output end of the N-way power divider 130 to receive the RF signal output by the N-way power divider 130. The second end S2 of the first switch can be connected to one end of the first RF load, and the other end of the first RF load is grounded. Similarly, the first end S1 of the second switch can be connected to the corresponding phase shift unit 140, the second end S2 of the second switch can be connected to the second RF load, and the third end S3 of the first switch can be connected to the third end S3 of the second switch.

[0069] When the control unit 110 outputs a high level to a switch unit 150 through the GPIO port, the switch unit 150 is turned on, and the first switch in the switch unit 150 switches from being connected to the first RF load to being connected to the third end S3 of the second switch; at the same time, the second switch switches from being connected to the second RF load to being connected to the third end S3 of the first switch.

[0070] When the control unit 110 outputs a low level to a switch unit 150 through the GPIO port, the switch unit 150 is disconnected, and the first end S1 of the first switch in the switch unit 150 is connected to the second end S2; at the same time, the first end S1 of the second switch is connected to the second end S2.

[0071] To achieve backward compatibility with conventional radio direction-finding receivers with fewer than N channels, the unused ports of the N-way power splitter 130 are connected to a 50Ω RF load to prevent signal reflections and affect the phase consistency of other connected ports. At the same time, the unused phase shifters 140 are also connected to a 50Ω RF load to ensure their stability.

[0072] In this embodiment, the phase shifter 140 may be composed of an amplifier, a matching network, and a digital phase shifter. Specifically, after receiving an RF signal, the amplifier in the phase shifter 140 amplifies the RF signal to ensure that the RF signal maintains sufficient strength throughout the phase shifting process. Furthermore, to ensure the proper operation of the digital phase shifter, the matching network must match the impedance of the digital phase shifter to the load impedance, ensuring that the load impedance matches the characteristic impedance of the digital phase shifter. This minimizes reflections and phase errors, ensuring that the phase shift of the digital phase shifter meets the requirements.

[0073] In this embodiment, the digital phase shifter uses the PE44820 chip. This 8-bit digital phase shifter covers a 358.6° phase range in 1.4° increments. For narrowband operation, it can be extended to the 1.1-3.0 GHz frequency band. The control interface supports both serial and parallel control, with an RMS (Root Mean Square) phase error of 1.0° and an RMS amplitude error of 0.1 dB. This is sufficient for simulating direction-finding antenna array reception signals and for phase offset adjustment when verifying algorithm robustness.

[0074] After the amplifier amplifies the RF signal, the amplifier outputs the amplified RF signal to the digital phase shifter, which then adjusts the phase shift angle according to the signal phase angle value sent by the control unit 110, thereby adjusting the phase of the RF signal to the desired phase and obtaining the target RF signal.

[0075] Each phase shift unit 140 is connected to each channel of the direction finder 200 to be measured. Different phase shift units 140 are connected to different channels of the direction finder 200 to be measured. The phase shift unit 140 can send the obtained target RF signal to the corresponding channel of the direction finder 200 to be measured.

[0076] With reference to the system structure of the verification system for the radio direction finder described above, the functions of each unit and the verification process of the direction finding capability of the direction finder 200 to be tested are first introduced in detail below.

[0077] In some embodiments, the control unit 110 is connected to the signal source unit 120 and each phase shift unit 140 respectively, and the N-way power splitter 130 is connected to the signal source unit 120 and each phase shift unit 140 respectively.

[0078] The control unit 110 is configured to send control instructions to the signal source unit 120, determine the signal phase angle value corresponding to each element in the antenna array based on the simulated antenna array pattern, and send the signal phase angle value corresponding to each element to the corresponding phase shifter 140. The signal source unit 120 is configured to generate an initial signal based on the control instructions and transmit the initial signal to the N-way power splitter 130. The N-way power splitter 130 is configured to split the initial signal into N equal-phase RF signals and output each RF signal to a corresponding phase shifter 140. The phase shifter 140 is configured to adjust the phase of the RF signal based on the received signal phase angle value to obtain a target RF signal and output the target RF signal to the corresponding channel of the direction finder 200 to be measured.

[0079] Specifically, when a verification test is required for the direction finder 200 to be tested, the control unit 110 can first send a control instruction to the signal source unit 120 through the interface 1. The control instruction may include relevant parameters of the signal to be generated, etc. The control instruction is used to instruct the signal source unit 120 to generate an initial signal with the required frequency and modulation method.

[0080] It should be noted that when initially verifying the direction-finding capabilities of the direction-finder 200 under test and the robustness of its built-in direction-finding algorithm, a CW signal can be used. A CW signal is a single-frequency continuous wave signal with a simple structure, easy to generate and control. If actual signal verification is required, analog modulation signals such as AM and FM or wideband digital modulation signals such as FSK and QPSK can be used. Digital modulation signals such as FSK and QPSK are used during the verification process to ensure that the system can meet the requirements of modern communication systems and maintain good performance under complex channel conditions.

[0081] Furthermore, the control unit 110 needs to simulate the antenna array configuration and determine the signal phase angle value corresponding to each element. It is understood that the different positions of the elements in the direction-finding antenna array will result in different directions in which each element can receive signals, and thus different signal phase angle values for each element receiving the signal. Therefore, to simulate the conditions under which the desired antenna array configuration receives signals, it is necessary to precalculate the directions in which each element can receive signals, that is, the theoretical signal phase angle values corresponding to each element.

[0082] It should be noted that the signal phase angle value refers to the phase offset angle value of each signal relative to one of the signals. For example, if the direction-finding antenna array is a circular antenna array, each array element can be digitally numbered. At this time, the signal phase angle value corresponding to each antenna array element is the phase delay relative to array element No. 1.

[0083] After calculating the signal phase angle value corresponding to each array element, the control unit 110 transmits each signal phase angle value to the corresponding phase shifting unit 140. It will be appreciated that the direction finder 200 to be measured has multiple channels. If a direction-finding antenna array is used for direction finding, each channel of the direction finder to be measured is used to receive the signal transmitted by a single array element. Therefore, similarly, in this embodiment, one phase shifting unit 140 is connected to one channel of the direction finder 200 to be measured, and one phase shifting unit 140 can be used to simulate and process the signal corresponding to one array element.

[0084] Furthermore, after the signal source unit 120 receives the control instruction sent by the control unit 110, the signal source unit 120 generates an initial signal of the target frequency and target modulation mode according to the control instruction. After generating the initial signal, the signal source unit 120 sends the initial signal to the N-way power divider 130, and the N-way power divider 130 distributes the initial signal power into N-way RF signals of equal phase. Finally, each RF signal is input into the corresponding phase shift unit 140 after passing through each switch unit 150. The phase shift unit 140 can control its phase shift angle according to the signal phase angle value sent by the control unit 110, thereby adjusting the phase of the RF signal to the required signal phase angle value to obtain the target RF signal. After obtaining the target RF signal, each phase shift unit 140 will send the target RF signal to the corresponding channel of the direction finder 200 to be measured.

[0085] After each channel of the direction finder 200 to be tested receives the target radio frequency signal, the direction finder 200 to be tested can use the built-in direction finding algorithm to perform direction finding on each target radio frequency signal to obtain the direction of each target radio frequency signal. Furthermore, the direction of the target radio frequency signal calculated by the direction finder 200 to be tested can be compared with the signal phase angle value initially calculated by the control unit 110 to verify the direction finding capability of the direction finder 200 to be tested for the signal at the target frequency point. It should be noted here that the reference arrival direction of the target radio frequency signal can represent the arrival direction of the signal, and the direction of the signal is the arrival direction calculated using the direction finding algorithm.

[0086] In some embodiments, the control unit 110 is further configured to determine a target phase shifter 140 connected to a channel of the direction finder 200 to be measured from all phase shifters 140 , and control the switch unit 150 connected to the target phase shifter 140 to close.

[0087] In the above embodiment, different phase shifters 140 are connected to different channels of the direction finder 200 to be measured. If the number of channels of the direction finder 200 to be measured is less than the number M of phase shifters 140, some phase shifters 140 will not be required to operate. Therefore, the control unit 110 must first determine the target phase shifters 140 connected to the channels of the direction finder 200 to be measured, and then control each target phase shifter 140 to phase shift the RF signal.

[0088] After the control unit 110 determines the target phase shifter 140 connected to the channel of the direction finder 200 to be measured from all the phase shifters 140, the control unit 110 can output a high level to the switch unit 150 connected to the target phase shifter 140, so that the switch unit 150 connected to the target phase shifter 140 is closed, thereby connecting the target phase shifter 140 to the N-way power splitter 130. In this way, the target phase shifter 140 can receive the RF signal sent by the N-way power splitter 130.

[0089] Specifically, the control unit 110 controls each switch unit 150 based on the number of channels of the connected direction finder 200 to be measured, connecting the channels connected to the direction finder 200 to be measured and disconnecting the channels not connected to the direction finder 200 to be measured. When the switch unit 150 is turned off, the corresponding ports of the N-way power divider 130 and the phase shifter 140 are automatically connected to a 50Ω RF load.

[0090] As an example, if the signal simulation device 100 includes nine phase shifting units 140, numbered 1 to 9, and the direction finder 200 to be measured has three channels, the number of phase shifting units 140 is greater than the number of channels of the direction finder 200 to be measured. In this case, the control unit 110 can only operate the phase shifting units 140 numbered 1, 2, and 3. Specifically, the phase shifting units 140 numbered 1, 2, and 3 are connected to the three channels of the direction finder 200 to be measured, respectively. These three phase shifting units 140 are the target phase shifting units 140. The control unit 110 closes the switch units 150 corresponding to the phase shifting units 140 numbered 1, 2, and 3, thereby connecting only these three target phase shifting units 140 to the N-way power divider 130. If the antenna array to be simulated has nine elements, the three target phase shifting units 140 can respectively simulate three elements and output target RF signals to the direction finder 200 to be measured.

[0091] Therefore, the verification system of the embodiment of the present application can achieve downward compatibility and verify direction finders with a number of verification channels less than N, thereby improving the applicability of the verification system.

[0092] In some embodiments, when each target phase shifting unit 140 receives a radio frequency signal for the first time, the phase shift angle of each target phase shifting unit 140 is set to 0°. The direction finder 200 to be measured is specifically configured to receive each target radio frequency signal sent by each target phase shifting unit 140 when the phase shift angle is set to 0°, and determine a correction coefficient corresponding to each channel based on each target radio frequency signal.

[0093] Specifically, after the N-way power splitter 130 first transmits the power-divided RF signal to each target phase shifter 140 via the switch unit 150, the target phase shifter 140 first switches the phase shift angle to 0°. When the phase shift angle of the target phase shifter 140 is 0°, the target phase shifter 140 does not adjust the phase of the RF signal, and the target RF signals obtained by each target phase shifter 140 remain of equal phase. Furthermore, each target phase shifter 140 outputs the target RF signal to the corresponding channel of the direction finder 200 to be measured.

[0094] After receiving the target RF signal, each channel of the direction finder 200 undergoes the same low-noise amplification, common local oscillator down-conversion, and filtering processes within the device. Furthermore, the target RF signal is converted to a digital signal using an analog-to-digital conversion module with a sampling rate of 204.8 MSPS. The direction finder 200 then divides the digital signal corresponding to each channel by the digital signal corresponding to the first channel to obtain the corresponding correction coefficient.

[0095] In some embodiments, the control unit 110 is further configured to determine an array element switching frequency based on the number of channels of the direction finder 200 to be measured, the number of array elements in the simulated antenna array, and the direction finding algorithm within the direction finder to be measured, and, if the array element switching frequency is greater than zero, determine a switching scheme based on the array element switching frequency. If the array element switching frequency is greater than zero, the control unit 110 is specifically configured to send the signal phase angle value corresponding to each array element to the corresponding target phase shift unit 140 in batches according to the switching scheme.

[0096] It is understandable that since the signal simulation device 100 simulates a variety of antenna array types, such as linear arrays, uniform circular arrays, rectangular arrays, etc., the number of array elements in different arrays may also be different, and the structure of each module of the signal simulation device 100 is fixed, and the number of channels of the direction finder 200 to be measured is fixed. If the number of array elements is greater than the number of channels of the direction finder 200 to be measured, there may be one channel used to receive target RF signals corresponding to multiple array elements.

[0097] Therefore, in this embodiment, the control unit 110 also needs to determine the number of array element switching operations based on the number of channels of the direction finder 200 to be measured and the number of array elements in the simulated antenna array. If the number of array elements is greater than the number of channels of the direction finder 200 to be measured, the number of array element switching operations must be greater than zero. In short, each target phase shifting unit 140 may need to simulate multiple array elements to transmit target RF signals of different phases to the corresponding channels.

[0098] Specifically, when the number of array element switching times is greater than zero, a switching scheme may be determined based on the number of channels of the direction finder 200 to be measured and the number of array elements in the simulated antenna array. The control unit 110 may send the signal phase angle value corresponding to each array element to each target phase shifting unit 140 according to the switching scheme, so that each target phase shifting unit 140 switches to a different phase shift angle, thereby simulating target radio frequency signals with different phase differences received by different array elements of the ideal direction finding antenna array with antenna element No. 1 as a reference, until the simulation of all array elements is completed.

[0099] As an example, if the direction-finding antenna array is a circular array and includes 9 elements, denoted as elements 1 to 9, and the direction finder 200 to be measured has 3 channels, denoted as channel 1, channel 2, and channel 3, the number of elements is greater than the number of channels of the direction finder 200 to be measured. The control unit 110 determines a switching scheme based on the number of channels of the direction finder 200 to be measured and the number of elements in the simulated antenna array. The switching scheme may be: channel 1 receives signals from elements 1, 2, and 3, then the target phase shifter 140 connected to channel 1 is used to simulate the target RF signals emitted by elements 1, 2, and 3. The control unit 110 sends the signal phase angle values corresponding to elements 1, 2, and 3 to the target phase shifter 140. Channel 2 receives signals from array elements 4, 5, and 6. The target phase shifter 140 connected to channel 2 is used to simulate the target RF signals emitted by array elements 4, 5, and 6. The control unit 110 sends the signal phase angle values corresponding to array elements 4, 5, and 6 to the target phase shifter 140. Channel 3 receives signals from array elements 7, 8, and 9. The target phase shifter 140 connected to channel 3 is used to simulate the target RF signals emitted by array elements 7, 8, and 9. The control unit 110 sends the signal phase angle values corresponding to array elements 7, 8, and 9 to the target phase shifter 140.

[0100] Therefore, the signal simulation device 100 can simulate various direction-finding antenna arrays and verify the direction-finders 200 to be tested with different numbers of channels, further improving the applicability of the verification system of the embodiment of the present application.

[0101] In some embodiments, the verification result includes a direction finding capability verification result.

[0102] The signal simulation device 100 is specifically used to send a target radio frequency signal to each channel of the direction finder 200 to be tested multiple times; during each transmission of the target radio frequency signal, the control unit 110 is specifically used to adjust the signal phase angle value corresponding to each array element according to a first preset step. The direction finder 200 to be tested is specifically used to correct the target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain a corrected target radio frequency signal, and to process the corrected target radio frequency signal using an internal direction finding algorithm to obtain the directionality of the target radio frequency signal. The direction finding capability verification result is determined based on the directionality of each target radio frequency signal and the reference incoming wave direction of the target radio frequency signal.

[0103] Specifically, after each target phase shifting unit 140 transmits a corresponding target RF signal to each channel of the direction finder 200 under test, the direction finder 200 under test performs the same low-noise amplification, common local oscillator down-conversion, and filtering processing on each target RF signal. Furthermore, the direction finder 200 under test performs analog-to-digital conversion on each target RF signal using an analog-to-digital conversion module with a sampling rate of 204.8 MSPS to obtain a corresponding digital signal.

[0104] After obtaining the digital signals corresponding to each channel, the direction finder 200 to be tested can use the correction coefficients corresponding to each channel to correct the corresponding digital signals to obtain the corrected target RF signals. This correction method is to divide the digital signals by the correction coefficients to obtain the corresponding corrected target RF signals. This can achieve correction of the RF link.

[0105] Furthermore, the direction finder 200 to be measured uses its internal direction finding algorithm to perform direction finding on the corrected target radio frequency signal to obtain the direction of the target radio frequency signal. It should be noted that the direction finding algorithm built into the direction finder 200 to be measured can be a currently existing direction finding algorithm. The specific direction finding process can refer to the existing direction finding process of the direction finding algorithm and is not specifically limited here.

[0106] After obtaining the directionality of the target RF signal, the directionality of the target RF signal can be compared with the reference incoming wave direction of the target RF signal to determine whether the two are consistent, thereby verifying the direction finding capability of the direction finder 200 to be tested.

[0107] After one verification, the control unit 110 can also adjust the signal phase angle value corresponding to each array element according to the first preset step, so that each target phase shift unit 140 obtains the target radio frequency signal in the new arrival direction, further completing the verification of the direction finding capability of the direction finder 200 to be tested at this frequency point.

[0108] It should be noted that the first preset step can be manually set by the staff according to the actual situation. For example, the first preset step can be set to 5°, that is, the signal phase angle value corresponding to each array element is adjusted in steps of 5° according to the reference incoming wave direction of the target RF signal, and ultimately the angles of all target RF signals can cover the entire range of 0° to 360°.

[0109] Therefore, by continuously adjusting the signal phase angle value corresponding to each array element, the signal simulation device 100 can send target radio frequency signals in various directions to the direction finder 200 to be tested, thereby verifying the direction finding capability of the direction finder 200 to be tested in various directions at the frequency point.

[0110] The robustness verification process of the direction finding algorithm inside the direction finder 200 to be tested is described in detail below.

[0111] In some implementations, the verification result includes a robustness verification result.

[0112] The signal simulation device 100 is specifically used to send a target radio frequency signal to each channel of the direction finder 200 to be tested multiple times; during each process of sending the target radio frequency signal, the control unit 110 is specifically used to adjust the deviation of the signal phase angle value corresponding to each array element according to a second preset step. The direction finder 200 to be tested is specifically used to correct the target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain a corrected target radio frequency signal, and process the corrected target radio frequency signal using an internal direction finding algorithm to obtain the directionality of the target radio frequency signal. The robustness verification result is determined based on the directionality of each target radio frequency signal and the directionality after the corresponding signal phase angle value is adjusted.

[0113] Specifically, when performing robustness verification of the direction finding algorithm, the control unit 110 may adjust the deviation of the signal phase angle value corresponding to each array element according to the second preset step, thereby simulating a process in which the phase value of the signal received by each array element continuously deviates from the phase value of the ideal signal.

[0114] The control unit 110 sends the signal phase angle value adjusted according to the second preset step to the corresponding target phase shift unit 140. The target phase shift unit 140 shifts the phase of the RF signal according to the adjusted signal phase angle value to obtain the target RF signal and sends it to the direction finder 200 to be measured. The direction finder 200 to be measured uses an internal direction finding algorithm to find the direction of the target RF signal to obtain the direction of the target RF signal. At this time, the calculated direction can be compared with the direction before the signal phase angle value is adjusted to check whether the deviation between the calculated direction and the direction before the signal phase angle value is adjusted (i.e., the simulated incoming wave direction) exceeds the required threshold (the threshold can be set according to actual needs).

[0115] The signal phase angle values corresponding to each array element are continuously adjusted according to the above steps until a critical signal phase angle is found at which the deviation between the directivity and the directivity before the adjustment (i.e., the simulated incoming wave direction) equals a required threshold. This provides the maximum phase value that each phase shifter 140 can deviate from the ideal phase value.

[0116] It should be noted that the second preset step can be manually set by the staff according to actual conditions. For example, the second preset step can be set to 1°.

[0117] As an example, if the reference arrival direction of the target RF signal is 15°, and the signal phase angle value corresponding to the first array element is 0°, and the second preset step is set to 1°, then the robustness verification of the direction finding algorithm is required. The control unit 110 can set the signal phase angle value corresponding to the array element to 1°. The control unit 110 sends the signal phase angle value of 1° to the corresponding target phase shifter 140. The target phase shifter 140 adjusts the phase of the RF signal according to the signal phase angle value of 1°. The phase angle values of the other array elements are the same as above. Finally, the corresponding target RF signal is obtained and sent to the direction finder 200 to be measured. The direction finder 200 to be measured uses its internal direction finding algorithm to find the direction of the target RF signal and obtain the direction of the target RF signal. At this point, the calculated direction of the target RF signal can be compared with the reference arrival direction of 15° of the target RF signal to check whether the deviation between the calculated direction of the target RF signal and the reference arrival direction of 15° (i.e., the simulated arrival direction) exceeds the required threshold (this threshold can be set according to actual needs).

[0118] Therefore, the above steps can realize the robustness verification of the direction finding algorithm inside the direction finder 200 to be tested.

[0119] For ease of understanding, the verification system and verification process of the radio direction finder of the present application are further described below through a specific example.

[0120] Figure 3 It is a structural diagram of a verification system of a radio direction finder of an example of the present application. Figure 4 It is a schematic diagram of an example direction-finding antenna array of the present application.

[0121] refer to Figure 3 and Figure 4 In this example, the signal simulation device in the verification system simulates a circular direction-finding antenna array consisting of nine elements. The power divider in the signal simulation device is a nine-way power divider, and the number of switch units and phase shift units is also nine.

[0122] The control unit acts as the master device controlled by the SPI1 interface and communicates with the signal source unit, which acts as the slave device of the SPI1 interface. The control unit acts as the master device controlled by the SPI2 interface and communicates with the nine digital phase shift units, which act as the slave devices of the SPI2 interface. The GPIO of the control unit is configured as a push-pull output high level to control the on and off of the nine switch units.

[0123] The control unit controls the signal output of the signal source unit, the on / off switching of each switch unit, and the phase shift angle of each phase shift unit. The signal source unit outputs an initial signal, which, after passing through a nine-way broadband 0° power splitter, is then split into nine equal-phase RF signals. Each RF signal then passes through each switch unit and phase shift unit before being fed into the direction finder under test.

[0124] The specific verification process is as follows:

[0125] The control unit sends a control instruction to the signal source unit through the SPI1 interface. After receiving the control instruction, the signal source unit determines the frequency and modulation mode that need to be verified according to the control instruction and generates the corresponding initial signal.

[0126] The initial signal passes through a 0° power splitter, which distributes the initial signal power into nine equal-phase RF signals.

[0127] Since the number of channels in the direction finder to be measured is the same as the number of elements in the simulated antenna array, each phase shifter can be connected to a channel of the direction finder to be measured. Each phase shifter is a target phase shifter. At this point, the control unit controls all nine switch units to be turned on.

[0128] The nine RF signals pass through nine interconnected switch units and enter nine phase shifters. At this point, all phase shifters set their phase shift angles to 0 degrees, generating nine target RF signals. Each phase shifter feeds the target RF signal into a nine-channel direction finder under test. Inside the nine-channel direction finder, the nine target RF signals undergo nine identical low-noise amplification, common local oscillator down-conversion, and filtering. Then, nine analog-to-digital conversions with a sampling rate of 204.8 MSPS are used to generate nine digital signals. Each of these nine digital signals is divided by the first digital signal to generate the corresponding correction coefficients for each of the nine channels.

[0129] Since the signal simulation device in the verification system simulates a circular direction-finding antenna array, the array elements of the direction-finding antenna array correspond one-to-one to the channels of the direction-finder to be measured. The output of the direction-finding result of one direction-finding algorithm does not need to be switched multiple times. The phase shift units of the nine channels connected to the channels of the direction-finder to be measured can be adjusted to different degrees at one time (simulating the nine signals with different phase differences received by different antenna elements of an ideal uniform circular array direction-finding antenna array with antenna element No. 1 as the reference).

[0130] The control unit determines the signal phase angle value of each element in the antenna array relative to element 1 based on the simulated circular array direction finding antenna array. The specific calculation formula is as follows:

[0131]

[0132] Where, φ iis a radian value, i = 2 to 9, r is the radius of the circle containing the phase center of each element in the uniform circular array, and c is the speed of light. When r is 0.25m and f is 1500MHz, the phase angle of the signal wavefront of element 1 is 0°. When θ is 15°, the corresponding signal phase angle values of the nine phase shifters are shown in Table 1 (the phase angle values of the received signals of elements 1 to 9 are simulated in 1.4° steps and converted to 0° to 360°).

[0133] Table 1 Signal phase angle values corresponding to each phase shift unit

[0134]

[0135] The θ angle is adjusted in 5° increments from 0° to 360° to ensure that the target RF signal's phase angle covers the entire range. Nine target RF signals at all angles are fed into the nine channels of the direction finder under test. Within the nine-channel direction finder, each of these signals undergoes a similar low-noise amplification, common local oscillator down-conversion, and filtering. Finally, nine digital direction-finding signals are generated through analog-to-digital conversion at a sampling rate of 204.8 MSPS.

[0136] The 9-channel digital direction-finding signal is divided by the corresponding channel's correction coefficient to obtain the 9-channel corrected digital direction-finding signal, completing the RF link calibration. The 9-channel corrected digital direction-finding signal is fed into the direction-finding algorithm within the direction-finder to be tested, resulting in the calculated direction-indicating angle. The direction-indicating angle of each target RF signal is compared with the corresponding incoming wave direction (i.e., the reference incoming wave direction of the target RF signal) to check whether the deviation is less than 1°, thus completing the direction-finding capability verification of the direction-finder to be tested at that frequency point.

[0137] The phase values of the nine digital phase shifters simulating the ideal nine-element uniform circular array direction-finding antenna array are continuously deviated from the phase value of the ideal direction-finding signal in 1° steps until the direction of the target RF signal calculated by the internal algorithm of the direction finder to be tested deviates from the direction of the incoming wave by more than 3°. The maximum phase value that the nine phase shifters can deviate from the ideal phase value is obtained, that is, the critical phase deviation value of the direction of the direction within the allowable deviation range that the algorithm can calculate, that is, the robustness of the internal algorithm of the direction finder to be tested is verified.

[0138] This enables single-machine verification of the direction-finding capability of the direction finder and robustness verification of the direction-finding algorithm within the direction finder. Furthermore, the verification process does not require field testing or darkroom testing in conjunction with the direction-finding antenna array, thus improving the accuracy and efficiency of the verification. Furthermore, the robustness of the direction-finding algorithm within the direction finder is accurately evaluated, avoiding the previous practice of using simulation for verification.

[0139] On the basis of the above-mentioned embodiment, an embodiment of the present application further provides a verification method of a radio direction finder, and the verification method of a radio direction finder can be applied to the verification system of the radio direction finder described above.

[0140] Figure 5 FIG. 1 is a flow chart of a verification method for a radio direction finder according to an embodiment of the present application. Figure 5 As shown, the method may include the following steps:

[0141] Step 510: The signal simulation device simulates the antenna array to send a target radio frequency signal to each channel of the direction finder to be tested; wherein the target radio frequency signal is obtained by the phase shift unit adjusting the radio frequency signal output by the N-way power divider according to the signal phase angle value sent by the control unit.

[0142] Step 520: The direction finder to be tested uses an internal direction finding algorithm to perform direction finding on the target radio frequency signals received by each channel to obtain the directionality of each target radio frequency signal. The directionality of each target radio frequency signal is used to determine the verification result.

[0143] Therefore, the control unit, signal source unit, N-way power splitter and phase shift unit in the signal simulation device are used to simulate the antenna array to send the target radio frequency signal to each channel of the direction finder to be tested. Therefore, there is no need to build equipment for verification such as the antenna array, which improves the efficiency of direction finding capability verification and robustness verification. Moreover, since the verification test can be achieved without relying on the antenna array and the external test environment, the accuracy of the direction finding capability verification results and the robustness verification results will not be affected, thereby improving the accuracy of the verification results.

[0144] In some embodiments, the signal simulation device includes a control unit, a signal source unit, an N-way power splitter, and M phase shifting units, where N≥1, M≥1, and N and M are positive integers. The signal simulation device simulates the antenna array sending a target radio frequency signal to each channel of the direction finder to be measured, which may include:

[0145] The control unit sends a control instruction to the signal source unit, and determines the signal phase angle value corresponding to each array element in the antenna array according to the simulated antenna array pattern, and sends the signal phase angle value corresponding to each array element to the corresponding phase shifter unit; the signal source unit generates an initial signal according to the control instruction, and transmits the initial signal to the N-way power divider; the N-way power divider divides the initial signal into N equal-phase radio frequency signals, and outputs each radio frequency signal to the corresponding phase shifter unit; the phase shifter unit adjusts the phase of the radio frequency signal according to the received signal phase angle value to obtain the target radio frequency signal, and outputs the target radio frequency signal to the corresponding channel of the direction finder to be measured.

[0146] In some embodiments, the signal simulation device further includes M switch units, each switch unit being connected to a phase shift unit and one output terminal of the N-way power splitter, with different switch units being connected to different phase shift units. The method further includes: the control unit further determining, from all phase shift units, a target phase shift unit connected to a channel of the direction finder to be measured, and controlling the switch unit connected to the target phase shift unit to close.

[0147] In some embodiments, the method further includes: when each target phase shift unit receives a radio frequency signal for the first time, setting the phase shift angle of each target phase shift unit to 0°; the direction finding device to be measured receives each target radio frequency signal sent by each target phase shift unit when the phase shift angle is set to 0°, and determining a correction coefficient corresponding to each channel based on each target radio frequency signal.

[0148] In some embodiments, the method further includes: a control unit determining the number of array element switching times based on the number of channels of the direction finder to be measured, the number of array elements in the simulated antenna array, and the internal direction finding algorithm of the direction finder to be measured, and when the number of array element switching times is greater than zero, determining a switching scheme based on the number of array element switching times; when the number of array element switching times is greater than zero, the control unit sending the signal phase angle value corresponding to each array element to the corresponding target phase shift unit in batches according to the switching scheme.

[0149] In some embodiments, the verification result includes a direction-finding capability verification result; the signal simulation device simulates the antenna array to send a target radio frequency signal to each channel of the direction finder to be tested, which can specifically include: the signal simulation device sends the target radio frequency signal to each channel of the direction finder to be tested multiple times; in the process of each time the target radio frequency signal is sent, the control unit is specifically used to adjust the signal phase angle value corresponding to each array element according to a first preset step.

[0150] The direction finder to be tested uses an internal direction finding algorithm to perform direction finding on the target radio frequency signal received by each channel to obtain the directionality of each target radio frequency signal. The directionality of each target radio frequency signal is used to determine the verification result, which can specifically include: the direction finder to be tested corrects the target radio frequency signal for any target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain the corrected target radio frequency signal, and processes the corrected target radio frequency signal using the internal direction finding algorithm to obtain the directionality of the target radio frequency signal; the direction finding capability verification result is determined based on the directionality of each target radio frequency signal and the reference incoming wave direction of the target radio frequency signal.

[0151] In some embodiments, the verification result includes a robustness verification result; the signal simulation device simulates the antenna array to send the target radio frequency signal to each channel of the direction finder to be tested, which can specifically include: the signal simulation device sends the target radio frequency signal to each channel of the direction finder to be tested multiple times; in the process of sending the target radio frequency signal each time, the control unit is specifically used to adjust the directionality after the signal phase angle value corresponding to each array element is adjusted according to the second preset step.

[0152] The direction finder to be tested uses an internal direction finding algorithm to perform direction finding on the target radio frequency signal received by each channel to obtain the directionality of each target radio frequency signal. The directionality of each target radio frequency signal is used to determine the verification result, which may specifically include: the direction finder to be tested corrects the target radio frequency signal for any target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain the corrected target radio frequency signal, and processes the corrected target radio frequency signal using the internal direction finding algorithm to obtain the directionality of the target radio frequency signal; the robustness verification result is determined based on the directionality of each target radio frequency signal and the corresponding signal phase angle value.

[0153] It should be noted that for details not disclosed in the verification method of the radio direction finder of this embodiment, please refer to the details disclosed in the embodiment of the verification system of the radio direction finder in the embodiments of this specification, and no further details will be given here.

[0154] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0155] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

Claims

1. A verification system for a radio direction finder, characterized in that: It includes a signal simulation device and a direction finder to be tested; The signal simulation device includes a control unit, a signal source unit, an N-way power splitter, and M phase shift units, where N≥1, M≥1, and N and M are positive integers; the signal simulation device is used to simulate the antenna array sending a target radio frequency signal to each channel of the direction finder to be measured; The direction finder to be tested is used to use an internal direction finding algorithm to perform direction finding on the target radio frequency signals received by each channel to obtain the directionality of each target radio frequency signal, and the directionality of each target radio frequency signal is used to determine the verification result.

2. The radio direction finder verification system according to claim 1, characterized in that: The control unit is connected to the signal source unit and each phase shift unit respectively, and the N-way power splitter is connected to the signal source unit and each phase shift unit respectively; The control unit is used to send a control instruction to the signal source unit, and determine the signal phase angle value corresponding to each array element in the antenna array according to the simulated antenna array pattern, and send the signal phase angle value corresponding to each array element to the corresponding phase shift unit; The signal source unit is used to generate an initial signal according to the control instruction, and transmit the initial signal to the N-way power splitter; The N-way power splitter is used to split the initial signal into N-way radio frequency signals of equal phase, and output each of the radio frequency signals to a corresponding phase shift unit; The phase shift unit is used to adjust the phase of the radio frequency signal according to the received signal phase angle value to obtain the target radio frequency signal, and output the target radio frequency signal to the corresponding channel of the direction finder to be measured.

3. The verification system for a radio direction finder according to claim 2, characterized in that: The signal simulation device further includes M switch units, each of which is connected to one of the phase shift units and one output end of the N-way power divider, and different switch units are connected to different phase shift units; The control unit is further configured to determine a target phase shift unit connected to a channel of the direction finder to be measured from all the phase shift units, and control a switch unit connected to the target phase shift unit to be closed.

4. The radio direction finder verification system according to claim 3, characterized in that: When each of the target phase shift units receives the radio frequency signal for the first time, the phase shift angle of each of the target phase shift units is set to 0°; The direction finder to be measured is specifically configured to receive each target radio frequency signal sent by each target phase shift unit when the phase shift angle is set to 0°, and determine a correction coefficient corresponding to each channel based on each target radio frequency signal.

5. The verification system for a radio direction finder according to claim 3, characterized in that: The control unit is further configured to determine the number of array element switching times according to the number of channels of the direction finder to be measured, the number of array elements in the simulated antenna array, and the internal direction finding algorithm of the direction finder to be measured, and determine the switching scheme according to the number of array element switching times when the number of array element switching times is greater than zero; When the number of array element switching times is greater than zero, the control unit is specifically configured to send the signal phase angle value corresponding to each array element to the corresponding target phase shift unit in batches according to the switching scheme.

6. The verification system for a radio direction finder according to claim 4, characterized in that: The verification result includes a direction finding capability verification result; The signal simulation device is specifically used to send the target radio frequency signal to each channel of the direction finder to be measured multiple times; during each transmission of the target radio frequency signal, the control unit is specifically used to adjust the signal phase angle value corresponding to each array element according to a first preset step; The direction finder to be measured is specifically used to correct any target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain a corrected target radio frequency signal, and process the corrected target radio frequency signal using an internal direction finding algorithm to obtain the directionality of the target radio frequency signal; The direction finding capability verification result is determined based on the directionality of each target radio frequency signal and the reference incoming wave direction of the target radio frequency signal.

7. The verification system for a radio direction finder according to claim 4, characterized in that: The verification result includes a robustness verification result; The signal simulation device is specifically used to send the target radio frequency signal to each channel of the direction finder to be measured multiple times; during each transmission of the target radio frequency signal, the control unit is specifically used to adjust the deviation of the signal phase angle value corresponding to each array element according to the second preset step; The direction finder to be measured is specifically used to correct any target radio frequency signal received by any channel using the correction coefficient corresponding to the channel to obtain a corrected target radio frequency signal, and process the corrected target radio frequency signal using an internal direction finding algorithm to obtain the directionality of the target radio frequency signal; The robustness verification result is determined based on the directivity of each target radio frequency signal and the directivity after the corresponding signal phase angle value is adjusted.

8. The radio direction finder verification system according to any one of claims 2 to 7, characterized in that: The signal source unit includes a processing control module, a frequency conversion module and a local oscillator module; The local oscillator module is used to generate fixed frequency and variable frequency; The processing control module is used to generate a basic signal based on the control instruction and the fixed frequency, and output the basic signal to the frequency conversion module; The frequency conversion module is used to perform secondary frequency conversion on the basic signal based on the variable frequency to obtain the initial signal.

9. The radio direction finder verification system according to claim 3, characterized in that: The switch unit is an absorptive switch unit, and the switch unit includes a first switch, a first radio frequency load, a second switch and a second radio frequency load; A first end of the first switch is connected to one output end of the N-way power divider, a second end of the first switch is connected to the first RF load, and a third end of the first switch is connected to the third end of the second switch; A first end of the second switch is connected to the corresponding phase shift unit, and a second end of the second switch is connected to the second RF load.

10. A method for verifying a radio direction finder, characterized in that: The verification system for the radio direction finder according to claims 1 to 9, wherein the method comprises: The signal simulation device simulates the antenna array to send a target radio frequency signal to each channel of the direction finder to be tested; wherein the target radio frequency signal is obtained by the phase shift unit adjusting the radio frequency signal output by the N-way power divider according to the signal phase angle value sent by the control unit; The direction finder to be tested uses an internal direction finding algorithm to perform direction finding on the target radio frequency signals received by each channel to obtain the directionality of each target radio frequency signal. The directionality of each target radio frequency signal is used to determine the verification result.

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