Self-calibration radar calibration method

Abstract

The invention provides a self-calibration radar calibration method. The method comprises the following steps: acquiring a target link gain parameter, transmitting the target link gain parameter to a microwave module through an intermediate-frequency link, sampling the amplitude of an intermediate-frequency signal by using an analog-to-digital conversion unit integrated in a signal generation module to obtain first amplitude data, and calculating the gain of the intermediate-frequency signal according to the first amplitude data and a preset link gain parameter. Controlling a down-varying attenuator and a power amplifier channel in the microwave module, transmitting the reference signal through a radio frequency link which is the same as an external input signal, sampling an intermediate frequency signal corresponding to the reference signal transmitted through the radio frequency link to obtain second amplitude data, and outputting the second amplitude data according to the preset output power of the reference signal and the second amplitude data; and determining the actual gain of the link, comparing the actual gain with the target link gain parameter to obtain a gain error, and adjusting the attenuation value of an upper variable attenuator in the microwave module until the gain error meets a preset error threshold, thereby completing the automatic calibration of the link gain of the radar calibration equipment.

Description

Technical Field

[0001] This application relates to radar calibration technology, and more particularly to a self-calibrating radar calibration method. Background Technology

[0002] As an important supporting device for radar systems, radar calibration equipment is typically used to calibrate the range, power, and echo characteristics of radar transmission and reception links to ensure the detection accuracy and measurement consistency of the radar during long-term operation.

[0003] In existing technologies, a common approach is to use external standard signal sources, spectrum analyzers, power meters, and other benchtop instruments, along with radar calibration equipment or the radar system under test, to perform segmented tests on the gain, linearity, and noise performance of the RF link. Then, manual adjustments or software adjustments to attenuators, power amplifier operating points, or local oscillator parameters are made based on the test results to calibrate the overall link gain. This approach typically requires connecting the standard instruments sequentially to the system under test via RF cables and performing multiple measurements at different operating frequencies and output power points to obtain a complete gain curve and compensation parameters.

[0004] While the existing solutions described above can achieve relatively accurate gain measurement and calibration under laboratory conditions, they have significant limitations in engineering applications. On the one hand, external test instruments are bulky, costly, and have specific requirements for operating environment and power supply, making them unsuitable for long-term deployment with the equipment at radar stations or on airborne or vehicle-mounted platforms. On the other hand, calibration processes relying on external instruments are typically cumbersome and time-consuming, requiring professional personnel and failing to meet the radar system's needs for rapid on-site recovery, online self-testing, and periodic self-calibration. Furthermore, even existing calibration equipment that integrates simple detection loops often only monitors local links and cannot complete closed-loop calibration on an RF path completely consistent with the actual external input signal, leading to deviations between calibration results and actual operating conditions.

[0005] Therefore, how to achieve automatic and accurate calibration of the entire radio frequency link gain within radar calibration equipment without the need for external large-scale test instruments, and how to maintain the stability of calibration results under different environmental conditions, remains a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] This application provides a self-calibrating radar calibration method for automatically calibrating the link gain of a radar calibration device.

[0007] This application provides a self-calibrating radar calibration method, including:

[0008] Obtain the target link gain parameters of the radar calibration equipment;

[0009] The signal generation module of the radar calibration device outputs an intermediate frequency (IF) signal, which is transmitted to the microwave module via an IF link. The amplitude of the IF signal is sampled using the analog-to-digital converter integrated in the signal generation module to obtain first amplitude data.

[0010] The link gain is initially set based on the first amplitude data and the preset link gain parameters;

[0011] A reference signal is output from the reference source module. The reference signal is transmitted through the same radio frequency link as the external input signal. The intermediate frequency signal corresponding to the reference signal after transmission through the radio frequency link is sampled to obtain the second amplitude data.

[0012] Based on the preset output power of the reference signal and the second amplitude data, the actual gain of the link is determined, and the actual gain is compared with the target link gain parameter to obtain the gain error, so as to adjust the attenuation value of the up-conversion attenuator in the microwave module until the gain error meets the preset error threshold.

[0013] The self-calibrating radar calibration method provided in this application obtains the target link gain parameters of the radar calibration equipment. The signal generation module of the radar calibration equipment outputs an intermediate frequency (IF) signal, which is transmitted to a microwave module via the IF link. The analog-to-digital converter (ADC) unit integrated in the signal generation module samples the amplitude of the IF signal to obtain first amplitude data. The main control module controls the down-conversion attenuator and power amplifier channel in the microwave module based on the first amplitude data and preset link gain parameters to initially set the link gain. The reference source module outputs a reference signal, which is transmitted via the same radio frequency (RF) link as the external input signal. The IF signal corresponding to the reference signal after RF link transmission is sampled by the ADC unit to obtain second amplitude data. The main control module determines the actual link gain based on the preset output power of the reference signal and the second amplitude data. The main control module compares the actual gain with the target link gain parameters to obtain the gain error. Based on the gain error, the attenuation value of the up-conversion attenuator in the microwave module is adjusted until the gain error meets the preset error threshold, thereby completing the automatic calibration of the link gain of the radar calibration equipment. Attached Figure Description

[0014] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0015] Figure 1 This is a schematic diagram of the structure of a radar calibration device according to an example embodiment of this application;

[0016] Figure 2This is a schematic flowchart illustrating a self-calibrating radar calibration method according to an example embodiment of this application;

[0017] Figure 3 This is a flowchart illustrating a specific implementation of S140 according to an example embodiment of this application;

[0018] Figure 4 This is a flowchart illustrating a specific implementation of S190 according to an example embodiment of this application;

[0019] Figure 5 This is a schematic diagram of the structure of an electronic device according to an example embodiment of this application.

[0020] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0022] This embodiment of the application can be executed in the radar's self-calibration mode. In self-calibration mode, the main control module controls the microwave module to shut down the external radio frequency input path, thus isolating the external radio frequency signal from the reference source signal. The main control module then starts the reference source module to output a reference signal with a preset frequency and preset power. After the self-calibration mode is completed, the main control module restores the external radio frequency input path.

[0023] Specifically, to control the microwave module to shut down the external RF input path and isolate the external RF signal from the reference source signal, the main control module can issue a path control command to the RF switch unit within the microwave module, setting the RF switch connecting the external RF input port and the downconverter unit input port to the off state. The main control module can then control the programmable attenuator or limiter connected to the external RF input port to enter maximum attenuation or limiting protection mode to suppress external RF signal leakage into the RF link. Finally, the main control module can detect the RF switch status feedback signal returned by the microwave module. When it confirms that the external RF input path is off, it marks the current operating mode as self-calibration mode and prohibits the issuance of external RF input-related operating commands.

[0024] The aforementioned reference signal, which activates the reference source module to output a preset frequency and preset power, can be obtained by the main control module selecting a reference frequency corresponding to the target operating frequency band and a reference output power matching the target link gain parameters from a preset reference source configuration table, based on the radar calibration equipment's operating mode. The main control module sends frequency and power setting commands to the reference source module to set the local oscillator synthesizer of the reference source module to the reference frequency and the internal variable attenuator of the reference source module to the corresponding attenuation value of the reference output power. The main control module then controls the RF switch unit connected to the output port of the reference source module to be turned on and sets the enable control pin of the reference source module to the working state, thereby activating the reference source module to output a continuous reference signal. Finally, the main control module reads the phase-locked loop (PLL) lock flag and output power monitoring code value returned by the reference source module. When it is confirmed that the reference source frequency is locked and the output power is within the preset tolerance range, the current reference signal state is marked as a valid reference source state.

[0025] After the self-calibration mode is completed, the external RF input path is restored via the main control module. This can be achieved by first sending a shutdown command to the reference source module, setting its enable control pin to the off state and setting the RF switch unit connected to the reference source module's output port to the off state, thus stopping the injection of the reference signal into the RF link. Next, the main control module sends a path restoration command to the RF switch unit within the microwave module, setting the RF switch connecting the external RF input port and the downconverter unit's input port to the on state, and restoring the programmable attenuator or limiter connected to the external RF input port to its normal operating attenuation value or normal protection threshold. Finally, the main control module reads the RF switch status feedback signal returned by the microwave module and the power detection result from the external RF input port's front-end detection circuit. When it confirms that the external RF input path is on and there is no abnormal high-power input, the current operating mode is switched from self-calibration mode to normal operating mode, and the issuance of external RF input-related operating commands is permitted.

[0026] Furthermore, it is worth noting that Figure 1 This is a schematic diagram of the structure of a radar calibration device according to an example embodiment of this application. For example... Figure 1 As shown, in the radar calibration equipment used in this embodiment, the antenna unit is connected to the calibration equipment host via an RF cable. The display and control unit is connected to the calibration equipment host via a network cable. The Beidou unit, antenna unit, and calibration equipment host are powered by a power supply unit. The signal generation module and main control module inside the calibration equipment host are connected via a parallel port, the microwave module and signal generation unit are connected via an RF port, the microwave module and main control module are connected via a parallel port, and the power amplifier module is connected to the microwave unit via an RF cable.

[0027] In a further implementation scheme, the microwave module is used to complete the frequency conversion, power amplification and RF path switching between the RF signal and the intermediate frequency signal. The microwave module includes an external RF input port, a downconversion unit, an intermediate frequency-RF upconversion unit, an upconversion attenuator, a downconversion attenuator, a power amplifier module, a circulator, and a first RF switch unit and a second RF switch unit.

[0028] The signal generation module is used to generate intermediate frequency (IF) signals with controllable frequency and power, and to sample the amplitude of the IF signals in the IF link. The signal generation module includes a local oscillator synthesizer, an IF signal source, an analog-to-digital converter (ADC), and an amplitude detection circuit connected to the ADC.

[0029] The reference source module is used to generate a reference signal with a preset frequency and preset power in self-calibration mode, and inject the reference signal into the RF link;

[0030] The main control module is used to centrally control the microwave module, signal generation module, and reference source module, and to execute target link gain parameter acquisition, link gain initial setting, actual gain measurement, and automatic calibration algorithm.

[0031] The external RF input port is connected to the RF input terminal of the downconversion unit via the first RF switch unit, and the RF output terminal of the reference source module is connected to the RF input terminal of the downconversion unit via a coupler, so that the external RF signal and the reference source signal can be switched or superimposed and transmitted in the same RF link.

[0032] The intermediate frequency output of the downconversion unit is connected to the intermediate frequency input of the signal generation module through the downconversion attenuator, and the intermediate frequency output of the signal generation module is connected to the input of the upconversion attenuator through the intermediate frequency-RF upconversion unit.

[0033] The output of the up-conversion attenuator is connected in sequence to the input of the power amplifier module, the output of the power amplifier module, and the input of the second RF switch unit. The output of the second RF switch unit is connected to the input of the circulator. The ports of the circulator are used to connect to the radar antenna port and the reflective load port in sequence.

[0034] The analog input terminal of the analog-to-digital converter is connected in parallel to the intermediate frequency output node of the signal generation module and the output node of the down-conversion attenuator to sample the amplitude of the intermediate frequency signal output by the signal generation module and the intermediate frequency signal corresponding to the reference signal transmitted through the radio frequency link.

[0035] The main control module is connected to the analog-to-digital converter, local oscillator synthesizer, down-conversion attenuator, up-conversion attenuator, and power amplifier module via SPI bus or TTL-232 bus, respectively, and is used to issue attenuation control commands, frequency control commands, channel control commands, and read the amplitude code value output by the analog-to-digital converter.

[0036] The main control module is connected to the enable control terminals of the first RF switch unit, the second RF switch unit, and the reference source module via a GPIO interface or a serial bus. It is used to control the on or off of the external RF input path, the on or off of the transmission path, and the on or off of the reference source module.

[0037] The main control module is further connected to the communication interface of the host computer or display and control unit to receive the target link gain parameters, self-calibration start command and working mode parameters, and store the target link gain parameters in the internal register of the main control module for use in executing the automatic link gain calibration process of claim 1.

[0038] The aforementioned signal generation module is specifically defined as follows: the local oscillator synthesizer is a phase-locked loop frequency synthesizer, whose reference clock input is connected to the system reference clock source, and its RF output is connected to the local oscillator input of the intermediate frequency signal source, and is used to provide a programmable local oscillator frequency for the intermediate frequency signal source.

[0039] The intermediate frequency (IF) signal source includes a digital-to-analog converter (DAC) and a subsequent IF filter and amplifier circuit. The data input terminal of the DAC is connected to the main control module or the internal waveform storage unit, and is used to generate a single-frequency or linearly frequency-modulated IF signal under the control of the main control module. Its analog output is output to the analog input terminal of the IF-RF upconversion unit and the analog-to-digital converter unit after passing through the IF filter and amplifier circuit.

[0040] The analog-to-digital converter unit is a 12-bit analog-to-digital converter. Its sampling clock input is connected to the system reference clock source or a dedicated sampling clock source, and its digital output is connected to the main control module via a TTL-232 bus or an LVDS bus to output the amplitude code value corresponding to the intermediate frequency signal amplitude in real time.

[0041] The amplitude detection circuit includes a front-end intermediate frequency buffer amplifier and a bandpass filter, which are used to buffer and filter the intermediate frequency signal at the sampling node to ensure that the amplitude and spectrum of the signal input to the analog-to-digital conversion unit meet the sampling requirements.

[0042] Figure 2 This is a schematic flowchart illustrating a self-calibrating radar calibration method according to an example embodiment of this application. Figure 2 As shown, the method provided in this embodiment includes:

[0043] S110. Obtain the target link gain parameters of the radar calibration equipment.

[0044] Specifically, the display and control software can be run by the industrial control computer in the display and control unit. The human-machine interface of the display and control software provides an input area for the target link gain parameters. The input area includes input controls for setting the target output power, operating frequency band, and power amplifier channel status.

[0045] The display and control software converts the target output power, operating frequency band, and power amplifier channel status entered or selected by the user in the input area into corresponding target link gain parameters. The target link gain parameter is the difference between the target output power and the standard input power.

[0046] The display and control software verifies the range of the target link gain parameters based on the calibration configuration file stored in the local storage medium. If the target link gain parameters exceed the preset allowable range, the human-machine interface will prompt an input error and prohibit the issuance of self-calibration commands.

[0047] When the target link gain parameter passes the range verification, the display and control software encapsulates the target link gain parameter into a self-calibration control message according to the preset communication protocol and sends it to the main control module via Ethernet bus or serial bus.

[0048] The main control module parses the received self-calibration control message, extracts the target link gain parameter, and stores the target link gain parameter in the internal register of the main control module for use in subsequent initial setting of link gain and automatic calibration steps.

[0049] The S120 radar calibration equipment's signal generation module outputs an intermediate frequency (IF) signal, which is then transmitted to the microwave module via an IF link.

[0050] The signal generation module includes an intermediate frequency (IF) signal source, a local oscillator synthesizer, and an IF buffer amplification and filtering circuit. The radio frequency (RF) output of the IF signal source forms the IF output port, which, after passing through the IF buffer amplification and filtering circuit, is connected to the IF input port of the microwave module via an IF link.

[0051] The reference clock input of the local oscillator synthesizer is connected to the system reference clock source, and its RF output is connected to the local oscillator input of the intermediate frequency signal source. It is used to generate the intermediate frequency operating frequency corresponding to the target link gain parameters under the control of the frequency setting command issued by the main control module.

[0052] The intermediate frequency signal source includes a digital-to-analog converter and its subsequent intermediate frequency amplifier circuit. The data input terminal of the digital-to-analog converter is connected to the main control module or the internal waveform storage unit, and is used to output a single-frequency or linear frequency modulated intermediate frequency baseband waveform under the control of the main control module. The intermediate frequency amplifier circuit is used to amplify the intermediate frequency signal output by the digital-to-analog converter to a preset intermediate frequency power level and limit its bandwidth.

[0053] The intermediate frequency (IF) buffer amplifier and filter circuit is located between the IF output port of the signal generation module and the IF input port of the microwave module. It is used to perform impedance matching, amplitude stabilization and bandpass filtering on the IF signal to ensure that the IF signal transmitted to the microwave module via the IF link meets the input amplitude and spectrum requirements of the IF-RF upconversion unit of the microwave module.

[0054] The intermediate frequency link is a coaxial cable with a characteristic impedance of 50 Ω or a microstrip transmission line on a printed circuit board. One end of the link is connected to the intermediate frequency output port of the signal generation module, and the other end is connected to the intermediate frequency input port of the microwave module. Radio frequency connectors or board-to-board connectors are provided at both ends to transmit the intermediate frequency signal output by the signal generation module to the microwave module with low loss without adding additional active components.

[0055] The main control module is connected to the local oscillator synthesizer via SPI bus or TTL-232 bus to configure the local oscillator output frequency and output power. It is also connected to the digital-to-analog converter via digital control interface to configure the frequency, amplitude and waveform type of the intermediate frequency signal. This allows the signal generation module to output an intermediate frequency signal that meets the target link gain parameter requirements, which is then transmitted to the microwave module via the intermediate frequency link.

[0056] S130. Using the analog-to-digital conversion unit integrated in the signal generation module, the amplitude of the intermediate frequency signal is sampled to obtain the first amplitude data.

[0057] Specifically, the signal generation module is equipped with an analog input port of the analog-to-digital converter (ADC). The analog input port of the ADC is electrically connected to the ADC output node of the signal generation module through an ADC sampling branch. The ADC sampling branch includes an ADC coupling unit and an ADC buffer amplifier circuit, which is used to couple a portion of the ADC signal to the analog input port of the ADC without significantly affecting the power and flatness of the ADC main path.

[0058] The intermediate frequency coupling unit is a directional coupler or a resistor divider network. Its main path is connected in series between the intermediate frequency output port of the signal generation module and the intermediate frequency link input port. The coupling end or voltage divider end is connected to the input end of the intermediate frequency buffer amplifier circuit, which is used to extract a fixed proportion of the intermediate frequency signal from the intermediate frequency main path.

[0059] The intermediate frequency (IF) buffer amplifier circuit includes an IF buffer amplifier and a bandpass filter, which are used to perform impedance matching, amplitude adjustment and band-limiting filtering on the IF signal coupled out by the IF coupling unit, so as to ensure that the amplitude of the IF signal input to the analog-to-digital converter unit is within the linear input range of the analog-to-digital converter unit and that the spectral components meet the sampling bandwidth requirements.

[0060] The analog-to-digital conversion unit is a 12-bit analog-to-digital converter with a sampling rate of not less than 500 MSPS and a dynamic range greater than or equal to 40 dB. The sampling clock input is connected to the system reference clock source or a dedicated sampling clock source to ensure that the intermediate frequency signal is sampled without aliasing within the Nyquist bandwidth.

[0061] The main control module is connected to the digital output of the analog-to-digital converter unit via a TTL-232 bus, SPI bus, or LVDS bus. It is used to periodically read the digital code value corresponding to the instantaneous amplitude of the intermediate frequency signal and perform averaging, square averaging, or peak detection calculation on the digital code value within each preset sampling window to obtain the first amplitude data corresponding to the current intermediate frequency signal power.

[0062] After completing a sampling period, the main control module stores the first amplitude data obtained through numerical calculation in an internal register or buffer unit, and compares the first amplitude data with the reference power data corresponding to the preset link gain parameters.

[0063] S140. The main control module controls the down-conversion attenuator and power amplifier channel in the microwave module according to the first amplitude data and the preset link gain parameters to perform the initial setting of the link gain.

[0064] Figure 3 This is a flowchart illustrating a specific implementation of S140 according to an example embodiment of this application. For example... Figure 3 As shown, the above-mentioned S140 includes:

[0065] S141. The current intermediate frequency signal power is determined by the main control module based on the first amplitude data.

[0066] Specifically, the main control module stores a calibration correspondence table between the amplitude code value of the analog-to-digital converter and the actual power of the intermediate frequency signal in a non-volatile memory. The calibration correspondence table is obtained by fitting the output code value of the analog-to-digital converter corresponding to different input power under standard power conditions and at 25°C.

[0067] The main control module performs code value averaging, DC bias removal, and temperature compensation on the first amplitude data when reading the first amplitude data output by the analog-to-digital conversion unit, and uses the compensated amplitude code value as the valid amplitude code value.

[0068] The main control module interpolates or searches the calibration correspondence table based on the effective amplitude code value to obtain the actual power value of the current intermediate frequency signal at the input of the analog-to-digital conversion unit. Then, based on the coupling coefficient or voltage division ratio of the intermediate frequency sampling branch, it converts the power of the current intermediate frequency signal at the intermediate frequency output port of the signal generation module to be used as the current intermediate frequency signal power.

[0069] S142. The main control module compares the current intermediate frequency signal power with the reference power corresponding to the preset link gain to determine the target attenuation value of the downconverter attenuator and selects the channel state of the power amplifier module.

[0070] Specifically, the main control module uses the target link gain parameter, the current operating frequency band, and the current operating mode as an index to look up the reference intermediate frequency power value corresponding to the target link gain parameter in the pre-stored reference power configuration table. The reference intermediate frequency power value is the recommended intermediate frequency input power to ensure the linearity and signal-to-noise ratio of the whole machine output.

[0071] The main control module compares the current intermediate frequency (IF) signal power with the reference IF power value and calculates the power difference between the current IF signal power and the reference IF power value.

[0072] The main control module calculates and determines the target attenuation value of the down-conversion attenuator based on the power difference and the attenuation step and adjustable range of the down-conversion attenuator in the microwave module. When the target attenuation value exceeds the hardware allowable range, it is limited to the maximum or minimum attenuation value of the down-conversion attenuator.

[0073] The main control module selects the power amplifier module channel status that matches the current target link gain parameters from the preset power amplifier channel configuration table, based on the target link gain parameters and the gain data of each channel of the power amplifier module in different working modes. The power amplifier module channel status includes at least a through channel, a low gain amplification channel, and a high gain amplification channel.

[0074] The main control module prioritizes ensuring that the power amplifier module operates within the linear region and safe power range when selecting the channel status of the power amplifier module. When the target link gain is low, the direct channel is selected first. When the target link gain is high but does not exceed the safe operating area of ​​the power amplifier, the amplification channel is selected. When there are multiple selectable channels, the preferred channel is selected based on the comprehensive indicators of noise figure, linearity and power consumption.

[0075] S143. Through the main control module, send attenuation control commands and power amplifier channel control commands to the microwave module to set the downconverter attenuator to the target attenuation value and set the power amplifier module to a through channel or an amplification channel.

[0076] Specifically, the main control module queries the corresponding attenuation control code in the pre-stored down-conversion attenuator control code lookup table based on the target attenuation value. The attenuation control code lookup table records the mapping relationship between different attenuation values ​​and corresponding digital control words.

[0077] The main control module sends the obtained attenuation control code to the down-conversion attenuator control interface in the microwave module via the SPI bus or parallel GPIO bus to set the down-conversion attenuator to the corresponding target attenuation value. After writing, the status feedback register of the down-conversion attenuator is read or the loop power change is detected to confirm that the down-conversion attenuator has been correctly loaded with the target attenuation value.

[0078] The main control module queries the corresponding channel control code in the power amplifier module channel configuration table based on the selected power amplifier module channel status. The channel control code includes the on / off status of the RF switches inside the power amplifier module, the enable status of the multi-stage power amplifier cascade structure, and the selection status of the bypass path.

[0079] The main control module sends the channel control code to the control unit of the power amplifier module via the GPIO interface, I²C bus or SPI bus to control the on and off of the RF switching unit inside the power amplifier module, thereby configuring the power amplifier module as a through channel or an amplification channel.

[0080] After completing the downconversion attenuator settings and power amplifier module channel switching via the main control module, the amplitude of the intermediate frequency signal is sampled again using the analog-to-digital conversion unit. The current intermediate frequency signal power is compared with the reference intermediate frequency power value. When the difference between the two exceeds the preset power deviation threshold, the target attenuation value of the downconversion attenuator is readjusted or the channel status of another power amplifier module is switched to ensure that the initial setting of the link gain meets the preset requirements.

[0081] S150, The reference source module outputs a reference signal, which is transmitted via the same RF link as the external input signal.

[0082] Optionally, the reference source module is integrated into the microwave module. Correspondingly, the reference source module outputs a reference signal, including: controlling the reference source module to output a reference signal whose frequency and power are closest to the current external input signal, via the main control module. The reference signal is injected into the RF link via a coupler. The RF link sequentially includes a down-conversion unit, a signal generation module, an intermediate frequency-to-RF up-conversion unit, a power amplifier module, and a circulator.

[0083] Specifically, the main control module can obtain the frequency information and expected input power information of the external input signal under the current radar operating status. The frequency information and expected input power information are issued by the host computer control command or the radar operating mode configuration table.

[0084] The main control module retrieves the reference frequency point closest to the external input signal frequency and the reference output power level closest to the desired input power from the reference signal configuration table pre-stored in non-volatile memory, using frequency information and desired input power information as search criteria. The reference signal configuration table records multiple discrete frequency points that the reference source module can output and their corresponding adjustable output power levels.

[0085] The main control module converts the queried reference frequency point and reference output power level into the local oscillator synthesizer frequency setting word and power control word of the reference source module, and writes them into the frequency control register and power control register in the reference source module via SPI bus or I²C bus.

[0086] The main control module controls the local oscillator synthesizer inside the reference source module to lock to the target reference frequency and enables the RF output switch inside the reference source module so that the reference source module continuously outputs a reference signal at the target reference frequency and target reference output power.

[0087] After the output of the reference source module stabilizes, the main control module reads the phase-locked loop lock flag, the radio frequency output enable flag, and the power detection result output by the internal detection circuit in the status register of the reference source module. When the detection result is within the allowable deviation range, it is confirmed that the frequency and power of the reference signal meet the requirement of being closest to the frequency and power of the current external input signal. Otherwise, the main control module fine-tunes the reference output power level until the detection result meets the preset error threshold.

[0088] Connect the input port of the coupler to the RF output port of the reference source module, connect the through port of the coupler in series between the external RF input path and the input terminal of the RF link, and connect the coupling port of the coupler to the input terminal of the downconversion unit of the RF link so that the reference signal is injected into the RF link through the coupling port with a predetermined coupling coefficient.

[0089] The coupler is a directional coupler, and its coupling coefficient is pre-selected based on the maximum allowable input power of the radar calibration equipment and the output power of the reference source module. This ensures that when the reference source module is operating at its rated output power, the reference signal power injected into the RF link through the coupler does not exceed the safe input power of the RF link front-end device. It also has a port isolation of not less than 20 dB to reduce the reverse leakage of the reference source signal to the external RF input port.

[0090] The main control module controls the RF switch unit inside the microwave module to place the coupler on the RF link shared with the external RF input signal. When executing the self-calibration mode, the RF switch corresponding to the external RF input path is turned off, while the RF switch corresponding to the reference source module injection path is turned on, so that the reference signal is injected into the RF link through the coupler, while the external RF input signal is isolated.

[0091] After the calibration process is completed, the main control module controls the RF switch unit to close the injection path of the reference source module and reopen the external RF input path, so that the RF link returns to normal operation.

[0092] Optionally, the RF input terminal of the downconversion unit is connected to the coupling port of the coupler to receive the reference signal injected by the reference source module through the coupler, and under the action of the local oscillator signal provided by the local oscillator synthesizer, downconvert the reference signal to a preset intermediate frequency point and output it to the intermediate frequency input port of the signal generation module.

[0093] When the signal generation module receives the intermediate frequency (IF) signal output from the downconversion unit, it performs amplitude adjustment and impedance matching on the IF signal through the internal IF buffer amplifier circuit, and sends the IF signal to the analog-to-digital conversion unit integrated in the signal generation module for amplitude sampling. At the same time, the IF signal is sent to the IF-RF upconversion unit through the IF input port of the IF-RF upconversion unit.

[0094] The intermediate frequency to radio frequency upconversion unit, driven by the local oscillator signal provided by the local oscillator source, upconverts the intermediate frequency signal to the target radio frequency point and outputs it to the input port of the power amplifier module. The local oscillator source can be shared with the downconversion unit or an independent local oscillator synthesizer can be used. The local oscillator source is uniformly configured by the main control module to ensure that the frequency ratio of the upconversion link meets the requirements of the radar operating mode.

[0095] After receiving the RF signal output from the intermediate frequency to RF upconversion unit, the power amplifier module performs either pass-through or power amplification on the RF signal according to the power amplifier channel state selected by the main control module during the initial link gain setting stage, and outputs the processed RF signal to the input port of the circulator.

[0096] The circulator's input port is connected to the power amplifier module's output port, its transmit port is connected to the radar antenna port or equivalent load port under test, and its receive port is connected to the radar receiver link. In self-calibration mode, it directs the RF signal output by the power amplifier module to the radar transmitter or internal matching load, while isolating the radar receiver link to prevent the reference signal from interfering with or damaging the radar receiver.

[0097] S160. Using the analog-to-digital conversion unit, the intermediate frequency signal corresponding to the reference signal transmitted via the radio frequency link is sampled to obtain the second amplitude data.

[0098] Specifically, the aforementioned analog-to-digital converter (ADC) is a 12-bit ADC with a sampling rate of 1 GSPS and a dynamic range greater than or equal to 40 dB. The main control module reads the amplitude code value output by the ADC in real time via the TTL-232 bus to obtain the current intermediate frequency signal power.

[0099] It is worth noting that the aforementioned intermediate frequency signal is a voltage signal obtained by the down-conversion unit converting the external input signal or the reference signal output by the reference source module from the working radio frequency band to the preset intermediate frequency working band through one or more mixing and conversions under the action of the local oscillator signal. Its center frequency is fixed at f, which is preferably 70 MHz or 140 MHz. The bandwidth is not less than 1.2 times the maximum signal bandwidth required by the radar working mode, and satisfies the matching relationship between the sampling rate of the analog-to-digital conversion unit and the Nyquist sampling theorem.

[0100] Before entering the analog-to-digital conversion unit, the intermediate frequency signal is processed by an intermediate frequency bandpass filter and an intermediate frequency buffer amplifier circuit. The passband range of the intermediate frequency bandpass filter is symmetrically set around the center frequency f, and its -3 dB bandwidth is adapted to the bandwidth of the radar working signal to suppress the image frequency component and out-of-band noise generated by mixing. The passband ripple is preferably less than 0.5 dB, and the out-of-band suppression is preferably not less than 40 dB.

[0101] The intermediate frequency (IF) buffer amplifier circuit is used to adjust the amplitude and match the impedance of the IF signal, so that the amplitude range of the IF signal input to the analog-to-digital converter (ADC) is limited to the range of (-3 dBFS, 0 dBFS) of the full-scale input range of the ADC. The input impedance is matched with the impedance of the analog input port of the ADC to ensure that the waveform distortion of the IF signal is no greater than 1%.

[0102] The intermediate frequency signal can be single-ended or differential, with a differential intermediate frequency signal structure preferred to reduce the impact of common-mode interference and ground potential fluctuations on sampling accuracy. The amplitude error between differential pairs is preferably no greater than 0.2 dB, and the phase error is preferably no greater than 3°.

[0103] The level range of the intermediate frequency (IF) signal throughout the entire link is preset according to the target link gain parameters and the dynamic range of the analog-to-digital converter (ADC). During the calibration process, it is adjusted by the down-conversion attenuator, up-conversion attenuator, and power amplifier module to ensure that the IF signal input to the ADC is within its effective dynamic range under different calibration conditions, thereby meeting the requirement of sampling the IF signal corresponding to the reference signal after transmission through the RF link.

[0104] S170. The main control module determines the actual gain of the link based on the preset output power of the reference signal and the second amplitude data.

[0105] In this step, the reference power before the reference signal is injected into the link can be determined based on the preset output power of the reference source module and the coupler coefficient. After sampling the intermediate frequency signal corresponding to the reference signal transmitted through the RF link by the analog-to-digital conversion unit, the link output power is determined using the second amplitude data. Then, the actual gain of the link is determined by the main control module based on the difference between the signal input power and the signal output power.

[0106] S180. The actual gain is compared with the target link gain parameter through the main control module to obtain the gain error.

[0107] Specifically, the actual gain of the link, determined based on the preset output power of the reference signal and the second amplitude data, can be stored in the actual gain register inside the main control module in decibels.

[0108] The main control module reads the target link gain parameters corresponding to the current working mode from non-volatile memory or configuration data issued by the host computer, and stores them in the target gain register inside the main control module in decibels.

[0109] The main control module performs numerical calculations between the actual gain register and the target gain register. Using the target link gain parameter as a reference, the gain error is calculated. The actual gain of the link is used as the actual gain, the target link gain parameter is used as the target gain, and the gain error is the difference between the actual gain and the target gain. The gain error is expressed in decibels.

[0110] The main control module compares the calculated gain error with a preset error threshold. When the absolute value of the gain error is greater than the preset error threshold, it is determined that the current link gain deviates from the target link gain parameter, and the attenuation value of the up-conversion attenuator in the microwave module needs to be adjusted. When the absolute value of the gain error is less than or equal to the preset error threshold, it is determined that the current link gain meets the calibration requirements.

[0111] The main control module stores the calculated actual gain, target link gain parameters, and gain error in the calibration data record area of ​​the main control module, indexed by timestamps, for subsequent automatic link gain calibration and maintenance analysis.

[0112] S190. Based on the gain error, adjust the attenuation value of the up-conversion attenuator in the microwave module until the gain error meets the preset error threshold.

[0113] In this step, the attenuation value of the up-conversion attenuator in the microwave module can be adjusted according to the gain error until the gain error meets the preset error threshold, thereby completing the automatic calibration of the radar calibration equipment link gain.

[0114] Figure 4 This is a flowchart illustrating a specific implementation of S190 according to an example embodiment of this application. For example... Figure 4 As shown, the above S190 includes:

[0115] S191. Through the main control module, look up the preset gain control code table, and query the corresponding up-conversion attenuator initial control code based on the current target link gain parameters, down-conversion attenuator attenuation value and power amplifier channel status.

[0116] Optionally, the preset gain control code lookup table is a three-dimensional lookup table generated under standard power supply conditions and at 25°C, based on the overall gain test results corresponding to different down-conversion attenuator attenuation values, different up-conversion attenuator attenuation values, and different power amplifier channel states.

[0117] Specifically, during power-on initialization or when entering self-calibration mode, the main control module loads the gain control code lookup table stored in non-volatile memory into the internal storage area of ​​the main control module. The gain control code lookup table is stored in partitions according to the target link gain parameters, down-converter attenuation values, and power amplifier channel status. Each combination of target link gain parameters, down-converter attenuation values, and power amplifier channel status corresponds to a unique up-converter initial control code.

[0118] The main control module converts the current target link gain parameter into the same unit and encoding format as the target link gain parameter index in the gain control code lookup table, and determines the target link gain parameter index that is closest to or exactly the same as the current target link gain parameter in the gain control code lookup table.

[0119] The main control module converts the actual attenuation value of the current down-conversion attenuator into the same unit and encoding format as the down-conversion attenuator attenuation value index in the gain control code lookup table, and determines the down-conversion attenuator attenuation value index that is closest to or exactly the same as the current down-conversion attenuator attenuation value in the gain control code lookup table.

[0120] The main control module reads the current channel status of the power amplifier module. The power amplifier channel status includes one or more working states of the pass-through channel status and the amplification channel status. The power amplifier channel status is then mapped to the corresponding power amplifier channel status index in the gain control code lookup table.

[0121] The main control module uses the target link gain parameter index, the down-converter attenuation value index, and the power amplifier channel status index as three-dimensional lookup keys to retrieve the corresponding up-converter initial control code in the gain control code lookup table. When the three-dimensional lookup key does not completely match the record in the lookup table, the main control module performs a nearest search or interpolation operation between adjacent indices according to preset priority rules to obtain the up-converter initial control code that is closest to the current operating condition.

[0122] The main control module temporarily stores the found initial control code of the up-conversion attenuator in its internal register and provides control word input for the up-conversion attenuator to be written to the microwave module later.

[0123] S192. The initial control code of the up-conversion attenuator is written into the up-conversion attenuator of the microwave module through the main control module to set the initial up-conversion attenuation value.

[0124] Specifically, through the main control module, when the system is powered on and initialized or enters self-calibration mode, the digital control bus used to control the up-conversion attenuator is configured so that the digital control bus works in a preset communication mode. The digital control bus includes one or more of the following: serial peripheral interface bus, general purpose input / output parallel bus, or low voltage differential signal bus.

[0125] The main control module formats the initial control code of the up-conversion attenuator obtained from the gain control code lookup table, and encapsulates the initial control code of the up-conversion attenuator into a control word that conforms to the communication protocol of the up-conversion attenuator chip. The control word includes at least a device address field, a register address field, and a control data field for setting the attenuation value.

[0126] Before writing the initial control code for the up-conversion attenuator, the main control module sends a chip select signal or enable signal to the microwave module to select the corresponding up-conversion attenuator channel and put the digital control bus into an active state.

[0127] According to the data timing requirements of the up-conversion attenuator chip, the main control module outputs each bit of the control word sequentially on the digital control bus. With the cooperation of the clock signal or the write trigger signal, the initial control code of the up-conversion attenuator is written into the corresponding up-conversion attenuator register in the microwave module.

[0128] After the main control module completes the writing process, it cancels the chip select signal or enable signal, and after the preset register update time, it reads the status register of the up-conversion attenuator or confirms that the up-conversion attenuator has successfully loaded the initial control code by detecting the change in the output power of the detection loop.

[0129] After successful writing, the main control module stores the current initial control code of the up-conversion attenuator, the corresponding target link gain parameters, the down-conversion attenuator attenuation value, and the power amplifier channel status in the main control module's operating parameter recording area, which serves as the initial reference for subsequent adjustments to the up-conversion attenuator attenuation value.

[0130] S193. Output a reference signal through the reference source module and measure the amplitude of the corresponding intermediate frequency signal through the analog-to-digital conversion unit to redetermine the actual gain of the link.

[0131] Specifically, after the main control module completes the initial control code writing of the up-conversion attenuator and sets the initial up-conversion attenuation value, it sends a reference signal configuration command to the reference source module. The reference signal configuration command is used to set the output frequency and output power of the reference source module. The output frequency is the same as the working frequency of the external input signal or is preset to a calibration frequency point within the same frequency band. The output power is the standard power value pre-calibrated by the reference source module.

[0132] The main control module controls the reference source module to start RF output, so that the reference signal is injected into the RF link through a coupler with a fixed coupling degree. The RF link includes a downconversion unit, a signal generation module, an intermediate frequency to RF upconversion unit, a power amplifier module, and a circulator in sequence, thereby ensuring that the reference signal and the external input signal are transmitted on the same physical link and gain path.

[0133] After the reference source module outputs a stable value, the main control module waits for a preset stabilization time to allow the active and passive components in the RF and IF links to reach thermal and power stability. The stabilization time is preset according to the hardware characteristics of the microwave module and the reference source module.

[0134] The intermediate frequency signal corresponding to the reference signal transmitted via the radio frequency link is continuously sampled through the analog-to-digital conversion unit. Multiple frames of amplitude code value data are acquired within a preset sampling time window. The main control module filters and averages the multiple frames of amplitude code values ​​to suppress instantaneous noise and random fluctuations, and obtains the second amplitude data for calculation.

[0135] The main control module converts the second amplitude data into an intermediate frequency (IF) output power value based on the amplitude code value and power correspondence of the analog-to-digital conversion unit. The IF output power value is then compared with the reference input power obtained from the preset output power of the reference source module and the coupler coefficient. Based on the difference between the signal output power and the signal input power, the actual gain of the entire RF link and IF link is recalculated.

[0136] After the actual gain is re-determined through the main control module, the output power of the reference source module is stopped or reduced to standby mode to reduce long-term power stress on the microwave module and related devices. The actual gain result measured this time, along with the corresponding attenuation values ​​of the up-conversion attenuator, down-conversion attenuator, and power amplifier channel status, are stored in the calibration data recording area of ​​the main control module for subsequent automatic calibration iteration process of link gain.

[0137] S194. If the difference between the current actual gain and the target link gain parameter is greater than the preset error threshold, the main control module will fine-tune the up-conversion attenuator according to the preset step value, and repeat the measurement and comparison process until the error between the actual gain of the link and the target link gain parameter is less than or equal to the preset error threshold.

[0138] Specifically, the main control module determines the fine-tuning direction of the up-conversion attenuator based on the difference between the current actual gain and the target link gain parameters. The main control module then adjusts the attenuation value of the up-conversion attenuator along this fine-tuning direction in steps no greater than 0.2 dB, with the minimum hardware step for the up-conversion attenuator being 0.1 dB. After each adjustment, the actual gain is remeasured using the reference source module and the analog-to-digital converter unit to determine if it meets the preset error threshold.

[0139] In this embodiment, by acquiring the target link gain parameters of the radar calibration equipment, the signal generation module of the radar calibration equipment outputs an intermediate frequency (IF) signal, which is transmitted to the microwave module via the IF link. The analog-to-digital converter (ADC) unit integrated within the signal generation module samples the amplitude of the IF signal to obtain first amplitude data. The main control module, based on the first amplitude data and preset link gain parameters, controls the down-conversion attenuator and power amplifier channel in the microwave module to initially set the link gain. A reference signal is output from the reference source module and transmitted via the same radio frequency (RF) link as the external input signal. The IF signal corresponding to the reference signal transmitted via the RF link is sampled using the ADC unit to obtain second amplitude data. The main control module, based on the preset output power of the reference signal and the second amplitude data, determines the actual link gain. The main control module compares the actual gain with the target link gain parameters to obtain the gain error. Based on the gain error, the attenuation value of the up-conversion attenuator in the microwave module is adjusted until the gain error meets a preset error threshold, thereby completing the automatic calibration of the radar calibration equipment's link gain.

[0140] Compared with existing technologies, the above embodiments, through the introduction of a signal generation module within the radar calibration equipment to output a measurable intermediate frequency signal, the integration of an analog-to-digital converter unit with a high sampling rate and large dynamic range within the signal generation module, the integration of a reference source module within the microwave module and the transmission of the reference signal on the same RF link as the external input signal, and the comprehensive scheme of coordinated control of the down-conversion attenuator, power amplifier channel, and up-conversion attenuator by the main control module, enable the equipment to form a complete measurement and adjustment closed loop in self-calibration mode. This allows for automatic and accurate calibration of the actual gain of the link without relying on external test instruments. The above embodiments achieve at least the following technical effects:

[0141] First, by using the signal generation module to output an intermediate frequency (IF) signal and transmitting it to the microwave module via the IF link, and then using the analog-to-digital converter integrated in the signal generation module to sample the amplitude of the IF signal, this invention enables the main control module to obtain high-resolution first amplitude data internally. Based on this data and preset link gain parameters, the down-conversion attenuator and power amplifier channel are controlled to achieve a reasonable initial setting of the link gain, thereby shortening the search range required for subsequent fine-tuning and improving the convergence speed of automatic calibration.

[0142] Secondly, by integrating a reference source module into the microwave module, the reference source module outputs a reference signal and transmits it through the same RF link as the external input signal. Then, the intermediate frequency signal corresponding to the reference signal is sampled using the same analog-to-digital conversion unit to obtain the second amplitude data. The main control module can determine the actual gain of the link based on the preset output power of the reference signal and the second amplitude data, so that the measured gain result is strictly consistent with the actual working path of the equipment, thereby significantly improving the accuracy and representativeness of the overall gain evaluation.

[0143] Secondly, the main control module compares the actual gain with the target link gain parameter to obtain the gain error, and looks up the initial control code of the up-converter attenuator by combining the preset gain control code with a table. Then, based on this, the actual gain is repeatedly measured by the reference source module and the analog-to-digital conversion unit. When the gain error does not meet the preset error threshold, the up-converter attenuator is fine-tuned according to the preset step value. This invention realizes closed-loop control of automatic gain setting and error correction, which greatly reduces the operation complexity and significantly shortens the calibration time compared with manual adjustment, and enables the final link gain to be stably controlled within a small error range near the target value.

[0144] Finally, since the entire calibration process in the above embodiments is completed entirely by relying on the internal modules and control logic of the radar calibration equipment itself, without the need for external spectrum analyzers, power meters, or other independent monitoring modules, the overall system cost and deployment complexity are reduced while ensuring gain calibration accuracy, and the maintainability and reliability of the equipment in field environments and long-term operating scenarios are improved.

[0145] It is worth noting that the reason why the above embodiments can achieve the above technical effects is mainly based on the unified planning of the internal signal path and control path of the radar calibration equipment and the system design of the observability and controllability of the link gain.

[0146] On one hand, by setting up a signal generation module and enabling it to output an intermediate frequency (IF) signal, which is then transmitted to the microwave module via an IF link, and simultaneously integrating an analog-to-digital converter (ADC) unit within the signal generation module, the same module functions as both an IF excitation source and an IF amplitude acquisition unit. When the main control module drives the signal generation module to output the IF signal according to preset link gain parameters, the ADC unit samples the amplitude of the IF signal at a high sampling rate and outputs the first amplitude data. Based on this, the main control module calculates the current IF signal power, compares it with the reference power corresponding to the target gain, and thus determines the target attenuation value of the down-conversion attenuator and the switching state of the power amplifier channel. By writing corresponding control commands, the configuration of the down-conversion attenuator and the power amplifier module is completed, thereby ensuring that the link gain is in an initial state close to the target value before entering the fine-tuning stage, reducing the subsequent adjustment step size and number of adjustments.

[0147] On the other hand, the above embodiment integrates a reference source module in the microwave module, and injects the reference signal output by the reference source module into the same RF link as the external input signal through a coupler. This RF link sequentially includes a down-conversion unit, a signal generation module, an intermediate frequency to RF up-conversion unit, a power amplifier module, and a circulator. Since the reference signal is transmitted in the same physical path and device combination as the external working signal, after being down-converted to the intermediate frequency at the link end, the corresponding intermediate frequency signal also returns to the signal generation module for sampling by the analog-to-digital conversion unit to output the second amplitude data. The main control module uses the known preset output power of the reference source and the coupler coefficient to convert the second amplitude data into the link output power, and compares it with the reference power before the reference signal is injected into the link, thereby calculating the actual gain of the entire RF link and related intermediate frequency links, realizing high-precision digital measurement of the overall gain.

[0148] After obtaining the actual gain, the main control module compares it with the target link gain parameters to obtain the gain error. To achieve accurate and rapid gain correction, the above embodiment pre-stores a gain control code lookup table in the main control module. This lookup table is a three-dimensional lookup table constructed under standard temperature and power supply conditions for different down-conversion attenuator attenuation values, up-conversion attenuator attenuation values, and power amplifier channel states. During the calibration process, the main control module first looks up the corresponding up-conversion attenuator initial control code from the lookup table based on the target link gain parameters, the current down-conversion attenuator attenuation value, and the power amplifier channel state, and writes this control code into the up-conversion attenuator in the microwave module to set the initial up-conversion attenuation value. At this time, the system is at the theoretically close to the target gain given by the lookup table.

[0149] Based on this, the main control module again controls the reference source module to output a reference signal and measures the corresponding intermediate frequency signal amplitude through the analog-to-digital converter unit to recalculate the actual gain of the link. If the difference between the actual gain and the target link gain parameter exceeds the preset error threshold, it indicates that the current operating point still has a deviation due to factors such as environmental changes, device discreteness, or nonlinearity. To eliminate this deviation, the main control module fine-tunes the attenuation value of the up-conversion attenuator according to a preset step value. The adjustment direction is determined by the sign of the gain error, and the adjustment magnitude is no greater than a reasonable multiple of the minimum step size of the up-conversion attenuator hardware. After each fine-tuning, the main control module again triggers the reference source module to output, acquires the intermediate frequency amplitude, and calculates the actual gain. Through multiple iterations, the error between the actual gain and the target link gain parameter is less than or equal to the preset error threshold, completing closed-loop convergence.

[0150] Through the above-mentioned signal path consistency design, high-precision amplitude acquisition based on analog-to-digital conversion unit, and control strategy combining table lookup coarse adjustment and step fine adjustment, this invention establishes a closed-loop control model internally for target gain parameters, attenuation control code, actual link gain, and gain error feedback, so that the link gain can still be automatically adjusted to the target range under changes in environmental and device conditions.

[0151] Figure 5 This is a schematic diagram of the structure of an electronic device according to an example embodiment of this application. For example... Figure 5 As shown, the electronic device 400 provided in this embodiment includes: a processor 401 and a memory 402; wherein:

[0152] Memory 402 is used to store computer programs, and the memory may also be flash memory.

[0153] Processor 401 is used to execute the execution instructions stored in the memory to implement the various steps in the above method. For details, please refer to the relevant descriptions in the preceding method embodiments.

[0154] Alternatively, the memory 402 can be either standalone or integrated with the processor 401.

[0155] When the memory 402 is a device independent of the processor 401, the electronic device 400 may further include:

[0156] Bus 403 is used to connect the memory 402 and the processor 401.

[0157] This embodiment also provides a readable storage medium storing a computer program, which, when executed by at least one processor of an electronic device, enables the electronic device to perform the methods provided in the various embodiments described above.

[0158] This embodiment also provides a program product including a computer program stored in a readable storage medium. At least one processor of an electronic device can read the computer program from the readable storage medium, and the at least one processor executes the computer program to cause the electronic device to perform the methods provided in the various embodiments described above.

[0159] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the claims.

[0160] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A self-calibrating radar calibration method, characterized in that, include: Obtain the target link gain parameters of the radar calibration equipment; The signal generation module of the radar calibration device outputs an intermediate frequency (IF) signal, which is transmitted to the microwave module via an IF link. The amplitude of the IF signal is sampled using the analog-to-digital converter integrated in the signal generation module to obtain first amplitude data. The link gain is initially set based on the first amplitude data and the preset link gain parameters; A reference signal is output from the reference source module. The reference signal is transmitted through the same radio frequency link as the external input signal. The intermediate frequency signal corresponding to the reference signal after transmission through the radio frequency link is sampled to obtain the second amplitude data. Based on the preset output power of the reference signal and the second amplitude data, the actual gain of the link is determined, and the actual gain is compared with the target link gain parameter to obtain the gain error, so as to adjust the attenuation value of the up-conversion attenuator in the microwave module until the gain error meets the preset error threshold.

2. The self-calibrating radar calibration method according to claim 1, characterized in that, The initial setting of the link gain through the main control module, based on the first amplitude data and preset link gain parameters, includes: The main control module determines the current intermediate frequency signal power based on the first amplitude data. The main control module compares the current intermediate frequency signal power with the reference power corresponding to the preset link gain to determine the target attenuation value of the downconverter and select the channel state of the power amplifier module. The main control module sends attenuation control commands and power amplifier channel control commands to the microwave module to set the down-conversion attenuator to the target attenuation value and to set the power amplifier module to a through channel or an amplification channel.

3. The self-calibrating radar calibration method according to claim 1, characterized in that, The reference source module is integrated into the microwave module; correspondingly, the reference signal output by the reference source module includes: The main control module controls the reference source module to output a reference signal that is closest in frequency and power to the current external input signal. The reference signal is injected into the RF link via a coupler. The RF link includes, in sequence, a downconversion unit, a signal generation module, an intermediate frequency-RF upconversion unit, a power amplifier module, and a circulator.

4. The self-calibrating radar calibration method according to claim 1, characterized in that, The sampling of the intermediate frequency signal corresponding to the reference signal after transmission via the radio frequency link includes: The analog-to-digital conversion unit is a 12-bit analog-to-digital converter with a sampling rate of 1 GSPS and a dynamic range greater than or equal to 40 dB. The main control module reads the amplitude code value output by the analog-to-digital conversion unit in real time through the TTL-232 bus to obtain the current intermediate frequency signal power.

5. The self-calibrating radar calibration method according to claim 1, characterized in that, Determining the actual gain of the link based on the preset output power of the reference signal and the second amplitude data includes: The reference power before the reference signal is injected into the link is determined based on the preset output power and coupler coefficient of the reference source module. After sampling the intermediate frequency signal corresponding to the reference signal transmitted through the radio frequency link by the analog-to-digital conversion unit, the link output power is determined using the second amplitude data; The actual gain of the link is determined by the main control module based on the difference between the signal input power and the signal output power.

6. The self-calibrating radar calibration method according to claim 1, characterized in that, Adjusting the attenuation value of the up-conversion attenuator in the microwave module until the gain error meets a preset error threshold includes: The main control module looks up the corresponding initial control code of the up converter from the preset gain control code table, based on the current target link gain parameters, down converter attenuation value and power amplifier channel status. The main control module writes the initial control code of the up-conversion attenuator into the up-conversion attenuator of the microwave module to set the initial up-conversion attenuation value. The reference source module outputs a reference signal, and the corresponding intermediate frequency signal amplitude is measured by the analog-to-digital conversion unit to redetermine the actual gain of the link. If the difference between the current actual gain and the target link gain parameter is greater than the preset error threshold, the main control module will fine-tune the up-conversion attenuator according to the preset step value, and repeat the measurement and comparison process until the error between the actual gain of the link and the target link gain parameter is less than or equal to the preset error threshold.

7. The self-calibrating radar calibration method according to claim 6, characterized in that, The preset gain control code lookup table is a three-dimensional lookup table generated under standard power supply conditions and at 25°C, based on the overall gain test results corresponding to different down-converter attenuation values, different up-converter attenuation values, and different power amplifier channel states.

8. The self-calibrating radar calibration method according to claim 6, characterized in that, The step of fine-tuning the attenuator by the main control module according to a preset step value includes: The main control module determines the fine-tuning direction of the up-conversion attenuator based on the difference between the current actual gain and the target link gain parameter. The attenuation value of the up-conversion attenuator is adjusted along the fine-tuning direction by the main control module in steps no greater than 0.2 dB, and the minimum hardware step of the up-conversion attenuator is 0.1 dB. After each adjustment, the actual gain is remeasured using the reference source module and the analog-to-digital conversion unit, and it is determined whether the preset error threshold is met.

9. The self-calibrating radar calibration method according to claim 1, characterized in that, The method is performed in self-calibration mode.

10. The self-calibrating radar calibration method according to claim 9, characterized in that, The execution in self-calibration mode includes: The main control module controls the microwave module to shut down the external radio frequency input path, so as to isolate the external radio frequency signal from the reference source signal. The main control module is used to start the reference source module to output a reference signal with a preset frequency and preset power. After the self-calibration mode is completed, the external RF input path is restored through the main control module.

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