A phased array self-calibration method and apparatus

Abstract

The application relates to a phased array self-calibration method and device. The method comprises the following steps: a single-tone signal is generated through a transmitting channel, and the single-tone signal is simultaneously injected into N receiving channels through a power division network. FIFOs of the channels are reset when the transmission starts, and time-domain sampling data is stored in a RAM in a mapping mode of 'channel number as high bit and data index as low bit' after the data is detected. The data collection is stopped when the data index reaches Fourier transform point number M. Then, only the discrete Fourier transform value of a single frequency component corresponding to a center frequency point is calculated for M sampling data of each channel, a frequency domain complex result is obtained, and then the amplitude value and the phase value of each channel at the center frequency point are extracted. Finally, one channel is selected as a reference, and the relative amplitude compensation value and the phase compensation value of the remaining channels are calculated, which are used for real-time correction of each radio frequency channel and elimination of amplitude and phase inconsistency. The method can realize continuous and efficient storage of multi-channel data with low hardware cost.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a phased array self-calibration method and apparatus. Background Technology

[0002] With the development of wireless communication and sensing technologies such as satellite communication, phased array radar, and 5G / 6G massive MIMO, digital phased arrays have become a core enabling technology due to their fast, flexible, and precise beamforming capabilities. This technology is characterized by achieving electronic scanning and spatial filtering of beam pointing through independent control of the amplitude and phase of each radio frequency channel in the array. To ensure beamforming quality, traditional methods typically rely on a one-time calibration before shipment. This involves using external instruments such as a vector network analyzer to measure the amplitude and phase consistency of each channel after the phased array is assembled, and then embedding the compensation parameters into the system.

[0003] However, this factory-calibrated method, which relies on external instruments, suffers from several drawbacks, including an inability to compensate for device aging drift, lack of online self-maintenance, and low calibration efficiency. Specifically, active devices experience continuous aging effects during operation due to factors such as hot carrier injection, electromigration, and temperature cycling, leading to time-varying drift in their gain and phase characteristics. Factory calibration results cannot predict or compensate for these long-term changes, causing a significant deterioration in key performance indicators of phased arrays, such as beam pointing accuracy and sidelobe levels, during the later stages of service. Furthermore, traditional methods require antenna disassembly, cable connection, and manual data recording, which is time-consuming and cannot be performed after system deployment (e.g., in satellite orbit, radar sites, or UAV-borne scenarios). Single-point measurements are also susceptible to thermal and quantization noise, resulting in large calibration errors. These shortcomings make it difficult for existing technologies to achieve a balance between low hardware overhead, high noise immunity, and online self-calibration. Summary of the Invention

[0004] Therefore, it is necessary to provide a phased array self-calibration method and device that can achieve low hardware overhead, continuous and efficient storage of multi-channel data, and solve the problem of beam quality degradation caused by device aging in phased arrays, in order to address the above-mentioned technical problems.

[0005] A phased array self-calibration method, the method comprising:

[0006] Based on the continuous generation of single-tone signals by the transmitting channel, which are simultaneously injected into the starting points of N receiving channels via a power splitting network;

[0007] When the transmit channel begins outputting a signal, the FIFO of each receive channel is reset. Once data is detected stored in each FIFO, the... NThe time-domain sampled data of each receiving channel is stored in RAM. Address mapping is performed using the channel number as the high-order address and the data index as the low-order address. The range of the data index is based on the number of points in the subsequent Fourier transform. M Sure;

[0008] When the data index of each channel reaches M When this happens, data acquisition stops, and signal output from the transmitting channel also stops; for each receiving channel, the acquired data... M The discrete Fourier transform value of each time-domain sampled data is calculated on the single frequency component corresponding to the center frequency point, and the complex result of each channel in the frequency domain is obtained.

[0009] Based on the frequency domain complex results of each channel, calculate the amplitude and phase values ​​of each channel at the center frequency.

[0010] Select N One of the channels is used as the reference channel to calculate the rest. N -1 amplitude compensation value and phase compensation value of the channel relative to the reference channel, and use the amplitude compensation value and phase compensation value to perform real-time correction of each radio frequency channel in the digital phased array.

[0011] A phased array self-calibration device, the device comprising:

[0012] The signal generation and injection module is used to continuously generate single-tone signals through the transmission channel, and simultaneously inject them into the power divider network. N The starting point of each receiving channel;

[0013] The FIFO reset module is used to reset the FIFO of each receiving channel when the transmitting channel starts outputting a signal;

[0014] The data acquisition and storage module is used to, upon detecting that data is stored in each FIFO, [transfer / store / process the data]. N The time-domain sampled data of each receiving channel is stored in RAM. Address mapping is performed using the channel number as the high-order address and the data index as the low-order address. The range of the data index is based on the number of points in the subsequent Fourier transform. M Sure;

[0015] The acquisition control module is used when the data index of each channel reaches... M At this time, data acquisition will stop, and signal output from the transmission channel will also stop.

[0016] The Discrete Fourier Transform calculation module is used to process the data acquired by each receiving channel. M The discrete Fourier transform value of each time-domain sampled data is calculated on the single frequency component corresponding to the center frequency point, and the complex result of each channel in the frequency domain is obtained.

[0017] The amplitude and phase extraction module is used to calculate the amplitude and phase values ​​of each channel at the center frequency point based on the frequency domain complex results of each channel.

[0018] The compensation value calculation module is used to select... N One of the channels is used as the reference channel to calculate the rest. N -1 amplitude compensation value and phase compensation value of the channel relative to the reference channel.

[0019] The aforementioned phased array self-calibration method and apparatus employs multi-sampling-point discrete Fourier transform calculation, effectively avoiding calibration errors introduced by single-point measurement; by calculating only the DFT of a single frequency component, the computational load is significantly reduced compared to full-point FFT; RAM address mapping with channel number as the high bit and data index as the low bit enables continuous and efficient storage of multi-channel data; finally, through amplitude and phase compensation relative to the reference channel, all channels have the same amplitude and phase when outputting static signals, maximizing the synthetic gain in the normal direction, thus solving the technical problem of beam quality degradation caused by device aging in phased arrays. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating a phased array self-calibration method in one embodiment;

[0021] Figure 2 This is a schematic diagram of the self-calibration process of the receiving channel in one embodiment;

[0022] Figure 3 This is a schematic diagram of the self-calibration process of the transmission channel in one embodiment;

[0023] Figure 4 This is a schematic diagram of the experimental results in another embodiment;

[0024] Figure 5 This is a structural block diagram of a phased array self-calibration device in one embodiment. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] In one embodiment, such as Figure 1 As shown, a phased array self-calibration method is provided, including the following steps:

[0027] Step 102: Based on the continuous generation of single-tone signals by the transmitting channel, the signals are simultaneously injected into the starting points of N receiving channels via the power divider network.

[0028] For receiving a phased array, a 1-to-N power divider network is required, with a DAC as the input to the power divider, transmitting signals to the starting points of each RF channel (between the antenna feed port and the LNA). In this step, the transmitter (DAC) continuously generates a single-tone signal as the calibration signal source.

[0029] Step 104: When the transmitting channel starts outputting a signal, reset the FIFO of each receiving channel. Once data is detected stored in each FIFO, [the process continues]. N The time-domain sampled data of each receiving channel is stored in RAM, where address mapping is performed using the channel number as the high-order address and the data index as the low-order address. The range of the data index is based on the number of points in the subsequent Fourier transform. M Sure.

[0030] During the self-calibration of the receiving phased array, the data output from the ADC of each receiving channel is input into a FIFO (one FIFO for each channel). When the transmitter starts outputting a signal, all FIFOs of the receiving channels are reset, clearing the data in the FIFOs to prevent residual data in the queue from interfering with the measurement. When data is detected in the FIFO, the data from N channels is stored in RAM, and its address is determined by the channel number and the data index (corresponding to the number of points sampled in continuous time). Specifically, the channel number is used as the high-order address, and the data index is used as the low-order address. The range of the data index is based on the number of points for which a Fourier Transform (FT) needs to be performed subsequently. M It was determined that.

[0031] Step 106, when the data index of each channel reaches M When this happens, data acquisition stops, and signal output from the transmitting channel also stops; for each receiving channel, the acquired data... M The discrete Fourier transform value of each time-domain sampled data is calculated on the single frequency component corresponding to the center frequency point, and the complex result of each channel in the frequency domain is obtained.

[0032] When the data index reaches M When this happens, data acquisition stops, and the DAC stops outputting data. Subsequently, [the process is repeated]. N The data from each channel undergoes a Fourier Transform (FT). Since only data from a single frequency point (center frequency) is needed, only the Discrete Fourier Transform (DFT) needs to be calculated for that point; there is no need to calculate the Fast Fourier Transform (FFT) for the entire frequency band. The corresponding receiver channel self-calibration procedure for this step can be found in [reference needed]. Figure 2 ( Figure 2 (A schematic diagram of the receiver channel self-calibration process).

[0033] Step 108: Calculate the amplitude and phase values ​​of each channel at the center frequency point based on the frequency domain complex results of each channel.

[0034] The amplitude of each channel is obtained by taking the modulus of the complex result in the frequency domain, and the phase of each channel is obtained by calculating the arctangent of the real and imaginary parts of the complex result in the frequency domain.

[0035] Step 110, select N One of the channels is used as the reference channel to calculate the rest. N -1 amplitude compensation value and phase compensation value of the channel relative to the reference channel, and use the amplitude compensation value and phase compensation value to perform real-time correction of each radio frequency channel in the digital phased array.

[0036] Reference channel is N One channel is arbitrarily selected from the channels, for example, channel 0 is selected as the reference channel. Amplitude compensation values ​​are used to adjust the signal gain of each RF channel, and phase compensation values ​​are used to adjust the signal delay of each RF channel, aligning all channels to the state of the reference channel. This calibration process ensures that each channel has the same amplitude and phase when outputting a static signal, maximizing the combined gain in the normal direction. Specifically, using the reference channel (channel 0) as the baseline, the remaining channels (channels 1 to 0) are... N -1) The amplitude and phase are aligned with the reference channel. The amplitude compensation value and phase compensation value of the reference channel are set to 0, i.e. , This indicates that it serves as a reference and does not require compensation. The amplitude compensation values ​​for the remaining channels... Phase compensation value The calculated amplitude and phase compensation values ​​are applied to the baseband data of the corresponding RF channels to achieve real-time amplitude and phase correction in transmit or receive modes. This eliminates amplitude and phase inconsistencies between channels caused by factors such as device aging and temperature drift, ensuring the quality of digital beamforming.

[0037] In the aforementioned phased array self-calibration method, the use of multi-sampling-point discrete Fourier transform calculation effectively avoids calibration errors introduced by single-point measurements; by calculating only the DFT of a single frequency component, the computational load is significantly reduced compared to the full-point FFT (the number of complex multiplications is reduced from...). Reduce to N -1, the degree of complex number addition is determined by Reduce to N -1) By mapping RAM addresses with channel number as the high bit and data index as the low bit, continuous and efficient storage of multi-channel data is achieved; finally, by using amplitude and phase compensation relative to the reference channel, all channels have the same amplitude and phase when outputting static signals, and the synthesis gain in the normal direction is maximized, thus solving the technical problem of beam quality degradation caused by device aging in phased arrays.

[0038] Specifically, since calibration only requires amplitude and phase information at the center frequency point and only calculates a single frequency component, the computational cost is further reduced compared to FFT (the number of complex multiplications is reduced from...). Reduce to N -1, the degree of complex number addition is determined by Reduce to N -1), which significantly reduces the consumption of computing resources and power consumption of embedded platforms such as FPGAs.

[0039] In one embodiment, calculating the amplitude and phase values ​​of each channel at the center frequency includes:

[0040] Calculate the amplitude and phase values ​​of each channel at the center frequency.

[0041]

[0042]

[0043] in, For channel n At the center frequency The range at that point, For channel n Frequency domain K The value of each component The frequency domain component corresponding to the center frequency point. For channel n At the center frequency Phase at that point, For the imaginary part of the data, For the real part of the data.

[0044] Specifically, this calculation formula can accurately extract the amplitude and phase information of each channel at the calibration frequency point from the frequency domain complex results, providing basic data for subsequent compensation value calculation.

[0045] In one embodiment, select N One of the channels is used as the reference channel to calculate the rest. N -1 channel's amplitude compensation value and phase compensation value relative to the reference channel, including:

[0046] Select N One of the channels is used as the reference channel to calculate the rest. N -1 channel amplitude compensation value relative to the reference channel

[0047]

[0048]

[0049] in, For the first n Amplitude compensation value for each channel, For channel n At the center frequency The range at that point, This represents the total number of receiving channels.

[0050] Specifically, when channel 0 is used as the reference channel, its amplitude compensation value is 0, that is... The amplitude compensation value for other channels is the ratio of the amplitude of that channel to the amplitude of the reference channel. Applying this compensation value to the corresponding channel will align the amplitude of all channels to the amplitude level of the reference channel.

[0051] In one embodiment, select N One of the channels is used as the reference channel to calculate the rest. N -1 channel phase compensation value relative to reference channel

[0052]

[0053]

[0054] in, For the first n Phase compensation values ​​for each channel, For channel n At the center frequency The phase at that point.

[0055] Specifically, when channel 0 is used as the reference channel, its phase compensation value is 0, that is... 0. The phase compensation value for other channels is the difference between the phase of that channel and the phase of the reference channel. Applying this compensation value to the corresponding channel aligns the phase of all channels to the phase level of the reference channel. Through dual alignment of amplitude and phase, the combined gain of the phased array in the normal direction is maximized.

[0056] In one embodiment, the address mapping uses the channel number as the high-order address and the data index as the low-order address, with the data index ranging from 1 to... M This makes each channel in RAM... M Each consecutive sampled data is stored in a contiguous address space.

[0057] Specifically, as shown in Table 1, address mapping is performed using the channel number as the high-order address and the data index as the low-order address. For example, data index 1 for channel 1 corresponds to address 0x00000, and data index M corresponds to address 0x00FFF; data index 1 for channel 2 corresponds to address 0x01000, and so on. This mapping method allows the M consecutive sampled data of each channel to be stored in a contiguous address space in RAM, facilitating subsequent sequential reading of data by channel for DFT calculation and improving data access efficiency.

[0058] Table 1

[0059]

[0060] In one embodiment, the method further includes a transmit channel self-calibration step: using only one receive channel, all transmit channels are calibrated sequentially by time-division polling each transmit channel, and the transmit channel is switched after each calculation of a transmit channel is completed.

[0061] Specifically, the launch channel calibration process is as follows: Figure 3 As shown ( Figure 3 (This is a schematic diagram of the transmit channel self-calibration process). Unlike receive calibration, transmit calibration uses only one receive channel as a reference, and calibrates all transmit channels through a time-division polling method. After the calculation of one transmit channel is completed, the transmit channel is switched until the calibration of all transmit channels is completed. This time-division polling method avoids the hardware overhead of equipping each transmit channel with a dedicated receive channel.

[0062] In one embodiment, in the self-calibration step of the transmission channel, a FIFO is used instead of a block random access memory (BRAM) to temporarily store data during each calibration process.

[0063] Specifically, during the transmit channel calibration process, the BRAM originally used for receive calibration can be replaced by a FIFO. After completing the calculation for one channel, the transmit channel is switched. Because transmit calibration is time-division multiplexing, only one channel's data needs to be processed at a time, unlike receive calibration which requires storing all channels simultaneously. N Large amounts of data in multiple channels. Using FIFO can further reduce storage resource usage and lower hardware costs.

[0064] In one embodiment, the single-tone signal is generated by a single digital-to-analog converter (DAC) and then processed by a splitter. N The power divider network simultaneously transmits power between the antenna feed ports of each receiving channel and the low-noise amplifier (LNA); the reference channel is... N The amplitude compensation value and phase compensation value of any selected channel in the channel are set to 0.

[0065] Specifically, after the DAC generates a single-tone calibration signal, it is simultaneously injected into the starting point of each receiving channel (i.e., between the antenna feed port and the LNA) through a 1-to-N power divider network. This ensures that all receiving channels receive the same calibration signal source, and the amplitude and phase differences are determined only by the hardware characteristics of each channel. The reference channel can be any one of the N channels, with its amplitude and phase compensation values ​​both set to 0, indicating that all other channels are aligned with this channel as a reference.

[0066] Specifically, such as Figure 4 As shown, the comparison between the proposed scheme and the traditional FFT scheme in terms of self-calibration resource consumption is presented. It can be seen that the proposed scheme significantly reduces the number of calculations for complex multiplication and complex addition, verifying the advantages of the proposed scheme in reducing computational resource overhead.

[0067] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order in which these steps are executed, and they can be performed in other orders. Furthermore, Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0068] In one embodiment, such as Figure 5 As shown, a phased array self-calibration device is provided, including: a signal generation and injection module, a FIFO reset module, a data acquisition and storage module, an acquisition control module, a discrete Fourier transform calculation module, an amplitude and phase extraction module, and a compensation value calculation module, wherein:

[0069] The signal generation and injection module is used to continuously generate single-tone signals through the transmission channel, and simultaneously inject them into the power divider network. N The starting point of each receiving channel;

[0070] The FIFO reset module is used to reset the FIFO of each receiving channel when the transmitting channel starts outputting a signal;

[0071] The data acquisition and storage module is used to, upon detecting that data is stored in each FIFO, [transfer / store / process the data]. NThe time-domain sampled data of each receiving channel is stored in RAM, where address mapping is performed using the channel number as the high-order address and the data index as the low-order address. The range of the data index is based on the number of points in the subsequent Fourier transform. M Sure;

[0072] The acquisition control module is used when the data index of each channel reaches... M At this time, data acquisition will stop, and signal output from the transmission channel will also stop.

[0073] The Discrete Fourier Transform calculation module is used to process the data acquired by each receiving channel. M The discrete Fourier transform value of each time-domain sampled data is calculated on the single frequency component corresponding to the center frequency point, and the complex result of each channel in the frequency domain is obtained.

[0074] The amplitude and phase extraction module is used to calculate the amplitude and phase values ​​of each channel at the center frequency point based on the frequency domain complex results of each channel.

[0075] The compensation value calculation module is used to select... N One of the channels is used as the reference channel to calculate the rest. N -1 amplitude compensation value and phase compensation value of the channel relative to the reference channel.

[0076] For specific limitations regarding a phased array self-calibration device, please refer to the limitations of a phased array self-calibration method described above, which will not be repeated here. Each module in the aforementioned phased array self-calibration device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the operations corresponding to each module.

[0077] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A phased array self-calibration method, characterized in that, The method includes: Based on the continuous generation of single-tone signals by the transmitting channel, which are simultaneously injected into the starting points of N receiving channels via a power splitting network; When the transmit channel begins outputting a signal, the FIFO of each receive channel is reset. Once data is detected stored in each FIFO, the... N The time-domain sampled data of each receiving channel is stored in RAM, where address mapping is performed using the channel number as the high-order address and the data index as the low-order address. The range of the data index is based on the number of points in the subsequent Fourier transform. M Sure; When the data index of each channel reaches M When this happens, data acquisition stops, and signal output from the transmitting channel also stops; for each receiving channel, the acquired data... M The discrete Fourier transform value of each time-domain sampled data is calculated on the single frequency component corresponding to the center frequency point, and the complex result of each channel in the frequency domain is obtained. Based on the frequency domain complex results of each channel, calculate the amplitude and phase values ​​of each channel at the center frequency. Select N One of the channels is used as the reference channel to calculate the rest. N -1 amplitude compensation value and phase compensation value of the channel relative to the reference channel, and use the amplitude compensation value and phase compensation value to perform real-time correction of each radio frequency channel in the digital phased array.

2. The method according to claim 1, characterized in that, Calculate the amplitude and phase values ​​of each channel at the center frequency, including: Calculate the amplitude and phase values ​​of each channel at the center frequency. in, For channel n At the center frequency The range at that point, For channel n Frequency domain K The value of each component The frequency domain component corresponding to the center frequency point. Sampling frequency, For channel n At the center frequency Phase at that point, For the imaginary part of the data, For the real part of the data.

3. The method according to claim 1, characterized in that, Select N One of the channels is used as the reference channel to calculate the rest. N -1 channel's amplitude compensation value and phase compensation value relative to the reference channel, including: Select N One of the channels is used as the reference channel to calculate the rest. N -1 channel amplitude compensation value relative to the reference channel in, For the first n Amplitude compensation value for each channel, For channel n At the center frequency The range at that point, This represents the total number of receiving channels.

4. The method according to claim 3, characterized in that, The method further includes: Select N One of the channels is used as the reference channel to calculate the rest. N -1 channel phase compensation value relative to reference channel in, For the first n Phase compensation values ​​for each channel, For channel n At the center frequency The phase at that point.

5. The method according to claim 1, characterized in that, The address mapping uses the channel number as the high-order address and the data index as the low-order address, with the data index ranging from 1 to... M This makes each channel in RAM... M Each consecutive sampled data is stored in a contiguous address space.

6. The method according to claim 1, characterized in that, The method also includes a self-calibration step for the transmission channels: using only one receiving channel, the calibration of all transmission channels is completed sequentially through time-division polling of each transmission channel, and the transmission channel is switched after the calculation of each transmission channel is completed.

7. The method according to claim 6, characterized in that, In the self-calibration step of the transmission channel, a FIFO is used to replace the block random access memory (BRAM) to temporarily store data during each calibration process.

8. The method according to claim 1, characterized in that, The single-tone signal is generated by a single digital-to-analog converter (DAC) and then divided into two parts. N The power divider network simultaneously transmits power between the antenna feed ports of each receiving channel and the low-noise amplifier (LNA); the reference channel is... N The amplitude compensation value and phase compensation value of any selected channel in the channel are set to 0.

9. A phased array self-calibration device, characterized in that, The device includes: The signal generation and injection module is used to continuously generate single-tone signals through the transmission channel, and simultaneously inject them into the power divider network. N The starting point of each receiving channel; The FIFO reset module is used to reset the FIFO of each receiving channel when the transmitting channel starts outputting a signal; The data acquisition and storage module is used to, upon detecting that data is stored in each FIFO, [transfer / store / process the data]. N The time-domain sampled data of each receiving channel is stored in RAM, where address mapping is performed using the channel number as the high-order address and the data index as the low-order address. The range of the data index is based on the number of points in the subsequent Fourier transform. M Sure; The acquisition control module is used when the data index of each channel reaches... M At this time, data acquisition will stop, and signal output from the transmission channel will also stop. The Discrete Fourier Transform calculation module is used to process the data acquired by each receiving channel. M The discrete Fourier transform value of each time-domain sampled data is calculated on the single frequency component corresponding to the center frequency point, and the complex result of each channel in the frequency domain is obtained. The amplitude and phase extraction module is used to calculate the amplitude and phase values ​​of each channel at the center frequency point based on the frequency domain complex results of each channel. The compensation value calculation module is used to select... N One of the channels is used as the reference channel to calculate the rest. N -1 amplitude compensation value and phase compensation value of the channel relative to the reference channel.

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