CN-122001499-A - AD self-adaptive digital calibration method and system based on FPGA platform

CN122001499ACN 122001499 ACN122001499 ACN 122001499ACN-122001499-A

Abstract

The application provides an AD self-adaptive digital calibration method and system based on an FPGA platform, belonging to the technical field of communication, wherein the method comprises the following steps: the method comprises the steps of sampling a plurality of analog-digital signals of a received signal to obtain a plurality of analog-digital signals, then carrying out digital down-conversion digital signal processing on the plurality of analog-digital signals to obtain a plurality of orthogonal zero intermediate frequency signals, then carrying out inter-channel digital calibration based on the plurality of orthogonal zero intermediate frequency signals to obtain a plurality of orthogonal zero intermediate frequency signals after calibration, then receiving a data transmission instruction sent by an upper computer, intercepting a plurality of orthogonal values of a target moment after self-adaption calibration, and sending the plurality of orthogonal values of the target moment to the upper computer so that the upper computer calculates a phase first difference value based on the plurality of orthogonal values of the target moment to calibrate. The AD self-adaptive digital calibration method and system based on the FPGA platform can reduce the probability of inconsistent in-phase and quadrature signal phases generated by different AD channels after digital signal processing digital down-conversion.

Inventors

NIU JIAWEI
LIU HAIPENG

Assignees

北京遥感设备研究所

Dates

Publication Date: 20260508
Application Date: 20251229

Claims (10)

1. An AD self-adaptive digital calibration method based on an FPGA platform is characterized by comprising the following steps: Receiving a signal through an antenna; the received signal is subjected to multiple analog-to-digital signal sampling, obtaining a plurality of paths of analog-digital signals; Performing digital down-conversion digital signal processing on the multipath analog-to-digital signals to obtain multipath orthogonal zero intermediate frequency signals; Carrying out inter-channel digital calibration based on the multi-channel orthogonal zero intermediate frequency signals to obtain calibrated multi-channel orthogonal zero intermediate frequency signals; intercepting multipath orthogonal values of target moments after self-adaptive calibration after receiving a data transmission instruction sent by an upper computer; And sending the multipath orthogonal values of the target time to the upper computer so that the upper computer calculates a phase first difference value based on the multipath orthogonal values of the target time to calibrate.
2. The method of claim 1, wherein for each analog-to-digital signal, performing digital down-conversion digital signal processing on the analog-to-digital signal to obtain a quadrature zero intermediate frequency signal, comprising: Multiplying and mixing the analog-digital signals to obtain two paths of orthogonal baseband signals; And processing the two paths of orthogonal baseband signals through the corresponding finite impulse response Fir low-pass filters to obtain the paths of orthogonal zero intermediate frequency signals.
3. The method according to claim 1, wherein the performing the inter-channel digital calibration based on the multiple orthogonal zero intermediate frequency signals to obtain calibrated multiple orthogonal zero intermediate frequency signals includes: calculating amplitude and phase values corresponding to each channel respectively based on the multi-channel quadrature zero intermediate frequency signals; Taking any channel as a reference channel, calculating each phase difference in parallel based on the phase value corresponding to each channel and the phase value of the reference channel, and calculating each amplitude compensation value in parallel based on the amplitude corresponding to each channel and the amplitude of the reference channel; calculating calibration coefficients corresponding to the channels respectively based on the phase differences and the amplitude compensation values; and calibrating the multipath orthogonal zero intermediate frequency signals through the corresponding calibration coefficients to obtain the calibrated multipath orthogonal zero intermediate frequency signals.
4. The method of claim 1, wherein the performing multiple analog-to-digital signal sampling on the received signal to obtain multiple analog-to-digital signals comprises: Based on the nyquist sampling law, the received signal is sampled by multiple AD analog-to-digital signals such that the signal falls within the first nyquist interval.
5. The method of claim 1, wherein the sending the multiple orthogonal values for the target time to the host computer comprises: And sending the multipath orthogonal value of the target moment to the upper computer through a 422 interface.
6. The method of claim 1, wherein the calculating of the phase difference value based on the multiple orthogonal values at the target time is performed by the host computer by: Carrying out 1024-point Fast Fourier Transform (FFT) on the multipath orthogonal values at the target moment to obtain frequency domain data of each multipath signal; the phase first difference is calculated based on the frequency domain data of each of the plurality of signals.
7. The method according to any one of claims 1-6, further comprising: Comparing and analyzing the first phase difference value and the second phase difference value to obtain an analysis result; The second phase difference value is obtained by analyzing and calculating the second phase difference value through a target simulation method based on the multipath orthogonal zero intermediate frequency signals.
8. An AD-adaptive digital calibration system based on an FPGA platform, comprising: The FPGA-based pipeline digital down-conversion computing unit is used for sampling multiple paths of analog-digital signals of a received signal passing through an antenna to obtain multiple paths of analog-digital signals, and performing digital down-conversion digital signal processing on the multiple paths of analog-digital signals to obtain multiple paths of orthogonal zero intermediate frequency signals; And the AD self-adaptive calibration calculation unit based on the FPGA is used for carrying out inter-channel digital calibration based on the multipath orthogonal zero intermediate frequency signals to obtain calibrated multipath orthogonal zero intermediate frequency signals, intercepting multipath orthogonal values of a target moment after self-adaptive calibration when a data transmission instruction sent by an upper computer is received, and sending the multipath orthogonal values of the target moment to the upper computer so that the upper computer calculates a phase first difference value based on the multipath orthogonal values of the target moment to calibrate.
9. The system according to claim 8, wherein the FPGA pipeline-based digital down-conversion computing unit is configured to, when performing digital down-conversion digital signal processing on each analog-to-digital signal to obtain a quadrature zero intermediate frequency signal, specifically: Multiplying and mixing the analog-digital signals to obtain two paths of orthogonal baseband signals; And processing the two paths of orthogonal baseband signals through the corresponding finite impulse response Fir low-pass filters to obtain the paths of orthogonal zero intermediate frequency signals.
10. The system according to claim 8, wherein the FPGA-based AD adaptive calibration calculation unit is configured to, when performing the inter-channel digital calibration based on the multiple orthogonal zero intermediate frequency signals to obtain the calibrated multiple orthogonal zero intermediate frequency signals: calculating amplitude and phase values corresponding to each channel respectively based on the multi-channel quadrature zero intermediate frequency signals; Taking any channel as a reference channel, calculating each phase difference in parallel based on the phase value corresponding to each channel and the phase value of the reference channel, and calculating each amplitude compensation value in parallel based on the amplitude corresponding to each channel and the amplitude of the reference channel; calculating calibration coefficients corresponding to the channels respectively based on the phase differences and the amplitude compensation values; and calibrating the multipath orthogonal zero intermediate frequency signals through the corresponding calibration coefficients to obtain the calibrated multipath orthogonal zero intermediate frequency signals.

Description

AD self-adaptive digital calibration method and system based on FPGA platform Technical Field The application belongs to the technical field of communication, and particularly relates to an AD self-adaptive digital calibration method and system based on an FPGA platform. Background The antenna system and the signal processing system are two important components in the radar system, and the performance of the antenna system and the signal processing system determines the performance of the whole radar system. Traditional Digital Signal Processing (DSP) computations are not satisfactory for high-speed computing scenarios. Programmable logic gate arrays (Field Programmable GATE ARRAY, FPGA) are often used in antenna beam control, digital signal processing interface design, and signal processing algorithms due to their extremely high parallel computing power. And the antenna system needs to be calibrated in analog-digital sampling, so that the normal operation of the back-end digital signal processing is ensured. The antenna calibration system is influenced by the accuracy of a phase shifter of a Transmit/Receive (TR) component, only a 5.625-degree accuracy range can be ensured, and meanwhile, due to the fact that a partial Analog-to-Digital (AD) conversion chip has no power-on calibration function, in-phase/Quadrature (I/Q) signal phases generated by different AD channels are inconsistent after Digital signal processing and Digital down-conversion are performed, so that a subsequent array signal processing algorithm cannot be completed. AD digital adaptive calibration is particularly critical in signal processing systems because of the large amount of AD analog-to-digital sampling used in the fields of radar, underwater acoustic communication, etc. Disclosure of Invention The application aims to provide an AD self-adaptive digital calibration method and system based on an FPGA platform, which are used for solving the problem that automatic calibration cannot be performed after an AD sampling chip is electrified. In a first aspect of the embodiment of the present application, an AD adaptive digital calibration method based on an FPGA platform is provided, including: Receiving a signal through an antenna; the received signal is subjected to multiple analog-to-digital signal sampling, obtaining a plurality of paths of analog-digital signals; Performing digital down-conversion digital signal processing on the multipath analog-to-digital signals to obtain multipath orthogonal zero intermediate frequency signals; Carrying out inter-channel digital calibration based on the multi-channel orthogonal zero intermediate frequency signals to obtain calibrated multi-channel orthogonal zero intermediate frequency signals; intercepting multipath orthogonal values of target moments after self-adaptive calibration after receiving a data transmission instruction sent by an upper computer; And sending the multipath orthogonal values of the target time to the upper computer so that the upper computer calculates a phase first difference value based on the multipath orthogonal values of the target time to calibrate. In a second aspect of the embodiment of the present application, an AD adaptive digital calibration system based on an FPGA platform is provided, including: The FPGA-based pipeline digital down-conversion computing unit is used for sampling multiple paths of analog-digital signals of a received signal passing through an antenna to obtain multiple paths of analog-digital signals, and performing digital down-conversion digital signal processing on the multiple paths of analog-digital signals to obtain multiple paths of orthogonal zero intermediate frequency signals; And the AD self-adaptive calibration calculation unit based on the FPGA is used for carrying out inter-channel digital calibration based on the multipath orthogonal zero intermediate frequency signals to obtain calibrated multipath orthogonal zero intermediate frequency signals, intercepting multipath orthogonal values of a target moment after self-adaptive calibration when a data transmission instruction sent by an upper computer is received, and sending the multipath orthogonal values of the target moment to the upper computer so that the upper computer calculates a phase first difference value based on the multipath orthogonal values of the target moment to calibrate. In a third aspect of the embodiment of the present application, there is provided an electronic device, including a memory, a processor, and a computer program stored in the memory and running on the processor, where the steps of the above-mentioned AD adaptive digital calibration method based on an FPGA platform are implemented when the processor executes the computer program. The electronic device may be a platform device based on FPGA. In a fourth aspect of the embodiments of the present application, there is provided a computer readable storage medium storing a computer program, which when