CN-122001727-A - Multi-frequency-point DPSK demodulation optimization method and system based on FPGA

CN122001727ACN 122001727 ACN122001727 ACN 122001727ACN-122001727-A

Abstract

The invention relates to the technical field of aerospace measurement and control, and provides a multi-frequency-point DPSK demodulation optimization method and system based on an FPGA, wherein the method comprises the steps of reading and caching binding parameter information after the FPGA is electrified and initialized; the method comprises the steps of receiving DPSK-FM modulation signals to be demodulated, carrying out Fourier transform operation on carrier signals containing the DPSK-FM modulation signals to be demodulated to obtain frequency point information of input signals, selecting filter configuration parameters of corresponding channels and carrying out down mixing processing based on the frequency point information of the input signals, uniformly converting the input signals of different carrier frequency points to the same target frequency point, carrying out demodulation processing to obtain demodulated instruction data, carrying out decoding comparison on the demodulated instruction data and binding parameter information, and outputting demodulation effectiveness judgment according to comparison results. The frequency point preprocessing unification in the FPGA program is realized, redundant processing of a plurality of frequency points in the traditional method is avoided, the unknown frequency points are uniformly converted into the same frequency, the universality of the FM-DPSK demodulation algorithm is improved, and the working efficiency of the receiver FPGA software is effectively improved.

Inventors

YE LEI
HAN SHENGXIANG
ZHU BOTAO
LIANG QINQIN
ZHANG RUI

Assignees

上海航天电子通讯设备研究所

Dates

Publication Date: 20260508
Application Date: 20260212

Claims (10)

1. A multi-frequency-point DPSK demodulation optimization method based on FPGA is characterized by comprising the steps of, Step S1, after the FPGA is powered on and initialized, reading and caching binding parameter information, wherein the binding parameter information at least comprises a plurality of preset carrier frequency points, filter configuration parameters corresponding to the carrier frequency points, down-mixing local oscillation signal parameters and instruction parameters for decoding and checking; S2, receiving a DPSK-FM modulation signal to be demodulated, wherein the carrier frequency point of the DPSK-FM modulation signal to be demodulated belongs to one of a plurality of preset carrier frequency points and the current input working frequency point is unknown; S3, carrying out Fourier transform operation on the carrier signal containing the DPSK-FM modulation signal to be demodulated to obtain frequency point information of an input signal; S4, selecting the filter configuration parameters and the down mixing processing of the corresponding channels based on the frequency point information of the input signals, uniformly converting the input signals of different carrier frequency points to the same target frequency point, and multiplexing the input signals uniform to the same target frequency point with the same demodulation module to perform demodulation processing to obtain demodulated instruction data; And S5, decoding and comparing the demodulated instruction data with the binding parameter information, and outputting demodulation effectiveness judgment according to a comparison result.
2. The FPGA-based multi-frequency point DPSK demodulation optimization method of claim 1, wherein step S1 comprises: after the FPGA is powered on, reset operation is executed, and an internal hardware module of the FPGA is initialized; reading the binding parameter information from a memory or an external configuration file, wherein the binding parameter information at least comprises the plurality of preset carrier frequency points, the filter configuration parameters corresponding to the carrier frequency points, the down-mixing local oscillation parameters and the instruction parameters for decoding verification; caching the read binding parameter information into an FPGA internal memory, and performing parameter validity verification to determine that the binding parameter information is accurate; And after caching and verifying that the binding parameter information is accurate, receiving the DPSK-FM modulation signal to be demodulated.
3. The FPGA-based multi-frequency point DPSK demodulation optimization method of claim 1, wherein step S2 comprises: Receiving the DPSK-FM modulation signals to be demodulated, and receiving modulation signals containing a plurality of preset carrier frequency points from a signal source, wherein the currently input working frequency point is unknown; sampling and converting the received DPSK-FM modulation signal to be demodulated into a digital signal form to obtain a discrete time domain signal, and performing preprocessing, wherein the preprocessing comprises amplitude adjustment, basic filtering processing and denoising; Randomly selecting one carrier frequency point from the plurality of preset carrier frequency points according to requirements, taking the selected carrier frequency point as an input frequency point, and generating the input signal based on the input frequency point.
4. The FPGA-based multi-frequency point DPSK demodulation optimization method of claim 1, wherein step S3 comprises: The method comprises the steps of inputting an input signal into an FFT computing module to carry out Fourier transform operation, converting a time domain signal into a frequency domain signal, identifying a main frequency part of the input signal from a frequency spectrum according to the frequency spectrum characteristics of a Fourier transform operation result, determining a corresponding carrier frequency point as frequency information, and ensuring that the selected carrier frequency point covers frequency offset based on a preset Doppler frequency shift range in a frequency point judging process so as to avoid frequency point selection errors.
5. The FPGA-based multi-frequency point DPSK demodulation optimization method of claim 1, wherein step S4 comprises: Based on the frequency point information of the input signals, the filter configuration parameters of the corresponding channels are selected through the channel selection module, the received input signals are input to the corresponding band-pass filters for filtering, after effective signal components centered on the carrier frequency points are extracted, the corresponding down-mixing local oscillation signal parameters are selected, the down-mixing processing is carried out on the filtered input signals and the selected local oscillation signals, and the input signals belonging to different preset carrier frequency points are uniformly converted to the same target frequency point.
6. The method for optimizing DPSK demodulation of multiple frequency points based on FPGA of claim 1, wherein in step S4, the input signals unified to the same target frequency point are multiplexed with the same demodulation module to perform demodulation processing, so as to obtain demodulated instruction data, which includes: The input signals unified to the same target frequency point are sequentially input to a multiplexing FM demodulation unit and a DPSK demodulation unit for demodulation processing, wherein the demodulation module comprises the FM demodulation unit and the DPSK demodulation unit, the FM demodulation unit is used for carrying out frequency modulation demodulation on the input signals to obtain baseband phase modulation signals, and the DPSK demodulation unit is used for carrying out differential phase demodulation on the baseband phase modulation signals to obtain demodulated instruction data.
7. The method for optimizing the demodulation of the multi-frequency-point DPSK based on the FPGA as recited in claim 1, wherein the step S5 is characterized by judging whether the demodulated instruction data is matched with the instruction parameters in the binding parameter information, if so, the demodulation is effective, and if not, a demodulation ineffective signal is output.
8. An FPGA-based multi-frequency-point DPSK demodulation optimization system employing the FPGA-based multi-frequency-point DPSK demodulation optimization method of any one of claims 1 to 7, comprising: The initialization module is used for reading and caching binding parameter information after the FPGA is electrified and initialized, and the binding parameter information at least comprises a plurality of preset carrier frequency points, filter configuration parameters corresponding to the carrier frequency points, down-mixing local oscillation signal parameters and instruction parameters for decoding and checking; The FFT calculation module is used for receiving a DPSK-FM modulation signal to be demodulated, wherein the carrier frequency point of the DPSK-FM modulation signal to be demodulated belongs to one of a plurality of preset carrier frequency points and the current input working frequency point is unknown; The channel selection module is used for selecting the filter configuration parameters and the down-mixing processing of the corresponding channels based on the frequency point information of the input signals and uniformly converting the input signals of different carrier frequency points to the same target frequency point; The demodulation comparison module is used for carrying out demodulation processing on the input signals unified to the same target frequency point by multiplexing the same demodulation module to obtain demodulated instruction data, carrying out decoding comparison on the demodulated instruction data and the binding parameter information, and outputting demodulation effectiveness judgment according to the comparison result.
9. The FPGA-based multi-frequency-point DPSK demodulation optimization system of claim 8, wherein in the FFT computation module, the input signal is input to the FFT computation module to perform the fourier transform operation, a time domain signal is converted into a frequency domain signal, a main frequency portion of the input signal is identified from a frequency spectrum according to a spectrum characteristic of a fourier transform operation result, a corresponding carrier frequency point is determined as the frequency information, and in a frequency point decision process, based on a preset doppler shift range, the selected carrier frequency point is ensured to cover a frequency offset, and a frequency point selection error is avoided.
10. The FPGA-based multi-frequency-point DPSK demodulation optimization system of claim 9, wherein in the demodulation comparison module, the input signals unified to the same target frequency point are sequentially input to a multiplexing FM demodulation unit and a DPSK demodulation unit to perform demodulation processing, wherein the demodulation module includes the FM demodulation unit and the DPSK demodulation unit, the FM demodulation unit is configured to perform frequency demodulation on the input signals to obtain baseband phase modulation signals, and the DPSK demodulation unit is configured to perform differential phase demodulation on the baseband phase modulation signals to obtain the demodulated instruction data.

Description

Multi-frequency-point DPSK demodulation optimization method and system based on FPGA Technical Field The invention relates to the technical field of aerospace measurement and control, in particular to a multi-frequency-point DPSK demodulation optimization method and system based on an FPGA. Background With the continuous development of space transportation systems and space tasks, the frequency of the launching tasks of the carrier is continuously improved, higher requirements are put forward on real-time performance, reliability, signal processing precision and the like of an on-board electronic system and ground matched measurement and control equipment, and meanwhile, the multi-frequency-point signal processing technology provides abundant signal resources for continuously expanding and perfected measurement and control and navigation systems. In the process of the carrier executing the task, when a preset safety trigger or a necessary fault condition occurs, the instruction receiver arranged on the carrier needs to work cooperatively with the ground control equipment to finish the receiving and judging processing of the safety control instruction. Under such application scenes, the safety instruction receiver has higher requirements on the real-time performance and reliability of demodulation of the modulation signals, and the demodulation performance is directly related to the response timeliness and the control accuracy of the system. With the application of multi-frequency point signal processing in the field of transportation, an instruction receiver capable of adapting to multi-frequency point security control signals has been developed. However, because carrier frequency differences exist between different working frequency points, the existing FPGA implementation generally configures a plurality of demodulation channels in parallel in software, and performs demodulation processing on each preset frequency point. When the actual input signal corresponds to a certain frequency point, demodulation channels corresponding to other frequency points are still in a working state, and only one channel outputs an effective decoding result. Although the implementation manner can meet the functional requirements of multi-frequency point demodulation, the demodulation algorithm has larger redundancy in FPGA software, occupies more logic resources and computing resources, and is not beneficial to the improvement of demodulation efficiency and the optimal utilization of system resources. Therefore, it is necessary to design a multi-frequency-point DPSK demodulation optimization algorithm based on FPGA software, so as to improve the demodulation efficiency of the instruction receiver and reduce the resource utilization rate of FPGA software on the premise of ensuring demodulation accuracy and instantaneity. Disclosure of Invention The invention aims to solve the problems, and provides a multi-frequency-point DPSK demodulation optimization method and a multi-frequency-point DPSK demodulation optimization system based on an FPGA, multiplexing of a DPSK-FM demodulation module can be realized through selecting an input carrier frequency point, optimization of a receiver demodulation algorithm is realized, and the utilization rate of FPGA software resources is reduced. The invention provides a multi-frequency-point DPSK demodulation optimization method based on an FPGA, which comprises the following steps of, Step S1, after the FPGA is powered on and initialized, reading and caching binding parameter information, wherein the binding parameter information at least comprises a plurality of preset carrier frequency points, filter configuration parameters corresponding to the carrier frequency points, down-mixing local oscillation signal parameters and instruction parameters for decoding and checking; Step S2, receiving a DPSK-FM modulation signal to be demodulated, wherein a carrier frequency point of the DPSK-FM modulation signal to be demodulated belongs to one of a plurality of preset carrier frequency points and a current input working frequency point is unknown; S3, carrying out Fourier transform operation on a carrier signal containing a DPSK-FM modulation signal to be demodulated to obtain frequency point information of an input carrier signal; Step S4, selecting filter configuration parameters and down mixing processing of corresponding channels based on frequency point information of input signals, uniformly converting the input signals of different carrier frequency points to the same target frequency point, and multiplexing the input signals uniform to the same target frequency point with the same demodulation module to perform demodulation processing to obtain demodulated instruction data; and S5, decoding and comparing the demodulated instruction data with the binding parameter information, and outputting demodulation effectiveness judgment according to the comparison result. Further, step S1 includes: afte