A method for generating a gps signal based on fpga

Abstract

The application provides a GPS signal generation method based on FPGA, and relates to the technical field of wireless communication.The generation method specifically comprises the following steps: S1.determining signal requirements, and performing a prefabricated signal rule template containing at least one variable rule according to a required signal direction and purpose; S2.determining a signal loading value of a signal generation frequency, a waveform and an amplitude.The method can be used for transmitting various GPS signals, does not need to additionally manufacture a signal source to realize signal source combination and transmission, can realize various styles of signals on any required frequency band, can change a combined mode in real time by inputting control parameters according to requirements, has simple structure, flexible control, time and cost saving, is also favorable to signal source improvement, has good adaptability and expansibility, and can quickly realize simulation of various system GPS signals by only adaptively modifying and adjusting variable parameters of the prefabricated signal template.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, specifically to a method for generating GPS signals based on FPGA. Background Technology

[0002] With the modernization of GPS, GPS satellites are increasingly using L2 carrier frequencies to transmit civilian signals, enabling civilian GPS users to use both L1 and L2 frequencies to correct ionospheric propagation errors. This signal uses special civilian medium-length code (CM code) and civilian long code (CL code) for time-division multiplexing, making it more suitable for use in weak environments such as indoors, tree-lined roads, and tunnels.

[0003] FPGA is a further development based on programmable devices such as PAL, GAL, and CPLD. It emerged as a semi-custom circuit within the field of Application-Specific Integrated Circuits (ASICs). FPGA stands for Field-Programmable Gate Array. Common applications of FPGAs include algorithm acceleration, video image processing, communications, medical applications, and security. Since Xilinx created the FPGA in 1984, this programmable logic device has secured a place in fields such as communications, medical, and security due to its significant advantages in performance, time-to-market, cost, stability, and long-term maintenance.

[0004] However, as can be seen from existing patents such as the DMRS signal generation method based on FPGA (Publication No.: CN110933003A), the PWM signal generation method based on FPGA (Publication No.: CN109857014A), and the active sonar signal generation method and system based on FPGA (Publication No.: CN113960577A), it can be seen that there are currently many types of signals generated by FPGA, but there is a lack of a generation method that can be applied to GPS signal generation and frequency conversion. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a GPS signal generation method based on FPGA, which solves the problem that existing FPGA-based signal generation methods lack methods for GPS signal application and conversion / frequency conversion.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a GPS signal generation method based on FPGA, specifically comprising the following steps:

[0009] S1. Determine signal requirements

[0010] Create a pre-made signal rule template containing at least one variable rule based on the required signal direction and purpose;

[0011] S2. Fixed-point generation

[0012] The signal loading values, including the signal generation frequency, waveform, and amplitude, are determined, and directional signal generation is performed based on the internal port resources of the FPGA.

[0013] S3. Signal Processing

[0014] By using 12-bit binary for fractional integration, a frequency synthesizer is used to receive the directional signal generated by the FPGA resource terminal and complete the character integration, while a cutting switch cuts the directional signal for output.

[0015] S4. Directional Conversion

[0016] The directional output signal that has completed the decimal integration, character integration and segmentation output processing in S3 is frequency-converted by the frequency conversion module;

[0017] S5. Signal issued.

[0018] The final frequency-converted directional output signal is sent to the transmitter. The final signal is generated and transmitted after the virtual and real calculations of the final signal are completed by the multiplication and trigonometric function operation modules.

[0019] Preferably, the variable rules included in the pre-made signal rule module in S1 include three major variables: signal type, frequency, and amplitude.

[0020] Preferably, the FPGA internal port resource terminal in S2 is based on the FPGA internal dual-port RAM resource. Directional signal parameters are written through port 1, and directional signals, preamble signals, and signal frequency control words and amplitude control words are output through port 2 according to the signal generation timing. The timing between the preamble signal and the directional signal is fixed and the preamble signal is output before the directional signal.

[0021] Preferably, in S3, the 12-bit binary fractional integration is performed by multiplying the fractional part using 12-bit binary multiplication and represented as an integer. The frequency synthesizer generates the corresponding connection wave signal based on the frequency control word and amplitude control word output by the FPGA.

[0022] Preferably, the frequency conversion module in S4 includes two generating clocks and an intermediate frequency signal frequency conversion, wherein the two generating clocks are designed in parallel.

[0023] Preferably, the frequency conversion module in S4 includes an FPGA-based frequency conversion unit and a signal frequency conversion unit based on an initial pre-made signal rule template, wherein the FPGA-based frequency conversion unit and the signal frequency conversion unit based on the initial pre-made signal rule template are connected in series.

[0024] A production system for a GPS signal generation method based on FPGA includes an integrated control unit and an FPGA unit. The integrated control unit is connected to a signal synthesizer, the signal synthesizer is connected to a frequency converter module, the frequency converter module is connected to a signal generator, the signal generator is connected to a signal transmitter, and the integrated control unit is electrically connected to the FPGA unit.

[0025] (III) Beneficial Effects

[0026] This invention provides a GPS signal generation method based on FPGA. It has the following beneficial effects:

[0027] 1. This invention provides a GPS signal generation method based on FPGA. The signal generated by this method is adjustable in frequency, amplitude, and various other parameters. It can be used to transmit a variety of different GPS signals without the need for additional circuit boards to combine signal sources for transmission. It can realize various signal styles on any required frequency band. The combination mode can be changed in real time by inputting control parameters as needed. It has a simple structure, flexible control, saves time and cost, and is also conducive to the improvement of signal sources. At the same time, the method has good adaptability and scalability. Only adaptive modifications are needed to adjust the variable parameters of the pre-made signal template to quickly realize the simulation of GPS signals of various systems. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Example:

[0030] This invention provides a GPS signal generation method based on FPGA, specifically including the following steps:

[0031] S1. Determine signal requirements

[0032] Create a pre-made signal rule template containing at least one variable rule based on the required signal direction and purpose;

[0033] The pre-defined signal rules module includes three main variables: signal type, frequency, and amplitude. These variables are used to determine the characteristics of the generated GPS signal, clarify the required direction, avoid problems with the direction of the generated signal, and allow for adjustments based on the three main variables and the frequency conversion requirements of the signal.

[0034] S2. Fixed-point generation

[0035] The signal loading values, including the signal generation frequency, waveform, and amplitude, are determined, and directional signal generation is performed based on the internal port resources of the FPGA.

[0036] The internal FPGA-based dual-port RAM resources are used to write directional signal parameters through port 1 and output directional signals, preamble signals, and signal frequency control words and amplitude control words according to the signal generation timing through port 2. The timing between the preamble signal and the directional signal is fixed and the preamble signal is output before the directional signal. The preamble signal arrives at the synthesizer first for output debugging to ensure that when the directional signal, which is after the timing, is output by the synthesizer, the synthesizer can output a stable frequency and amplitude.

[0037] S3. Signal Processing

[0038] By using 12-bit binary for fractional integration, a frequency synthesizer is used to receive the directional signal generated by the FPGA resource terminal and complete the character integration, while a cutting switch cuts the directional signal for output.

[0039] The 12-bit binary fractional integration uses 12-bit binary multiplication to expand the fractional number, and then rounds the final number up to represent it as an integer; the frequency synthesizer generates the corresponding connection wave signal based on the frequency control word and amplitude control word output by the FPGA; and the cutting switch is electrically connected to the FPGA output control terminal through the communication module, and through the control of its control terminal, the continuous wave signal is cut into various signals as required.

[0040] S4. Directional Conversion

[0041] The directional output signal that has completed the decimal integration, character integration and segmentation output processing in S3 is frequency-converted by the frequency conversion module;

[0042] The frequency conversion module used includes two generation clocks and an intermediate frequency signal frequency conversion. The two generation clocks are designed in parallel. The internal FPGA's operating clock is generated by the frequency conversion module and divided by two within the digital-to-analog converter unit before being sent to the FPGA. Since the FPGA uses two digital-to-analog converter units, a parallel design method is adopted internally. That is, the high-speed sampling data sent to the digital-to-analog converter unit and its matching clock are generated entirely by the clock sent by the other digital-to-analog converter unit, and are completely independent of the clock sent by the other digital-to-analog converter unit. This maintains the independence between the signals, thereby greatly increasing the system's flexibility.

[0043] Meanwhile, the frequency conversion module includes an FPGA-based frequency conversion unit and a signal frequency conversion unit based on an initial pre-defined signal rule template. The FPGA-based frequency conversion unit and the signal frequency conversion unit based on the initial pre-defined signal rule template are connected in series, so that the generated signal can be adjusted in frequency, amplitude and other parameters. It can not only be used to transmit a variety of different GPS signals, but also achieve various signal styles on any required frequency band without the need for additional board manufacturing to combine and transmit signal sources. The combination mode can be changed in real time according to the input control parameters.

[0044] S5. Signal issued.

[0045] The final frequency-converted directional output signal is sent to the transmitter. The final signal is generated and transmitted after the virtual and real calculations of the final signal are completed by the multiplication and trigonometric function operation modules.

[0046] A production system for GPS signal generation based on FPGA includes an integrated control unit and an FPGA unit. The integrated control unit is connected to a signal synthesizer, which is connected to a frequency converter module. The frequency converter module is connected to a signal generator, which is connected to a signal transmitter. The integrated control unit and the FPGA unit are electrically connected. The integrated control unit controls the entire system and includes signal parameters and signal types. The signal parameters include signal pattern, operating frequency, power output, modulation index, delay time, frequency hopping rate, etc. The signal generator includes a parameter conversion module and a signal generation module, which generates signals with specific control parameters.

[0047] The signal generated using this method and system is adjustable in frequency, amplitude, and various other parameters. It can be used to transmit a variety of different GPS signals without the need for additional circuit boards to combine and transmit the signal sources. It can realize various signal styles on any required frequency band. The combination mode can be changed in real time by inputting control parameters as needed. It has a simple structure, flexible control, saves time and cost, and is also conducive to the improvement of signal sources. At the same time, the method has good adaptability and scalability. Only the pre-made template required for operation needs to be adapted and the variable parameters of the pre-made signal template need to be adjusted to quickly realize the simulation of GPS signals of various systems.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A GPS signal generation method based on FPGA, characterized in that, Specifically, the following steps are included: S1. Determine signal requirements: Create a pre-made signal rule template containing at least one variable rule based on the required GPS signal direction and purpose; S2. Fixed-point generation: The signal loading values, including the signal generation frequency, waveform, and amplitude, are determined, and directional signal generation is performed based on the internal port resources of the FPGA. S3. Signal Processing: By using 12-bit binary for fractional integration, a frequency synthesizer is used to receive the directional signal generated by the FPGA resource terminal and complete the character integration, while a cutting switch cuts the directional signal for output. S4. Directed Conversion: The directional output GPS signal, which has completed the decimal integration, character integration, and segmentation output processing in S3, is frequency-converted by the frequency conversion module; S5. Signal issued: The final frequency-converted directional output signal is sent to the transmitter. The final signal is generated and sent after the virtual and real calculations of the final signal are completed by the multiplication and trigonometric function operation modules.

2. The GPS signal generation method based on FPGA according to claim 1, characterized in that: The pre-made signal rule module in S1 contains three main variable rules: signal type, frequency, and amplitude.

3. The GPS signal generation method based on FPGA according to claim 1, characterized in that: The S2 is based on the FPGA internal port resource terminal, which is based on the FPGA internal dual-port RAM resource. The directional signal parameters are written through port 1, and the directional signal, preamble signal, and signal frequency control word and amplitude control word are output through port 2 according to the signal generation timing. The timing between the preamble signal and the directional signal is fixed and is output before the directional signal.

4. The GPS signal generation method based on FPGA according to claim 1, characterized in that: The 12-bit binary fractional integration in S3 uses 12-bit binary multiplication to expand the fractional value and represents it as an integer. The frequency synthesizer generates the corresponding connection wave signal based on the frequency control word and amplitude control word output by the FPGA.

5. The GPS signal generation method based on FPGA according to claim 1, characterized in that: The frequency conversion module in S4 includes two generating clocks and intermediate frequency signal frequency conversion, with the two generating clocks designed in parallel.

6. The GPS signal generation method based on FPGA according to claim 1, characterized in that: The frequency conversion module in S4 includes an FPGA-based frequency conversion unit and a signal frequency conversion unit based on an initial pre-defined signal rule template, wherein the FPGA-based frequency conversion unit and the signal frequency conversion unit based on the initial pre-defined signal rule template are connected in series.

7. A GPS signal generation method based on FPGA according to claim 1, comprising a signal generation system, characterized in that: The system includes an integrated control unit and an FPGA unit. The integrated control unit is connected to a signal synthesizer, the signal synthesizer is connected to a frequency converter module, the frequency converter module is connected to a signal generator, and the signal generator is connected to a signal transmitter. The integrated control unit is electrically connected to the FPGA unit.