Portable beidou civil short message space signal simulator

Abstract

The application discloses a portable Beidou civil short message space signal simulator and relates to the technical field of Beidou short message communication systems.The simulator is composed of a data simulation module, a signal processing module, a clock module and a power module, and has the functions of civil RDSS outbound signal simulation transmission and inbound signal reception.The data simulation module sends RDSS outbound signal simulation data to the signal processing module, and the signal processing module modulates the simulation data to generate outbound spread spectrum signals; meanwhile, the signal processing module receives inbound signals, performs tracking and demodulation, and sends observation data to the data simulation module for further analysis.The information processing module of the application is designed to be compatible with the analog signal channels of RDSS special outbound and popular consumer mobile phone outbound, and can receive RDSS special inbound signals and popular consumer mobile phone inbound signals.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of Beidou short message communication system, and relates to a portable simulator integrating Beidou civilian RDSS outbound signal simulation transmission and inbound signal reception. BACKGROUND

[0002] With the formal operation of Beidou No. 3 system, Beidou short message dedicated communication terminals and mass consumer mobile communication terminals emerge as the times require. The Beidou short message dedicated communication terminal relies on a dedicated civilian RDSS center station transceiver system, and the mass consumer mobile communication terminal relies on a mobile terminal RDSS transceiver system. The two are different in signal system, so the simulators used for testing the Beidou short message dedicated communication terminal and the mass consumer mobile communication terminal are also different in design. In order to meet the testing requirements of the Beidou short message dedicated communication terminal and the mass consumer mobile communication terminal, new requirements are put forward for the simulators. The portable Beidou civilian short message space signal simulator designed in the application is compatible with the civilian RDSS dedicated transceiver signal system and the mass consumer mobile signal system, and can meet the multiple testing requirements of the two types of terminals. SUMMARY

[0003] The application aims to realize a portable Beidou civilian short message space signal simulator, which has the functions of civilian RDSS outbound signal simulation transmission and inbound signal reception. In the design of outbound signal simulation transmission, the simulation signal channel compatible with the RDSS dedicated outbound and mass consumer mobile outbound is designed, and the simulator can be controlled to transmit the dedicated RDSS outbound simulation signal or the mass consumer mobile outbound simulation signal according to the requirement. In the design of inbound signal reception, the simulation signal channel compatible with the RDSS dedicated inbound and mass consumer mobile inbound is designed, and the simulator can receive the RDSS dedicated inbound signal or the mass consumer mobile inbound signal.

[0004] The application is realized by the following technical scheme:

[0005] The portable Beidou civilian short message space signal simulator comprises a data simulation module, a signal processing module, a clock module and a power module. The data simulation module sends RDSS outbound simulation data to the signal processing module, and the signal processing module modulates the simulation data to generate outbound spread spectrum signals. At the same time, the signal processing module receives the inbound signals sent from the outside, tracks and demodulates the inbound signals to generate observation data, and sends the observation data to the data simulation module for further analysis. The clock module and the power module provide the required time and frequency signals and power signals for the signal processing module. The signal processing module is used for signal transmission and signal reception, and the transmission and reception functions are independent of each other.

[0006] Further, the data simulation module generates RDSS outbound data simulation, including constellation simulation, user trajectory simulation, propagation environment simulation, signal simulation and communication control information processing; the information processing module processes the inbound signal, including analyzing the observation data obtained after inbound receiving processing and performing communication control;

[0007] The signal generation process of the signal processing module is information frame generation, pseudo code generation, signal modulation and digital to analog conversion in sequence; and the signal receiving process is analog to digital conversion, fast acquisition, signal tracking and demodulation and time delay measurement in sequence.

[0008] Further, the outbound simulation data of the data simulation module is simulated by constellation simulation, user trajectory simulation, propagation environment simulation and signal simulation to realize real simulation of RDSS satellite signals; the constellation simulation includes satellite navigation message simulation, which includes four modes: mode one, RDSS dedicated terminal outbound signal message simulation, mode two, RDSS mass consumer mobile terminal outbound signal message simulation, mode three, preset test message issuing, and mode four, forwarding message issuing; wherein, mode one and mode two are real messages generated by the data simulation software itself, mode three is to issue pre-prepared fixed messages to adapt to test requirements, and mode four is to forward the messages input by external modules.

[0009] Further, the message analysis of the data simulation module on the observation data includes three modes: mode one, RDSS dedicated terminal inbound signal message analysis, mode two, RDSS mass consumer mobile terminal inbound signal message analysis, and mode two, test message analysis.

[0010] Further, the signal generation process of the signal processing module: receives the simulation data of the data simulation module, the simulation data is sent to the message processing module, and the required navigation signal is generated in combination with the pseudo code generation module, the spread spectrum processing module is responsible for spread spectrum processing, the digital to analog conversion module is responsible for completing the conversion from digital to analog, and at the same time, the output radio frequency modulation signal is output through quadrature modulation, and finally the radio frequency space signal simulation is completed;

[0011] The message processing module is compatible with the messages of the two signal systems according to the feature that the lengths of the RDSS dedicated terminal outbound signal message and the mass consumer mobile terminal outbound signal message are consistent after encoding; then the message is sent to the backend module for modulation, and the selection control of the simulation message issued by the data simulation module is matched, realizing the functions of RDSS dedicated terminal outbound signal simulation transmission and RDSS mass consumer mobile terminal outbound signal simulation transmission.

[0012] Further, the signal processing module is used as a signal receiving function, the inbound signal is first converted into an intermediate frequency by frequency conversion and AD conversion, and then sent to the fast capture module, the fast capture module performs fast capture processing, and according to the busy state of the current inbound signal processing terminal, the capture pulse, the corresponding Doppler estimation parameter and the signal information are distributed to the subsequent signal tracking demodulation module, and the subsequent signal tracking demodulation module completes fast synchronization and tracking, information demodulation, time delay measurement processing under the start of the capture parameter, and reports the observation data obtained after processing to the data simulation module;

[0013] When tracking and demodulating the inbound text, according to the difference between the RDSS special terminal inbound signal text and the mass consumer mobile terminal inbound signal text in the signal system, two kinds of text format processing methods are included, and the processed inbound text is reported to the data simulation module, and the data simulation module can select to control the analysis of different formats of text, so that the function of supporting the reception of RDSS special terminal inbound signals and the reception of RDSS mass consumer mobile terminal inbound signals can be realized.

[0014] Further, the information processing module is mainly realized through a signal transceiver general board, adopts AD9371 and FPGA, Zynq and DSP architecture, contains RapidIO interface, serial port, high-speed serial port and LVTTL interconnected data interaction; the information processing module mainly realizes that the FPGA configures the AD9371 through JESD204B, and outputs the baseband signal to the AD9371, and can interconnect with other modules in the system and the Zynq and DSP data interaction of the board.

[0015] Compared with the prior art, the advantages of the present application are that:

[0016] 1. The portable Beidou civilian short message space signal simulator designed in the application has small size and high integration, and a signal processing board can realize the functions of parallel AD and DA through different configurations of the AD9371 chip, so that the functions of signal generation and signal reception can be realized simultaneously, and the transmission and reception functions are independent of each other.

[0017] 2. The portable Beidou civilian short message space signal simulator designed in the application has four kinds of navigation text modes in the outbound signal simulation design of the data simulation module: RDSS special terminal outbound signal text simulation, RDSS mass consumer mobile terminal outbound signal text simulation, preset test text (supporting outbound special text and mass consumer mobile text format) issuing and forwarding text (supporting outbound special text and mass consumer mobile text format) issuing.

[0018] 3、The portable Beidou civil short message space signal simulator designed in the application, in the design of the in-station signal data processing, designs three modes of in-station text analysis mode, namely, RDSS special terminal in-station signal text analysis, RDSS mass consumer mobile terminal in-station signal text analysis, and test text (supporting out-station special text and mass consumer mobile text format) analysis;

[0019] 4、The signal processing module of the portable Beidou civil short message space signal simulator designed in the application, when used as a signal generation function, has compatible processing of two kinds of signal system texts in the text processing module, and then, in cooperation with the selection control of the data simulation module in the issuance of different simulation texts, realizes the functions of supporting RDSS special terminal out-station signal simulation transmission and RDSS mass consumer mobile terminal out-station signal simulation transmission;

[0020] 5、The signal processing module of the portable Beidou civil short message space signal simulator designed in the application, when used as a signal receiving function, in the in-station signal tracking and demodulation, has processing modes suitable for two kinds of text formats, and then, in cooperation with the analysis of different format texts by the optional control of the data simulation module, realizes the functions of supporting RDSS special terminal in-station signal reception and RDSS mass consumer mobile terminal in-station signal reception; BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the overall structure framework diagram of the application.

[0022] Figure 2 is the design diagram of the data simulation module of the application.

[0023] Figure 3 is the design diagram of the signal processing module of the application. DETAILED DESCRIPTION

[0024] The specific implementation of the application will be further described in detail in combination with the drawings and examples.

[0025] On the hardware design, the portable Beidou civilian short message space signal simulator is composed of a data simulation module, a signal processing module, a clock module and a power module. The data simulation module sends the RDSS outbound signal simulation data to the signal processing module, and the signal processing module modulates the outbound spread spectrum signal after receiving the simulation data. At the same time, the signal processing module receives the inbound signal, performs tracking and demodulation, and sends the observation data to the data simulation module for further analysis. The time-frequency module and the power module provide the required time-frequency signal and power signal for the signal processing module. Among them, the signal processing module uses a signal transceiver universal board card, which can be used for signal generation and signal reception at the same time, and the transmission and reception functions are independent of each other, thereby reducing the number of board cards used, thereby achieving the purpose of low cost, small size and high integration;

[0026] The data simulation module is mainly software designed and does not occupy hardware space. This module generates RDSS outbound signal simulation data and sends it to the signal processing module, while receiving the observation data reported by the signal processing module for further analysis. Among them, the RDSS outbound signal data simulation design includes: constellation simulation, user trajectory simulation, propagation environment simulation, signal simulation and communication control information processing; the inbound signal data processing design includes: analyzing the observation data (inbound text, time delay observation, key signal parameters) obtained after inbound reception processing and performing communication control. This module is compatible with special signal systems and mass consumer mobile phone signal systems in terms of outbound signal data simulation and inbound signal observation data analysis;

[0027] The function of the signal processing module is mainly realized by FPGA. This part includes RDSS outbound signal generation and inbound signal reception. Among them, the design of the outbound signal generation part mainly includes: information frame generation design, pseudo code generation design, signal modulation design, digital to analog conversion design; the design of the inbound signal reception part mainly includes: analog to digital conversion design, fast capture design, signal tracking and demodulation design, time delay measurement design. When designing information frame generation and signal tracking and demodulation, the signal processing module fully considers the differences between Beidou civilian RDSS outbound and inbound special signal systems and mass consumer signal systems, and respectively designs a transmitting signal processing universal channel and a receiving signal processing universal channel compatible with the two signal systems;

[0028] The clock module uses high-precision clock crystals and clock processing board cards, and designs time-frequency internal and external clock switching and clock branching. It can receive external reference clock and output it, or directly branch the local clock crystal, automatically switch to external reference when there is external reference clock input, reduce operation, and provide the corresponding time-frequency reference for the signal processing module according to the needs;

[0029] The power module includes a power filter and a power conversion module, and the power conversion module is used for converting AC 220V into 12V and 5V for power supply to other modules in the simulator, both of which are designed to be small in size.

[0030] The design of the information processing module is mainly realized through a general-purpose signal transceiver board card, and uses AD9371 and FPGA, Zynq and DSP architecture, and contains RapidIO interface, serial port, high-speed serial port and LVTTL interconnected data interaction. The information processing module mainly realizes the frequency point configuration of AD9371 by FPGA through JESD204B, and outputs the baseband signal to AD9371, and can interconnect with other modules in the system RapidIO and the data interaction of Zynq and DSP on the board.

[0031] The design requires small size and high integration, so the orthogonal modulation mode is considered in the design of the simulator. The advantage of orthogonal modulation is that the modulation output has no intermodulation component and no image frequency generation, and the output signal does not need to be filtered, which greatly reduces the size of the device. The signal processing module used in this design is composed of a carrier board and a sub-board. The carrier board and the sub-board are tightly connected together through a connector to become an integral whole. The sub-board structure uses FMC structure conforming to VITA57.1 standard, with a size of 69mm x 76.5mm.

[0032] The orthogonal modulation used in this design is AD9371 chip, which is one of the most advanced DAC chips of AD company. It uses JESE204B digital interface, supports frequency division duplex and time division duplex working mode, and is fully integrated with independent dual-channel transmitter and receiver, with a working frequency of 300MHz to 6GHz. Through different configurations of AD9371 chip, the functions of parallel AD and DA are realized, which can be used for signal generation and signal reception at the same time, and the transmission and reception functions are independent of each other.

[0033] Step 2 includes the following steps:

[0034] The data simulation module simulates the RDSS satellite signal through constellation simulation, user trajectory simulation, propagation environment simulation and signal simulation in the outbound signal simulation design. The constellation simulation includes satellite navigation message simulation. Four modes are designed in the satellite navigation message simulation, i.e., RDSS special terminal outbound signal message simulation, RDSS mass consumer mobile terminal outbound signal message simulation, preset test message (supporting outbound special message and mass consumer mobile message format) issuing and forwarding message (supporting outbound special message and mass consumer mobile message format) issuing. The first two modes are to simulate real messages by the data simulation software itself, the third mode is to broadcast pre-prepared fixed messages to meet the test requirements, and the fourth mode is to forward the messages input by an external module, so that the simulation test of the design meets more flexible test requirements.

[0035] The data simulation module processes the inbound signal data by receiving the observation data after the inbound tracking and demodulation. The message analysis includes three modes, i.e., RDSS special terminal inbound signal message analysis, RDSS mass consumer mobile terminal inbound signal message analysis and test message (supporting outbound special message and mass consumer mobile message format) analysis.

[0036] The step 3 includes the following steps:

[0037] When the signal processing module is used as a signal generation function, it receives the simulation data of the data simulation module. The simulation data is sent to the message processing module, combined with the pseudo code generation module, to generate the required navigation signal. After the spread spectrum processing, the spread spectrum signal (or frequency modulation signal) is generated. The DA module (AD9371) is responsible for completing the digital-to-analog conversion of the signal, and simultaneously performs quadrature modulation to output the radio frequency modulation signal, and finally completes the radio frequency space signal simulation. The message processing module is designed according to the consistent length of the RDSS special terminal outbound signal message and the mass consumer mobile terminal outbound signal message after encoding. The two signal system messages are compatible processed, and then the message is sent to the back-end module for modulation. In combination with the selection control of the simulation message issued by the data simulation module, the function of supporting the RDSS special terminal outbound signal simulation transmission and the RDSS mass consumer mobile terminal outbound signal simulation transmission is realized.

[0038] When the signal processing module is used as a signal receiving function, the inbound signal is first down-converted to an intermediate frequency by the AD9371 and sent to the fast capture module after AD conversion, the fast capture module performs fast capture processing, and according to the busy state of the current inbound signal processing terminal, the capture pulse, the corresponding Doppler estimation parameter and the signal information are distributed to the subsequent signal tracking demodulation module, and the subsequent signal tracking demodulation module completes the fast synchronization and tracking, information demodulation, time delay measurement processing under the starting of the capture parameter, and reports the observation data (inbound text, time delay observation, signal key parameter) obtained after processing to the data simulation module. Here, when processing the inbound text, according to the difference between the RDSS special terminal inbound signal text and the mass consumer mobile terminal inbound signal text in the signal system, the processing mode suitable for two kinds of text formats is made, and after the processed inbound text is reported to the data simulation module, the data simulation module can select to control the analysis of different formats of text, realizing the functions of supporting the reception of RDSS special terminal inbound signals and the reception of RDSS mass consumer mobile terminal inbound signals.

[0039] The technical solution will be further described below with reference to the drawings:

[0040] Figure 1 It is the overall framework diagram of the portable Beidou civil short message space signal simulator designed by the application.

[0041] The portable Beidou civil short message space signal simulator designed by the application is composed of a data simulation module, a signal processing module, a clock module and a power supply module.

[0042] According to the principle of lightness and miniaturization, the RDSS outbound signal transmission and inbound signal reception are integrated on a board which can be used as a signal generation board and a signal receiving board, thereby forming a portable Beidou civil short message space signal simulator with small volume and high integration degree.

[0043] The data simulation module sends RDSS outbound signal simulation data to the signal processing module, and the signal processing module modulates and generates outbound spread spectrum signals after receiving the simulation data. At the same time, after receiving the inbound signal, the signal processing module performs tracking and demodulation, and sends the observation data to the data simulation module for further analysis.

[0044] The time frequency module and the power supply module provide the required time frequency signals and power supply signals for the signal processing module.

[0045] Figure 2 It is the design diagram of the data simulation module of the application.

[0046] The data simulation module includes two functions: RDSS outbound signal data simulation and inbound received signal data analysis.

[0047] The outbound analog signal data simulation includes four modes of satellite navigation signal message simulation, namely RDSS special terminal outbound signal message simulation, RDSS mass consumer mobile terminal outbound signal message simulation, preset test message issuing and retransmission message issuing.

[0048] The inbound received signal data processing includes three modes of inbound message analysis, namely RDSS special terminal inbound signal message analysis, RDSS mass consumer mobile terminal inbound signal message analysis and test message analysis.

[0049] Figure 3 It is a design diagram of the signal processing module.

[0050] The signal processing module includes two functions, RDSS outbound signal generation and RDSS inbound signal reception.

[0051] The RDSS outbound signal generation part includes the following contents: message processing module, pseudo code generation module, spread spectrum processing module and DA module.

[0052] The RDSS inbound signal reception includes the following contents: AD module, fast acquisition module and signal tracking demodulation module.

Claims

1. A portable BeiDou civilian short message space signal simulator, characterized in that, It includes a data simulation module, a signal processing module, a clock module, and a power supply module. The data simulation module sends RDSS outbound simulation data to the signal processing module, which then modulates and generates an outbound spread spectrum signal upon receiving the simulation data. Simultaneously, the signal processing module receives incoming signals from external sources, tracks and demodulates them to generate observation data, and sends the observation data back to the data simulation module for further analysis. The time-frequency module and the power supply module provide the necessary time-frequency and power signals to the signal processing module. The signal processing module is used for both signal transmission and reception, and the transmission and reception functions are independent of each other. The data simulation module's outbound simulation data achieves realistic simulation of RDSS satellite signals through constellation simulation, user trajectory simulation, propagation environment simulation, and signal simulation. The constellation simulation includes satellite navigation message simulation, which includes four modes: Mode 1, RDSS dedicated terminal outbound signal message simulation; Mode 2, RDSS mass consumer mobile phone terminal outbound signal message simulation; Mode 3, pre-set test message distribution; and Mode 4, forwarded message distribution. Among these, Modes 1 and 2 are real messages generated by the data simulation software itself, Mode 3 is to broadcast pre-set fixed messages to meet testing requirements, and Mode 4 is to forward messages input from external modules. The data simulation module performs message analysis on the observed data in three modes: Mode 1, message analysis of RDSS dedicated terminal inbound signal, Mode 2, message analysis of RDSS mass consumer mobile phone terminal inbound signal, and Mode 3, message analysis of test messages. The signal generation process of the signal processing module is as follows: the simulation data is received from the data simulation module, the simulation data is sent to the message processing module, and then combined with the pseudocode generation module to generate the required navigation signal. After the spread spectrum processing module spreads the signal to generate a spread spectrum signal or a frequency modulation signal. The digital-to-analog conversion module is responsible for converting the signal from digital to analog. At the same time, after quadrature modulation, the radio frequency modulation signal is output, and finally the radio frequency space signal simulation is completed. The message processing module is compatible with both RDSS dedicated terminal outbound signal messages and mass consumer mobile phone terminal outbound signal messages because the encoded lengths are the same. The message is then sent to the back-end module for modulation. Combined with the selection control of the data simulation module when sending simulated messages, it realizes two functions: simulated transmission of RDSS dedicated terminal outbound signals and simulated transmission of RDSS mass consumer mobile phone terminal outbound signals.

2. A portable Beidou civilian short message space signal simulator according to claim 1, characterized in that, The data simulation module generates RDSS outbound data simulations, including constellation simulation, user trajectory simulation, propagation environment simulation, signal simulation, and communication control information processing; the signal processing module processes inbound signals, including parsing the observation data obtained after inbound reception and processing, and performing communication control. The signal generation process of the signal processing module consists of information frame generation, pseudocode generation, signal modulation, and digital-to-analog conversion. Its signal reception process consists of analog-to-digital conversion, fast acquisition, signal tracking and demodulation, and time delay measurement.

3. A portable Beidou civilian short message space signal simulator according to claim 2, characterized in that, When the signal processing module is used for signal reception, the incoming signal is first down-converted to intermediate frequency and then converted by AD before being sent to the fast acquisition module. The fast acquisition module performs fast acquisition processing and, according to the busy / idle status of the current incoming signal processing terminal, distributes the acquisition pulse, the corresponding Doppler prediction parameters, and signal information to the subsequent signal tracking and demodulation module. The subsequent signal tracking and demodulation module completes fast synchronization and tracking, information demodulation, and time delay measurement processing under the activation of the acquisition parameters, and reports the processed observation data to the data simulation module. During tracking and demodulation, the processing of inbound messages includes two message formats, based on the differences in signal systems between inbound signal messages from dedicated RDSS terminals and those from mass-market consumer mobile terminals. After processing, the inbound messages are reported to the data simulation module. The data simulation module can then be used to selectively control the parsing of different message formats, thus enabling the reception of inbound signals from both dedicated RDSS terminals and mass-market consumer mobile terminals.

4. A portable Beidou civilian short message space signal simulator according to claim 1, characterized in that, The signal processing module is mainly implemented through a general-purpose signal transceiver board, adopting an AD9371 and FPGA, Zynq, and DSP architecture. It includes RapidIO interface, serial port, high-speed serial port, and LVTTL interconnect for data interaction. The signal processing module mainly enables the FPGA to configure the frequency of AD9371 through JESD204B, output baseband signals to AD9371, and perform RadpidIO interconnect with other modules in the system, as well as data interaction with Zynq and DSP on this board.

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