Intelligent police service system and method combined with Beidou digital twin platform

Abstract

An intelligent police service system combined with a Beidou digital twinborn platform is configured to receive satellite signals from a GPS, a GLONASS and a Beidou satellite navigation system, perform high-gain low-noise amplification processing and filtering on the satellite signals to obtain radio frequency input signals, and is configured to be in communication connection with a three-mode receiving module to obtain the radio frequency input signals. And the radio frequency front-end receiving module is used for receiving the radio frequency input signal, converting the radio frequency input signal into an intermediate frequency signal, and being configured to be in communication connection with the radio frequency front-end receiving module to obtain the intermediate frequency signal, and performing differential receiving processing on the intermediate frequency signal to convert the intermediate frequency signal into a corresponding digital signal. By combining the Beidou digital twin platform, the system not only provides high-precision positioning service, but also has strong command and dispatch capability, and realizes cross-region and cross-department flexible command and dispatch through equipment such as the public network cluster command and dispatch server, the cluster talkback, the public network talkback intelligent terminal and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent police service system, and particularly relates to an intelligent police service system combined with a Beidou digital twin platform and a method thereof. BACKGROUND

[0002] With the continuous development of global satellite navigation system (GNSS) technology, GPS, GLONASS and Beidou satellite navigation systems have become indispensable positioning means in modern society. However, the traditional police service system often has problems such as inaccurate positioning, unstable signal reception and poor system applicability when receiving and processing these satellite signals.

[0003] In the prior art, the traditional police service system can only receive signals of a single satellite system when receiving satellite signals, which limits the accuracy and reliability of positioning data. Due to the differences in signal frequency bands and characteristics of different satellite systems, a single reception mode cannot meet the positioning needs in different environments.

[0004] Secondly, in terms of signal processing, the signal processing process adopted by the traditional police service system is relatively simple, and lacks advanced differential reception processing, capture, tracking, synchronization, pseudorange measurement and navigation solution technologies. This leads to the system being easily disturbed in a complex electromagnetic environment, unstable signal reception quality, and further affects the accuracy and speed of positioning.

[0005] In addition, due to the lack of effective data security measures, the traditional police service system is vulnerable to network attacks and data leaks, which not only threatens the confidentiality and security of police work, but also has a negative impact on society. SUMMARY

[0006] In view of the above, in order to overcome the defects of the prior art, the application provides an intelligent police service system combined with a Beidou digital twin platform and a method thereof, to at least partially solve the above technical problems.

[0007] The technical solutions adopted by the application are as follows: The application provides an intelligent police service system combined with a Beidou digital twin platform, which comprises: a three-mode reception module configured to receive satellite signals from GPS, GLONASS and Beidou satellite navigation systems, and to perform high-gain low-noise amplification processing and filtering on the satellite signals to obtain a radio frequency input signal; a radio frequency front-end reception module configured to be in communication connection with the three-mode reception module to obtain the radio frequency input signal, and to convert the radio frequency input signal into an intermediate frequency signal; An intermediate frequency signal processing module is configured to be communicatively connected with the radio frequency front end receiving module to obtain the intermediate frequency signal and to perform differential receiving processing on the intermediate frequency signal to convert the intermediate frequency signal into a corresponding digital signal; A general baseband signal processing module is configured to call a corresponding algorithm according to the type of the satellite signal, to perform data processing and positioning calculation on the digital signal through the corresponding algorithm, and to obtain navigation positioning data; A terminal device is configured to be communicatively connected with the general baseband signal processing module, to display the navigation positioning data through a man-machine interface of the terminal device, and to feed back an operation instruction generated based on the man-machine interface to the general baseband signal processing module.

[0008] In an embodiment of the present application, the triple-mode receiving module comprises: a first low-noise amplifier configured to amplify a satellite signal from GPS received through a triple-frequency antenna; A second low-noise amplifier is configured to amplify a satellite signal from GLONASS received through a triple-frequency antenna; A third low-noise amplifier is configured to amplify a satellite signal from a Beidou satellite navigation system received through a triple-frequency antenna; A band-pass filter is configured to be communicatively connected with the first low-noise amplifier, the second low-noise amplifier and the second low-noise amplifier, respectively, to filter the satellite signal from GPS, the satellite signal from GLONASS or the satellite signal from the Beidou satellite navigation system to obtain the radio frequency input signal.

[0009] In an embodiment of the present application, the intermediate frequency signal processing module comprises: a first differential converter configured to convert the intermediate frequency signal into a first differential signal; A second differential converter is configured to convert the intermediate frequency signal into a second differential signal; A first analog-to-digital converter is configured to convert the first differential signal into a corresponding digital signal and transmit the digital signal to an interface of an FPGA intermediate layer board card; A second analog-to-digital converter is configured to convert the second differential signal into a corresponding digital signal and transmit the digital signal to the interface of the FPGA intermediate layer board card; A phase-locked loop is configured to output a sampling clock signal to the first analog-to-digital converter and the second analog-to-digital converter through a crystal oscillator to provide a reference clock; The general baseband signal processing module comprises: an FPGA chip configured to obtain the digital signal from the interface of the FPGA intermediate layer board card to perform capture, tracking and pseudorange measurement processing on the digital signal; A DSP chip is configured to be connected with the FPGA chip through an SRIO protocol to perform navigation positioning calculation on the digital signal, and the DSP chip is connected with the terminal device through a user datagram protocol to realize data interaction and operation instruction feedback based on a human-computer interaction interface.

[0010] In an embodiment of the application, the FPGA chip comprises a sampling rate conversion module configured to perform sampling rate conversion on the received digital signal to generate corresponding digital quantities. A three-mode receiving compatible channel is configured to perform signal acquisition, tracking and pseudo-range measurement processing on the digital quantities according to the type of satellite signals. An SRIO interface module is configured to transmit the processed digital quantities to the DSP chip to enable the DSP chip to perform navigation calculation to obtain navigation positioning data. The three-mode receiving compatible channel comprises a carrier oscillator module configured to output a carrier phase to address and output two-way quadrature signals I and Q to a sine table module according to a frequency control word sent by the DSP chip through a capture / tracking bus, and a code oscillator module configured to output a chip clock signal for driving a pseudo-code generator according to a frequency control word sent by the DSP chip through the capture / tracking bus. A digital down-conversion module is configured to down-convert the intermediate frequency signal to a baseband signal according to the digital quantities, the quadrature signals I and Q.

[0011] A pseudo-code generator is configured to generate early code, late code and prompt code according to a phase code control word sent by the DSP chip through the capture / tracking bus, and perform integration operation on the quadrature signals I and Q output by the digital down-conversion module. A bit / frame synchronization module is configured to perform bit / frame synchronization processing on the integration result of the integration operation to obtain navigation messages, and transmit the navigation messages and original observations to the DSP chip through the SRIO interface module.

[0012] In an embodiment of the application, a method for a smart police system combined with a Beidou digital twin platform comprises the following steps: S1, the working frequency range of the three-mode receiving module is 2MHz~3GHz, which can meet the frequency coverage of the Beidou navigation system, the GPS navigation system and the GLONASS navigation system, the three-mode receiving module converts the received satellite signal into a radio frequency input signal and inputs the radio frequency input signal into the radio frequency front-end receiving module, the radio frequency front-end receiving module converts the radio frequency input signal into an intermediate frequency signal (70MHz or 220MHz) and outputs the intermediate frequency signal to the intermediate frequency signal processing module, the intermediate frequency signal processing module converts the input intermediate frequency signal into a digital signal after differential receiving processing and outputs the digital signal to the general baseband signal processing module, the general baseband signal processing module calls corresponding algorithms according to the type of the satellite signal to perform operations such as capture, tracking, synchronization, pseudorange measurement and navigation solution, and outputs navigation positioning data to a terminal device, and the terminal device sends operation instructions to the general baseband signal processing module; S2, the first low-noise amplifier suitable for GPS, the second low-noise amplifier suitable for GLONASS and the third low-noise amplifier suitable for the Beidou satellite navigation system are integrated in the three-mode receiving module, and the working frequency range is 2MHz~3GHz, which can meet the frequency coverage of the B1 frequency point, the B2 frequency point and the B3 frequency point of the Beidou second-generation satellite navigation system, wherein the working frequency of the B1 frequency point is 1561.098±2.046MHz, the working frequency of the B2 frequency point is 1207.14±2.046MHz, and the working frequency of the B3 frequency point is 1268.52±10.23MHz; the frequency coverage of L1, L2 and L5 frequency bands of GPS can also be met, wherein the working frequency of L1 is 1575.42MHz±1.023MHz, the working frequency of L2 is 1227.60MHz±1.023MHz, and the working frequency of L5 is 1176.45MHz±1.023MHz; the frequency coverage of L1 and L2 working frequency bands of GLONASS can also be met, wherein the working frequency of L1 is 1602+0.5625*k(MHz), and the working frequency of L2 is 1246+0.4375*k(MHz); S3, the sampling rate conversion module performs 5 times down-sampling on the 250MHz / 12bit digital signal output by the intermediate frequency signal processing module to obtain 50MHz / 12bit digital output, and then parallelly inputs the obtained digital quantity into the three-mode receiving compatible channel, only four channel signals in the three-mode receiving compatible channel are needed to complete the capture, tracking and pseudorange measurement of the digital signal, then the processed digital quantity is transmitted to the DSP chip through the SRIO interface module and the corresponding algorithm is called to complete the navigation data solution, and finally the navigation positioning data is obtained.

[0013] In an embodiment of the present application, the intelligent police system combined with the Beidou digital twin platform further comprises: The command platform, the public network server, the switch, the firewall, the Beidou command machine and the Beidou satellite body; The Beidou satellite and the Beidou command machine are connected through the signal transmission and reception technology of the Beidou satellite navigation system. The Beidou command machine and the firewall are connected through the determination of network architecture, the connection of the Beidou command machine and the front-end server, the configuration of the front-end server, the setting of the firewall, the configuration of the firewall rule, the security isolation device and the test and verification, so as to ensure the safe transmission of data. The public network server, the switch, the firewall and the Beidou command machine are connected through physical connection, server configuration, connection line test, switch configuration, configuration verification, firewall connection and public network server connection in sequence. The public network server and the command platform are connected through the deployment of the public network cluster command and dispatch server, the configuration of the cluster intercom gateway, the use of the public network intercom intelligent terminal, the deployment of the converged communication telephone gateway and the use of the IP telephone and the IP intercom terminal.

[0014] In an embodiment of the present application, the specific connection mode and configuration steps of the Beidou command machine when configuring the firewall may be different due to different network environments, device models and security requirements.

[0015] In an embodiment of the present application, the Beidou command machine is directly connected to the front-end server through a serial port (such as RS232, RS422) or a network port.

[0016] The beneficial effects of the technical scheme of the present application are as follows: The present application can receive and process signals from GPS, GLONASS and Beidou satellite navigation systems simultaneously through the integration of a three-mode receiving module, which not only improves the accuracy and reliability of positioning, but also enhances the applicability of the system in a global range.

[0017] The present application adopts an advanced signal processing procedure from the radio frequency front-end receiving module to the intermediate frequency signal processing module, and then to the general baseband signal processing module, including differential receiving processing, capture, tracking, synchronization, pseudo-range measurement and navigation solution operations, the application of the sampling rate conversion module and the SRIO interface module, which optimizes the transmission and processing efficiency of digital signals, so that the system can respond more quickly and provide accurate positioning information.

[0018] The application ensures the safe transmission of data between the Beidou command machine and the public network server, switch, firewall and other devices through complex network connection and configuration steps, the firewall provides additional security for the system, prevents data leakage and illegal access, and the Beidou command machine directly connected to the front-end server through a serial port or a network port further enhances the stability and security of data transmission.

[0019] The application combines the Beidou digital twin platform, the system not only provides high-precision positioning services, but also has strong command and dispatch capabilities, through the public network cluster command and dispatch server, cluster intercom, public intercom intelligent terminal and other devices, the system realizes flexible command and dispatch across regions and departments, and integrates the application of communication telephone and IP telephone and IP intercom terminal, so that the system can support multiple communication modes, and improve the convenience and efficiency of communication.

[0020] Additional aspects and advantages of the application will be described in part below, will become apparent from the following description, or will be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0021] The above and / or additional aspects and advantages of the application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which: Fig. 1 The first schematic diagram of the intelligent police system combining the Beidou digital twin platform for the embodiment of the application is shown. Fig. 2 The second schematic diagram of the intelligent police system combining the Beidou digital twin platform for the embodiment of the application is shown. Fig. 3 The system method of the intelligent police system combining the Beidou digital twin platform for the embodiment of the application is shown. DETAILED DESCRIPTION

[0022] The embodiments of the application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0023] The intelligent police system and method combining the Beidou digital twin platform for the embodiment of the application are described below with reference to the accompanying drawings.

[0024] As shown in Figs. 1 to 3 The embodiment of the application provides an intelligent police system combining a Beidou digital twin platform, which comprises: The three-mode receiving module is configured to receive satellite signals from GPS, GLONASS and Beidou satellite navigation systems, and to perform high-gain low-noise amplification processing and filtering on the satellite signals to obtain a radio frequency input signal; The radio frequency front-end receiving module is configured to be in communication connection with the three-mode receiving module to obtain the radio frequency input signal, and to convert the radio frequency input signal into an intermediate frequency signal; The intermediate frequency signal processing module is configured to be in communication connection with the radio frequency front-end receiving module to obtain the intermediate frequency signal, and to perform differential receiving processing on the intermediate frequency signal to convert it into a corresponding digital signal; The general baseband signal processing module is configured to call corresponding algorithms according to the types of the satellite signals, to perform data processing and positioning calculation on the digital signal through the corresponding algorithms, and to obtain navigation positioning data; The terminal device is configured to be in communication connection with the general baseband signal processing module, to display the navigation positioning data through a human-computer interaction interface of the terminal device, and to feed back operation instructions generated based on the human-computer interaction interface to the general baseband signal processing module.

[0025] In specific applications, the three-mode receiving module has high integration and compatibility, and can simultaneously receive satellite signals from three global satellite navigation systems, namely GPS (Global Positioning System), GLONASS (Global Navigation Satellite System) and Beidou satellite navigation system. The satellite signals are subject to various interferences in the transmission process, such as atmospheric attenuation and multipath effect. Therefore, the three-mode receiving module performs high-gain low-noise amplification processing on the received satellite signals to improve the strength of the signals and reduce the interference of noise. At the same time, the filtering circuit in the module further purifies the signals to obtain radio frequency input signals with higher quality.

[0026] The radio frequency front-end receiving module establishes a communication connection with the three-mode receiving module to obtain the radio frequency input signal that has been preliminarily processed from the latter. The main task of the radio frequency front-end receiving module is to down-convert the radio frequency input signal to an intermediate frequency, which helps to reduce the frequency of the signal and make it more suitable for subsequent digital signal processing. In the down-conversion process, the radio frequency front-end receiving module mixes the intermediate frequency signal generated by the mixer and the local oscillator with the radio frequency input signal, thereby obtaining the intermediate frequency signal.

[0027] The intermediate frequency signal processing module subsequently receives the intermediate frequency signal from the radio frequency front-end receiving module and performs differential receiving processing on it. The differential receiving technology suppresses common-mode noise and interference by comparing two intermediate frequency signals with a phase difference of 90 degrees, thereby improving the anti-interference ability and stability of the signal. After differential receiving processing, the intermediate frequency signal is converted into a corresponding digital signal, providing a basis for subsequent data processing.

[0028] The general baseband signal processing module calls corresponding algorithms according to the received satellite signal type (GPS, GLONASS or Beidou), and the algorithms include multiple steps such as signal acquisition, tracking, demodulation, decoding and the like, aiming to extract navigation information from the digital signal and perform positioning calculation, through complex mathematical operation and model optimization, the general baseband signal processing module can accurately calculate the position, speed and time and the like of the terminal device. Finally, the terminal device and the general baseband signal processing module establish a communication connection, receive and display the navigation positioning data.

[0029] The terminal device is usually equipped with an intuitive man-machine interface, such as a touch screen or a display screen, and the user can view the position information, travel trajectory and the like of the user in real time through the interface. At the same time, the terminal device also supports the feedback function based on the operation instruction generated by the man-machine interface, and the user can input the instruction through touch, key and the like, such as adjusting the navigation mode, selecting the destination and the like, and the instruction will be fed back to the general baseband signal processing module in real time, so that the system can make corresponding adjustment and optimization according to the user demand.

[0030] In one possible implementation, the three-mode receiving module comprises: a first low-noise amplifier configured to amplify the satellite signal from GPS received through the three-frequency antenna; a second low-noise amplifier configured to amplify the satellite signal from GLONASS received through the three-frequency antenna; a third low-noise amplifier configured to amplify the satellite signal from the Beidou satellite navigation system received through the three-frequency antenna; a band-pass filter configured to be in communication connection with the first low-noise amplifier, the second low-noise amplifier and the second low-noise amplifier respectively, so as to filter the satellite signal from GPS, the satellite signal from GLONASS or the satellite signal from the Beidou satellite navigation system to obtain the radio frequency input signal.

[0031] In specific application, the three-frequency antenna serves as the entrance of the signal, and can receive different frequency band signals from GPS, GLONASS and the Beidou satellite navigation system at the same time. The signal has experienced a complex space propagation process and is accompanied by certain attenuation and interference before entering the three-mode receiving module. For different types of satellite signals, three independent low-noise amplifiers are arranged in the three-mode receiving module: the first low-noise amplifier is specially responsible for amplifying the satellite signal from GPS; the second low-noise amplifier focuses on amplifying the GLONASS satellite signal; and the third low-noise amplifier amplifies the signal of the Beidou satellite navigation system. The three low-noise amplifiers all adopt advanced low-noise technology, which can effectively improve the strength of the signal without introducing too much noise, and provide a solid foundation for subsequent signal processing.

[0032] After being processed by the low-noise amplifier, the satellite signal enters the band-pass filter stage. The band-pass filter is a filter with a specific frequency response that allows only signals within a certain frequency range to pass through while suppressing signals of other frequencies. In this system, the band-pass filter is connected to three low-noise amplifiers respectively, and performs accurate filtering processing on satellite signals from GPS, GLONASS and Beidou satellite navigation systems. Through filtering, noise and interference components in the signal can be further removed, obtaining a more pure radio frequency input signal.

[0033] The band-pass filter fully considers the signal characteristics of different satellite navigation systems, including signal frequency range, bandwidth and other parameters, to ensure the optimization of filtering effect. At the same time, the filter also adopts a multi-stage cascaded structure to further improve the filtering accuracy and stability. After completing the filtering process, the radio frequency input signal is sent to the subsequent radio frequency front-end receiving module for further processing. In this stage, the radio frequency input signal will be converted into an intermediate frequency signal and further processed for signal conditioning and digitization, finally obtaining a digital signal that can be used for positioning calculation.

[0034] In one possible implementation, the intermediate frequency signal processing module comprises: a first differential converter configured to convert the single-ended intermediate frequency signal into a first differential signal; a second differential converter configured to convert the single-ended intermediate frequency signal into a second differential signal; a first analog-to-digital converter configured to convert the first differential signal into a corresponding digital signal and transmit it to the interface of the FPGA intermediate layer board card; a second analog-to-digital converter configured to convert the second differential signal into a corresponding digital signal and transmit it to the interface of the FPGA intermediate layer board card; a phase-locked loop configured to output a sampling clock signal to the first analog-to-digital converter and the second analog-to-digital converter through the crystal oscillator to provide a reference clock; a general baseband signal processing module comprising: an FPGA chip configured to obtain the digital signal from the interface of the FPGA intermediate layer board card to capture, track and measure the pseudorange of the digital signal; a DSP chip configured to communicate with the FPGA chip through an SRIO protocol to perform navigation positioning calculation on the digital signal, and the DSP chip is connected to the terminal device through a user datagram protocol to realize data interaction and operation instruction feedback based on a human-computer interaction interface.

[0035] In a specific application, the intermediate frequency signal (obtained by down-conversion by the radio frequency front-end receiving module) is input into the intermediate frequency signal processing module. The module internally includes two differential converters, a first differential converter and a second differential converter. The two converters respectively convert the single-ended form of the intermediate frequency signal into a differential signal form, i.e., a first differential signal and a second differential signal. The differential signal transmission has the advantages of strong anti-interference ability and good signal integrity, which helps the accuracy of subsequent analog-to-digital conversion.

[0036] The first differential signal is input into a first analog-to-digital converter (ADC), and the second differential signal is input into a second analog-to-digital converter. The two analog-to-digital converters convert the analog differential signal into a digital signal. During the conversion process, a phase-locked loop (PLL) outputs a stable sampling clock signal to the two analog-to-digital converters through a crystal oscillator, providing them with an accurate reference clock. The stability and accuracy of the sampling clock are crucial to the accuracy and reliability of analog-to-digital conversion. After analog-to-digital conversion, the obtained digital signal is transmitted to the interface of the FPGA middle layer board card. The FPGA chip, as one of the cores of the general baseband signal processing module, acquires these digital signals from the interface of the FPGA middle layer board card. Inside the FPGA, through pre-programmed algorithms and logic circuits, the digital signal is processed for capture, tracking, and pseudorange measurement. The capture stage mainly identifies and locks the satellite signal, the tracking stage continuously tracks the locked satellite signal to maintain signal stability, and the pseudorange measurement estimates the distance between the receiver and the satellite by calculating the satellite signal propagation time.

[0037] The digital signal processed by the FPGA is transmitted to the DSP chip. The DSP chip and the FPGA chip are connected through the SRIO (Serial RapidIO) protocol for high-speed communication. Inside the DSP chip, the digital signal is further processed for navigation positioning calculation through complex navigation algorithms. This step aims to accurately calculate the position, speed, and time of the receiver.

[0038] The DSP chip establishes a communication connection with the terminal device through the user datagram protocol (such as UDP). The terminal device usually includes display screens, control panels, and other human-computer interaction interfaces on police vehicles. The DSP chip sends data such as navigation positioning calculation results to the terminal device through the UDP protocol for real-time viewing and operation by police personnel. At the same time, the operation instructions (such as adjusting the navigation mode, selecting the target location, etc.) on the terminal device are also fed back to the DSP chip through the UDP protocol, which is further processed by the DSP chip and transmitted to the FPGA or other related modules to realize closed-loop control and intelligent operation of the system.

[0039] In a possible implementation, the FPGA chip comprises: a sampling rate conversion module configured to perform sampling rate conversion on the received digital signal to generate corresponding digital quantity; A three-mode receiving compatible channel configured to perform signal acquisition, tracking and pseudorange measurement processing on the digital quantity according to the type of the satellite signal; An SRIO interface module configured to transmit the processed digital quantity to a DSP chip to enable the DSP chip to perform navigation solution to obtain navigation positioning data; The three-mode receiving compatible channel comprises: a carrier oscillator module configured to output two-way quadrature signals I and Q to address and output a sine table module according to a carrier phase output by the DSP chip through a frequency control word sent by a capture / tracking bus; and a code oscillator module configured to output a chip clock signal for driving a pseudo-code generator according to a frequency control word sent by the DSP chip through the capture / tracking bus. A digital down-conversion module configured to down-convert an intermediate frequency signal to a baseband signal according to the digital quantity, the quadrature signal I and the quadrature signal Q.

[0040] A pseudo-code generator configured to generate early code, late code and prompt code according to a phase code control word sent by the DSP chip through the capture / tracking bus, and perform integration operation on the quadrature signal I and the quadrature signal Q output by the digital down-conversion module. A bit / frame synchronization module configured to perform bit / frame synchronization processing on the integration operation result of the integration operation to obtain navigation messages, and transmit the navigation messages and original observation quantity to the DSP chip through the SRIO interface module.

[0041] In a specific application, the FPGA chip receives a digital signal from the intermediate frequency signal processing module, the digital signal is a result of satellite navigation signal after analog-to-digital conversion, and contains satellite navigation information as well as noise and interference; in order to adapt to the requirements of the subsequent processing module, the sampling rate conversion module first performs sampling rate conversion on the digital signal to generate digital quantity meeting the system requirements.

[0042] The three-mode receiving compatible channel can compatibly process signals from GPS, GLONASS and Beidou satellite navigation systems. For each type of satellite signal, the three-mode receiving compatible channel will perform signal acquisition, tracking and pseudorange measurement processing. In this process, the carrier oscillator module generates a carrier phase matching the satellite signal carrier frequency according to the frequency control word sent by the DSP chip through the capture / tracking bus. Then, the carrier phase is used to address the sine table module to output two orthogonal signals I and Q. These two orthogonal signals are the basis for subsequent signal processing. At the same time, the code oscillator module also outputs a chip clock signal for driving the pseudo-code generator according to the frequency control word sent by the DSP chip. The pseudo-code generator generates early code, late code and prompt code according to the phase code control word. The pseudo-code and the orthogonal signals I and Q output by the digital down-conversion module are integrated to achieve accurate acquisition and tracking of satellite signals.

[0043] The digital down-conversion module down-converts the intermediate frequency signal to a baseband signal. By using the received digital quantities, orthogonal signals I and Q, and through mixing and filtering steps, the signal is moved from the intermediate frequency to the baseband, which helps to reduce the bandwidth of the signal and improve the efficiency of signal processing. The result of the integration operation is sent to the bit / frame synchronization module. The module extracts the navigation message by synchronously processing the integration result. The navigation message is the data information sent by the satellite navigation system to the user, which contains time, position, speed and other key navigation parameters. At the same time, the bit / frame synchronization module also transmits the original observation (such as pseudorange, carrier phase, etc.) to the DSP chip through the SRIO interface module.

[0044] After receiving the navigation message and the original observation from the FPGA chip, the DSP chip uses the built-in navigation algorithm to perform navigation calculation. According to the received satellite signal information, the receiver's accurate position, speed and time information are calculated, and the calculation result is returned to the terminal device through the corresponding interface for the police to use.

[0045] In one possible implementation, the method of the intelligent police system combined with the Beidou digital twin platform includes the following steps: S1. The operating frequency range of the three-mode receiving module is 2MHz to 3GHz, which can meet the frequency coverage of the Beidou navigation system, GPS navigation system and GLONASS navigation system. The three-mode receiving module converts the received satellite signal into a radio frequency input signal and inputs it into the radio frequency front-end receiving module. The radio frequency front-end receiving module converts the radio frequency input signal into an intermediate frequency signal (70MHz or 220MHz) and outputs it to the intermediate frequency signal processing module. The intermediate frequency signal processing module converts the input intermediate frequency signal into a digital signal after differential reception processing and outputs it to the universal baseband signal processing module. The universal baseband signal processing module calls the corresponding algorithm to perform operations such as capture, tracking, synchronization, pseudorange measurement and navigation solution on the input digital signal according to the type of satellite signal, and then outputs the navigation positioning data to the terminal device. The terminal device sends an operation instruction to the universal baseband signal processing module. S2. The three-mode receiving module integrates a first low-noise amplifier for GPS, a second low-noise amplifier for GLONASS, and a third low-noise amplifier for the BeiDou satellite navigation system. Its operating frequency range is 2MHz to 3GHz, which can meet the frequency coverage of the B1, B2 and B3 frequencies of the BeiDou-2 satellite navigation system. Among them, the operating frequency of the B1 frequency is 1561.098±2.046MHz, the operating frequency of the B2 frequency is 1207.14±2.046MHz, and the operating frequency of the B3 frequency is 1268.52±10.2 3MHz; it can also meet the frequency coverage of GPS L1, L2 and L5 bands, among which the operating frequency of L1 is 1575.42MHz±1.023MHz, the operating frequency of L2 is 1227.60MHz±1.023MHz, and the operating frequency of L5 is 1176.45MHz±1.023MHz; it can also meet the frequency coverage of GLONASS L1 and L2 operating bands, among which the operating frequency of L1 is 1602+0.5625*k(MHz), and the operating frequency of L2 is 1246+0.4375*k(MHz); S3, the sampling rate conversion module downsamples the 250MHz / 12bit digital signal output by the intermediate frequency signal processing module by 5 times to obtain a 50MHz / 12bit digital output, and then inputs the obtained digital quantity in parallel into the three-mode reception compatible channel. It only needs to obtain four channel signals in the three-mode reception compatible channel to complete the capture, tracking and pseudo-range measurement of the digital signal. The processed digital quantity is then transmitted to the DSP chip through the SRIO interface module and the corresponding algorithm is called to complete the navigation data solution, and finally the navigation positioning data is obtained.

[0046] In a specific application, the three-mode receiving module has a frequency range of 2MHz to 3GHz, and can comprehensively receive satellite signals of the Beidou navigation system, the GPS navigation system and the GLONASS navigation system. The signals are first converted into radio frequency input signals and input into the radio frequency front-end receiving module. The radio frequency front-end receiving module converts the radio frequency input signals into intermediate frequency signals, and the intermediate frequency signals are usually selected as 70MHz or 220MHz, which helps to reduce the frequency of the signals and facilitate subsequent digital signal processing.

[0047] The intermediate frequency signal processing module is subjected to differential receiving processing, which can effectively improve the anti-interference capability of the signals. Subsequently, the intermediate frequency signals are converted into digital signals and output to the general baseband signal processing module for further processing. According to the type of the received satellite signals, the general baseband signal processing module calls corresponding algorithms to perform operations such as acquisition, tracking, synchronization, pseudorange measurement and navigation solution. The algorithms can accurately extract navigation information in the satellite signals and calculate key parameters such as the position, speed and time of the receiver.

[0048] Inside the three-mode receiving module, low-noise amplifiers for different navigation systems are integrated. The amplifiers can automatically select the working frequency band according to different satellite signal types and provide sufficient gain to ensure that the signal-to-noise ratio of the signals reaches the optimum. The digital signals output by the sampling rate conversion module are subjected to 5 times down-sampling processing by the sampling rate conversion module to obtain 50MHz / 12bit digital quantities, which reduces the sampling rate of the signals, reduces the data volume of subsequent processing, and maintains the integrity of the signals.

[0049] The processed digital quantities are input in parallel into four channels of the three-mode receiving compatible channel. The four channels are respectively responsible for key operations such as acquisition, tracking and pseudorange measurement. Through parallel processing and algorithm optimization, the system can efficiently complete these tasks. The processed digital quantities are transmitted to the DSP chip through the SRIO interface module. The DSP chip uses powerful computing capability to call corresponding algorithms to complete navigation data solution, and finally obtains accurate navigation positioning data.

[0050] The navigation positioning data is transmitted to terminal equipment such as police cars, handheld devices, etc. through appropriate interfaces. These devices can perform real-time path planning, position display and alarm reminding operations according to the navigation positioning data, and provide strong support for police work. The terminal equipment can also send operation instructions to the general baseband signal processing module according to actual needs, such as adjusting the receiving frequency, switching the navigation system, etc.

[0051] In a possible implementation, the intelligent police system combined with the Beidou digital twin platform further includes a command platform, a public network server, a switch, a firewall, a Beidou command machine and a Beidou satellite body. The Beidou satellite and the Beidou command machine are connected through the signal transmission and reception technology of the Beidou satellite navigation system. The Beidou command machine and the firewall are connected through determining the network architecture, connecting the Beidou command machine and the front-end server, configuring the front-end server, setting the firewall, configuring the firewall rules, the security isolation device, and testing and verifying, to ensure the safe transmission of data. The public network server, the switch, the firewall and the Beidou command machine are connected in sequence through physical connection, server configuration, connection line testing, switch configuration, verification configuration, firewall connection and public network server connection. The public network server and the command platform are connected through deploying the public network cluster command and dispatch server, configuring the cluster intercom gateway, using the public network intercom intelligent terminal, deploying the converged communication telephone gateway, and using the IP telephone and IP intercom terminal.

[0052] The specific connection mode and configuration steps of the Beidou command machine when configuring the firewall may be different due to different network environments, equipment models and security requirements. The Beidou command machine is directly connected to the front-end server through a serial port (such as RS232, RS422) or a network port.

[0053] In the specific application of the embodiment of the application, the network architecture is determined according to the actual demand and the security policy to determine the network architecture of the entire system, including determining the connection mode and topology structure between the Beidou command machine, the front-end server, the firewall and the public network server. The Beidou command machine is directly connected to the front-end server through a serial port (such as RS232, RS422) or a network port, and the connection ensures the reliability and stability of data in the transmission process.

[0054] The front-end server needs to be configured as a data transfer station, including setting IP address, port number, protocol type, etc., to ensure normal communication with the Beidou command machine and the firewall. The firewall needs to be configured with corresponding rules according to the security policy to limit illegal access and ensure data security, including setting access control list (ACL), port forwarding rule, etc. In the firewall, various rules need to be configured in detail to ensure that only authorized data flow can pass, including allowing or denying access to specific IP address, port or protocol type.

[0055] To further enhance the security of the system, additional security isolation devices such as DMZ area or virtual private network (VPN) can be deployed after the firewall to provide an additional security layer to prevent unauthorized access and data leakage. After all the configurations are completed, the entire connection needs to be tested and verified, including checking the transmission speed, accuracy of data and security performance of the firewall, etc. Through testing and verification, it can be ensured that the entire connection is safe and reliable.

[0056] Connect the public network server, switch, firewall, and Beidou command machine through physical connection lines such as network cables. Configure the public network server as necessary, including installing the operating system, configuring network parameters, installing necessary software and services, etc. The configuration ensures that the public network server can normally receive and process data from various components. Use network testing tools to test the connection lines to ensure their connectivity and stability.

[0057] As the core device of the network, the switch needs to be configured in detail, including setting VLAN, port mirroring, flow control, etc., to optimize network performance and security. After completing all configurations, the entire network needs to be verified, including checking the connectivity of the network, data transmission speed, and the cooperative work between various components, etc.

[0058] Connect the switch with the firewall to ensure that the data is protected by the firewall during transmission. Connect the public network server to the Internet to realize remote access and data sharing. This allows police personnel to access important data and information in the system from any location. Deploy a cluster command and dispatch server on the public network server, which is responsible for receiving dispatch requests from various terminals and conducting unified management and dispatch, allowing police personnel to work more efficiently, improving response speed and processing efficiency.

[0059] By configuring the cluster intercom system, police personnel can communicate and share information instantly. Equip police personnel with public intercom intelligent terminals, which can communicate with the cluster command and dispatch server through the Internet, allowing police personnel to receive dispatch instructions and related information from any location.

[0060] The converged communication telephone system can integrate multiple communication methods, including telephone, intercom, and SMS, allowing police personnel to choose communication methods more flexibly and improve communication efficiency and quality. Use IP phones and IP intercom terminals: IP phones and IP intercom terminals are communication devices based on Internet technology, which can communicate through the network without geographical restrictions. This allows police personnel to make voice calls and intercom operations from any location.

[0061] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; thus the use of any

[0062] The above description of the application and its embodiments is not restrictive, and the embodiments shown in the drawings are only one of the embodiments of the application, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired by it, without departing from the purpose of the application, without creative design, similar structure and embodiments of the technical solution can be designed, which should belong to the protection scope of the application.

Claims

1. An intelligent policing system combined with the Beidou digital twin platform, characterized by: include: A tri-mode receiving module is configured to receive satellite signals from the GPS, GLONASS, and BeiDou satellite navigation systems, and perform high-gain low-noise amplification and filtering on the satellite signals to obtain radio frequency input signals; a radio frequency front-end receiving module, configured to communicate with the three-mode receiving module to obtain the radio frequency input signal and convert the radio frequency input signal into an intermediate frequency signal; an intermediate frequency signal processing module, configured to communicate with the RF front-end receiving module to obtain the intermediate frequency signal and perform differential reception processing on the intermediate frequency signal to convert it into a corresponding digital signal; a universal baseband signal processing module, configured to call a corresponding algorithm according to the type of the satellite signal, perform data processing and positioning calculation on the digital signal using the corresponding algorithm, and obtain navigation positioning data; The terminal device is configured to communicate with the universal baseband signal processing module, display the navigation positioning data through the human-computer interaction interface of the terminal device, and feed back the operation instructions generated based on the human-computer interaction interface to the universal baseband signal processing module.

2. The intelligent policing system combined with the Beidou digital twin platform according to claim 1 is characterized in that: The tri-mode receiving module includes: a first low-noise amplifier configured to amplify and process the satellite signal from the GPS received through the tri-band antenna; a second low-noise amplifier configured to amplify a GLONASS satellite signal received through the tri-band antenna; a third low-noise amplifier configured to amplify and process satellite signals from the Beidou satellite navigation system received through the tri-band antenna; The bandpass filter is configured to be communicatively connected to the first low-noise amplifier, the second low-noise amplifier, and the second low-noise amplifier, respectively, to filter the satellite signal from the GPS, the satellite signal from the GLONASS, or the satellite signal from the BeiDou satellite navigation system to obtain the RF input signal.

3. The intelligent policing system combined with the Beidou digital twin platform according to claim 1 is characterized in that: The intermediate frequency signal processing module includes: a first differential converter configured to convert the intermediate frequency signal into a first differential signal in a single-ended manner; a second differential converter configured to convert the intermediate frequency signal into a second differential signal in a single-ended manner; A first analog-to-digital converter is configured to convert the first differential signal into a corresponding digital signal and transmit the digital signal to an interface of the FPGA middle layer board; A second analog-to-digital converter is configured to convert the second differential signal into a corresponding digital signal and transmit the digital signal to an interface of the FPGA middle layer board; a phase-locked loop, configured to output a sampling clock signal to the first analog-to-digital converter and the second analog-to-digital converter through a crystal oscillator to provide a reference clock; The universal baseband signal processing module includes: an FPGA chip configured to obtain the digital signal from the interface of the FPGA middle layer board to capture, track and perform pseudorange measurement processing on the digital signal; The DSP chip is configured to communicate with the FPGA chip via the SRIO protocol to perform navigation and positioning solutions on the digital signal, and the DSP chip is communicated with the terminal device via the user datagram protocol to achieve data interaction and operation instruction feedback based on the human-computer interaction interface.

4. The intelligent policing system combined with the Beidou digital twin platform according to claim 1 is characterized in that: The FPGA chip includes: a sampling rate conversion module configured to perform sampling rate conversion on a received digital signal to generate a corresponding digital quantity; A three-mode receiving compatible channel is configured to perform signal acquisition, tracking and pseudo-range measurement processing on the digital quantity according to the type of satellite signal; The SRIO interface module is configured to transmit the processed digital quantity to the DSP chip so that the DSP chip performs navigation calculations to obtain navigation positioning data; The three-mode reception compatible channel includes: a carrier oscillator module configured to address a sine table module with an output carrier phase according to a frequency control word sent by the DSP chip via a capture / tracking bus to output two orthogonal signals I and Q; the three-mode reception compatible channel also includes: a code oscillator module configured to output a chip clock signal for driving a pseudo code generator according to the frequency control word sent by the DSP chip via a capture / tracking bus; a digital down-conversion module, configured to down-convert the intermediate frequency signal into a baseband signal according to the digital quantity, the quadrature signal I, and the quadrature signal Q; The pseudo code generator is configured to generate an advance code, a lag code and an immediate code according to a phase code control word sent by the DSP chip through the capture / tracking bus, and perform integration operations with the quadrature signal I and the quadrature signal Q output by the digital down-conversion module; The bit / frame synchronization module is configured to perform bit / frame synchronization processing on the integral operation result of the integral operation to obtain a navigation message, and transmit the navigation message and the original observation value to the DSP chip through the SRIO interface module.

5. The intelligent policing method in combination with the Beidou digital twin platform according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. The operating frequency range of the three-mode receiving module is 2MHz to 3GHz, which can meet the frequency coverage of the Beidou navigation system, GPS navigation system and GLONASS navigation system. The three-mode receiving module converts the received satellite signal into a radio frequency input signal and inputs it into the radio frequency front-end receiving module. The radio frequency front-end receiving module converts the radio frequency input signal into an intermediate frequency signal and outputs it to the intermediate frequency signal processing module. The intermediate frequency signal processing module converts the input intermediate frequency signal into a digital signal after differential reception processing and outputs it to the universal baseband signal processing module. The universal baseband signal processing module calls the corresponding algorithm to perform operations such as capture, tracking, synchronization, pseudorange measurement and navigation solution on the input digital signal according to the type of satellite signal, and then outputs the navigation positioning data to the terminal device. The terminal device sends an operation instruction to the universal baseband signal processing module; S2. The three-mode receiving module integrates a first low-noise amplifier for GPS, a second low-noise amplifier for GLONASS, and a third low-noise amplifier for the BeiDou satellite navigation system. Its operating frequency range is 2MHz to 3GHz, which can meet the frequency coverage of the B1, B2 and B3 frequencies of the BeiDou-2 satellite navigation system. Among them, the operating frequency of the B1 frequency is 1561.098±2.046MHz, the operating frequency of the B2 frequency is 1207.14±2.046MHz, and the operating frequency of the B3 frequency is 1268.52±10.2 3MHz; it can also meet the frequency coverage of GPS L1, L2 and L5 bands, among which the operating frequency of L1 is 1575.42MHz±1.023MHz, the operating frequency of L2 is 1227.60MHz±1.023MHz, and the operating frequency of L5 is 1176.45MHz±1.023MHz; it can also meet the frequency coverage of GLONASS L1 and L2 operating bands, among which the operating frequency of L1 is 1602+0.5625*k(MHz), and the operating frequency of L2 is 1246+0.4375*k(MHz); S3, the sampling rate conversion module downsamples the 250MHz / 12bit digital signal output by the intermediate frequency signal processing module by 5 times to obtain a 50MHz / 12bit digital output, and then inputs the obtained digital quantity in parallel into the three-mode reception compatible channel. It only needs to obtain four channel signals in the three-mode reception compatible channel to complete the capture, tracking and pseudo-range measurement of the digital signal. The processed digital quantity is then transmitted to the DSP chip through the SRIO interface module and the corresponding algorithm is called to complete the navigation data solution, and finally the navigation positioning data is obtained.

6. The intelligent policing system combined with the Beidou digital twin platform according to claim 1 is characterized in that: Also includes: Command platform, public network server, switch, firewall, Beidou command machine and Beidou satellite body; The BeiDou satellites and BeiDou command aircraft are connected through the signal transmission and reception technology of the BeiDou satellite navigation system; The Beidou control center and the firewall are connected by determining the network architecture, connecting the Beidou control center and the front-end server, configuring the front-end server, setting up the firewall, configuring firewall rules, security isolation devices, and testing and verification to ensure secure data transmission; The public network server, switch, firewall and Beidou command machine are connected in sequence through physical connection, server configuration, cable testing, switch configuration, configuration verification, firewall connection and public network server connection. The public network server and the command platform are connected by deploying a public network cluster command and dispatch server, configuring a cluster intercom gateway, using a public network intercom intelligent terminal, deploying a converged communication telephone gateway, and using IP phones and IP intercom terminals.

7. The intelligent policing system combined with the Beidou digital twin platform according to claim 6 is characterized in that: The specific connection method and configuration steps when configuring the firewall of the Beidou command center may vary depending on different network environments, device models and security requirements.

8. The intelligent policing system combined with the Beidou digital twin platform according to claim 6 is characterized in that: The Beidou control machine is directly connected to the front-end server through the serial port or network port.

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