A brief discussion on the design of a new monitoring and alarm system based on 4G technology

With the development of information technology, wireless communication has become popular, but our usual monitoring method is still contact-based. The disadvantages of contact monitoring are: contact control mostly transmits the collected information remotely through a wired network, which is costly and greatly limits the scope of use; it has a narrow scope of application and poor flexibility, and is more difficult to play a role in some high-risk and inconvenient places where personnel are directly monitored; with the continuous development of modern electronic technology, the means of cracking contact monitoring are increasing, which greatly reduces the safety performance of contact monitoring. With the vigorous development of social economy and the improvement of living standards, people have put forward newer requirements for personal and property safety while pursuing the quality of life, so new and more superior anti-theft alarm systems have become a mainstream of market demand. This system is a new monitoring alarm system based on satellite positioning and 4G technology developed to address the shortcomings of traditional monitoring alarm products, which is used to achieve long-distance, accurate and real-time monitoring alarm and navigation positioning.

This system uses the car as the development platform. By installing sensor monitoring devices, it collects information and transmits it to the control system centered on the single-chip microcomputer. After analysis and processing, the alarm information is notified to the user through the GSM (Global System for Mobile Communications)/GPRS (General Packet Radio Service) network through telephone, SMS (Short Message Service) or MMS (Multimedia Messaging Service), thereby realizing long-distance, accurate and real-time alarm. The GPS (Global Positioning System) on the market can achieve accurate positioning and general navigation, but the core technology of GPS is in the hands of the United States. If the United States closes the application in the event of a war, the consequences will be disastrous, especially not conducive to military use. Therefore, we use GPS and the "Beidou Double Star" dual-mode navigation and positioning technology independently developed by China.

1. Hardware system

This system consists of 5 parts: MCU control module, data acquisition module, information receiving and sending module, GPS module and Beidou Double Star positioning module. The data acquisition module uses different sensors to send the collected signals to the MCU. After analysis and processing, the MCU sends control information and alarm instructions to the GSM module, and then transmits alarm information to the user through the GSM/GPRS network or Beidou Double Star to achieve the purpose of monitoring and alarm. The system will take actions such as remote warning, remote photography and oil line cutting to ensure vehicle safety according to the user's decision. At the same time, the system also uses the dual-mode positioning method of GPS and Beidou dual-star to achieve all-weather, high-precision real-time navigation positioning, with a positioning accuracy of 3m to 10m.

MCU realizes physical connection with GSM, GPS and Beidou dual-star terminals in serial communication, and has an RS-232 serial communication interface with PC. Beidou dual-star positioning terminal is used to achieve rapid positioning, and the location information is sent to users and central stations through GSM or dual-star short communication. At the same time, the two-way short message communication function of Beidou satellite can realize regional alarm.

1.1 MCU control module

This module receives, analyzes and processes sensor alarm information and user control information, and is the core component of this system. Its design includes power supply part, level conversion part, memory design part and external interface part (including sensor signal input, MCU control external device signal output display, and communication interface between MCU and Beidou dual-star positioning module and GSM module).

1.2 Data acquisition module

There are many types of sensors available in the data acquisition module, such as vibration sensors, pressure sensors, switch type and disconnection type sensors. When the car is vibrated, the door is opened or someone sits in the seat, different information will be generated. The different data and information collected by these sensors are input into the system MCU for subsequent processing. The

design idea of ​​this module is to make full use of the existing safe and mature products on the vehicle as part of the system. Its advantages are: the system security and stability will be greatly improved; the system status control problem can be better solved. If only considering the use of mobile phone text messages for defense and disarming, it is not only inconvenient, but also the long-term additional information costs cannot be ignored; it can be modified on the original basis to reduce the cost of the product, and at the same time, the existing vehicle-mounted equipment can be reasonably and effectively used to make resources reasonably and effectively configured.

1.3 Information receiving and sending module

With the GSM module as the core, the information interaction between the system and the user is realized, and the function of sending alarm information and receiving user responses is played in the system. The module communicates data through the GSM network, without setting up an operation center, which greatly reduces the production and promotion costs. The design idea of ​​this module is: use the GSM module with good openness, and strictly implement the European Telecommunication Union's GSM0707, GSM0705, GSM0338 and other specifications and protocols to facilitate system software development and enhance the versatility of system software.

1.4 GPS module

GPS technology is mature in both military and civilian applications. By using GPS and Beidou dual-star dual-mode positioning methods, the accuracy of navigation positioning can be greatly improved.

1.5 Beidou dual-star positioning terminal

This terminal is used to achieve rapid positioning, and the location information is sent to the user and the central station through GSM and dual-star short communication, and the dual-star short communication is used to achieve regional alarm. The main functions are: rapid positioning, providing all-weather, real-time positioning services for users in the service area, and the positioning accuracy is equivalent to GPS; short message communication, which can transmit up to 120 Chinese characters at a time; precise timing, with an accuracy of 20ns.

2. Software Design

This system software is mainly designed and edited with reference to the European Telecommunications Union's GSM0707, GSM0705, GSM0338 and other specifications and protocols, combined with the standard AT instruction set, and realizes two-way communication between MCU and GSM module, CPS module and Beidou dual-star navigation and positioning terminal through RS-232 serial port transceiver. After a large number of tests, the software runs stably on the system, and its versatility and portability are very good. System software design process.

The main process and related procedures are described as follows:

a) First, initialize the MCU to make it enter the normal working mode. The program controls the GSM module through the MCU's UART interface. The serial port initialization function is serial-init(). The MCU and GSM module, Beidou dual-star navigation and positioning terminal, GPS module and PC's external display processing interface are defined and explained in detail. At the same time, the input or output mode of the corresponding sensors and control pins is correctly set.

b) In order to correctly establish the communication between MCU and GSM module, detect the serial port communication rate. After setting MCU reasonably, the microcontroller sends out ATE detection signal. If the communication is not established correctly, continue to detect and wait for GSM to respond OK to confirm that the communication is established normally.

c) In order to make the GSM module work under the conditions that meet the user's requirements, it needs to be initialized, including turning off vibration and ringtones, setting SMS memory, mode, prompt method, etc.

d) Entering the working mode, including two aspects of work:

one is to detect each sensor, first detect the sensor with a high alarm level. If an alarm signal is sent, the MCU controls the editing and sending of mobile phone text messages (or calls) to notify the user;

the second is to detect whether there is a new text message or an incoming call. If there is, read it back and decode it to execute the command sent by the user through the text message or control the GSM module to automatically answer after verifying the user's call. Since there are inevitable errors when reading a large amount of data from the serial port, in order to prevent the execution of wrong commands, the MCU will read the same text message twice in a row. The command in the text message will be executed only if the two times are the same, otherwise the text message will be read again.

3. System functions and performance

a) User password setting: Users can edit the text message "Change password****" to the GSM module. After the user receives the text message feedback "Execution successful" or "Execution failed", he can know the execution status of the password change.

b) Change user: Users can edit the text message "Change user****" (the last 4 digits are the set password) and determine the result when the user receives the text message feedback.

c) SMS alarm: When the vehicle safety is threatened by the outside world, the on-board sensor collects information and passes it to the MCU to determine the threat level, and then sends a command to control the GSM module to edit mobile phone text messages such as "door open" and "car stolen" to notify the user at the first time.

d) MMS image monitoring: When the user receives the message that the vehicle safety is threatened, he can edit the text message "take a photo" to the car phone. After receiving the command, the MCU controls the GSM module to take a photo and send it to the user through the GPRS network at the first time, so that the user can understand the specific situation of the vehicle safety.

e) Remote monitoring and shouting warning: When the user receives an alarm SMS, he can directly call the car phone, and the system will automatically connect the phone to facilitate the user to monitor, or use the system's built-in amplifier and speaker to amplify the warning.

f) Remote braking: When the user receives a text message or finds that the vehicle is threatened through telephone monitoring, he can edit the text message "turn off" to the car phone, and the system will automatically cut off the oil line to stop the car.

g) Remote control warming up the car: The user can edit the mobile phone text message "warm up the car" to the GSM module, and the MCU will control the existing relay to warm up the car in advance.

h) Beidou dual-star navigation and positioning: fast positioning; short message communication; precise timing.

i) Regional communication and alarm: When the system of a certain car detects a dangerous situation, it can use the short communication function of Beidou dual-star to send an alarm message to the neighboring system, jointly improve the safety protection level and prevent the spread of the dangerous situation.

j) GPS and Beidou dual-mode positioning: The system has an external interface for the GPS module, which can use GPS combined with the positioning data of Beidou dual-star to perform differential comparison to obtain more accurate navigation and positioning information.

k) With the continuous development of GIS (Geographic Information System), the system information processing capability will be continuously improved, and more efficient real-time navigation positioning and tracking can be achieved.

4. Conclusion

This design is a new high-tech monitoring alarm and navigation positioning product that integrates traditional vehicle-mounted anti-theft alarm unit, Beidou dual-star navigation positioning terminal, GPS module, GSM/GPRS network and GIS. The system meets the urgent needs of the majority of users in terms of function, practicality, reliability and ease of use. At the same time, with the rapid increase in the demand for private cars in China and the rapid development of the economy, the market prospect of this system is very broad and the market potential is huge!