With the development of information technology, wireless communication has become popular, and our usual monitoring methods are still contact. The disadvantage of contact monitoring is that most of the contact control uses the wired network to transmit the collected information remotely, which has a high cost and greatly limits the scope of use. It has a narrow application range and poor flexibility. In some occasions where high-risk and inconvenient personnel directly monitor It is more difficult to play a role; with the continuous development of modern electronic technology, the means of cracking contact monitoring is increasing, which greatly reduces the safety performance of contact monitoring. With the vigorous development of the social economy and the improvement of living standards, people have put forward updated requirements for personal and property security while pursuing the quality of life. Therefore, a new type and more superior anti-theft alarm system has become a mainstream market demand. This system is a new type of monitoring and alarm system based on satellite positioning and 4G technology developed for the shortcomings of traditional monitoring and alarm products. It is used to achieve long-distance, accurate and real-time monitoring and navigation and positioning. This system uses a car as a development platform. Through the installation of a sensor monitoring device, the collected information is passed to the control system centered on the single chip microcomputer. After analysis and processing, it will pass the GSM (Global System for Mobile Communications) / GPRS (General Packet Radio Service) network. The alarm information is notified to the user through telephone, SMS (short message service) or MMS (multimedia information service), etc., so as to realize long-distance, accurate and real-time alarm. GPS (Global Positioning System) on the market now can achieve precise 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 war, the consequences will be disastrous, especially not conducive to military use, so We have adopted 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 collection module uses different sensors to send the collected signals to the MCU. After the MCU analyzes and processes the MCU, it sends control information and alarm instructions to the GSM module, and then transmits the alarm information to the user through the GSM / GPRS network or Beidou Double Star to achieve the monitoring alarm. the goal of. According to the user's decision, the system will take actions such as remote shouting and warning, remote photographing and oil cut off to ensure the safety of the vehicle. At the same time, the system also uses GPS and Beidou double-star dual-mode positioning method to achieve all-weather, high-precision real-time navigation positioning, positioning accuracy can reach 3 m ~ 10 m. The MCU realizes the physical connection with the GSM, GPS and Beidou Double Star terminals through serial communication, and the one with the PC is reserved. RS-232 serial communication interface. Use the Beidou double-star positioning terminal to achieve fast positioning, and send the location information to the user and the central station through GSM or double-star short communication. At the same time, the Beidou satellite's two-way short message communication function can realize regional alarm. The overall design block diagram of the system is shown in Figure 1. 1.1 MCU control module This module plays the role of receiving, analyzing and processing 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, communication interface between MCU and Beidou Shuangxing positioning module and GSM module). 1.2 Data collection module A variety of sensors are available in the data acquisition module, such as vibration sensors, pressure sensors, switch-type and disconnection sensors, etc. When the car is subject to vibration, the door is opened, or someone is sitting on the seat Different information will be generated, and the different data and information collected by these sensors will be 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 in the vehicle as the system part. Its advantages are: the system security and stability will be greatly improved; it can solve the system status control problem well. If only considering the use of mobile phone SMS for arming and defensive, not only is it inconvenient, but also the long-term additional information costs can not be ignored ; It can be modified on the original basis to reduce the cost of the product. At the same time, it can also use the existing on-board equipment reasonably and effectively, so that the resources can be reasonably and effectively allocated. 1.3 Information receiving and sending module Taking the GSM module as the core, the information interaction between the system and users is realized, and the functions of sending alarm information and receiving user responses are played in the system. The module performs data communication through the GSM network without the need to set up an operation center, which greatly reduces the cost of production promotion. The design idea of ​​this module is: use a better open GSM module, 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 very mature in military and civilian applications. By using GPS and Beidou dual-star dual-mode positioning methods, the accuracy of navigation and positioning can be greatly improved. 1.5 Beidou Double Star Positioning Terminal Use this terminal to realize fast positioning, and send location information to users and central station through GSM and double star short communication, and use double star short communication to realize regional alarm. The main functions are: fast positioning, providing all-weather, real-time positioning service for users in the service area, and the positioning accuracy is comparable to GPS; short message communication can transmit information of up to 120 Chinese characters at a time; precision timing, accuracy reaches 20 ns. 2 Software design This system software mainly refers to the GSM0707, GSM0705, GSM0338 and other specifications and protocols of the European Telecommunication Union, which is designed and edited in combination with the standard AT instruction set, and realizes the MCU and GSM module, CPS module and Beidou Double Star Navigation through the RS-232 serial port transceiver Two-way communication of positioning terminal. After a lot of experiments, the software runs stably on the system, and its versatility and portability are very good. The flow chart of system software design is shown in Figure 2. 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