New monitoring and alarm system based on satellite positioning and 4G technology

This system is a new monitoring and alarm system based on satellite positioning and 4G technology developed to address the shortcomings of traditional monitoring and alarm products. It is used to achieve long-distance, accurate and real-time monitoring and alarm and navigation positioning.

This system uses the car as a 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 a war breaks out and the United States closes the application, 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 my country.

1 Hardware System

The system consists of MCU control module, data acquisition module, information receiving and sending module, GPS module and Beidou dual-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 the alarm information to the user through the GSM/GPRS network or Beidou dual-star to achieve the purpose of monitoring and alarm. The system will take actions such as remote shouting, remote photography and cutting off the oil line according to the user's decision to ensure vehicle safety. 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 and positioning, with a positioning accuracy of 3 m to 10 m.

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

The overall system design block diagram is shown in Figure 1.

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, level conversion, memory design and external interface (including sensor signal input, MCU control external device signal output display, 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 sensors, disconnection sensors, etc. 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; it can better solve the problem of system status control. 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, it can reasonably and effectively use the existing vehicle-mounted equipment 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 system plays the role of sending alarm information and receiving user responses. 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 to use the GSM module with good openness and strictly implement the European Telecommunications 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 has mature applications in both military and civilian fields. By using the dual-mode positioning method of GPS and Beidou dual-star, the accuracy of navigation and 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 users and central stations through GSM and dual-satellite short communication, and regional alarm is realized by dual-satellite short communication. The main functions are: rapid positioning, providing all-weather, real-time positioning services for users in the service area, with positioning accuracy comparable to GPS; short message communication, which can transmit up to 120 Chinese characters at a time; precise timing, with an accuracy of 20 ns.

2 Software Design

The 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. The system software design flow chart is shown in Figure 2.

The main processes and related procedures are described as follows:

a) First, the MCU is initialized to make it enter the normal working mode. The program controls the GSM module through the UART interface of the MCU. The initialization function of the serial port is serial-init(). The MCU and GSM module, Beidou dual-star navigation and positioning terminal, GPS module and the external display processing interface of the PC 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 the MCU properly, the microcontroller sends an ATE detection signal. If the communication is not established correctly, continue to detect and wait for the GSM to respond OK to confirm that the communication is established normally.

c) In order for the GSM module to work under conditions that meet user 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:

First, detect each sensor, first detect the sensor with a high alarm level. If an alarm signal is sent, the MCU will control the editing and sending of text messages to the mobile phone (

or call) to notify the user;

The second is to detect whether there is a new SMS or incoming call. If there is, read it back and decode it to execute the command sent by the user through SMS or control the GSM module to automatically answer the call 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 repeatedly read the same SMS twice in succession. If the two times are the same, the command in the SMS will be executed, otherwise the SMS will be read again.

3 System Functions and Performance

a) User password setting: The user 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 will be informed of the execution status of the password change.

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

c) SMS alarm: When the vehicle safety is threatened by external factors, the on-board sensors collect information and pass it to the MCU to determine the threat level. It then sends instructions to control the GSM module to edit mobile phone text messages such as "door open" and "car stolen" to notify the user as soon as possible.

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

e) Remote monitoring and warning: When the user receives an alarm text message, he can directly call the car phone. The system will automatically connect the call 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 discovers that the vehicle is threatened through phone monitoring, he can edit the text message "shutdown" to the car phone, and the system will automatically cut off the oil circuit and stop the car.

g) Remote control warm-up: Users can edit the text message "warm-up" to the GSM module, and the MCU will control the existing relays 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 a car's system detects a dangerous situation, it can use the Beidou dual-star short communication function to send alarm information to neighboring systems to 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 the positioning data of GPS and BeiDou to perform differential comparison to obtain more accurate navigation and positioning information.

k) With the continuous development of GIS (Geographic Information System), the system's information processing capabilities will continue to improve, enabling more efficient real-time navigation, positioning and tracking.

4 Conclusion

This design is a new high-tech monitoring alarm and navigation positioning product that integrates traditional vehicle-mounted anti-theft alarm units, Beidou dual-star navigation and positioning terminals, GPS modules, GSM/GPRS networks 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 demand for private cars and the rapid development of the economy in my country, the market prospects of this system are very broad and the market potential is huge!