Design And Implementation Of Parking Vehicle Detection System Based On Inductive Magnetic Sensor

With the rapid improvement of people's living standards,vehicles are the main means of transportation for people.According to data released by the Ministry of Public Security,as of the end of 2018,the number of motor vehicles in China has exceeded 300 million.However,the number of parking spaces in China is far less than the number of vehicles.The problems of travel time wasted,environmental pollution and even traffic accidents caused by "difficult parking" are not uncommon.As a result,"difficult parking"has become a topic of great concern to the society.Although local governments have introduced lots of parking management policies,these policies have had little effect.In order to solve the problem of "difficult parking",experts from all walks of life have set their sights on the way of smart parking.Smart parking refers to the use of information technology to make "Smart Location" and "Smart Payment" more convenient,using the Internet and the Internet of Things to make the parking process more intelligent."Smart Location" uses technology of the Internet of Things and wireless sensor networks to detect parking spaces and send relative information,so that owners can remotely view the number and location of all vacancies and choose the optimal solution.The key to "Smart Location" is the detection of parking spaces.The current detection methods include induction coil detection,video detection,ultrasonic detection,radar detection and geomagnetic detection.Among them,geomagnetic detection stands out among many detection methods with its many advantages.It has been widely favored by researchers in the industry.However,at present,all vehicle detection technologies still have many problems such as missed detection and misdetection false detection.In-depth discussion of this issue,accelerating the landing of smart parking has important application value to solve the "difficult parking" problem as soon as possible.This thesis puts the eyes on the outdoor parking lot and designs and implements the vehicle detection system based on the inductive magnetic sensor.The main completed contributions in this thesis are:(1)Design and implement a parking space vehicle detection hardware circuit with inductive magnetic sensor,which consists of two parts.One part is magnetic field data acquisition and processing part composed of inductive magnetic sensor and MSP430.The other part is LoRa transceiver part composed of STM32 and SX1276 and RF circuit.(2)Propose a parking vehicle detection algorithm based on geomagnetic field by analyzing the research of the influence of vehicles to the earth's magnetic field.The geomagnetic field data changing status on the parking space is divided into steady state and fluctuating state.And the change process of park:ing space state is abstracted into a state transition model with hidden state process.The vehicle detection results are calculated by data processing of different states.(3)Complete the construction of the parking space vehicle detection system,including the postgreSQL-based database and the Windows Forms-based client sofrtware.And complete the gateway uploading packet processing on the server.Users can access the database on the server through the client software,and view the number and location of all the parking spaces in the parking lot in real time,and can issue commands to remotely control the designated nodes.(4)Test the functions of the detection node and the system.The system function test includes the function of vehicle detection and the function of the client software.And the detection node test includes the power consumption of the node,the vehicle detection accuracy and stability under various interference conditions.After testing,the vehicle detection accuracy rate is 98%.