Shenzhen professional truck GPS positioning system wholesale
Shenzhen professional truck GPS positioning system wholesale_Motorcycle GPS positioning system to join
<br><br><br><br><br><br><br><br><br><br><br><br><br> How to choose and use the anti-theft device There are many kinds of anti-theft devices on the market, ranging from simple door locks to complete anti-theft systems, different vehicles and different driving habits. The requirements for anti-theft devices are not the same, and it is also very important to identify the anti-theft devices. It depends on whether the sales or installation shop is qualified to operate and install the anti-theft device. Is the purchased anti-theft device marked with the name of the place of production? Anti-theft device manufacturer's authorization and warranty card, etc. If divided according to the structure, car alarm can be divided into mechanical, electronic and network, biometric four categories. Here we will introduce one by one from these four aspects, to see what kind of car alarm your car is suitable for. Mechanical anti-theft is the main principle is to lock a car on a body so that it can not play its due role. There are a variety of existing methods such as: transmission gear locks, steering wheel locks, brake pedal locks, clutch pedal locks, etc. The trouble is that the mechanical lock has a large size, and the owner must carry a key with him. Through these anti-theft locks to lock the car's operating components, so that thieves can not drive away the car. However, there are many ways to crack, because the core is a lock, which can not stop the door. Even more brutal means such as hydraulic shears ... Electronic anti-theft devices are also available in the roadside shop, the price is also about 100-200 yuan, but due to the frequency of use of such electronic anti-theft alarm is generally limited to In the amateur frequency band of 300~350MHz, there are many sources of electronic wave interference in this frequency band. Radio waves, lightning, industrial welding, etc., as well as wind disturbances, will interfere with it and cause false alarms. At present, it tends to be eliminated. Network-type anti-theft network-based car anti-theft system is currently more popular and more advanced and practical in the world. It is a new type of automobile anti-theft method that fully summarizes the previous several anti-theft methods. There are two main types: One is the global satellite positioning, and the CAS anti-theft system for locating and tracking vehicles through wireless transmission via GSM and anti-theft and robbery. It is commonly called "ground network". The biggest advantage of this type of anti-theft system is that it changes the single anti-theft function of the traditional anti-theft device, and adds the air defense function. It can over-build the sky and ground “net” to promptly alarm and track the vehicle, thus making the police quicker. The police chased down the stolen vehicle. GPS terminal The GPS terminal is the front-end equipment of the GPS monitoring system. It is usually installed in various vehicles or worn on people or pets. The GPS terminal equipment is mainly composed of the main CPU, GPS module, GPRS module, I/O interface and peripheral circuits. composition. Monitoring Platform The monitoring platform is the core of GPS monitoring and is a remote visual command and monitoring management platform. Once a GPS monitoring device is installed on a vehicle or a GPS monitoring device is worn on a person, the GPS module on the device will drive the vehicle or person in real time. The location information is sent to the monitoring center through the wireless network. The visual location of the vehicle, person or pet can be seen on the electronic map of the monitoring center. The monitoring center can remotely monitor the vehicle, person or pet through the wireless network. The device performs settings, such as setting an upload interval by issuing commands, rebooting the device remotely, and so on. The transmission network can use GPRS wireless communication network or CDMA wireless communication network, or can use short message mode for data transmission. The positioning of GPS originally understood that in the fifties, the former Soviet Union launched the first man-made earth satellite. In the course of its follow-up study, American scientists discovered the phenomenon of multiple frequency shifts and used this principle to promote multiple pu. The establishment of the LEU satellite navigation and positioning system TRANSISIT has achieved great success in military and civil use. It is a leap in the navigation and positioning history. China has also introduced multiple multi-pull receivers for the sea island joint survey and earth exploration. And other fields. However, due to the low orbit height of multi-pull satellites and the low frequency of signal carriers, it is difficult to improve the orbital accuracy, which results in low positioning accuracy, so as to meet the requirements of geodetic survey or engineering survey, it is even more difficult to be used for astronomical geodynamics research. In order to improve the accuracy of satellite positioning, the United States has been planning to establish the Global Positioning System (GPS) since 1973. After going through the program demonstration and system test phase, it started launching a working satellite in 1989 and completed it in 1994 and put into use. The space portion of the GPS system consists of 21 satellites and is evenly distributed on 6 orbital surfaces. The ground height is more than 20,000 kilometers, the orbital inclination is 55 degrees, the flat heart rate is about 0, the period is about 12 hours, and the satellite launches to the ground. The carrier signal of the two bands, the carrier signal frequency is respectively 1575.442 MHz (L1 band) and 1227.6 MHz (L2 band). The atomic clock with high accuracy is installed on the satellite to ensure the stability of the frequency and the modulation is expressed on the carrier. Satellite broadcast ephemeris, ranging C/A and P code, and other system information, can provide high-precision, all-weather, continuous, real-time three-dimensional speed measurement to any number of users worldwide , three-dimensional positioning and timing. The control part of the GPS system consists of five monitoring stations located in the United States. These stations continuously observe the GPS satellites and update the calculated and forecasted information from the injection station to the satellite information. The user of the GPS system is very covert. It is a one-way system where the user only receives and does not have to transmit signals, so the number of users is also unlimited. Although the GPS system was initially established for military purposes, it has rapidly grown in civilian use. Various types of GPS receivers and processing software have emerged. At present, receivers appearing on the market in China mainly include NovAtel, ASHTECH, TRIMBLE, and CMC. A receiver capable of observing two frequencies is called a dual-frequency receiver. A receiver that can only observe one frequency becomes a single-frequency receiver, and they all have large differences in accuracy and price. <br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br> Overview Terminal equipment includes: control unit (CPU), display unit (optional), GPS receiver, GSM mobile phone (or other communication modules: such as Siemens TC35 or MC35, but redesigned peripheral circuits based on the handset module interface), burglar alarm (optional). The main functions are: (1) Anti-theft alarm function: When an emergency occurs, the user can trigger a hidden alarm button. The vehicle-mounted unit will automatically transmit the position data in the GPS receiver to the monitoring center through the short message function of the GSM mobile phone. Anti-theft activation function, when the vehicle encounters illegal intrusion, automatically sends alarm information to the control center; (2) Navigation function: GPS provides accurate data such as position, speed, and direction of the moving target. No differential positioning accuracy is about 10m, and the differential accuracy is 3-5m. The system can navigate through the dispatch center or store electronic maps on the terminal. (3) Calling function: Car GSM mobile phone can make a call. When the user leaves the car, the mobile phone can also be used normally. (4) Service: Provides a set of service buttons. When the car owner needs the service, he presses the corresponding button and the service center provides the service. (2) The GPS differential reference module in the monitoring center of the monitoring center is used to generate differential correction information and sent to the middle yang processor; the yang processor will manage the database and various scheduling, command information and differential correction information will be passed through the GSM communication module. Send to each vehicle unit, and send the information sent by each vehicle unit to the electronic map or database for storage; the electronic map of GIS module of GIS will accurately display the real-time position of all monitored vehicles; GSM communication module The function is to send the command and differential correction signal sent by the middle yang processor to each onboard unit and receive the GPS information and sensor information of the vehicle sent by each onboard unit. (3) GSM Communication Service System The GSM communication service system consists of a GSM communication module and a GSM communication network. Its function is mainly to transmit data between the on-board unit and the monitoring center to ensure vehicle GPS information and sensor information sent by each onboard unit. The instructions sent by the yang processor and the differential correction signals are transmitted stably between the on-board unit and the monitoring center. Communication software uses VC++ to achieve: COMM_SEVER and COMM_CLIENT communication using WINSOCK components.