Vehicle navigation and GPRS network monitoring based on GPS

Absrtact: This paper introduces an electronic navigation and remote monitoring system based on the combination of GPs and GPRS. The position information data of the GPS module output is sent to the micro industrial computer through the RS-232 serial interface, the GIS running on the industrial control computer shows the current position of the vehicle, realizes the autonomous navigation, meanwhile, uses the GPRS wireless communication module to send the information of the vehicle Terminal GPS module to the Remote Data Service center The remote real-time monitoring and scheduling is realized.

Introduction

In recent years, the demand for effective monitoring, emergency rescue and the provision of various information services for mobile and numerous moving targets has been particularly prominent in the fields of passenger transport, public security, banking and logistics. The advent of Universal Packet Radio Service (GPRS) enables people to carry out nationwide, real-time and all-weather monitoring and scheduling of mobile targets. The combination of GPS positioning technology and GPRS has a wide application prospect.

System Structure

The whole positioning and navigation monitoring system consists of two parts, namely, the vehicle terminal (including micro-industrial computer, touch screen, GPS receiving module, GPRS communication module and power supply) and the Monitoring Data Center DSC (TCP/IP network server).

The GPS module of the vehicle terminal receives the position and time of the Global Positioning satellite, on the one hand, sends the micro-board computer to the car, obtains the vehicle's current position and displays on the electronic map; On the other hand, the data will be sent to the remote Monitoring Center server via the GPRS terminal module, The Monitoring center can obtain the position information of all vehicles in real time, and provides the basis for the vehicle safety monitoring and remote dispatching.

Car Terminal

The vehicle terminal hardware composition is shown in Figure 1.

Fig. 1 schematic diagram of hardware composition of vehicle terminal

GPS receiver Module

GPS consists of three parts, space constellation, ground monitoring and user receiver part. The space constellation is composed of 24 navigation satellites, which is equivalent to providing 24 known space points. The ground monitoring part is used to monitor the state of the satellite and to revise the satellite orbit information. The user receiver is used to receive the satellite signal and complete the analysis and calculation of the signal to obtain the necessary navigation and positioning information.

This paper chooses the Lassen SQ/IQ series GPS receiver module of Tianbao (Trimble) company. The data format supported by this module is TSIP and NEMA0183, and in the current software system, the data in NEMA0183 format is usually used. The NEMA 0183 protocol allows a signal source to send data in serial communication to one or more receivers via a twisted pair of cables.

Micro Industrial Control Machine

GPS module data through the RS-232 serial port directly to the micro-industrial control machine, through the industrial control computer running on the electronic map software, can show the current location of the vehicle and the main geographical location. Micro-industrial control machine not only has the common computer all functions, and has a very high integration, small size, light weight, easy to install.

GPRS Communication Module

The vehicle terminal is embedded in the GPRS communication module, it sends the position information of the GPS receiving module to the remote Database Monitoring center in real time, realizes the monitoring and dispatching of all vehicles.

As a monitoring and dispatching system, we must first consider the requirements of coverage, real-time, scheduling, vehicle capacity and refresh rate, select the appropriate wireless data link and electronic map, and develop the corresponding business software. The GPRS/IP/TCP/UDP protocol stack can realize the real-time exchange of data, and has the largest bandwidth in the existing public wireless communication system, compared with the current popular short message transmission mode, the communication cost of the same data length and the same time interval is 1/6, or even less. This paper uses the GPRS DTU H7000 Series Wireless communication module of Shenzhen Wang Electric Company to realize GPRS network connection and data transmission. When the wireless communication module is logged to the GPRS network, the position information of the GPS receiving module will be sent to the remote Monitoring Center for monitoring and dispatching use in real time.

Software design of monitoring Center

The Monitoring Center is a network server with a public network IP address, by writing data center monitoring system software (mainly composed of communication module, electronic map database, vehicle information database, etc.), the Monitoring center will receive the data sent by the vehicle terminal through the wireless communication module in real time, and analyze and store it, The position and motion status of all vehicles are displayed on the electronic map. And for different situations to prompt and alarm.

Monitoring Center can also adopt the Webgis technology, using C/s or b/I framework, monitoring Center and data server can be in different physical locations. Because the data server to the equipment reliability and the corresponding operation, the maintenance request is high, therefore from the economic efficiency, constructs a data server to the hardware and the software request is very high. Can take advantage of the current. NET Technology Network Service, through the local monitoring center to access the data server, to obtain data information, send commands and so on.

This article uses Microsoft Visual C #. NET as the development platform, using the dynamic development Library of the Shenzhen Macro-electric GPRS module, the dynamic Development library provides some operation functions used in the GPRS wireless communication process. The important structure in the development package is as follows:

1. Terminal module Registration information interface Structure
typedef struct GPRS_USER_INFO
{
Char m_userid[12]; Terminal module number
UInt32 m_sin_addr; Proxy host IP address for terminal module access to the Internet
UInt16 M_sin_port; Proxy host IP port for terminal module access to the Internet
UInt32 m_local_addr;//Terminal module in mobile network IP address
UInt16 m_local_port;//Terminal module in mobile network IP port
Char m_logon_date[20]; Terminal Module logon time
Char m_update_date[20]; Terminal Module Update time
Uint8 M_status; Terminal module Status
}user_info;

2. Data packet Interface Structure
typedef struct GPRS_DATA_ Record
{
Char m_userid[12]; Terminal module number
Char m_recv_date[20]; The time that the packet was received
Char m_data_buf[1024]; Store received data
UInt16 M_data_len; Packet length received
Uint8 M_data_type; Packet Type received
}data_record;

Conclusion

The system integrates GPS satellite positioning technology and GPRS wireless network transmission technology, and applies them in vehicle navigation and monitoring scheduling.
The system can be applied to all kinds of operating vehicles, and now it has been used in two-person and no-power sightseeing touring car, and has achieved good results.

Reference Documents
1 Trimble Company, Lassen SQ GPS Receiver System Designer Reference manual[m], Revision A, U.S.: June 2002
2 Jean-lien C. Wu, Wei-yeh Chen, Hung-huan Liu, Radio Resource allocation in Gsm/gprs Networks, lecture Notes in Computer Science, Volume 2343/2002, January 2002, pages:457-468