The Research And Development Of A-GPS Based Hybird Positioning Terminal System

In the near future, mobile positioning will become another dominant mobile service, which is only second to voice service and which can be applied to such fields as tracking, navigating and security. The hybrid positioning system researched and designed in this article is based on GPS system and GSM/GPRS mobile communication network. It provides services for various positioning operations in the market.Hybrid positioning system consists of hybrid positioning terminal and hybrid positioning server. User device that initiates request is a third party device which has customized the hybrid positioning system service. The third party device can be a mobile phone. The data interaction among positioning server, positioning terminal and user device is on the basis of current mobile communication network and is implemented by means of short message and GPRS data. Positioning terminal includes GPS modules that can communicate with GPS satellite and GSM/GPRS modules that can communicate with mobile communication network. After user initiates request, the positioning terminal collects the positioning parameters from satellite and sends them back to positioning server, which, then, calculates the positioning result and returns it to user.This article firstly introduces the positioning principle of GPS and illustrates the application of GPS system in hybrid positioning system. Then it presents the network architecture and work flow of hybrid positioning system, among which the key point is the hardware research and development of hybrid positioning terminal. After that, Chapter 4 lays emphasis on the hardware design and implementation of hybrid positioning terminal. It illustrates, in detail and separately, hardware design object, terminal operating principle, hardware architecture, main functions needed to be designed and implemented, as well as PCB design. On the basis of sufficient research and elaborate design over related hardware, we have finished making the board to implement the hardware system of hybrid positioning terminal given to experimenting, which, via testing, completely meets the preconcerted designing object, and which proves the validity of interrelated theories discussed in this article.