The Study Of TDOA Location Algorithm Based On Mobile Broadcast Networks

With the development of wireless technology, mobile positioning terminal provides fast and high accurate position information, which really brings convenience to people’s lives. Although the satellite positioning has been widely used in the military and civilian aspects with its high precision and efficiency, it still has many shortcomings, such as high cost, poor indoor positioning performance and so on. In recent years, with its convenience, massive base stations and users and other advantages, wireless position technology based on mobile networks has developed significantly and rapidly, making it possible for people to obtain the necessary location information more conveniently, timely and accurately.In a variety of mobile networks, mobile communication system makes the cost of location services more expensive because of its scarcity of bandwidth resources. However, mobile broadcast networks uses multipoint communication with high bandwidth efficiency, so each user shares lower service cost, and its advanced modulation technology brings better ability of anti-multipath, what’s more, it has the advantages of wide coverage, good signal transmission. Moreover, it has good universal of application and promotion by using ordinary mobile phones as a carrier. Positioning based on mobile broadcast networks may has good value and will have broad application and market prospects on LBS, such as personal service and traffic information extraction.The study of TDOA algorithm based on the mobile broadcast networks in this dissertation includes: (1) Provide TDOA location algorithm with NLOS elimination based on Kalman filter to get reconstructed TOA value of LOS environment in positioning system of mobile broadcast networks. This algorithm can greatly improve the accuracy of location service in NLOS environment of the wireless communication.(2) In the complex environment, the accuracy of TDOA measurement is not easy to improve because of the channel error, especially in indoor environment. So after the collection and analysis of the wireless signals propagation time delay values and received signal strength indication values, a location method based on the feature of grids in service area is proposed. The values of the wireless signals from the base station nearby to the mobile terminal are used as the feature of grids. And the signal complement method in the indoor environment and the smoothing method with Kalman filter improved the positioning precision further. With this algorithm, the positioning system of mobile broadcast networks can achieve higher accuracy and greater environmental adaptability.In summary, the study of TDOA location algorithm based on the mobile broadcast networks helps greatly to the development of national high accuracy positioning system based on mobile broadcast networks.