Based On 3G Wireless Localization Engineering Research And Practice

Wireless location technology research began in the 1960s of Automatic Vehicle Location System, and then the technology in the public transport, taxis scheduling and tracking, and other public security within the framework of wider application. In recent years, with cellular mobile communications systems and the further development of universal, we can use signal strength, carrier phase, signal arrival angle measurements and time parameters, such as composition and positioning of their estimates, the results obtained users the position, as LBS systemLBS standards by 3GPP and 3GPP2, and LIF Forum. 3GPP was established in December 1998 by the European ETSI, Japan ARIB and Korea TTA and the United States T1, and other components. In 1999 in January, 3GPP2 also officially established, the TIA from the United States, Japan ARIB, Korea TTA, and other components. The three organizations to develop a commonality of the LBS system, regardless of any standard phone can be realized.3GPP formulated a three Positioning Method: CELL ID, OTDOA and A-GPS. CELL ID positioning technology is the most simple positioning technology, it is through the principle of access to the cellular phone goals district ID to determine the location in which it is providing to the positioning users. Simple CELL ID method can not consider accuracy, so get the positioning error is the size of a honeycomb. This method does not need to achieve the existing networks to make any changes, despite the great error, it is economic. OTDOA location method is the basic principle: mobile station measuring different base station downlink pilot signals are different from the base station downlink pilot TOA (Time of Arrival, arrived moments), the so-called pilot phase measurement. According to the survey findings, and coordinates with the base station using a suitable location estimation algorithm, we can calculate the location of mobile units. But the many complex algorithms, in the suburbs and rural mobile station will be located in 10 to 20 m range; positioning in the City of 100 ~ 200 meters. A-GPS positioning means steps are as follows: GPS-supported network received information network will complement the information sent to the phone; phones are GPS information, calculate and draw their own precise location of cell phone location information will be sent to the core network. A-GPS positioning methods in urban areas the range of 50 meters around, but the relatively high terminal requirements, the need to install GPS receiver devices, increased operating costs.LBS system targets mobile terminals in accordance with the location of mobile terminals to provide objective information surrounding environment, including: navigation maps, traffic conditions, weather forecasts, restaurants, hotels, shopping malls, post offices, telecommunications bureau, banks, hospitals, tourist attractions, gas stations, car parks, and other mobile users need access to environmental information services. Experimental Bureau in Changchun opened Find friends location information services, vehicle management systems and MMS and positioning technology integration services. OTDOA technology used by signal arrival time measurements or measurement signal arrival time difference, the positioning means. It is spread by measuring the number of receiver from the transmitter signal propagation time or bad time to determine the location of mobile users, is a kind of radio wave transmission time based on the positioning technology. Positioning accuracy can be increased to 50 m or so. The need to launch a new business with SP providers, we can provide the level of service platform, specifically in the future if the business after its look, what the business needs of operators and providers to realize SP.There is already A-GPS technology, 3G and GPS combination of close up. The technology in the GPS program, also requires an increase in mobile phone GPS receiver module, and transform phone antenna at the same time, in the construction of mobile network location server, a differential GPS base stations and other equipment. A-GPS solutions in its main advantages of positioning accuracy. Outdoors, and other open areas, the accuracy of GPS work in a normal environment can reach 10 meters around called current maximum positioning accuracy of a location technology. Another advantage of the technology: the first time captured GPS signals in the general only a few seconds, unlike the first GPS acquisition time may be 2 to 3 minutes. Although the A-GPS technology high positioning accuracy, the first GPS signal capture short time, but the technology has some drawbacks. First, the issue of indoor positioning is still not satisfactorily resolved. In addition, A-GPS positioning must be achieved through multiple network transmission (up to six one-way transmission), which occupied the operators, a large number of air resources. However, A-GPS users is the key issue for business use of mobile location must be difficult to accept the replacement phone. But A-GPS mobile phones in power consumption than on the additional burden to a certain extent, indirectly reducing the cell phone of standby time. Through the use of foreign operators found, positioning business is also facing a lot of problems. 1, the relatively low market awareness. In the survey by the 21 mobile value-added service in the No. 11, well below downloading ringtones (67.2 percent), picture download (57.8%), send and receive MMS (48.4%) and CRBT service (39.1%) cognitive rate. 2, the contents of a single service. Currently, operators and SP location services are provided by the GIS system is based on "positioning, navigation traffic, provide positioning information surrounding points" of the "pure position" services, and other applications are not integrated. 3, positioning technology needs to be raised, the three above-mentioned shortcomings are positioning technology, we can not meet the current demand for positioning. 4, privacy protection need to be addressed urgently. As society advances, more and more sensitive to people's privacy. How to protect the privacy of personal support provided under the premise of business is constrained location positioning technology development. 5, the industry chain is not sound. Mobile location business requires a large amount of support for location information, such as detailed bus lines, restaurants and other locations, and the need to update, geographic information building will be a huge project, from data collection, sorting, classification, processing, updating , to the inquiry of all the development, improve, we need to have a set of sound mechanisms and systems to protect. But China in this regard foundation is still comparatively weak. 6, terminal styles are few and expensive. Location-based services is facing a terminal, network bottlenecks and other constraints. The current domestic support A-GPS terminal or GPSone patterns are few and expensive. Finally Looking to the next location for the future development of business, from a macro point of view, China's mobile location-based services market environment for the development is good. China's overall economic strength of steady growth, increase the intensity of investment in telecommunications infrastructure to create the conditions for 3G network construction and mobile location technology is improving daily, mobile positioning business will create a good environment for consumption, and ultimately to mobile location business quality has climbed steadily, and triggered by the social development needs of the broad masses, but will also be conducive to the cultivation of the concept of consumer users, and ultimately promote the prosperity of the entire market..