OBTAINING PILOT PHASE OFFSET TIME DELAY PARAMETER FOR A WIRELESS TERMINAL OF AN INTEGRATED WIRELESS-GLOBAL POSITIONING SYSTEM

摘要

An integrated wireless global positioning system determines the location of the wireless terminal from satellite measurements and wireless network measurements. The accuracy of the identified location depends on the quality of the measurements from the wireless network, which, unfortunately, may include measurement errors such as bias. The bias is caused by the time delay that can occur during signal processing and transmission. The time delay varies for each sector / base station and for each type of wireless terminal model used. This measurement of bias is important for the success of the Integrated Wireless Global Positioning (WGP) system. In a small network system with only a small number of base stations / wireless terminals, a specific system for measuring the time delay for each base station and / or wireless terminal may be set up. However, one problem is that it is costly, time consuming and causes a lot of errors. Such as a commercial system in which hundreds of base stations and dozens of different types of wireless terminals are associated. The present invention is directed to a method of using an integrated WGP system to obtain a pilot phase offset delay parameter, continuously improve the quality of the obtained value, and to adjust parameters appropriately against possible changes. The method does not require a particular system to be set up for measurement nor requires a team of technical experts to perform field measurements. According to the present invention, a wireless terminal capable of receiving a GPS signal without interference is used to determine a pilot phase offset time delay parameter estimate and then used to update previously obtained parameters in the database. The estimated pilot phase offset time delay parameter is used to measure the pilot phase offset applied to the position fix of the wireless terminal that is not disturbed and can not receive the GPS signal.