| 摘要 |
A local positioning system (LPS) uses the radio propagation parameters in a CDMA forward link or TDMA reverse link to establish a mobile station's position. The mobile station receives pilot channel signals from at least three distinct base stations and records the PN chip offset of the pilot channel signals. The LPS time difference of arrival triangulation approach requires no additional signal detection capabilities. Base stations send out pilot channel signals that arrive at a mobile station with a particular phase and at least a predetermined minimum strength. The mobile station reports back the "visible" pilot channel signals, their phases and signal strength to the LPS which uses a location non-linear system, expressed as a set of cost functions, to estimate the mobile location. The LPS can also solve the 9-1-1 mobile location problem for wireless CDMA systems by determining the position of a person in distress that has a digital cellular phone. |
