Browse Prior Art Database

Original Publication Date: 2000-Dec-25
Included in the Prior Art Database: 2003-Jun-19
Document File: 2 page(s) / 52K

Publishing Venue



The system to be disclosed is a method of using the Differential Global Positioning System

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The system to be disclosed is a method of using the Differential Global Positioning System

(DGPS) in combination with a wireless communication system to report the accurate location

of an individual in an emergency situation. The Global Positioning System (GPS) was mainly

developed for military use and its accuracy can be controlled by the authority, for instance, the

accuracy is only about 100 meters when the C/A (coarse acquisition) code for civilian usage is

turned on. This accuracy is considered not sufficient to locate an individual in most emergence

scenes. Using the DGPS where the accuracy can be as high as 1 meter is therefore proposed.

The Personal Emergency Locator (PEL) disclosed here has a GPS receiver and an

emergency response processor which can be shrunk down to a very small size and placed

inside a wireless mobile unit. The PEL receives the GPS satellite signals as well as signals

from the base station of a wireless communication service provider where the DGPS signal is

sent, so that a position down to 1-2 meters can be determined at the mobile unit. Alternatively,

the PEL receives the GPS satellite signals and sends the coarse location data to a safety

monitoring station to combine with the DGPS signals at the monitoring station and calculate a

better estimate of the location of the PEL. The signals coming from the base station may

contain the location data of the base station which will help to speed up the initialisation

of the GPS receiver in the PEL.

The communication system can be a cellular telephone system, Personal Communication

System (PCS), wireless LANs or any other mobile wireless communication channels such as

a two-way paging system. Using cellular phone as an example, the DGPS may be sent to the

PEL by the Mobile Telephone Switching Office (MTSO) using a common or designated

channel. The PEL then calculates and reports its position to the MTSO which in tu...