The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 29, 2000
Filed:
Dec. 23, 1997
Ulf Goran Forssen, Saltsjo-Boo, SE;
Jan-Erik Berg, Sollentuna, SE;
Walter Ghisler, Upplands Vasby, SE;
Telefonaktiebolaget L M Ericsson, Stockholm, SE;
Abstract
The disclosure describes a novel Time Difference of Arrival (TDOA) method and system for determining the position of a first mobile radio terminal within an associated mobile radio system, which is based on Time of Arrival (TOA) measurements, including a plurality of radio base stations, measuring devices, network controller, and service node. The measuring devices are synchronized in otherwise unsynchronized radio base stations. The measuring devices measure TOA on demand and (optionally) Direction of Arrival (DOA), on a digital uplink time slot or on digital information on an analog uplink traffic channel in one or more radio base stations. The TOA and DOA information and the traffic channel number are reported to a Mobile Services Switching Center, which obtains the first mobile terminal's identity from the traffic channel number and sends the terminal identity and TOA and DOA measurement information to a Service Node. The Service Node calculates the position of the first mobile radio terminal using the TOA information (supplemented by the DOA information when available). A second mobile radio terminal is colocated on a mobile platform (auto, emergency vehicle, etc.) with one of the radio base stations, which can be moved into relatively close proximity with the first mobile radio terminal. Consequently, by moving one of the radio base stations close to the region of interest (near the first mobile radio terminal), the position determination accuracy is significantly improved.