Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
94 words
A method for locating a mobile station (21) wherein it is measured in the mobile station (21) an observed time difference (OTD) between signals received from at least two base stations (21, 22, 23), and position coordinates for the mobile station (21) are determined on the basis of said observed time difference (OTD), characterized in that the time difference (OTD) is transferred from the mobile station (21) to a mobile communication system (22, 26) and said position coordinates are calculated in the mobile communication system (26) on the basis of said time difference (OTD).
Claim 2
Dependent Claim
98 words
The method of claim 1, characterized in that - signals from a first (22) and a second base station (23) are received, - a first timing value between the mobile station's internal clock and the clock of the signal received from the first base station is measured, - a second timing value between the mobile station's internal clock and the clock of the signal received from the second base station is measured, - the difference of said first timing value and second timing value is calculated, and - said difference is used as said observed time difference (OTD).
Claim 3
Dependent Claim
124 words
The method of claim 2 wherein there is stored in a mobile station information about the training sequences used by a base station, characterized in that to measure said first and second timing values - a burst is extracted from a received signal, - a training sequence is extracted from the burst, - a cross-correlation measurement is performed between the training sequence extracted from the burst and the training sequences stored in the mobile station in order to generate a timing profile | h ( k )|, - a point of time (k p ) corresponding to the maximum (P) of said timing profile is calculated, and - a timing value is generated on the basis of said point of time (k p ).
Claim 4
Independent Claim
49 words
The method of any one of the preceding claims, characterized in that an observed time difference (OTD) is measured in a mobile station (211) for signals received from base stations, whereby the strength of at least one received signal remains below the minimum decoding level of the mobile station.
Claim 5
Independent Claim
39 words
The method of any one of the preceding claims, characterized in that said time difference information is transferred from a mobile station (21) to a base station (22) encoded in one or more messages of a signalling channel (SACCH).
Claim 6
Dependent Claim
98 words
A mobile station positioning system comprising a mobile communication system which includes several base stations (22, 23, 24, 25) and mobile stations (21), characterized in that - a mobile station (21) receives signals transmitted from at least two base stations (22, 23, 24), - the mobile station (21) measures time differences between said received signals to obtain time difference information, - the mobile station (21) sends said time difference information to a base station and - the mobile communication system (26) determines a position estimate for the mobile station (21) on the basis of said time difference information.
Claim 7
Dependent Claim
65 words
A mobile station (21) comprising means (210) for receiving signals from at least two base stations (22, 23, 24) and means (211) for performing a time difference measurement for said signals to obtain time difference results, characterized in that the mobile station (21) includes means (212) for transmitting said time difference results or information deduced from them from the mobile station to a base station.
Claim 8
Dependent Claim
28 words
The mobile station of claim 7, characterized in that it comprises means (212) for transmitting said time difference information to a base station on a signalling channel (SACCH).
Claim 9
Dependent Claim
44 words
The mobile station of claim 7 or 8, characterized in that to determine a time difference the mobile station is arranged so as to extract a training sequence from a burst the strength of which remains below the decoding level of the mobile station.
Claim 10
Dependent Claim
37 words
The mobile station of any one of claims 7 to 9, characterized in that it has means for measuring the timing of a received signal on the basis of training sequences extracted from at least two bursts.
Claim 11
Dependent Claim
46 words
The use of the method of any one of claims 1 to 5 or the positioning system of claim 6 or the mobile station of any one of claims 7 to 10 in the GSM system, DCS 1800/1900 system, US-TDMA system or in the JDC system.