| 摘要 |
A method and a system for evaluating a positional indication of a mobile unit in a cellular radio net, such as the GSM-system, in the form of a horizontal position line. Signal bursts are transmitted essentially simultaneously via a respective antenna of two base stations. Information relating to the exact positions of the antennas is also sent via said antennas. The net is synchronized, i.e. has a common clock source. The actual time delay between a burst triggering pulse in the clock source up to the actual time point at which said burst leaves the antenna concerned is measured for each antenna. The mobile unit detects the time difference between the bursts and also receives information relating to the time delay of said antennas, via the antenna signals. The mobile unit is now able to calculate itself a position line along which it is located. By repeating the procedure with another pair of antennas in the net for instance, there is obtained a further position line, wherewith the position of the mobile unit lies at the intersection between the position lines. The position of the mobile unit along said position line may alternatively be determined with other information obtainable from the net. |
