| 摘要 |
A method and apparatuses for disseminating an item of terrestrial standard time information (12) to radio clocks (18) which can be operated world-wide and which directly display the correct local time (16) rely for information transmission purposes on a network of satellites (13) with low orbits (14), referred to as LEOS, for example as are planned for world-wide person-related direct telecommunication connections. Each satellite (13) receives an item of terrestrial standard time information (12) from a control transmitter (11) directly or by way of a reference satellite (13.0) which is in a better reception position, and possibly from the control transmitter also an item of synchronous information (17) for the instantaneous, positiondependent time zone shift of the local time (16) which is to be sent back from the satellite (13) to a limited region of the earth. The local time may additionally contain information about the association thereof with a given time zone (15) so that, for a radio clock (18) which is operated in a given time zone (15), it is possible to ascertain from that item of additional information relating to the received local time (16) - or from the Doppler change in the local time (16) - where the orbit (14) is in relation to the reception time zone (15). If the received local time (16) is not directly associated with said time zone (15), then in addition to the decoded local time (16) a corresponding time zone shift is also to be taken into consideration in the display. The time zone shift can be derived in an association means (23) within the radio clock (18) in order to monitor the display means (20) which is operated by the autonomous time-keeping circuit (19) and if necessary correct the instantaneous time display in proper relationship with the respective time zone. (Drawing) |
