Time transfer system

• US 5,521,887 A
• Filed: 07/30/1993
• Issued: 05/28/1996
• Est. Priority Date: 07/30/1993
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Loomis, Peter V. W.
• Primary Examiner(s): Roskoski, Bernard
• Application Number:
  US08/099,907
• Time in Patent Office: 1,033 Days
• Field of Search: 368/46-55
• US Class Current: 368/47
• CPC Class Codes: G04R 20/02 the radio signal being sent by a satellite, e.g. GPS
• CPC Class Codes: G04R 20/14 the radio signal being a telecommunication standard signal, e.g. GSM

Abstract

Apparatus for providing accurate local time for one or more timed devices that depend on such time for operation. In one embodiment, a Satellite Positioning System (SATPS), such as GPS or GLONASS, provides the time signal information. In another embodiment, the time signal information is provided by telecommunication means, such as a telephone, cellular telephone or similar apparatus. The local time signal is distributed by a time signal distribution module to one or more timed devices by a wire or transmission line, by radio waves, or by direct contact with an input terminal of a timed device. The time signal distribution module may be a single station, a master station for a system of timed devices, or a portable module that can be moved from one timed device to the next.

Claims

1. Apparatus for providing accurate local time for one or more timed devices, the apparatus comprising:

an SATPS antenna positioned to receive SATPS signals from one or more SATPS satellites;

an SATPS receiver/processor, connected to the SATPS antenna, to receive the SATPS signals and to compute an SATPS-determined local time based upon the location of the SATPS antenna; and

portable timing signal transfer means, separate from and communicating with the receiver/processor, for receiving a sequence of at least two SATPS-determined local times as radio wave signals from the receiver/processor and for communicating a signal representing local time to at least one timed device that has a timed device input terminal, the timing signal transfer means having an output terminal that, when the output terminal is placed adjacent to and no more than about 300 meters from the timed device input terminal, communicates the SATPS-determined local time to the timed device.