Importance

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Abstract

A time interval measurement system for the timing between events occurring at two spaced apart locations comprising at each location a dual frequency Global Positioning System (GPS) receiver having operatively associated with it a GPS antenna, wherein both the GPS receiver and the antenna are dual frequency (L1, L2) and the former is capable of both Coarse Acquisition (C/A) Code and carrier phase measurements, an accurate frequency reference source giving local time, a data-logger for logging the GPS data, a Time Interval Counter (TIC) means is used to measure the time of a local event relative to the local time and further comprising a central processor system (CPS) and a communication system via which the logged GPS data and time interval data are received at the CPS from each location, the CPS being arranged to derive a time-offset figure, in accordance with a predetermined algorithm which is indicative of the difference between times as measured in dependence upon the frequency reference sources at the two locations.

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First Claim