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Time and frequency dissemination using GPS: Recent improvements



Tom Parker, Demetrios Matsakis


This is an article for a general audience that reviews recent imporvements in time and frequency delivery by the Global Positioning System (GPS). A significant improvement in direct time delivery was achieved when Selective Availability (SA) was turned off in 2000. This has allowed time delivery to the civilian user at better than 100 nanoseconds accuracy if the user exercises reasonable care. More sophisticated users can make use of the phase of the microwave carrier of the GPS signal to achieve sub-nanosecond precision.
GPS World


frequency, GPS, satellite, time


Parker, T. and Matsakis, D. (2004), Time and frequency dissemination using GPS: Recent improvements, GPS World, [online], (Accessed April 17, 2024)
Created October 31, 2004, Updated October 12, 2021