A Detailed Synopsis of Using GPS Technology as a Frequency Standard
Global Positioning System Disciplined Oscillator (GPSDO) is a quartz (or rubidium in some cases) controlled frequency standard that uses GPS technology and connectivity to provide primary standard traceability from any location and is used by calibration laboratories as their primary standard for frequency. In fact, Calibration and metrology laboratories have been using GPSDO for quite sometime as an alternative to cesium-based references.
GPSDOs are commonly used as a source of timing in a range of applications. GPSDOs are also used as the basis for Coordinated Universal Time around the world making UTC is the official accepted standard for time and frequency. Furthermore, GPS based standards are utilized for the purpose of administering synchronization to wireless base stations.
How Does GPDSDO Work?
Practical Instruments, Inc. designs and manufactures their own frequency calibrator that is sold on their website. They understand the importance of properly calibrating sensitive equipment and were kind enough to provide some information on just how GPDSDO works…
GPSDO’s primary purpose is to receive signals from GPS satellites and to use the information contained in these signals to control the frequency of a local quartz or rubidium oscillator. These are trusted signals for 2 primary reasons: They originate from atomic ocillators and they must be accurate in order for GPS to meet it’s specifications as a positioning and navigation system. GPS’ specifications can be used a a form of proof in this case.
Using clock corrections from earth-based controls stations roughly every 12 hours, a high quality GPSDO will transfer the accuracy and stability contained within the correction signals to the signals generated by a local quartz or rubidium oscillator. This is the general idea on how GPSDO works.